Tuesday, December 27, 2011

Yeasu Digital Radios imminent?

Was browsing Yeasu's website this evening and discovered something interesting listed in their HT and Mobile radio sections. A listing with no picture labeled "Digital". Clicking on it gives a little blurb about downloading information about digital communications in the amateur radio world. It is a 6mb PDF file that contains a brochure talking about digital radio. Vertex Standard produces a line of HT and Mobile radios that do APCO-25, and another mode with uses TDMA. Time Division Multiple Access. On page 14 of this PDF, they say they are going to bring out an HT and a Mobile radio in early 2012 that does C4FM modulated digital voice in either FDMA (Frequency Division Multiple Access) or TDMA for the Amateur Radio market. C4FM is opposed to GMSK like what D-Star uses. I'm sure they'll probably wind up using the same or similar audio codec as D-Star though, AMBE. I would love to hear otherwise, especially if they decided to use the unfinished Codec2 somehow. I doubt it though.

TDMA would be interesting to see. You can have repeaters that allow two conversations at the same time, as if it was two repeaters, with just one set of hardware.

It's going to be an interesting year next year. "Amateur Radio should be progressive." is what the brochure says, I agree.

Let me know if this link doesn't work, it's a direct link to the PDF file.

Monday, November 28, 2011

PIC12LF1840T48A integrated radio transmitter

Just read about this on the Electronics Bus blog,
It's a new PIC microchip with an integrated radio transmitter intended for keyfobs and the like. There are 8 preset channels covering a couple of bands: 418-443.92 and 864-869.85mhz per the datasheet (Page 361). There's an application note as well. It supports FSK and OOK. FSK mode can run up to 100kbps(!) at a power output of up to +10dBm. (About 10mw if the online conversion tool I used is right).

Can you receive FSK with AFSK demodulation? This chip would be interesting paired with code and a cheap GPS chip to make a small, low-power, cheap APRS beacon. Add a homebrew power amp for the 430 or 440mhz band and you could have a platform for a remote APRS sensor or sensor network. Although, since it's just the transmitter, I'm guessing you'd have to be careful of collisions.

Friday, November 18, 2011

Of 3D printers and themes

Okay, so the theme I had up wasn't working for me. It was a new dynamic layout that Google is offering and even on my computer it was kinda bogging down. And my computer used to be fast... 4 years ago.

This is a new 3D printer project that I heard about. Called Printrbot, of course. What is a 3D printer? Wikipedia I've been following the news of a couple of homemade 3D printers for years, mostly the RepRap and the Makerbot. This seems to be a new one that is made to be easy to build and inexpensive. And actually, from reading the Kickstarter page there.. It's a special version of the RepRap? I don't know. Anyways, $500 there will get you all the parts to assemble one of these 3D printers. $750 will get you one assembled and ready to go.
"Printrbot is small and intended to be your FIRST printer. The print area is roughly 5″ x 5″ x 5″. It does make a few sacrifices to keep things simple, but it is designed to be upgradable and expandable. You can easily increase the build area to whatever size you want. You can mount it inside a box or frame for rigidity. The included hardware is “full-sized” and on par with the Prusa – the current high-resolution champ. While Printrbot could happily serve your 3D printing needs sitting on your desk in your office, right next to your computer, it could also be the seed that spawns a never-ending series of upgrades to a bigger and better 3D future. You’ve got options."
I could easily see this being beneficial to homebrewers. You could print plastic cases, a front panel for a radio, knobs.. small ones or big VFO wheels, standoffs, plastic morse code key?, insulators for antennas, etc I'm sure there are a ton more things you could use a 3D printer for.

Saturday, November 12, 2011

New theme, TM-241, etc

I'm trying out a new theme to go with the changes behind the scenes at Blogger. It's a little less plain than my old one but I'm not sure if the navigation is going to be a pain, especially for people with older computers. If anyone experiences that, leave me a message on this post?

I haven't forgotten about my work on reverse engineering the remote control protocol for the Kenwood TM-241a radio. I've been very busy with school work lately. I'm in my final month of my Associates degree at IvyTech for Computer Information Technology. I am on track to keep my 4.0 GPA too, which is great. It's caused me no end of stress right now though. I'm on a program that let people who had their jobs displaced to other countries go back to school for a 2-year degree. Many of us did so with the idea that the economy was going to be in much better shape by now. At least, I did. I've been applying for positions since June and haven't had much luck even getting interviews. Once my education program ends, so does my unemployment. Shortly after that... we're going to be in trouble. Of course, one of the places I have applications at right now may come through and save us at the last second. Not that I can count on that though.

I'm thinking about trying some ads on here to see if I can get a little ad money.

If anyone knows anyone hiring within 30-60 minutes of Richmond, IN.. please, let me know. I'll have an Associates degree and I also already have my A+ certification. I'll be taking the Network+ soon and should get that easily.

Speaking of the Kenwood TM-241a work.. I haven't managed the basic application to fuzz out the numbers. It seems doing serial comms under .NET is a little hairy. Also, the Bus Pirate's binary mode is easy to get into but a little hard to use so far. I'm a little inexperienced in it, so it might just be I'm not understanding it right. From what little by-hand fuzzing I've done using a terminal mode on the Bus Pirate.. I feel like my original theory is wrong. I was hoping it would be a simple 3 byte command.. an address and two bytes for the command. The protocol to send the display information out seems to have 1 nibble of data along with 1 nibble of check information. So for example, 0x00 0x04 0x04 0x04 0x08 might be a valid packet with the first nibble having data and the second nibble being a check digit of some kind. The nibbles might have BCD numbers or be bit-level information for single LCD elements. My theory with the control scheme was with 1 byte for address, and 2 bytes for data.. that's 2 nibbles or one whole byte for data giving 256 possible combinations of buttons or commands.

Now, in previous experiments I have managed to affect something while sending data. Once I managed to have the radio skip around in the memory channels by significant steps. Another time, before I figured out the exact communication settings, I managed to overwrite the memory channels with bogus data. That's probably the greatest clue that what I may be dealing with is direct control over the internal memory of the radio. If so, my job is significantly harder. I need to figure out how to address specific areas of memory and what the contents mean, all while not being able to read it directly.


Or can I? Looking at the service manual, there's no information on what the main cpu is, and it looks like no external memory. If I could figure out what the cpu is, I can at least figure out my constraints. Working further on fuzzing the interface, I may be able to figure out the correct way to issue address commands and data. The main questions are: How many bytes do I need for an address? Do they require the checkdigits like what is used to talk to the LCD? How many bytes do I send after the address? Checkdigits? What is the constraints on memory area I can address? With that, I can start poking values into memory to see what happens. I know there's a soft power off feature, so you can turn the radio off from the remote control interface. There's also got to be a method to key the transmit, because the PTT line is one used for the communications.

There's apparently an internal basic scripting language on the newer Bus Pirate firmwares. I may need to look into upgrading mine. If it doesn't work, I have a cheap ICSP capable programmer here that I can maybe revert it with.

Saturday, October 29, 2011

TM-241 again

Figured out how to read the S-meter data when it is active. Not too shabby. Still trying to figure out what kind of format the button data is in when transmitted. I have been doing a little hand fuzzing, aka sending random data bytes. I had a theory that they used the exact same control scheme not only on the remote control interface, but also on the internal configuration. That might be true for the LCD commands, but upon closer examination of the schematic, the buttons are in a matrix on CPU pins, SQL and VOL are variable resistors and the VFO knob is a quadratic encoder. Still, it might be valuable to open it up, and patch into the internal LCD signals if it helps me figure out which bits control what LCD elements.

I might also need to write a basic program to start fuzzing. If I could figure out some representative commands, maybe I could go from there and send test commands that are more likely to have a response. At the very least, I need to figure out: VFO knob, VFO button, MEM button, VOL, SQL, and PTT. The last one is important because the MIC connection on the radio is part of the communication scheme for the remote control interface.

Thursday, October 27, 2011

TM-241 Progress

After a misstep where I had faulty data, I am getting valid data out of it now. I can tell because I have figured out how the frequency is encoded and I can predict the results of changing to a different one. There's a lot of work still to be done because so far all I can do is read. I also don't know how everything is encoded.

So far I can read the frequency, if there's an offset and which direction, if I'm in VFO mode, CALL mode or Memory channel mode and which channel. I can also see if there's a signal but I haven't figured out how the S-meter is transmitted yet.

There are several bytes where I'm sure data is encoded at the bit level, I've already seen it with offset, CALL and there's a bit that is set if I'm receiving a signal.

There are quite a few LCD elements that I don't know where they map yet. Much of my experimentation so far has been to set something on the radio, turn it off, configure the Bus Pirate, turn the radio on and read it. If I had a RC-10 or especially RC-20 I could probably rig it up to drive it from the Bus Pirate. Then I could configure the packet of bytes to feed it and see what it does. I could also use it to send control packets to the radio to see what they are. I'm guessing the remote control interface is like a "dumb terminal".. if you push a key, it send that key to the radio instead of doing processing itself. That explains why the radio isn't sending a lot of information out such as what the offset is, or if there's a CTCSS tone and what it is. All the radio is sending is what should be displayed on the LCD. I can probably expect a different packet if I'm in a screen to change the tone, for example. Already I have noticed that when I'm on the CALL channel, it omits data for the VFO and MEM channel.

I'm also a little curious as to how the IF-20 sends information to the RC-20 when there's a second (at least) radio connected. The TM-241a only sends out information for itself. The IF-20 would connect to multiple radios and format the information from all of them into a form that can drive the main and sub display on the RC-20. I'm guessing it's an addressing change.

I know Kenwood killed off the remote control displays sometime after the x41 series. I wonder if the protocol survived in the x51 and future radios? Probably not, but you never know. There's a lot of potential power here, this could have been a major selling feature even now.

Wednesday, October 26, 2011

Kenwood TM-241a

I'm working on reverse engineering the remote control interface on my TM-241a. When it was a new radio you could buy options to use it: RC-10, RC-20, IF-20. The RC-20 looks like any other remote head but with the IF-20 you could hook it up to 4 radios. You could end up with one control and microphone to drive a 2m radio, 440, 220 or 1.2ghz. It also worked across different revisions of the radios although I think the x41 were the last ones.

I emailed Kenwood looking for any information on this interface awhile back, they couldn't help me with the protocol but they were kind enough to send me PDF documents with schematics on the RC-20 and IF-20. Between those, and a PDF service manual for the TM-241a I found.. I have figured out how to do an electrical interface. I'm using a Bus Pirate v3 from Sparkfun to do it. Not entirely sure if I'm interfaced correctly, but I am getting repeatable data. It's quite noisy because I am just using the unshielded probe cables I got with my Bus Pirate.

I did accidentally overwrite a couple of the memories already with junk information. Somehow one wound up with 444.900 and the other had 109.490 in it. Obviously didn't try transmitting there. The radio probably wouldn't have let me, it gave me the error beep when I pushed the REV button to see where the offset ended up. I'm mostly concentrating on receiving the display data that the radio constantly sends out right now. I'm making a bit of progress on the puzzle but it would probably go a lot quicker if I had a RC-10 or RC-20 to experiment with.

All well, I love a puzzle.

My next step may be to collect a lot of information and make Visual Basic programs to help me analyse it. Both for errors, and also for changes between samples (ie, data for one frequency in a memory channel, and then data for another frequency in the same channel)

Monday, September 12, 2011

Freescale MC13260 SoC Two-Way Radio IC

Found this in a mailing-list post the other day. Very neat, it's a System-on-Chip that is almost everything you need to make a radio from 60MHZ-960MHZ.

From the Freescale website:

Target Applications:
Comprehensive analog FM radio
Comprehensive digital radio (DMR, P25, TETRA, dPMR)
Dual-mode analog FM and digital voice/data
"Talk around the network" feature for cellular applications


ARM926EJ-S™ MCU operating at clock speeds up to 150 MHz
Modem processor (software-defined radio) operating at clock speeds up to 100 MHz
640 KB of integrated RAM
MCU peripherals to support control and monitoring functions
High-performance integrated RF transceiver supporting RF frequencies of 60 MHz–960 MHz
Fully integrated, high-performance RF fractional-N synthesizer
Integrated 13-bit audio CODEC with analog input/output
Three 12-bit DACs for support functions
10-bit general purpose ADC with four multiplexed inputs
Receiver supports linear modulation
Linear transmit support using integrated I and Q DACs and an external modulator
Advanced Encryption Standard (AES) module for secure communication
Full-speed USB device with integrated PHY

Pretty feature rich! I assume the RF components you need amount to bandpass filtering, preamp, transmit/receive switch, and filtering, power amp for transmit side. This chip implements the SDR conversion, AD/DA conversion, etc. It has an ARM9 CPU and a separate "modem" DSP. I'm unclear if the DSP handles the FM mod/demod and any modem processes such as encoding or decoding PSK, FSK, GMSK, QAM, etc.

This chip is pre-release, according the press release the chip will be available in Q1 2012.

Press Release: http://media.freescale.com/phoenix.zhtml?c=196520&p=irol-newsArticle&ID=1537559
Product Details: http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MC13260&tid=vanSoCRadio
Fact Sheet: http://cache.freescale.com/files/rf_if/doc/fact_sheet/MC13260FS.pdf?fr=g
Support Info: http://cache.freescale.com/files/rf_if/doc/support_info/MC13260_TRN_SI.pdf?fr=g
Product Brief: http://cache.freescale.com/files/rf_if/doc/prod_brief/MC13260PB.pdf?fpsp=1

Other chips I've covered include:
CMX7163 QAM Modem
The CMX7163 QAM Modem is a low power half-duplex device supporting multiple channel spacings under host microcontroller (µC) control. Its Function Image™ (FI) is loaded to initialise the device and determine modulation types.
The 7163FI-4.x supports 4-, 16- and 64-QAM modulations up to 96kbps in a 25kHz channel, with channel estimation and equalization to provide robust performance under realistic channel conditions.
Flexible bit rates support a wide range of applications requiring a selectable bit rate and robustness.

An integrated analogue interface supports 'direct connection' to zero IF I/Q radio transceivers with few external components; no external codecs are required.TI CCxxxx series
From my blog post on the Ubertooth One:

A CC2591 2.4ghz PA/LNA,CC2400 2.4ghz RF transceiver and a LPC175x series ARM chip.
What inspired him to use a chip like the CC2400? He previously played around with a kids toy called an IM-ME. It's a pink pager-like device meant for girls to send instant messages over the Internet (via a usb dongle plugged into a computer)... He was able to turn it into aninexpensive spectrum analyzer type device. How? It has a CC1110 chip. This is an RF transceiver chip with an integrated 8051 cpu. According to the linked site:

Frequency range: 300 – 348 MHz, 391 – 464 MHz and 782 – 928 MHz
Pretty neat, it's capable of operation in the 70cm and 33cm bands at up to 500kBaud. This was in a toy that was less than $20 on ebay.

Raspberry Pi ARM Single-Board Computer

This is the Alpha prototype board according the the wiki.

This is a very low cost ARM SBC that is being developed right now. It is unreleased but once it comes out, there could be a multitude of applications in Ham Radio for it. They are talking about making two versions, Version A for $25 and Version B for $35.
Here are the "Provisional Specifications" from the community written wiki

  • 700MHz Broadcom media processor featuring an ARM11 (ARM1176JZF-S) core, Broadcom GPU core, DSP core and support for Package-on-Package (PoP) RAM
  • 128MiB (Model A) or 256MiB of SDRAM (Model B), stacked on top of the CPU as a PoP device
  • OpenGL ES 2.0
  • 1080p30 H.264 high-profile decode
  • Composite and HDMI video output
  • One USB 2.0 port provided by the BCM2835
  • SD/MMC/SDIO memory card slot
  • General-purpose I/O (About 16 3v3) and various other interfaces, brought out to 1.27mm pin-strip
  • Optional integrated 2-port USB hub and 10/100 Ethernet controller (Model B)
  • Open software (Ubuntu, Iceweasel, KOffice, Python)
  • Capability to support various expansion boards

Anyone's guess if it will come out at the price point they are hyping up. In my experience stuff like this tends to slip into higher price ranges when people get excited about it. Kinda like electrons jumping into higher orbits.

Besides including 256MB RAM, the B version is also suppose to have a chip on board that is a 2-port USB hub and ethernet controller. I'm assuming the ethernet will also use your USB bandwidth.

It is interesting to me that they are stacking the RAM chips right on the processor. That should save some space at least! The Broadcom SoC seems to be pretty neato too. It has the ARM11 CPU, a GPU that does Open GL and 1080p30 H.264 decode, and a DSP but there's currently not enough information known to access that yet.

16 GPIO at 3v3, I2C and SPI interfaces will come in handy, it also has stereo audio out. I wonder if it would also have stereo audio in? That could make a very small interface to something like a SoftRock. They also talk about being able to interface to a cheap LCD module for portable operation. Otherwise, it looks like HDMI output.

v---Click on the sbc label to see my other single-board computer posts.

Thursday, September 8, 2011

"High-Speed" data and digital voice

It's a sham that faster digital modes haven't really caught on. I've read about 56k packet in the past. Most radios today support 9600 baud packet, if you can find the discontinued equipment that support those speeds. What does this have to do with digital voice?

Codec2 can squeeze voice into 2550bit/s AMBE can do voice in 2400bit/s and MELP can do it in 2000bit/s. D-Star does a continuous bitstream at 4800baud with 2400 for AMBE voice and 1200 for FEC(Forward Error Correction) (And the voice frames are transmitted blank if you're doing data only, FEC doesn't cover data and you really only get 751bit/s data, I'm not a fan of the protocol)

If someone built a system with Codec2, some FEC and a packetized modem at 9600 baud (or, better 19.2k for the overhead). I'm betting we could have a single-channel digital voice digipeater. I think you'd have to be careful not to use 50% of the channel on each side just because of overhead from headers and the like. It'd be like 802.11, I tx some time, you tx some time, I tx some time, etc. 1 frequency digital repeater. No duplexer cans.

In fact, if the data speed was fast enough we could probably do multiple logical channels with simultaneous users on the same frequency.

More to come.

Monday, September 5, 2011

D-star, P25, other AMBE/IMBE modes

For some reason people are going around saying that "the DSP chip in D-Star, etc radios is really no different than having a DSP in modern HF radios. People don't suddenly refuse the operate their HF radio because they can't see what the DSP is doing."

This statement is a prime example of wrong thinking. What's worse is the same people explain to me that the only difference is the HF radios use the DSP for "IF-level modulation and detection" while the chips in D-Star are just vocoders.

Okay, what is a vocoder? (I am playing stupid here for the benefit for people who really don't know)

Wikipedia.org defines it as:
vocoder (play /ˈvkdər/, short for voice encoder) is an analysis/synthesis system, mostly used for speech. In the encoder, the input is passed through a multiband filter, each band is passed through an envelope follower, and the control signals from the envelope followers are communicated to the decoder. The decoder applies these (amplitude) control signals to corresponding filters in the (re)synthesizer.
I don't understand the math behind it. Basically, instead of digitizing the speech and sending it directly over.. the vocoder system renders it into a series of much smaller operations that can be done on the other side to recreate the speech.

This quote from codec2.org backs this up:
vocoder works by analyzing speech and encoding it as phonemes and other higher-level information, rather than as a continuous waveform. It can thus compress speech into substantially less bandwidth than a waveform codec. Vocoders are generally less intelligible than codecs. They reproduce an evocation of the orginal voice, rather than the actual voice, but sophisticated vocoders like AMBE do so well enough that - except at the lowest bandwidths - the speaker's identity is immediately and easily recognizable. 
The problem with that is certain operations can be patented which will make your vocoder unable to be reproduced legally by anyone other than yourself.

Dave Rowe writes on his website:
Proprietary codecs typically have small, novel parts of the algorithm protected by patents. However proprietary codecs also rely heavily on large bodies of public domain work. The patents cover perhaps 5% of the codec algorithms. Proprietary codec designers did not invent most of the algorithms they use in their codec. Typically, the patents just cover enough to make designing an interoperable codec very difficult. These also tend to be the parts that make their codecs sound good.
So, no one can make a codec that will be compatible with DVSI's codecs, but it is possible to make a codec that works just as good. Codec2 is such a project. It sounds pretty good to me right now, but it is just alpha software at the moment.

The only company that can make chips that are compatible with the vocoder in D-Star, P25 and other radios that use AMBE or IMBE is DVSI. It's true that DVSI just provides the programming on the chips and they are DSP chips from TI. You might even find the same model DSP chip in your HF radio. The problem is to communicate by D-Star you have to have a chip from DVSI in both sides of the conversation.

On the other hand, anyone with a homebrew radio that can do modulation in CW/SSB/AM or FM can communicate with any Gee-Whiz HF radio with a DSP inside of it just fine.

Anyone who says that the DSP in a D-Star radio and a DSP in an HF radio is equivalent is acting in a dishonest manner.

As soon as someone makes a legal source code available that I can load onto a fresh DSP from TI or any other DSP company, build into a radio and communicate with D-Star radios, then I'll stop complaining about the chip inside of them. While DVSI is the only source in the world for said chips, then I'm not going to shut up about it.

Friday, August 26, 2011

Downloading programs over Ham Radio

Wanted to have this as a separate post. Someone on a digital radio mailing list posted this video from 1984:

It's a mostly alarmist piece about how piracy is destroying the software industry. It seems to be intact nearly 30 years later. In the last 30 seconds or so it includes a bit about Hams who are doing basically shared development of software by sending it back and forth over the radio. The software was stored on cassette tapes in this. The Ham at the end holds his microphone up to the tape player and hits play.

I wonder how long he had to sit there like that. Hah. Those things only ran at 1200baud I think. Maybe it was a really short program, just like 1 or 2k.

Icom 900A, etc

I was clued into these radios awhile back: http://www.universal-radio.com/catalog/fm_txvrs/900a.html
It's a very neat idea. Get a common control point and then buy swappable modules that cover the band you want. I know other radios did the same sort of thing internally: Kenwood TM 741/742/941/942, Yeasu 726R/736R, and a few others.

Kenwood even had a remote head RC-20 that would work with a bunch of their otherwise standalone mobiles. I think it worked from the X21 to the X41 series. IE TM-221, TM-241, etc. With the optional IF-20 accessory you could even hook up 4 different radios to it. You could attach radios for 2m/220/440/1.2 to it.

Neat concept, I'm sure it got expensive though. These systems were probably all phased out for single radios with everything in them. Makes me wish someone had settled on an open protocol for connecting external controls to these radios. Even make it industry wide, not just Ham Radio. Would it be against the rules to have a single control head and microphone that can switch between controlling 1 or more Ham Radios, a CB radio, GMRS, scanner, etc. Each radio could be type-certified for their task but controlled from one vantage point? I guess you would have to be careful to conduct yourself appropriate for the service you are using.

Sunday, August 21, 2011

Kenwood's new TM-281 2m radio

Link: http://www.universal-radio.com/catalog/fm_txvrs/0281.html

With exciting new features!
LCD backlight color now back to orange instead of green!
Hi Power boosted to an incredible 65W. That's a whole 5W more than the TM-271! Wow!

Throw that old junk away and buy today!
Only $164.95

Thursday, August 4, 2011

ARISSat-1 Finally Deployed from ISS


Just got the announcement from the ARRL about ARISSat. I've read the news before about it being deployed. The word is the NASA-tv feed showed it and that it was being handled rather roughly. I didn't see the stream, I wonder if anyone managed to screen capture that and post it somewhere like Youtube or Vimeo? I guess it's rather regrettable that the UHF antenna was forgotten/lost/broken. You would think after all the time it took to get it up there, they would be a little more conscientious with it. According to the ARRL bulletin, if they scrubbed the deployment, the next opportunity would be Feb 2012. Well, it's taken this long to get it up what's 6 more months? Especially since now the UHF component will never work? Then again, maybe it was basically a "now or never" decision, I doubt we'll ever know.

Well, on brighter news I heard a couple of seconds worth of SSTV from it last night. I haven't managed to find any tracking elements so I don't know where it is. I had my Kenwood 241A tuned to 145.950 and heard a few seconds of SSTV even though my antenna is a Ringo Ranger 2. Still want to try to find resources around here to make a WA5VJB cheap yagi sometime.

Tuesday, August 2, 2011

SSTV images in video games

I'm very late to the parade on this one but I don't know if there's been enough attention paid to this. In March last year Valve Software updated one of their games, Portal, to have radios that would play Morse Code and SSTV signals when you carried them to specific spots in the game. They did this as part of an Alternate Reality Game that led to the announcement of the sequel game, Portal 2. They actually included 4 more SSTV images in the sequel. One can be received during the first play through of the game, and the other 3 are part of a developer's commentary. More info about the Portal ARG here.

To receive these images, you can use any computer software such as MMSSTV and point the soundcard input to StereoMix, or similar. It's even possible to receive off of the youtube video in the above link.

Friday, May 6, 2011

2 interesting new(?) Chinese HTs

Couple of neat Chinese radios I've learned about recently. The first is the Baofeng UV-3R. It is a shirt pocket sized 2m/440 DUAL BAND radio. It does both bands in the same radio. Apparently it does 2w out, no indication if that's true for both bands. G4ILO has reviewed this handheld. One thing that he notes is that his came with separate vhf and uhf antennas, but some sellers on ebay are offering them with dualband antennas as well. It is currently $54.50 on 409shop.

The second one is the Puxing PA968. Here's something interesting.. You can buy it in either 2m or 440 varieties. The usual frequency ranges too, 136-176 or 400-470mhz. BUT, not only is it a radio, it is also a quadband GSM cellphone, with provision for 2 sim cards. This one is upwards of $194.74 on aliexpress

Tuesday, April 19, 2011

What would a modern BBS look like?

I remember the good old days of dialing into a BBS before the Internet was really big. You could use a terminal emulator included with Windows or something more specialized like Minicom in DOS. Sometimes you'd have to wait for hours to get connected because someone was tying up the telephone line and you'd end up getting busy signals. Then finally, you'd get connected! Then you could login and navigate pretty much a text-only system, with the only graphics being ASCII art or anything you downloaded and viewed offline. I had a 2400 baud modem through most of my BBS days. I think it took an hour to download 1MB. Anyone could run a BBS, it just took a dial-up modem and software on your computer.

What would a modern one look like?
I think it would be based entirely off of the Internet technologies that have become more popular since the 90's. You could set up a dial-up server with TCP/IP connections. Anyone who connects in would get a private IP address, then have a captive portal (such as used in wifi hotspots) to redirect people into a webserver you have set up. You could run a phpBB instance on the webserver and call it a day. That would get you forums, you could run other servers for other services. For example, have a FTP server set up for files. The users might even upload a file and link it in a forum post. Or run an email server for the users.

Depending on location or access to locations, it could be possible to set up wifi access points to allow for high-speed access to this modern BBS. It's a shame that DSL isn't a little more like dial-up, not speed-wise but with dial-up's ability to just call anyone and get a digital conversation going.

Uses? Community-oriented network, really private network, backup communications path if a group loses access to the Internet, maybe useful in places like Egypt etc. I could see a case where wifi access is available and someone walks by with a Windows CE palmtop or similar device to send/receive email real quick.

Thursday, March 31, 2011

Experimental AMPS mini-basestation

This is really neat. Mark Atherton has put together a very basic, working, replica of a base station for analog cellular phones. I've blogged about something similar for GSM phones in the past. This analog system is pretty fascinating for me.

We really have the parts to put together something basically similar for ham radio. The audio could be exactly the same as it is now. Add in a control channel and people could call you even if you have the volume turned all the way down. There have been in-channel methods for quite a long time of course. Signalling systems such as CTCSS, DCS, DTMF have been constructed in the past, and barely used. As of yet, noone has constructed an out-of-channel signalling method. The capability is there for APRS I believe. Some APRS capable radios can advertise a frequency you are monitoring in your report. I think one or two may even allow you to QSY to an advertised frequency.

It'd be pretty cool if you could send out an APRS call, have the other parties' radio QSY to your freq if they answer it, test the path, maybe QSY to a mutually accessible repeater if necessary, etc. I have no delusions that this would be constructed or used though. Previous in-channel signalling methods have been around for decades and remain fairly unused, except to access a repeater. Other neat technologies have falling by the wayside, like Kenwood's DCS-based ID tech.

You know what they say, a rolling stone gathers no moss.

Friday, March 25, 2011

A new challenger has appeared: BJ-UV55

Found this on Alibaba the other day. It is a Baojie BJ-UV55 dual band mobile. Emailed the seller and it's not out yet but they expect it to release in May. It seems that Wouxun's as yet unreleased KG-UV920R is spurring other Chinese manufacturers to make their own mobile radios.

The specs are fairly typical. 136-174mhz and 400-470mhz. 45W VHF, 35W UHF.

What I don't know:

  • If the front panel can be remotely mounted.
  • If it has crossband repeat
  • Price
I doubt this company is going to go through the FCC certification process either so your mileage may vary. I just like to keep track of these things.

I guess it's also listed under the model number TC-UV55 and a different company. Not too unusual in China.

Saturday, March 12, 2011

HTPC Capacitors

Ahh, the dreaded bulging capacitor problem. This is a Geforce 5200FX graphics card from my HTPC. Granted, it's pretty old. I built this machine back in 2006 which makes it pretty ancient for computer technology. A couple nights ago I sat down to watch a recording only to have it crash a few seconds into the video. I did a little troubleshooting today to find that the machine gets to POST only when I take the video card out. (Of course, once I do it gives me the error codes for no video card.) I found these caps when examining the card. 4 electrolytic capacitors 6.3v 1000uf all were bulging. The single 16v cap looked perfectly fine. I ordered a new card, but I think I may add some electrolytics to my next Mouser order to see if I can't revive this one too.

I've been playing something of a handyman this past year anyways.

Thursday, March 10, 2011

Another ARM single board computer (SBC)

This is the i.MX53 Quick Start Board:

Full specifications

This should be a pretty neat SBC. It costs $149 and includes a Freescale 1ghz Cortex-A8 ARM processor, 1GB ram, 4GB microsd card with Linux, 5v power supply with worldwide adapters. Expansion boards include a $49 HDMI output and a $199 4.3 800x600 LCD screen. (Which seems a mite overpriced to me given the glut of under-$50 7" photo frames.)

I've also covered the Chumby Hacker Board here. It's $89, and also includes a Freescale ARM processor but only at 454MHZ, 64MB ram and a 512MB microsd card with Linux. On the other hand, while a lot of the processing specs are lower, the Cumby Hacker Board includes several GPIO connections and is even compatible with Ardunio shields. Could be handy for more low level interfacing than this board.

I have yet to find anyone using these boards in a Ham Radio capacity yet. Rig control, Digital modes, Micro Repeater controller, SDR, D-Star adapter (with dongle), Codec2.. There are a lot of possibilities.

Link to the full information on the i.MX53 Quick Start Board on the Freescale website.
Here's the blog post on the Freescale website that I learned about this board.

Sunday, March 6, 2011

Electronic Project Lab

This is one of my favorite "toy"s from my childhood. This was actually my second one, the first was the venerable 200 in one Electronic Project Lab. Radioshack used to carry these things before they decided to become a cellphone kiosk. I'm actually looking to acquire a used 200 in one again, that was always my favorite but mine got really ratty and destroyed many years ago. :(

The radio club is unofficially thinking about finding some of these for a basic electronics class. I'm thinking, why not build a kit of our own? You could probably buy enough components to build 20 of these for $20. The asking price was never really for the hardware. The instruction books with all the projects are really what is valuable. Unfortunately, those aren't freely available. It'd be great to find a community driven project to make a series of circuits to fill this role. It's hard to find freely available circuits that use the same parts.

I loved the spring based hookups that these kits used. Breadboards are good for testing circuits out, but these are very neat in that all your components are fixed in place and you can pretty quickly run wires from one to another. It's nice for car rides also, no risk of losing tiny components as the car is moving. The spring idea is probably covered under some sort of patent though. So any community made clone would probably have to do something different. It'd be great if some place offered a strip of breadboard like material where each hole could be wired up separately underneath. Or, what else could you do?

Circuits could include:
A basic circuit
operation of resistors, resistors in series, parallel, variable
operation of capacitors, showing they store energy, use as time delay, pass AC but block DC, etc.
operation of transistors, as switches, as amplifiers, darlington pair
operation of diodes, rectify AC, etc
operation of transformers, upconvert/downconvert voltage. etc
operation of relays
operation of inductors (???) never covered in the kits I had
voltage dividers
Simple logic circuits (and, nand, or, not, xor, flip flop, latch, etc)

Not only have purely theory based circuits but also edutainment ones such as sirens, "police light"s, timer games etc. Code practice oscillator, crystal radio, AM radio, FM? Radio would be very nice, especially for a radio club! You could wire two kits up to send Morse Code back and forth to each other... neat demonstration for a field day setup.

Anyone wire one up to use as a QRP CW transmitter? I was once playing with my 200in1 kit and accidentally affected our TV. I was maybe 11 and built the metal detector circuit which involved a radio signal. Well, I was somewhat randomly changing parts around and ended up making something that I could sweep around and all of a sudden our TV looked like it was scrambled. It was on ch 6 or 8. So I tuned the TV around the channels and then tuned my circuit with the variable cap and I was able to knock out any channel up to 13. I wrote down my changes, or so I thought.. next time I tried to build that circuit it never worked again. Probably for the best though. :)

Inexpensive digital multimeters can be had for less than $5 shipped on ebay. That can be useful for teaching the skill of using one with such a kit.

These kits are probably the reason I got into electronics and they have also nurtured my love of science (although Mr Wizard had a huge role there too!). I intend on passing on something like this to my kids one day. It'd be incredible if others could do the same as well.

Saturday, February 26, 2011

Volkswagen making a $600 car that gets 258mpg? Probably not.

The part that seems too good to be true is the price. I don't know where that came from. I did some google searching and came across a page that casts some skepticism on that low of a price point. Now, that page claims it'll cost more like $26,000. If so, no thanks.. I'd be interested if it were $600 actually.

This is a really neat little car anyways. One website says it's actually two seats, the other one is right behind the front seat... like a jet fighter. The motor is a 299cc single-cylinder diesel engine. I'm not a mechanical person, is single-cylinder even possible? I'm sure it doesn't have the acceleration of a jet fighter :) But with gas prices probably never dropping again, unless we have another deep recession, anything that uses less gas is awesome in my book.

Begin tangent here....

Electric cars are available now, but only really economical if you build one. It's very much like the early days of the Ham Radio pioneers or the computer hobbyists of the 70's. If you want one, it's better and cheaper to build than it is to buy.

Here's a link to a blog of an Aussie ham who has posted about his EV (Electric Vehicle).

According to him, the electric car uses pennies per km of electricity. Their electricity prices cost more there than they do here, that's for sure. I believe they also have a solar panel array set up, although I don't know the capacity, that actually supplies all the energy the car needs.

I'm just going to copy & paste a chart from a .doc file on this page
 (The actual .doc file is here)

Myths about Electric Cars
Electric Cars are ExpensiveYou can convert a small car for between $8,000 and $15,000. You can convert a small car and install solar PV panels to charge it for less than the price of a new medium size petrol car!
Electric Cars are SlowOur EV has faster acceleration that it did as a petrol car. It has so much torque it can can pull 5th gear from 0 rpm.
They don't have enough rangeWe drive up to 80km every day. This is perfectly adequate for metro driving. We have a second petrol car for long distance use. But we hardly ever use it and are considering selling it.
But we need infrastructure like charging stationsAll you need is a power point. There are many more power points that petrol stations already. We have never needed a charging station while driving around Adelaide as our range is fine for a full days driving.
The power stations will be overloadedPower stations are idling at night and could be put to better use. For an average day of 30km driving our EV uses just 5 kWh. We have offset this with a PV solar array that generates 8 kWh/day. So we drive an electric car, pay nothing for fuel, and use less electricity than before!
Charging is slowYou don't sit next to the EV waiting for it to charge. We just plug in at night and unplug in the morning. Like a mobile phone. It's easier and takes less time than going to a petrol station.

Eh, why not include the specifications from the same file. 

Battery pack 36 Lithium Cells, 3.2V each, better than 10 year life time or 150,000km
Operating Voltage 120V DC
Range 80 to 130 km
Top speed 130 km/hr
Conversion Cost Around $15,000
Economy 200Wh/km or 4 cents/km. Free “fuel” if you install PV Solar panels at home.
Servicing No servicing is required for Electric Cars. There are no oil changes, radiators, or spark plugs. The only wearing parts are brakes and tyres.
Motor 40kW, 200Nm DC motor. 1,000,000 km life expectancy
Seats 4 Adults
Weight 900kg (40kg above previous weight as an internal combustion car)
Driving Like an automatic. The car is placed in 3rd gear for all forward speeds between 0 and 80 km/hr. No gear changes.
Green House Emissions Zero. The electricity we use in charging is less than the energy our PV solar system makes every day. By recycling an old petrol car we avoided the GHG emissions involved in manufacturing a new car (even a new electric car).

Mr. Rowe is a pretty good salesman for EVs, I have to say. :)

Wednesday, February 16, 2011

Transmit and Receive simultaneously on one frequency?

Just read an article on ZDNet about researchers at Stanford coming up with a way to transmit and receive with the same radio at the same time.

I guess the key is the put a receive antenna precisely positioned between two transmit antennas. The idea is that the waves from the transmit antennas will cancel each other out and the receive antenna sits in the null zone. I wonder what the radiation plot is for that antenna arrangement, hah.

Here's the video from the article:

They are talking about applications for wifi. Could be useful for ham radio?

Saturday, February 12, 2011

ICOM 9100 clears FCC?

This appears to be the FCC ID: AFJ318300

Word on the internet is that the price when it comes out will be either $3600 or $4000. It's all rumors right now but I guess it's suppose to go on sale at Dayton.

Personally, I think that price is extremely overkill. They wouldn't sell it at that price if people wouldn't pay for it though. It's also for a very niche market so they have fewer units to spread fixed costs over as well. It's simple economics. Once they sell all the units to people who are willing to pay such a price, maybe they'll lower the price in order to sell more units.

There are cheaper ways of doing D-star on HF if that's what you want.

D-star adapter$600 (inc. UT-118 Dstar codec module and case)
Kenwood TS-2000$1549
$1999 w/1.2ghz

So for roughly $2600 you could have a set up that can do basically everything the 9100 can do. Less than that if you can find the TS-2000 used for a good price. You can't do the 128k high-speed data on 1.2ghz, but last I heard, neither will the 9100. Correct me if I'm wrong.

Heck, you might be able to do that cheaper.. I've heard about a soundcard GMSK modem that can use a DV Dongle to let you talk D-star on a 9600 capable radio like the TS-2000 for the price of the dongle, $200. I can't find the program right now though. (I'll update if I do.)

Thursday, February 10, 2011

Ubertooth One

Check out the video on that page. It's a roughly 50 minute talk given by Michael Ossmann about his Ubertooth project. The project is a 2.4ghz transceiver that is able to monitor the entire communication between Bluetooth devices. This is useful because most, if not all, bluetooth adapters cannot be used in the same way.. they automatically strip information out before it gets to your computer. With this Ubertooth dongle he can better perform a security audit on bluetooth devices than previously possible.

What I find more interesting about this is that this wasn't all that complicated hardware wise. The protocol sounds like it was a real pain, but he's had prior experience with implementing that on the USRP. The dongle, as it stands, is mostly 3 chips. A CC2591 2.4ghz PA/LNA, CC2400 2.4ghz RF transceiver and a LPC175x series ARM chip.

What inspired him to use a chip like the CC2400? He previously played around with a kids toy called an IM-ME. It's a pink pager-like device meant for girls to send instant messages over the Internet (via a usb dongle plugged into a computer)... He was able to turn it into an inexpensive spectrum analyzer type device. How? It has a CC1110 chip. This is an RF transceiver chip with an integrated 8051 cpu. According to the linked site:
Frequency range: 300 – 348 MHz, 391 – 464 MHz and 782 – 928 MHz
Pretty neat, it's capable of operation in the 70cm and 33cm bands at up to 500kBaud. This was in a toy that was less than $20 on ebay. I'm guessing that chip was unsuitable for the bluetooth use that he wanted, therefore the choice of the CC2400 chip.

Something else I found interesting was the Kickstarter site itself. Quoting from the About link:
Kickstarter is the largest funding platform for creative projects in the world. Every month, tens of thousands of amazing people pledge millions of dollars to projects from the worlds of musicfilmarttechnologydesignfoodpublishing and other creative fields.
A new form of commerce and patronage. This is not about investment or lending. Project creators keep 100% ownership and control over their work. Instead, they offer products and experiences that are unique to each project.
All or nothing funding. On Kickstarter, a project must reach its funding goal before time runs out or no money changes hands. Why? It protects everyone involved. Creators aren’t expected to develop their project without necessary funds, and it allows anyone to test concepts without risk.
It's a neat idea. I don't know how well it has worked out in the past since this is the first I've heard of it. You can pledge a few dollars to help a project out without expecting anything in return or there are bonuses to pledging more. For the Ubertooth project, $15 will get you a pcb and a stencil, $30 gets you that and an assembled serial board to help you load the firmware, $100 or more gets you a fully assembled board, etc. I'm sure that Mr Ossmann would deliver, but I'm not sure if the website has ever had problems of someone refusing to deliver after getting the funding. I still like the idea though.

Michael Ossmann has a very nice blog: Here
Travis Goodspeed has a blog about similar such things: Here
(He has a project for a conference badge that includes somewhat similar but different brand wireless components. I may ramble on about that at another time, in another post.)

Saturday, January 8, 2011

RF over Fiber Optic

I have recently come across this idea. It's apparently possible to buy boxes that can convert RF signals into optical signals that can be sent over fiber and reconstructed on the other side with another box. There are converters for one way or transceiver purposes. Some have bandwidths of 2500mhz or even 4000mhz.

Here is a PDF with the basics.

Has anyone ever used something like this for Ham Radio purposes? I'm still looking around but it seems pretty obscure to me still. I'll make a new post if I find anything.

Monday, January 3, 2011

Tokyo Hy-Power HX-240 2m -> HF xverter


This is backwards from what you'd normally expect. You hook a 2m all-mode rig up to this and use it to receive and transmit HF. 2.5W/10W in on 2m translates to 30-40W out on HF. The going price is roughly $200. Neat.

Sunday, January 2, 2011


This is a handheld radio from a CB manufacturer, Magnum, that purports to do 10 meter and 12 meter all mode operation: AM/FM/SSB.

It's pretty shameful when a CB manufacturer does something that not even a ham radio one is doing. I know these are meant to be for freebanders but I kinda want one. I am normally 100% opposed to this sort of thing. They aren't fooling anyone when they sell the "10 meter amateur radios" on ebay that look and act exactly like a CB. If you ever bother to look up the manual for one, you see it's braindead easy to mod it for 11 meter use. They may as well put a switch on the front panel for crying out loud. I don't know if this handheld has a VFO mode or if it's more channelized junk. I haven't found out much information on it, besides lots of listings on stores that are primarily CB oriented. Some of them don't even pretend this is intended for amateurs who want a 10m or 12m HT, they list it strictly as a CB. It's a little pricey too, $210-$280 from what I've seen, and you have to mod it if you intend to switch bands from 10 to 12m.

Let's not pretend for a second that these are intended for amateurs though, these are meant for people who are going to "mod" them for CB use.

QAM modem IC?

While browsing some of the tapr HSMM information, including one of the message boards, I found a post referencing a very highly integrated modem IC for doing QAM data with an I/Q interface. Here is the post. and Here is the IC in question.

I'm going to quote from the webpage:
The CMX7163 QAM Modem is a low power half-duplex device supporting multiple channel spacings under host microcontroller (µC) control. Its Function Image™ (FI) is loaded to initialise the device and determine modulation types. 
The 7163FI-4.x supports 4-, 16- and 64-QAM modulations up to 96kbps in a 25kHz channel, with channel estimation and equalization to provide robust performance under realistic channel conditions. 
Flexible bit rates support a wide range of applications requiring a selectable bit rate and robustness.
 An integrated analogue interface supports 'direct connection' to zero IF I/Q radio transceivers with few external components; no external codecs are required.

The odd thing is the message board post quotes 64kbps in a 25khz channel but the chip maker's website says 96kbps. Obviously that'd be the 64QAM modulation. That's still very impressive, in my opinion. I'd love to see these incorporated into a design for a 440mhz or higher HSMM radio.

Just read the datasheet, you can do 96kbps with 64QAM, 64kbps with 16QAM and 32kbps with 4QAM. That is assuming 18,000 symbols/s (your baud rate). This falls well within the 19.6kilobaud limit on 2m but outside the bandwidth limit of 20khz. If you reduced the baud rate to 9000 symbols/s you'd take up half the bandwidth. It'd fit within the 56kilobaud/100khz limits in the 440 band just find though.

The downside is that these are only available in 64 pin packages, VQFN and LQFP. Small pins with little space inbetween but I've seen people who could solder it.

Return to Mt. Packet

KE9V has posted a list of basically New Years resolutions for ham radio and his #1 item is to set up a 1200 baud packet node again. I'd like to resolve to do the same. It's a shame that the old packet radio network(s) were tore down as the Internet got big. Even if packet was only 1200 baud, it's got reliability on it's side. Sure, the Internet's probably pretty resilient, but that doesn't include your connection to it. 1200 baud is super pokey but it's much faster than 0 baud. I would like to investigate HSMM installations but that will have to wait on personal funding and contingent on interest from other hams in the area, of which few have interest in computer technology I think.

Kenwood RC-D710 (D710) Control head... with other radios?!

I was clued into this on the Curling Smoke blog ran by KE9V. Here
As an aside, this links to a TAPR mailing list which is talking about the control head being on sale at HRO for $150. The posting was dated 12/25/10 but today (1/2/11) I can't find it on HRO's website.

Apparently the control head for the Kenwood D710 radios can be bought seperately because you can buy the radio without the APRS functions. The TNC and APRS logic are both in the control head so just buying the right one and adding it to the radio will let you add that functionality in. The interesting part comes Here. With the right cable, you can plug the head into any radio to decode APRS packets, even an HT! (Thanks to Bob, WB4APR for detailing this)

Apparently it's even still possible to connect the Kenwood AVMAP device to show the icons on a map.

Bob writes:
CONCLUSION: On long trips, no matter where you are, we hope you will see not only one of these recommended voice repeaters on your screen, but also the nearest IRLP or EchoLink node as well... This combined with APRS Voice Alert will guarantee that if there is someone nearby wanting to chat, we will find each other.

I've made the mistake of believing APRS is for tracking only in the past. I think it would be far more useful if people would use it to advertise local services, such as repeaters and echolink nodes.  Mr Bruninga really stresses this on his website and I really respect that.