VE7XEN's electronics blog

Quansheng TG-45UV Protocol Reversing

Quansheng TG-45UV
On a whim, I recently purchased the apparently new Quansheng TG-45UV to replace the Quansheng TG-UV2 I lost this last summer. A review and/or video might be forthcoming, but in the meantime I spent some time reverse engineering the serial protocol / data structure. If you have one of these radios and want programming software, the Quansheng TG-K4AT UV software works and is what I based my efforts on.

Read more →

Recording NBFM Scanner with RTLSDR

Old School Scanner
Ever want to use your $20 RTLSDR dongle as a simple FM scanner to listen to your local public safety or ham radio repeater traffic? @nottheoilrig on my local hackspace’s mailing list inquired about how to record analog FM off the air to a file. After some fiddling, I found this is quite simple with the rtl_fm tool included in the osmocom rtl-sdr distribution. The dongle and software does quite a good job scanning too, its pickup time is very quick even monitoring many channels.

Read more →

Canon PowerShot S110 repair attempt

Canon PowerShot S110 imager
Ever wonder what’s inside your digital camera? Here’s the imager and optics assembly from a Canon PowerShot S110 that I destroyed with mineral-y water and was trying to repair. Click for gigantic. Isn’t that CMOS sensor beautiful?

Read more →

Programming the ATtiny841 with avrdude

Working with my good friend Daniel McLaren on a cool interactive art project, I designed a board around the ATtiny841, which is a nifty new entry to the AVR portfolio. Unfortunately when intial power up of the board was successful, I found I was totally unable to write code to the device with avrdude as I normally would; the chip is unsupported in even the latest version. I found a helpful post on AVRFreaks with a code listing for avrdude.conf that was purported to work, but I found it produced verfication errors (and a non-working chip) every time.

After much mucking around and recreating the part in avrdude a dozen times, I got it to work.

Read more →

eBay AD9850 board performance testing

Prompted by user Skimask over on the eevblog forums, I undertook some performance testing of an AD9850 module, readily available from eBay (search 'AD9850 DDS') for under $10 shipped. These are advertised as 0-40MHz devices, and appear to include the datasheet-recommended 5-pole output filter and a 125MHz canned oscillator. Measured distortion and spurious performance is excellent, especially for the bargain-basement price. Skimask was curious about the performance at audio frequencies, so I undertook some measurements at 1KHz and 5V. Read more →

Project Start: tinyCounter low power HF frequency counter

I've ordered myself an EA3GCY ILER-20 kit, and being a single-band QRP hand-tuned radio, I want a convenient counter. I'm going to be using this in the field on battery power, so it's got to sip the juice and be small (tiny!) and light. The design should be suitable for any small HF rig (and maybe 6 metres) with an easily accessible point to measure the VFO. I put together a design and just ordered PCBs. Read more →


DSCF1907.JPG It's been a while since I've posted here, and many of the things I pledged to follow up on... haven't been followed up on. I've started several blogs in my life, and never seem to get past the 10 past mark without losing interest and giving up. This one's no exception, but if anyone is following this (or reads it in an archaeological dig 100s of years from now), here's the short version: Read more →

Workman WEP2000 - killed!

A couple posts ago I mentioned the WEP2000 I'd purchased to give mobile VHF a try, contrary to my original plan to just use it for APRS. For a while, I was reasonably happy with it; it was a pain to tune, but I was getting good signal reports and receive was good enough for my purposes. In the past week or two though I'd noticed that while it was working, the receive power was much lower than it should have been, so I went to check the tuning on the through-the-glass box on the rear window. Read more →

Antennas Ordered & Future Projects

Shortly after getting my ham license I started fooling around with antennas. Built myself a very shoddy 2m ground plane 1/4 wave just to get an antenna outside for use with my HT, as the whips can't get anywhere from inside. Then I decided to upgrade to a proper antenna - a coaxial dipole design by W6NBC published in the July 2009 QST. This worked fantastically well for a couple of months, then a solder joint broke between the antenna connector and the radiator element. Read more →