SDR - The cheap and fun way!

   So this months QST magazine had an article about using a USB TV tuner dongle as a cheap SDR receiver capable of receiving ~60Mhz - 2.2Ghz (you can buy/build a converter to cover HF).  I picked up this [amazon.com] tuner and followed the instructions in QST including using the automatic configuration script.  It was amazingly easy to setup and worked first try.  In the picture above it is receiving an AM aircraft signal at 133.75mhz.  I did notice the accuracy isn't always perfect, it took me a second to find a local 440mhz repeater since it was a bit off.  Also, I've noticed a couple of times that when I turned it off and come back later the frequency I was listening to had shifted slightly.  But, with how cheap it is I really can't complain.
   There are a few programs out there that work with these devices.  SDR#, above, is probably one of the easiest.  Most programs support AM, NFM, WFM, DSB, SSB, and CW with a few also supporting things like DRM.  It is possible to listen to digital voice like p25 however that takes a lot more work and you need a pretty fast computer to keep up (as I understand it, I haven't figured that part out yet).  I have also tried moving this to my linux laptop.  After fighting with the RTL-SDR driver (the compile scripts refused to find libusb even though it was right where it was looking....) it did eventually install everything including the SDRSharp windows binaries which do run under mono since they are in C#, though I had to grab the source and compile myself as the precompiled binaries would just crash right away.  It turns out a core duo running it under mono just didn't have the power, I would get 1-2 sec of audio followed by a few seconds of silence as it worked on the next bit. 
   One interesting thing a lot of people seem to be doing is monitoring airplanes ADS-B signals up on 1090mhz.  There the planes ID themselves and provide a position which can then be mapped real time on your computer.  It's like having an air traffic control terminal in your home.  That might be next on my list, I got the receiver/decoder working I just need to find some software to try since the popular programs are payware and I'm more just doing it for the neat factor at this point.
   Anyway, until next time..  73 de N0QBX sk

The state of VHF/UHF in the extreme north metro...

     So recently I decided to pull out the old TNC and see what was going on locally in 2m packet.  I also picked up a FT-60R dual band HT since my old Icom 24AT (and older icom 2A) need at least new batteries. 

     After googling around for awhile I couldn't find much about local packet activity, at least nothing from 2012 or even 2011.  I tried a few old frequencies like 145.67, 145.01, and 145.05.  Sadly, there was almost no activity at all.  I don't think it's just a part of living way out in the sticks of North Branch.... It really looks like 2m packet is dead here.  There is an emergency network on 145.67 and I was able to bounce around nodes but never saw anyone talking (that was an old keyboard to keyboard chat frequency).  On .05 I saw absolutely nothing after a couple days of monitoring and on .01 I saw a few network nodes but nothing else.  Sad to say I put away the TNC after about 2 weeks of watching.

     For local repeaters it's been pretty mixed... There is no where near the level of activity there was 10-20 years ago when I was last active on VHF.  That said, the rise of internet connected repeaters has lead to some interesting changes.  After searching the internet for awhile, I was able to find an updated list of repeaters thanks to the Minnesota Repeater Council's website.  After getting about 30 frequencies in the memory of the HT I hooked it up to my dual band Ringo on the roof and tuned around.  It was sadly dead also...  In the past drive time would have almost all the local repeaters filled with people so it was sad to hear hours with no activity.  Occasionally I would here a couple locals on the North Branch 440 machine, then one day I realized it was hooked to the internet.  For a weekend I listened to folks in Alaska work on their APRS setups, occasionally with a random Texas or Florida station saying "Hi".  When I had moved on from the repeater scene 10 or so years ago Echolink was still somewhat new so it was interesting to not only have these stations on the local repeater but also the fact that they all knew each other.  One gentleman in Texas was in the hospital and they all knew him and were wishing him well.  It sounded like having that connection to people he knew really was helping him deal with the issues causing his need to stay there.  While it takes away some of the mystery of working HF and being at the mercy of the ionosphere, it's fun to see that they have made friendships around the country and talk regularly with a large close knit group like that.  So while a lot has changed, and it is no where near the activity level of the past, there is still a lot of good conversations to be found on the local repeaters...it just might take a little longer to find it.

    One more plus side to the new handheld... As a long long time flight-sim junkie, its always fun to stick a few local airports approach frequencies, along with Minneapolis Center into the radio.  Also, as a photographer who has gone trainspotting a couple times, I put the railroad frequencies in also.  Having 1000 memories is a huge improvement over the 16 in my old Kenwood!  Anyway, enough for now, thanks for reading.  ....73 de N0QBX