Sunday, September 16, 2012

My Amateur Radio Hardware

So I finally decided to write about my ham radio setup. This is a blog post I promised in a tweet a long time ago:

 Wow, almost a year. Wait, what? Tomorrow (Sept 16th -- or possibly today by the time I actually publish this post) will be exactly one year since I got my license. Let's see my equipment so far.

Wouxun KG-UVD1P
A really neat hand-held FM dual-bander. Costs around $100 and works quite well. No fancy features (unless you count the flashlight as fancy), but does everything I'd expect it to do. It has nameable channels, keypad for entering the frequency, scan mode and it can even listen to two frequencies at once (or rather scan between them). TX power: 5W. Channels are computer programmable via a USB cable.

Baofeng UV-3R
Another hand-held FM dual-bander, but this one's smaller and cheaper. I think it can be found for around $50 on eBay, and it has 2W of TX power. A few downsides compared to the Wouxun: channels can not be named, nor does it have a keypad for entering the frequency. This makes it inconvenient to operate on too many repeaters or to program manually, but if you only have a few favorites, it'll do just fine. Programming cable is a must. Did I mention it's tiny?

SlimJim Antenna (from N9TAX)
This is a nice antenna (I have the dual-band 2m/70cm version) made from a section of ladder-line. It's durable and also flexible. So far I reached repeaters up to 25 miles away, but I'm planning to put the antenna up in the attic and try again for some further away ones. The fact that I'm surrounded by hills surely doesn't help.

SignaLink USB
This is basically a USB sound-card, but dedicated to interfacing between the radio and the computer. It can be used for digital modes with a SSB radio, or even to get on the air via Skype (I tried that with my handheld!).

In addition to these, I've also built a number of kits recently.

SoftRock Ensemble RXTX
This is a software defined radio (SDR) that can be built for a choice of frequency ranges. What I like about SDR's is that you can see a good chunk of the spectrum at once, in a waterfall view. Allows you to see all transmissions in that frequency range, and tune in by clicking one with the mouse. The transmit power of the RXTX is 1W, and I built mine for the 20m/30m/40m range. For the RXTX to work, two stereo audio cables need to be connected to a sound-card on your computer. This means that if you also want to hear anything, you'll need two sound-cards (you might get around with just one for the digital modes).

Peaberry SDR
This is clone of the SoftRock RXTX, that solves the cable clutter inherent to the RXTX by including a sound-card on the SDR device itself. Thus, only an USB cable needs to connect to your computer. Moreover, the Peaberry includes a second sound-card (with jack connectors so you can plug in your headphones and microphone), such that you can have a fully operational radio even if your computer doesn't have any sound hardware at all (embedded, anyone?) or you don't want to use it for any reason (e.g. me playing with the radio while YL watching a movie next to me on the same computer). Compared to the SoftRock, the Peaberry uses mostly surface mount components, which I actually find easier to assemble.

Other kits include K5BCQ's 20W amplifier and KitsAndParts' low-pass filters and SWR bridge, but these are more straightforward and don't really need explanation. Unfortunately, I haven't yet been able to transmit at the full 20W. I still need some more reliable means of connecting all my boards together and let's not even mention that everybody seeing my boards tells me I need boxes!

Antenna System
I'm not proud at all about my antenna. It's a 20m dipole, set up in the attic of my house. The problem is, I had to zig-zag it around a little, trying to keep it away from the various metallic things in the attic (some smaller, but others quite large).. And the other problem is, it's probably not tall enough, as my house is half-way inside a ditch. It's connected directly to a twin-lead cable which again connects directly to my Peaberry (I know this is probably extremely bad, and I promise I'll fix it using RG-58 coax and a homebrew balun as soon as the coax arrives). I also have a  2m dipole which connects to the same cable, but I polarized it wrong (it's horizontal while I only work FM on that band). When I'll install the coax I'll also replace the 2m dipole with my SlimJim, and I'm curious what my range will be after that.

I'm still looking for a solution to get active on other bands. I could either set up a 40m loaded dipole, or do my best to tune the 20m dipole (I don't have a tuner and I'm not planning to get one). Alternatively, I could build a magnetic loop antenna for the 20-40m bands: I already have the copper pipes assembled, all I need is to weld/solder them and  get/make a large enough variable capacitor to withstand the approx 1500 volts that are likely to build up from my 20W amplifier.

With that I think I exhausted all the ham radio stuff that I own. On VHF it works just fine, but on HF I'm still to make my first QSO (I have plenty of contacts on WSPR though - more on that in a later post).

73... KK4EDI

Friday, January 6, 2012

Android apps I use

I am not going to start telling people to use Android instead of iPhone/iPad (although they should!), but I've been using an Android tabled for the past couple of months, and there are some apps that I have found useful. This list will serve as a backup for me (sort of), but it may also help others.

So here it is:

  • Dolphin Mini Browser (tabbed web browser)
  • Skype (video chat)
  • MoboPlayer (excellent video player)
  • APV PDF Viewer (light pdf viewer, supports invert colors)
  • imo (multiple instant messenger client)
  • CSipSimple (soft-phone, SIP client)
  • DropBox, Ubuntu One (file hosting)
  • TeamSpeak (voice conferencing software)
  • KeePass (password manager)
  • screenshot (com.geeksoft.screenshot - take pics of your screen)
  • ClockSync (because the clock resets when it runs out of battery)