We took our TRO-2 2m AM transmitters to Mt. Airy Forest last weekend (Feb. 26, 2006), and it was great.  We put out three transmitters, just close by, to check them out, diagnose problems, and just generally wring them out.  It's been 8 months or so since I hunted 2m AM, and I forgot how much harder it is than having a transmitter on for one full minute at a time (rather than off between the morse characters).

 Bob WA6EZV finished assembling his transmitter, antenna, and batteries first.

 You can see the BNC connectors and the antenna elements. He's got 7 cells in there.

Dick WB4SUV finished his next. 

 This is an early version with small threaded connectors for the antenna. He changed to 8-32 studs and aluminum arrows later (see below). Bob is running 12 Alkaline AA batteries, 18V, into a 9V regulator.

I'm hoping to eventually do as well as them, but while Dick was up until 3am or so getting his ready, at 2am, I decided to punt, more or less as I predicted; so mine is a kludged-together mess. The board is in a ziplock bag, and the batteries and on-off switch are just loose in the tube. 

You can see my turnstile with 12 gauge electric wire.  These elements are similar to the stand-alone turnstiles that Bob built.  They're convenient, but the biggest problem is that they extend below the big tube, and that means they're going to get bent inside a backpack. The biggest reason I went this was was because it's the cheapest way to build a turnstile I could think of.  The elements do wear out from the bending, but they're very cheap to replace. I'm using 10 NiMH AAs into a 9V regulator.

Here are all three. On the middle one (Dick's), you can see the 8-32 studs (a standard, non-metric machine thread---It's similar in size to metric M3). If you make the studs the right length (not too long and not too short), you can thread on aluminum shafts from archer's arrows, which are seen in the photo.

We've decided to standardize on the arrow shafts.  The only problem with this is the need to have a dummy load.  We're thinking about the best way to do that.

I should also say that Brian (K4BRI) did a great job getting the software changed for these.  He's also ordered 2 more boards so we can have a set of 5.   

After we set them out, I took off.  To make a long story short, I screwed up the order and ended up crossing a big reentrant twice.  I was having flashbacks to the 2004 World Championships in Brno, where I first hunted 2m AM. If you're used to FM-MCW, I just can't explain how much harder it is.  It's definitely fun.  Even Emily got all three transmitters.

A little story I must tell.  I was thinking about battery consumption, and wanted to see how long these would run on the battery pack I used (10 2500mA-Hr NiMHs with a 9V regulator), so I left it running after the hunt, took it home, set it on the kitchen table, and measured the voltage every few hours.  All day I was half-expecting a knock on the door from from angry RDF-capable hams, but...nothing.  I turned it off after about 12 hours, probably 10pm or so.  A few hours later I noticed my phone had a call from Brian, but it was too late to call him back.  So I went to bed, then to work.  I checked my e-mail, and it turns out Brian got a few phone calls.  Apparently, our 145.525 signal was keying up a repeater with 145.530 input all day long, one minute on, two minutes off.  They were able to copy the AM of the club's callsign, luckily. We've changed to 145.02.  Let's see how that works. (Oh.  The pack should last at least 30-36 hours of 1-on, 4-off transmitting.  Wow.)

More Photos from Mt. Airy and of the Gear