Updates: FT-102 and Arduino Memory Keyer

I have two updates from previous posts. First, Mal just called and said my FT-102 is ready. The problem appears to have been a bad 10 MHz crystal reference oscillator. It wasn't putting out enough signal so the phase comparator wasn't working so the PLL wasn't locking up. I should get the radio back in a week or two, I just have to (gladly!) pay for the repair.

The Keyer, Well, It Doesn't Work

I've wanted a memory keyer for a long time, but they tend to be expensive and I don't work enough CW to really justify it. However, about three years ago it occurred to me that you could make a memory keyer out of an Arduino. (An Arduino is an amazingly cheap microcontroller board that some clever Italians designed. See, e.g. http://www.arduino.cc/ for more information.) Anyway, a while after I thought of that, I decided that I didn't want to spend a bunch of time designing the hardware and programming the Arduino.

A Glimmer of Hope

You may recall that I'm trying to build a compact whole-band antenna for 80 meters, and the simulations I've done show some odd results that I'd like to resolve. To that end I've built a scale model that should work for both 10m and 12m. Unfortunately, the scale model doesn't work and it doesn't work in interesting ways. In particular, it looks like the antenna wire wasn't cut to the right length. I've been wondering what mistake I could have made that would give me the results, but I hadn't been able to come up with anything.

It Still Doesn't Work

I re-measured and cut new wire and added a ground grid (a four-foot square of chicken wire) and it still doesn't work. The way that it appears to not work is interesting, so I'm recording it. The feedpoint impedance is very small. I was expecting about 100 ohms, and it's less than 20 ohms from 24.682 MHz to around 30.508 MHz and at most of the frequencies in the range, it's less than 10 ohms. I also discovered that I needed to disconnect the resonator from the ground plane to get those numbers. The simulations all connected the resonator to the ground plane.

JT65 on HF. Exciting? Or Watching Paint Dry?

It's about 3:00 on a Sunday afternoon, and I'm sitting in my shack in a pair of shorts watching dots crawl down a waterfall display. I can feel the aftereffects of the migraine I woke up with and the medication I took to feel almost normal. Sunday is my day for household chores, and I should be doing them, but I'm not. I've got post-convention work I have to do for ApolloCon, the science fiction convention I ran this year while y'all were having fun at Field Day, (lucky bastards,) but I'm not doing that, either. Instead, I'm watching dots crawl down a waterfall display.

KD5SBI and the Unified Microsystems SCI-6

I've been offline for a while because of ApolloCon, but I'm back at it. My XYL, KD5SBI, has expressed a desire to do PSK31 on 2-meters FM (and I've confirmed that there is such a thing) and has indicated that she understands the need for an interface box. To that end, she suggested that I purchase the UMI SCI-6 and assemble it, for it is a kit, for her birthday, which is coming up soon.

Update on my FT-102

Last night, Dr. Mal Eiselman and I spent an hour on the phone going over my radio and the news is pretty uniformly bad. There is no loose connection or anything that I'm confident I can fix in the radio. The problem is that the local oscillator board is not working. So, it's back to the good doctor for repair.

The one bright spot is Dr. Eiselman whose efforts to assist me are much appreciated even though they were ultimately unsuccessful. I can definitely recommend NC4L as the guy to fix FT-102's.


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