Mariana Islands DX Association - PO Box 445 - Agana Guam 96932
Volume 2 Number 3 - July 1999
Edited by KH2D
Published Quarterly by MIDXA
Email Items to MIDXA
QRP Anybody ? by KH2D
I got the box out of the closet a few weeks ago that's marked 'KITS'. Seems I buy a few kits here and there but never put them together. Anyway, I decided it was time to get the soldering out and see if it still worked.
A couple years ago when we were making an effort to get those 'other guys' interested in HF, I bought a few kits from Ten-Tec. One was a keyer, which I built as soon as I got it, but never put it in a case.. Nothing fancy, just your average 12 dollar keyer. The other kit I hadn't built yet was a 20 meter transceiver, the 3 watt QRP model. So I figured I'd give it a shot so we could try QRP at the beach for Field Day this year.
The kit cost $95.00 which includes EVERYTHING you need to build the radio except solder - case, hookup wire, the whole nine yards. The circuit board is extremely good quality, with plated thru holes - which can be a pain if you need to unsolder stuff. First thing I did was sort out the parts, all 219 of them, and stuck them in a hunk of styrofoam for easy access. Here's what the mess looked like at the beginning of the project:
The manual, the circuit board, and most of the parts. The manaul is pretty good, but there are two or three 'erata' sheets that came with the kit - fixes for mistakes in the manual, and a few changes.
I'm careful when I build stuff, I scrape all the component leads and verify resistor values with a meter (which saved me a couple mistakes) and the kit took me about a week to put together, working on it evenings (and a few all nighters). Probably at a leasurly pace it would be about a 2 week project if you take you time and work on it a few hours every evening.
The kit is built in eight steps (sections) of the radio and one of the really nice feature is that there is a testing process at the end of most steps that lets you verify that the section you just built works. Started out with the keying circuit, then the VFO, the transmit mixer, etc. No fancy test equipment is needed, an analog volt meter and another radio with a dummy load (or an antenna) are about all you really need - and in my case, the magnifying light (so I can see the parts).
Anyway, here's what it looked like after a week or so and it was all ready for testing on the air:
I guess the most difficult part of the project was winding coils - there are five coils that you have to wind around torroids - one for the VFO and four for the transmitter final. The VFO coil determines the tuning range of the radio and is very touchy - when you get it finished you need to nail it in place - I covered mine with Super Glue once I had the tuning range where I wanted it. I found I had to add one extra turn to the VFO coil than what was suggested in the manual. The finished radio covers from 14.008 to 14.074, which is about the range the manual suggests it will tune, but you can build it for any section of the 20 meter band you want to.
After I peaked the transmitter, I was tuning around to see what I could hear and DS1BHE was CQing near the bottom of the band so I called him - and got a 579 report. So I guess three watts works.... Here's the finished project (next to a Super CMOS II memory keyer I built the week before the QRP rig):
The receiver seems to work great - the JA's are LOUD and the night I finished the receiver section I was also hearing a bunch of loud stateside stations who were working K4SXT/KH2 in the middle of the band. I still seem to be having a little RFI problem with the transmitter (go figure, 3 watts and RFI problems?) but I'll fool around with the thing and see if I can figure out what's causing that. Anyway, look for the little black box on the table at Field Day...
Ten Tec makes the radio for 20,40, or 80 meters and their web page says the 15 and 17 meter versions will be out soon. Price wise, I think it's probably the best QRP rig around.
MIDXA Field Day - 1999
The Guam gang did Field Day this year at WH2U's beach in Talofofo, despite the bad weather. Sunday was a rainy, humid, yucky day but we showed up in the morning anyway and put our 5 element 20 meter quad up in the trees. Propagation, as predicted was not great during the day, but by about 4 PM in the afternoon, we were working some stateside stations and were even amazed that our CQ's were being answered for the first time in many Field Days...... We used KH2JU's Icom 735, and battery power for the station. The late crew, KH2JU, WH2U, and KH2D got so busy they were logging with a portable computer. The PDN reporter came by in the afternoon, so we managed to get our picture in Monday's paper for some publicity and some bonus points. KH2JU was in charge of the cooking, and despite the bad weather and lousy propagation, a good time was had by all.
PSK-31, Hot New Mode ?
If you get the ARRL email newsletter, or you've been reading their web page, or you've been banging around on Usenet, you've probably heard the term PSK-31. Everybody's yelling and screaming about ham radio's hotest NEW mode.
WHAT IS PSK-31?
The reason it's being advertised as 'NEW' is because there is now some Windows software which allows everybody to use it, and that's fairly new. PSK-31 was invented by Peter Martinez, G3PLX, who happens to be the same gentlemen who invented AMTOR. It's a keyboard to keyboard chat mode, not intended for file transfers but for QSO's, and it uses the Varicode character coding at 31.5 baud, or approximatly 50 words per minute. One of the things that I have noticed about RTTY over the years is that you needed to be receiving a fairly strong signal to copy much, and RTTY is very subject to interference from other noise on the band. RTTY works best, for me anyway, in the FSK mode with a CW filter, and not very well in the AFSK mode..
WHAT YOU NEED TO DO PSK-31
HOW WELL DOES PSK-31 WORK ?
IS PSK-31 EASY TO USE?
MY IMPRESSION OF PSK-31
It's 1999 guys, and if you have a soundcard and a computer,
and you aren't using it for ham radio, you are missing a bunch of stuff
that's fun to play with. You're missing Slow Scan TV, you're missing
DSP audio filters, you're missing DVK software, and now you're missing
PSK-31. Go build the soundcard interface for your radio, and I'm sure
you'll be glad you did.
Pacific Radio Waves is published quarterly by
the Mariana Islands DX Association.
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