Wednesday, January 28, 2009
The second half of the AWA Linc Cundall OT CW Contest was this past weekend. Between Saturday evening and Sunday afternoon I added 4 contacts to my log including W0LGU(MN), WA9QNN(WI), WB9WHG(MN) and NG9D(IL). While not a lot of contacts this year my push-pull 6L6 transmitter seemed to work pretty well. I suspect my low antenna (only 10-15ft off the ground) resulted in a lot of RF going straight up. I did OK for nearby stations but heard/worked no east coast stations.
Friday, January 23, 2009
The first half of the AWA Linc Cundall OT CW Contest ran Wednesday evening through Thursday late afternoon. This coming Saturday is the second half of the "contest".
My station this year is a 1938 vintage NC-101X and a homebrew crystal controlled push-pull 6L6 oscillator. Electrically this transmitter is based on the QSL Push-Pull in QST, June 1940. I added cathode current metering, a load control and regulated the screen voltage to 150V. I ran mine with only 300V on the plates for about 20 watts input and around 10 watts output on 80 and 40. Cosmetically this transmitter is based on what I had on the shelf to work with, an old amplifier build in an even older Meissner Signal Shifter cabinet.
Here in SE Minnesota using my low hung 105' inverted "L" antenna I heard no AWA stations on the air Wednesday night but did work W0NYQ(MN), KB0ROB(MN), VE3AWA(OT) and AA9DH(IL) late Thursday afternoon.
Wednesday, January 14, 2009
When using my vintage transmitters I've missed not having a keyer. Many older tube transmitters are cathode keyed. The voltage across the key terminals can be high enough to fry the output transistor of a typical modern keyer. In some cases the voltage can even be high enough to be a safety problem.
I already had a K1EL K10 keyer board ( http://k1el.tripod.com/K10.html ). I added a Keyall from Jackson Harbor Press ( http://home.att.net/~jacksonharbor/keyall.htm ) to make a keyer capable of keying up to 500V at 2.A. It works great! I even installed a jack for a straight key so that I use the K10 CW monitor plus the Keyall isolator on Straight Key Night.