Easy fix: Just spread out the turns on the "double-coil"... the one made with the continuous length of heavy wire at the grid-tank for the finals. The reason is that this drastically improves the Q and you will probably see a 2-3 ma grid drive improvement. The turns of the coil pair are usually close spaced (touching) when people build the kit. I also pulled off the 47K 1/2W Q loading resistor off the driver's plate coil. Tuning is sharper, and provides more drive. Also, There is a cap you can add to the crystal oscillator that increases the VFO output, but I forget exactly... I think it is at the screen of the crystal oscillator. That was a good mod. I can get 8 ma grid drive on TEN and 110 watts out with 120% modulation peaks (audio mods). George AB2KC
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mark Bell Sent: Sunday, October 17, 2004 10:12 PM To: AM List Subject: [AMRadio] DX-100B Low Output on 15 and 10 Meters Folks -- I'm getting low output on 10 and 15 Meters. Typical output on the other lower bands is well over 100 Watts. All tubes test good, and I re-did the Buffer Coil adjustments as per the manual. After tune up on 15 Meters, here's my readings: Driver current is at 6 ma Ig is at 2 ma Ip is 250 ma Output power 50 W After tune up on 10 Meters, my readings are: Driver current is at 6 ma Ig is at 2 ma Ip is 250 ma Output power 65 W As a reference, after tune up on 20 meters, my readings are Driver current is at 6 ma Ig is at 6.5 ma Ip is 250 ma Output power 130 W Just for "fun", on both 15 and 10, I upped the driver current to max, which was 10 and 7 mA respectively. The respecitve Ig's were 10+ and 5 mA, and the output power (both bands) jumped to 80W. So, seems I have a problem with the grid current on 10 and 15 M. I figure I'd start looking at the circuit around the Driver section of the bandswitch. I was wondering, though, is this a known problem with the DX-100B that might be attributed to (perhaps) neutralization? Any and all comments welcome. Thanks & 73 Mark K3MSB ______________________________________________________________ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
