It's not normal for the LOAD cap to be fully meshed on any band when operated into a 50 Ohm load. On 80m, a 500pF (I think) padder is switched in parallel with the tunable LOAD capacitor, but it's no
Hello Steve, I had the same thought about 80 and the extra 'C' and changed it out for a new one, I also tried increasing it's value and checked the switch out but although everything was fine I still
You could see the same effect if the tank coil inductance is too low - eg if part of it was shorted out when it should be in circuit. Max load cap. gives you a high anode load resistance. The circuit
Hello Steve, I was wondering about the tank coil although I've not noticed a problem with it visually, perhaps adding a turn or two?? The HT runs at 2100 off load and 1950 on load. As I've said in ot
Can't see a problem with trying it as an experiment - I'd been thinking along the lines of whether part of the coil was left shorted by the bandswitch. I don't know the amp, but from what I read that
Hello Steve, Firstly Steve thanks for your help. The next time the thing is on the bench I'll maybe add a turn or two on the tank coil and see what happens. The anode current reads, for 500w out, 340
Efficiency as high as 75% indicates heavy saturation, which ties up with the high anode load resistance. You will be getting higher gain, but at the expense of linearity and maximum output power. I'd
Hello Steve, Well as I said I doubt the readings are accurate, given +/- 10% the efficiency could be in the 60-65% range and as it looks good on the scope it probably is. I'll note your comments thou
I have been following this thread and have something to offer here. I can't think of why the loading problem , BUT, the hi voltage appears too low. Has it been measured with an external voltmeter?? I
Hello Carl, Well the spec says the max volts on the anode should be 2400, so maybe Heathkit decided to save the valves a little. The HT supply has been re-built. My mistake next...... On the FT-1000M
Hello Phil, I'll add it to the list of things to do next time the amp is on the bench, thanks. -- Best regards, John mailto:kvp@bigfoot.com _______________________________________________ Amps mailin