Re: [Elecraft] Elecraft K2 Bifilar Windings

David and all, I do the same thing with the addition of using a couple of turns of masking tape each end to prevent slipping while clamping and inserting into chuck. 73, Ted G7BQM On 12 Feb 2010, at 03:06, David Robertson wrote: > I used this trick to evenly twist wires together for bifila

[Elecraft] Interesting KPA100 partial power control loss

Good evening all, K2/100 #5822 started yesterday producing nearly double the requested power. Below 10W fine. 50W requested gave about 100W and max power was approaching 160W on lower bands!! I searched the reflector archive to confirm my memory of posts on the problem over the years. A

Fwd: [Elecraft] Grounding mic connector body on K2 front panel board

Dear All, Having read and thought about this one since building in Feb last year I 'attacked' the problem over the last two days. A survey with the left side panel removed showed access was a bit tight and the run to the grounding loop a bit long. So stripped the front panel right down t

Re: [Elecraft] Hi current/low power out on 20 meters w KPA100

Gregg, The problem appears to have been a batch of 1.6 ohm metal film resistors (R19,20) that had 6 turns and produced a weak 10MHz or thereabouts trap with C80,81 (4700pF). I believe Elecraft have sourced some resistors with lower inductance. For the Brits, locally obtained Vishay resistor

Re: [Elecraft] KPA100 power on 20m/30m, update

Geoff, Don, As an ex sufferer of this disease, my 2p worth. My investigations, admittedly only with the limited kit available to me including 20MHz scope and 2 or 3 different wattmeters, I think it was, showed that the output across all the bands up to 21MHz was remarkably constant for a give

Re: [Elecraft] KPA100 power on 20m/30m, update

Vic, I agree with you, Vic. As perhaps the third to suffer this in recent kits, I have spent much time, with help from experienced guys at my club, investigating this. Increasing the caps (C80,81) cured most but not all kits at the recommended level (+900pF). My caps measured at 4600 & 470

Re: [Elecraft] KPA100 Low Power on 30m & 20m bands

Barry, Hard luck but do not worry, you are not alone! You are the third that we know of in the UK and there was another in the USA. Let Gary Surrency at support know. In my case, a scope along the RF chain showed that there were signal voltage (and estimated current) losses across the base

Re: [Elecraft] Re: Which Capacitor is it?

C72 0.01uF decouples the gate of Q6 if I read it right. Can someone please check this out before I need to get a solder sucker out!! 73 to all, thanks for the excellent reflector and those at Elecraft for the excellent manuals. Looking forward to joining you with the build and on the air.