Re: [Elecraft] Low outout power on higher bands, K2
Thanks for the tip Lee, it got me to looking at the TX mixer / buffer part of the chain. The ALC / BFO line into the mixer is consistent across bands, (however the micro controller quickly drives the ALC to max at 28 mhz). The mixer output looks ok, as well as the output on pin 6 of the buffer. However when I measure of the cathode end of D6 the relative output is down, as if the bandpass filter is sinking the energy. Leigh L Klotz, Jr. [EMAIL PROTECTED] wrote: Check the bottom of the RF board for a missing capacitor. You can search for my callsign and low power for a message trail including part numbers. 73, Leigh/WA5ZNU On Sun, 2 Sep 2007 1:35 pm, Beth Wenzel wrote: 13+ watts out. 20m about 12, then a rapid drop off until I get about 1.5 watts on 10 meters. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] Low outout power on higher bands, K2
Hi guys, Been working on this problem for some time now,with no luck. 30 meters and below, I get 12-13+ watts out. 20m about 12, then a rapid drop off until I get about 1.5 watts on 10 meters. I have checked all of the relays for proper switching in the bandpass and low pass filters, Have replaced the finals. Have rewound all of the transformers in the PA, and have cross checked all of the components in the RF chain. 10 meters peaks ok at 1.5 watts, but the ALC is in full drive to get 1.5 out. The gain ratios in the PA look ok relative to the lower frequencies, however the bandpass filters on 15 through 10 seem to exhibit a higher insertion loss than the lower frequencies, (using a sig generator and an o-scope to check) in fact if I jumper the filters out, the PA puts out full power in 15m but only 5 watts on ten (I'm guessing there is an impedance mismatch problem). Any ideas? this is getting to be very frustrating. 73 Mark AB9LZ. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] K2 Bandpass Filter Mystery
Hi guys, My K2 works perfectly on 80 40 and 30 meters (12 plus watts on all bands), however as I go higher in frequency the power output falls off until I only get about a watt out on 10 meters. I've check the relays to insure two filters weren't in line at once, checked all of the component values etc. Finally with an 0-scope in hand I've found that there is significant attenuation at the center cap in each of the higher filters. Bridging the 10 meter filter with a jumper netted about 7 watts. Putting a 10pf cap in parallel with C22 has boosted the 20 meter output to 10 watts, putting a 33pf cap in place of C46 has decreased the attenuation to allow about 4 watts out on 10m (up from about 0.9). The inductors do peak at about the center of their travel, the four cans for the higher frequencies are the matt silver type with the tiny flathead screw top, and match the description in the manual. Any ideas as to whats up? Seems very weird. 73 Mark AB9LZ. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] KSB2 No Transmit Audio
Hi guys, i built my k2 about a year and a half ago, I've recently decided to add a Ksb2, all wen together well, but... alas it doesn't work. I've checked all of the signal voltages, everything is ok. I've traced (with an o-scope) a nice looking modulated signal to the top of D3, then nothing. Checking D3 in circuit it looks ok (.6 ohm forward, 100k reverse) I'm assuming the sig should pass through to the base of Q3 (?). Is there a circuit description that can help me with the trace? 73 AB9LZ Mark, ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
