FW: Took one turn off all the toroids!
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FW: Took one turn off all the toroids!
 
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Well, I am scratching my head.
I unwound 1 turn off every toroid and transformer, I did not do any of the RFC marked toroids as if they are acting as chokes, one more turn wont hurt I guess. No improvement in power out, it might actually be down a bit, but I think I found my problem area. The rig will actually put out 15 watts or more on all bands but 10 meters where it will do over 10, but only if I load down the RF output detector voltage. The digital display and the bar graph on the rig both show serious over power above 40 meters. On 80 and 40 things track, but above that the rig reads the output much higher than it is, on 10 meters the readout is over 10 or 12, the real power is 5 watts out. What I did was to put a 10K ohm across R69, which reduces the voltage output of the rf sense circuit. When I do this, the power output on 80 and 40 is close to or more than 20 watts, and stays above 15 up to 10 meters where its down to 12 or there abouts. Now the RF output detector talks to the cpu and that outputs the values that read out on the bar graph and the digital readout in the tune mode. The cpu does correct the power, the cpu completely controls the power, and that is my problem, since the output sense circuit reports high above 40 meters, the cpu turns the power down. The RF output detector circuit is 4 resistors that measure correctly, a .001 uf cap that is the correct value (tried another as a test with no difference), and the 1N5711 diode. This circuit is right on the antenna jack, and it reports to the cpu. I have 50 ohms right on the antenna jack, no SWR, yet the blasted thing reads high above 40 meters. Could it be the diode? Could a diode work better and put out more signal at higher frequencies? Here are the readings I get in the tune position: Band watts requested digital readout actual output output sense voltage 80 10 12.8 12 4.12 40 10 11.5 10.2 3.83 20 10 11.6 8.8 3.85 15 10 11.6 7 3.8 10 10 11.3 6 3.65 I just don't get it. Brett N2DTS _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
Re: FW: Took one turn off all the toroids!
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Brett,
Did you actually count the turns before removing one? Arbitrarily removing one turn may create more chaos. The number of turns called for in the manual are correct, and must not be altered. The problem Ron had alluded to was that some builders can accidentally wind an extra turn because they count the number of turns on the outside of the core. The proper number of turns is determined by the number of passes through the CENTER of the core. There are no partial turns on a toroid. On your power issues, that is so extreme and unusual that I am beginning to suspect either your dummy load is frequency sensitive or there is something else wrong. Did you measure the dummy load with an antenna analyzer at the frequency of operation or did you just measure it at DC with an ohmmeter? I would advocate that you either use your 'scope with a 10X probe or an RF Probe to measure the actual RF voltage directly at the BNC Antenna jack. Do the measurement at a power level of 4 to 5 watts. Use the RF voltage produced to calculate the power and compare that with the power displayed on the K2. If the displayed power and the calculated power are close to each other, there is nothing wrong inside the K2. You can continue to scratch your head about your other equipment, but using a diode detector or 'scope to measure the RF output directly will give you the answer to the 'where is the problem' question quickly. 73, Don W3FPR Brett gazdzinski wrote: > Well, I am scratching my head. > I unwound 1 turn off every toroid and transformer, > I did not do any of the RFC marked toroids as > if they are acting as chokes, one more turn wont hurt > I guess. > > No improvement in power out, it might actually be down a bit, > but I think I found my problem area. > > The rig will actually put out 15 watts or more on all > bands but 10 meters where it will do over 10, but only > if I load down the RF output detector voltage. > > The digital display and the bar graph on the rig both show > serious over power above 40 meters. > On 80 and 40 things track, but above that the rig reads > the output much higher than it is, on 10 meters the > readout is over 10 or 12, the real power is 5 watts out. > > What I did was to put a 10K ohm across R69, which reduces > the voltage output of the rf sense circuit. > > When I do this, the power output on 80 and 40 is close to > or more than 20 watts, and stays above 15 up to 10 meters > where its down to 12 or there abouts. > > Now the RF output detector talks to the cpu and that outputs > the values that read out on the bar graph and the digital > readout in the tune mode. > > The cpu does correct the power, the cpu completely > controls the power, and that is my problem, since the output > sense circuit reports high above 40 meters, the cpu turns the > power down. > > The RF output detector circuit is 4 resistors that > measure correctly, a .001 uf cap that is the correct value > (tried another as a test with no difference), and the > 1N5711 diode. > > This circuit is right on the antenna jack, and it > reports to the cpu. > > I have 50 ohms right on the antenna jack, no SWR, yet > the blasted thing reads high above 40 meters. > > Could it be the diode? > Could a diode work better and put out more signal > at higher frequencies? > > > Here are the readings I get in the tune position: > > Band watts requested digital readout actual output output sense voltage > > 80 10 12.8 12 4.12 > > 40 10 11.5 10.2 3.83 > > 20 10 11.6 8.8 3.85 > > 15 10 11.6 7 3.8 > > 10 10 11.3 6 3.65 > > > > I just don't get it. > > Brett > N2DTS > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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 mailing list Post to: [hidden email] 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 |
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