FW: Took one turn off all the toroids!

Posted by Brett gazdzinski-2 on Mar 23, 2007; 4:19am
URL: http://elecraft.85.s1.nabble.com/FW-Took-one-turn-off-all-the-toroids-tp445004.html

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

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