Russ Hines <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Hello Floyd:
Sounds like your TR7 may be suffering from a common ailment. Let me
recommend checking the PIN diodes on the high-pass filter board. There
are (3) UM9401's and (2) MPN3404's on the board that, if they are
"leaky" or fail, can make the receiver "deaf" and roll off the power
output on the higher bands.
GL es 73,
Russ
WB8ZCC
Floyd Sense wrote:
"Floyd Sense" <[EMAIL PROTECTED]> made an utterance to the drakelist
gang
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I've just finished aligning and checking out my TR7, and note that the
output power I see is less than most folks report. I've been through
the list archives and the eHam reviews, and it appears that there's a
great deal of variability in the outputs reported, particularly on the
higher bands. On CW, I can get 85 watts out on 15, and 75 watts on 12
and 10 meters. This was measured with a Bird 43 meter and a 50 ohm
dummy load.
In the Service Manual, section 3-12, ALC Adjustment, it says you
should be able to set the output to 140-150 watts on 20 meters. I can
get around 125 there. I've checked all voltages, including bias on
the drivers and finals - everything looks normal. Since the output is
clearly not being limited by the ALC, I'm wondering where the problem
might be. The rig is drawing around 25 amps from a 13.8V supply, so
perhaps the drive level is adequate and the input power is what it
should be.
Any ideas on why the efficiency is so low on the higher bands?
Problems with the low pass filters?
K8AC
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