Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Karl -
The "bassy" and "hissy" audio on the sidebands indicates the Carrier
Oscillator is off frequency. Normally, the two filters form a letter
"M", with the Carrier Oscillator "in the middle". As the carrier moves
to one side of 9.000 MHz, the audio response goes bassy on "USB" and
hissy on "LSB". If the carrier moves the "other way", then the bassy
and hissy are reversed.
Do you have an accurate frequency counter? Or a "modern" digital
readout transceiver?
The Carrier Oscillator should be on 9.000 MHz in the "non -X" mode and
approximately 9.001 MHz in the "-X" mode. If it is NOT, and cannot be
set to frequency by adjusting C130, then you likely have a bad crystal.
If it is, or if it can be set to 9.000 MHz by adjusting C130, then tune
in a stable "CW" signal on any band. This signal could be another
transmitter loaded into a dummy load, etc. Tune slowly through this
signal while watching the S meter. The meter should show no signal,
then rise rapidly, then stay relatively constant for about 2.5 kHz, then
drop rapidly as you tune through the signal. Do this in both sideband
positions. If the S meter reading does not follow this pattern as you
tune through a signal, (may stay "up" less than 2.5 kHz, or may have a
"dip" in the center,) then you likely have a bad filter.
Filters from parted out units show up on EBay from time to time, BUT may
also be bad. The INRAD filters are excellent, but they are $100 each,
which doesn't make much sense in a $250 transceiver unless it has
sentimental value!
73, Garey - K4OAH
Atlanta
Drake C-Line Service Manual
<http://www.k4oah.com>
Karl Corder wrote:
I have tried adjusting the balanced modulator and the carrier
(c130)and neither
one will allow the sideband switch in the X position to give me any
drive at all
beyond the .1 miliamps. With the sideband switch in the NON X position
I can get drive and adjust the resting drive current to the .15 as
they recommend.
I cannot get equal noise pitch using the C130.
As long as the sideband
switch is in the NON X position and the other switch is in the X-CW
position
I can get drive but as soon as I put the ssb switch in the X position
there
isn't any drive from the rf gain control.
Does this mean that one or both of the ssb filters have croaked? I
can hear (make out signals in the lower sideband but they are
poor and hard to tune in the audio isn't good at all, it is bassy
and the usb mode is Hissy( can't change it to bassy or bassy to hissy).
Appreciate any recommendations? Karl Corder wa20vj
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