----- Original Message -----
From: "Jim Bo" <[email protected]>
To: <[email protected]>
Sent: Friday, October 01, 2010 10:28 PM
Subject: Drake R-4C and T-4XC frequency problem when in transceive mode
Sorry for long post, but this will be a BIG issue for me for November
SweepStakes CW.
I have a problem which is noted when my R-4C is paired with the T-4XC. I
tune in a CW station with the R-4C, switch a Sherwood 600 Hz roofing and
250 Hz filter and adjust the passband to clearly copy the station. As you
know, with the 250 Hz filter, at 700 Hz, the signal is on the skirt of the
filter and is down significantly (or even out of the passband). The
frequency of the audio of the CW signal needs to be in the 500Hz (plus /
minus) range to be able to hear the station. I also prefer a 500Hz "tone"
when receiving CW. I then "spot" the xmitter to the same frequency such
that I can hear the spot signal in the tight passband. The receiver and
xmitter is on the same frequency and the other station can hear me just
fine when I transmit.
The problem arises when I use the R-4C PTO as the master oscillator
(tranceive mode). I can tune in an external carrier generated by a
Kenwood transceiver on the R-4C such that is in the passband and is solid
copy. I then use a completely different receiver (Drake R8B) to receive
the same carrier(using different antenna of course) such that it is in the
R8B passband and at the same tone (500 Hz). I use a Timewave 599ZX with
center frequency set at 500 Hz and the bandwidth knob to10 (ten) Hz for
the three conditions below. Very Narrow Audio!
If I then:
1. Turn T-4XC to spot mode (xmitter osc.), tune the mxitter VFO so the
spot signal can clearly be heard on both the R-4C and the R8B, and through
the Timewave. No Problem.
2. Transmit carrier with the T-4XC xmitter (xmitter is master ocs.), I
can clearly hear the T-4XC xmitter on both the R-4C and the R8B, and
through the Timewave. No Problem.
3. If I then turn the switch so the R-4C is the master oscillator
(transceive mode), transmit a carrier, and listen to the R8B, the signal
is no longer in the passband! Problem. I need to tune the R8B lower in
frequency by 300 Hz to hear the carrier.
The 300 Hz difference is significant and I do not get return calls when
using the C-Line in transceive mode. If I spot the T-4XC and call the
station then, I get return calls.
I checked the carrier oscillator signal from both the R-4C and T-4XC and
they are within 18 Hz of each other.
I do recall having this issue before when I first got the C-line "back in
the day" and did an adjustment to one of the rigs such that the receive
and transmit frequence were the same when using the R-4C as the master
oscillator (transceive mode), but do not recall what I adjusted.
Any and all help / comments greatly appreciated.
Jim
WA9ZBV
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