Lee -
No. This is normal. For SSB transceive, anything over about 10-20 Hz difference between
transmitter and receiver frequency is audible and makes 'some' want to re-tune.
In the earlier 4-Series twins, there was a procedure called 'Transceive Align', that consisted of a
trimmer cap inside the receiver to match its frequency 'exactly' to the transmitter Carrier
Oscillator frequency, for SSB transceive. Even though both oscillators were crystal controlled,
this adjustment had to be made fairly often to keep the two exactly together over time and temperature.
So in the 4C-Series Drake added one more cable (CAR OSC) between the two units to carry the Carrier
Oscillator signal over to the receiver to ensure the two are on the EXACT same frequency, and
eliminating the adjustment.
The Carrier Oscillator is used as the Master since its frequency is the most critical (placed
between the sideband filters).
Compared to the Transceive Alignment and often off-frequency transceive in the earlier units, the
need to retune the receiver 50 -100 Hz when the transmitter is turned on or off is a bargain!
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
kc9...@aol.com wrote:
Garey,
So, Is this normal or do I need a new xtal in the T-4XC?
73,
Lee
Lee Simmonds
Summit DCS LLC
260-799-4077 Office
260-403-6936 Cell
-----Original Message-----
From: Garey Barrell <k4...@mindspring.com>
To: kc9cdt <kc9...@aol.com>
Cc: drakelist <drakelist@zerobeat.net>
Sent: Thu, Jul 21, 2011 10:45 pm
Subject: Re: [Drakelist] C line...TX on changes freq. 100 cps
Because the T-4XC Carrier Oscillator controls the 3rd IF LO when it is on. When
the T-4XC is
disconnected, or off, the R-4C uses it's own internal crystal. This is in lieu
of the 'Transceive
Align' procedure in the earlier 4-Line pairs. The two crystals are ~100 Hz
apart.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
kc9...@aol.com wrote:
Hi everyone...
WOW is it hot here in Northern IN.
Question...anyone have an idea as to why the R-4c changes freq. about
100
cycles UP when I turn
the T-4XC off??
Everything works FB, just kind of bugs me.
Thanks,
73,
Lee, KC9CDT
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