F3WT <[EMAIL PROTECTED]> made an utterance to the drakelist gang
----------------------------------------------------------------------
Hi Garey,
Very clear explanation below!
I have a related question I was wondering about for a while:
Why were TR4s - and others by he way - designed with 2 sideband
filters and 1 Xtal ( 9MHz ) rather than todays set of 1
sidebandfilter and 2 Xtals (SSB) or 3 including CW?
Was it a problem then shifting VFO without loosing stability?
73, Pierre - F3WT
Le 20 déc. 05 à 15:24, Garey Barrell a écrit :
Garey Barrell <[EMAIL PROTECTED]> made an utterance to the
drakelist gang
----------------------------------------------------------------------
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
----------------------------------------------------------------------
Submissions: [email protected]
Unsubscribe: [EMAIL PROTECTED] - unsubscribe
drakelist in body
Hopelessly Lost: [EMAIL PROTECTED] - help in body of
message
Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net
----------------------------------------------------------------------
----------------------------------------------------------------------
Submissions: [email protected]
Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body
Hopelessly Lost: [EMAIL PROTECTED] - help in body of message
Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net
----------------------------------------------------------------------
