Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Bruce -
If I am understanding your test conditions correctly, it sounds normal.
I am suspicious of your power output vs plate current in Test #3
however. Assuming you are using an AC-4 Drake power supply?? If so,
nominal plate voltage is 650VDC. At 270 mA of plate current your input
power would be 175.5W. 120W output would mean 68% efficiency, which is
NOT typical of these transmitters. 60% or a little less is more
likely. The plate meter shunt is (2.7 ohms, 1/2W carbon comp) prone to
change value, but _usually_ goes UP in value causing the plate current
meter to read HIGH rather than low, as you are (perhaps) seeing. The
other possibility is that your W-4 is reading a little high. On the
other hand, 120W output is typical in TUNE mode.
When in the TUNE mode, the mic amp stage in the transmitter is converted
to a phase shift audio oscillator and the resulting tone is applied to
the transmitter. If you increase the GAIN control further, you will
find that the plate current continues to increase, and typically around
10:30 - 11:30 will stop increasing. This is the transmit ALC taking
over and limiting the transmit power.
If you switch to the CW mode, the ALC is disabled and you can continue
increasing the GAIN for a higher transmit power, adjusting the PLATE and
LOAD controls as necessary, to 140+ watts output on the lower bands.
ALWAYS adjust the PLATE control for minimum plate current as the LAST
step in tuning the transmitter. This should coincide with maximum power
output from the transmitter. If it does not coincide, then the
neutralization needs adjusting.
I would strongly suggest that you get a copy of the manual, either from
BAMA or the WB4HFN website.
73, Garey - K4OAH
Atlanta
Drake B & C-Line Service CDs
<http://www.k4oah.com>
[EMAIL PROTECTED] wrote:
Just purchased a TR-44B (decal on side) at a garage sale. Was told it
had been in storage since '85. Used a Variac (2days) to revive. The
receiver works better than I could hope for.
My knowledge of Drake equipment = zero. I did download the manual for
the T-4B transmitter. TR-44B Tune-up problem?
Settings TR-44B 40 meters 7.238 Gain- From the "On" position
until the 9:30 position there is no response from the RF Tune
control. At the 9:30 position, the RF Tune can be increased to a max.
of .15 plate amps. (Higher Gain settings increase the plate amps.)
Test #1 Test
#2 Test #3
Gain - 9:30 Gain -
10:00 Gain - 10:30
RF Tune - .15 amps RF Tune - .15
amps RF Tune - .15 amps
Plate control - 6 3/4 Plate control - 6
1/2 Plate control - 6 1/2
Load control - 2 1/2 Load control - 3
1/4 Load control - 4
Plate amps. - .18 Plate amps. -
.25 Plate amps. - .27
Wattmeter (W-4) - 40 Wattmeter (W-4) -
100 Wattmeter (W-4) - 120
Question - Do I have a problem with the Gain, RF Tune or should I
leave well enough alone?
Thanks
Bruce Wright WA5DDZ
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