"David & Chris Drake" <[EMAIL PROTECTED]> made an utterance to the drakelist
gang
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Rich,
Forget the mic for the time being. Do this first: Most of the three tube
TR's with fresh finals will/should show between 180 and 200 watts out on
40m. Tune it up this way: ......Set the mic gain at 10:00. Set mode to
the x-cw position and, watching the wattmeter (any will do), adjust the load
and tune for maximum output, as well as the RF tune control (peak all
three). Don't leave the rig in x-cw for more than a few seconds at a time.
Again, using the wattmeter only, peak all three controls by placing the rig
in the x-CW mode. This is the lock down/key down tune up position. Once
you have peaked the rig here, key the mike and speak into the microphone in
a normal voice and adjust the mic gain up or down from the 10:00 position
previously set, until you see a small amount of movement upscale on the rigs
meter. This should be about right for SSB work. It aslo means that the agc
is in engaged.
As an example, a D-104 or a Shure 444d, both high impedance mics, will be at
the correct setting at about 10:00 +/-. A low impedance mic just won't
work. Most any of the shure mics will work fine with a drake if they are
high impedance. The rig does like impedances of upwards of 50k ohms, but
generally, anything above 10k or so should work, just not sound as well as
the others. Some of the Shure hand mics also work very good. I believe one
was the 404?. But in the day of mobil operation with these jewels, that was
the mic of choice.
Another check to make, if the chosen mic does'nt seem to provide output on a
peak reading meter, put the rig is x-cw and move the mic gain back and then
advance it. At the point where no further ouput is seen, you are set about
right. Normally, you want the gain control back just a tad for SSB to avoid
overdriveing the audio. The AGC circuit should be in control, but with
older rigs, it may not be up to par, so for best operation look at your rigs
meter and adjust as previously stated.
Once you have the rig tuned to max output as above and set the mic gain as
indicated, you should see the output suggested above. If not you have
another problem. If output is ok, move on to solve the mic question.
Remember, if you have a rig problem, no mic is going to work right. So
check the rig first.
Good luck,
David
Wd9cmd
----- Original Message -----
From: "Ron Wagner" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, January 21, 2008 5:34 AM
Subject: RE: [drakelist] Microphone question
Ron Wagner <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Rich,
The radio is a 300 watt INPUT radio. At the best linear efficiency you
could expect ~60% output on the radio, or 180 watts peak. I know there
are those who say they get way more then that reading, but they are either
running into an uncalibrated meter, or are putting more the 300 watts into
to the rig. And I can see the hate mail coming on this :-)
I would do the following: 1) you know you have an improper mic impedence,
get that fixed. 2) see how many watts are coming out in CW mode.
#2 will get you and idea how good your RF chain is in the TX. I would
expect about 150 watts OUTPUT on CW. That should be easy to measure, but
don't leave the rig in CW mode "key down" too long. The sweep tube finals
are not made for "key down" duty. Seems to me that the TR3 did not need a
key in the jack to be "key down" aka the key jack is closed by default.
Was easy way to tune the rig as I recall.
#1 will get good audio into the radio. Then see what your peak reading
watt meter says. BTW, do both the CW and the SSB on peak reading mode of
the meter. Peak reading modes are basically a "hang" amplifier. Charge a
cap and use its voltage to driver the meter via a set of internal amps.
The peak on CW, is *basically* what you would expect to see on peak of SSB
if your meter is working correctly. Also, for CW on peak, you should see
you meter go up quickly on keying the rig, and then slowly go back to 0
when you let off the CW carrier. If it does not, then your peak meter is
not working as I would expect it to.
73,
Ron WD8SBB
On Sun, 20 Jan 2008, Rich Carter wrote:
"Rich Carter" <[EMAIL PROTECTED]> made an utterance to the drakelist
gang
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Ron
I'm using a Daiwa HF wattmeter on the peak setting. While I realize the
meter should show a low reading, I would expect that a I should need to
reduce the RF gain from max to prevent overdriving the rig. Since the
rig
lacks speech compression, I don't know what I should measure, but I would
expect a 300W rig to drive at least 10W or or more. What do others see
on
their meters?
It seems to me that the collins mic I have is not matched properly. I
have
my hands full alignment issues. It may be best for me to replace the mic
with something that is known to work with this rig.
Rich - KE1EV
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