On Oct 17, 2004, at 1:34 PM, NW7US, Tomas wrote:
Hi,
I am wondering if there is an error in the tuning instructions for the
Ameritron AL-80A in my copy of an old manual.
It states:
8. Apply only enough drive to indicate a grid current of 50 mA or an
Ip of no more than 200 mA. Tune the PLATE control for maximum grid
current. It is normal for the plate current to dip at this point. If
the grid current goes over 100 mA reduce the drive at once. Unkey the
exciter.
Ok - the part I am wondering about is "Tune the PLATE control for
maximum grid current." It seems, in every band that I do this
procedure, there is no "maximum" on the grid meter - but there is ONE
spot that is a DIP in readings. And, this is where the power out on
the watt meter increases. In other words, no matter where I move the
PLATE control, the grid meter level stays about the same, except for
one tuning spot where the grid current DIPS - and this is where I
notice increase power out... so either the manaul is misleading me, or
I am doing something incorrectly.
I'm just learning the Amp, and I am not an Amp user - this being my
first Ameritron, and second Amp I've ever operated. I am wishing to
operate the Amp properly so I don't ruin the equipment. Any pointers
would be appreciated.
Tomas - -To tune up a g-g amplifier, apply maximum drive, tune and load
for maximum relative output. Observe anode-I. It should not exceed
the rated maximum. If it does and you have an adjustable output level
transceiver, adjust the level for the rated max anode-I and retune. If
your transceiver output is not adjustable, add some R in series with
the cathode coupling C so that the tube will not be over driven.
- end
Thanks,
73 de Tomas, NW7US (AAR0JA/AAA0WA)
: Propagation Editor for CQ, CQ VHF, and Popular Communications :
: Creator of live propagation center - http://prop.hfradio.org/ :
: Member, US Army Miltary Affiliate Radio Service (MARS) AAR0JA :
: 122.93W 47.67N / Brinnon, Washington USA - CN87 - CW/SSB/DIGI :
: Website, software, database design - http://newwebmakers.com/ :
: Washington State Army MARS, State Army MARS Director - AAA0WA :
: 10x56526, FISTS 7055, FISTS NW 57, AR Lighthouse Society 144 :
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Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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