- Original Message -
From: Alan Ibbetson a...@g3xaq.net
To: drakelist@zerobeat.net
Sent: Tuesday, September 25, 2012 10:49 AM
Subject: [Drakelist] R4C overall gain specification
I have the data I was seeking on R4C overall gain, thanks
to Steve Wedge W1ES/4. The original 1974 QST review gives
it as 0.1uV or less for 10dB S+N/N. Although my receiver
can detect a 0.1uV signal it's well short of that amount of
audio output, so it looks like I have some work to do to
find a bit more gain.
--
Alan Ibbetson
a...@g3xaq.net
Older receiver specs gave a minimum audio output level
for a given input level. This is useful for seeing if the
receiver is working correctly and is, I think, what you
want. The spec as given above does not specify an output
level so it really does not indicate gain. Its a typical
old style spec for noise level and is again useful for
checking a particular kind of receiver for normal function
but not much else.
The R4C book gives a spec of 0.7 watt of audio at the
AVC threshold and a minimum power output of 2 watts at less
than 5% THD. You can check the power output using a
resistor load and voltmeter but monitor with a scope to keep
from going into overload. 5% is just visible. Presumably,
the AVC threshold is where the S meter just begins to
indicate, or just a bit below that. I would do the S meter
adjustment procedure before trying this measurement.
If you find the receiver is really not up to snuff its
worth going through the entire adjustment procedure.
I think Garrey Barrell has a disc for the R4C and it
may have stage gain info, contact him about this. He is
_not_ on this list. www.k4oah.com
--
Richard Knoppow
Los Angeles
WB6KBL
dickb...@ix.netcom.com
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