Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Jim -
For anything less than heavy contest use on the low bands, the addition
of the 500 Hz or even the 250 Hz 2nd IF filter is plenty. The Drake
filters are fine, but they have gotten expensive enough that the Inrad
filters are not very much more and you get a little better, New, filter
without messing around with EBay!
The 8 pole, 8 kHz roofing filter is only a little better than the 4
pole, 8 kHz "stock" roofing filter. Sharper skirts, keeping a little
more "unwanted" RF out of the 1st Mixer, but again not really
significant in day-to-day use.
Personally, I prefer the 1.2 kHz filter for CW for normal use. I like
to know what is going on around my frequency, and get claustrophobic
with narrow filters! It IS nice to have the narrower ones very
occasionally when some "alligator" decides to move in "on" top of your
QSO! :-)
The best audio mod is to change C100 from 0.1 uF to 0.68 uF (or so) to
bring the low end audio up. The stock audio is a little "hissy" because
of a high end peak / low end rolloff.
For contests, especially on the low bands where you can have VOLTS of RF
on the antenna from two dozen, 2KW, 80 dB or 9 signals within the 8 kHz
roofing filter, the 600 Hz roofing filter and all the other Sherwood
stuff can help a LOT!!
The Sherwood 3rd mixer can be nice, since 6EJ7s have a tendency to be
noisy. You have to select, even from NOS tubes, to get a quiet one.
Once you do though, it will last for years. On the other hand, I've
seen more than a few receivers screwed up by improper installation of
this mixer!
I don't think the C can ever sound as good as the B, maybe it's that
"tube sound"! :-) Some even prefer the R-4A, claiming it sounds
better because even more stages are tube based. Shades of the audio crowd!
Just my opinion, worth exactly what you paid for it!
73, Garey - K4OAH
Atlanta
Drake C-Line Service Manual
<http://www.k4oah.com>
[EMAIL PROTECTED] wrote:
I'm lucky to have just aquired a C-line in very fine condition.
Ser #s are 24xxx and the rigs have been stored in plastic wrap for
years here in the high desert of NM. Most all of the tubes are
Sylvania and I get 140 watts from the T4XC.
The R4C rcvr is stock with a 1.2 khz plug in CW filter.
There were a few intermittent troubles which were cured with DeOxit on
the wafer switches.
The xmtr is equivent to by B-line rigs but the rcvr seems less than
an R4B ...
the audio is not nearly as pleasant, nor is the selectivity.
My question is:
as a CW op, what is the best cure for selectivity ?
I have read of the Sherwood mods and the Xtals from INRAD .....
I plan to order a 500 hz second IF filter from INRAD but am hoping for
suggestions
on the GUF-1 INRAD first IF 8khz filter. I wonder if it would be of
benefit to a CW guy
and wonder about the diffiulty of the modification. Anyone have an
any experience with that mod ?? Easy/difficult ... worth it for CW ?
Any ideas on the audio .... the R4B beats it HI !
any ideas welcome tks jim
N5KY
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