Folks
Does anyone have experience of the R4B as-fitted xtal fliter showing a -3dB
bandwidth of just 250Hz, from 5644.910 to 5644.660kHz
This suggests to me that only one crystal is in circuit, but I do not have the
circuit of what is in the can so I can be sure.
Is there a circuit available?
Gwyn,
Are you really meaning a R4B? I am fairly sure that the B series RX has an LC
circuit in the 60Khz range for its selectivity. I didn't think the RX had xtal
filters till the C series.
73,
Ron WD8SBB
--- On Sun, 7/18/10, Griffiths G. g.griffi...@noc.soton.ac.uk wrote:
From: Griffiths
Ron
The R4B does have a roofing xtal filter at the first IF. But you are right,
in that the main selectivity (at four switched bandwidths) is at the second IF
at 50kHz with LC filters. The problem here is that at the input to the second
mixer grid, the bandwidth is only 250Hz after the
Gwyn -
Certainly sounds like a bad filter. Can't say I've ever seen or heard
of one failing that way. Seems highly unlikely.
I'd start by just connecting a wire between the leads going to the input
and output of the filter, after disconnecting them from the filter itself.
The filter is
I can endorse the Panasonic Panaflo series. It is not only a quality fan,
it is relatively quiet.
Dennis AE6C
On Sat, Jul 17, 2010 at 7:55 AM, Jim Shorney jshor...@inebraska.com wrote:
On Sat, 17 Jul 2010 09:16:50 -0500, Don Cunningham wrote:
Evan,
Would you share the make and model of the
Garey -
Many thanks.
Linking across the (disconnected) filter brings the bandwidth to what one would
expect with just the IFTs at first IF. The selectivity is then properly
controlled at the bandpass LC filter as it should be.
I removed T6, the xtal filter can. There are only two xtals in a
Gwyn -
Very interesting. I've been fortunate to avoid this sort of problem in
almost 50 years of working on Drake gear! :-)
I would suspect T5 at this point as well because it's about the only
other thing around! I assume you have subbed a 12BE6, a 'shaky' tube at
best. I HAVE seen
Gwyn -
Sorry, read 'Plate-Suppressor' short below.
Very interesting. I've been fortunate to avoid this sort of problem in almost 50 years of working
on Drake gear! :-)
I would suspect T5 at this point as well because it's about the only other thing around! I assume
you have subbed a
WTB Drake TR4C +AC4
paypal , shipping to NJ
please offers to email
Thanks
Serge___
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I need a good working AC-4. I really do.
KB8NXO
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