Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Gerry -
Yes, they are completely interchangeable. Same schematic and design.
Just a slight modification to capacitor values to change the b/w and add
the fourth position. They all use a novel design and it's amazing to
think that it was done with a slide rule, not a computer! I suspect
there were more than a few iterations involved!
The widest passband in the 4 Series was achieved by disabling the fourth
section entirely.
There was also a mechanical filter adapter offered by Henry Radio for
the 2-B using a Collins mechanical filter.
73, Garey - K4OAH
Atlanta
Drake R-4C Service Information CD
http://www.k4oah.com
Gerry wrote:
An interesting aside is that the L/C pass band filter in both the 2-B and
R-4 series below the C are interchangeable. I had a parts unit R-4B with a
good filter unit and transplanted it temporarily in my 2-B just for
curiosity. It worked fine but of course I would have had to make some kind
of switch plate for the front panel to identify the selectivity positions
and the tuning ranges. Instead I'm building a 2 section coupled resonator to
use on the 2-B strictly for AM reception. I don't like that 3.6kHz position
in the 2-B and modifying the filter unit for a wider pass band is not
practical.
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Garey Barrell
Sent: Wednesday, December 07, 2005 12:46 PM
To: Steve Berg
Cc: [email protected]
Subject: Re: [drakelist] 2B vs. R4B
Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Steve -
The 2-B Passband tuner has three L/C bandwidths available.
0.5 kHz at -6 dB // 2.75 kHz at -60 dB
2.1 kHz at -6 dB // 7.50 kHz at -60 dB
3.6 kHz at -6 dB // 10.5 kHz at -60 dB
The R-4/A/B all have four L/C bandwidths.
0.4 kHz at -6 dB // 2.6 kHz at -60 dB
1.2 kHz at -6 dB // 4.8 kHz at -60 dB
2.4 kHz at -6 dB // 8.2 kHz at -60 dB
4.8 kHz at -6 dB // 20 kHz at -60 dB
The R-4C has two crystal bandwidths standard.
2.4 kHz at -6 dB // 4.2 kHz at -60 dB
8 kHz at -6 dB // 28 kHz at -60 dB (Roofing Filter)
Optional filters were available.
250 Hz at -6 dB // 600 Hz at -60 dB
500 Hz at -6 dB // 1000 Hz at -60 dB
1.5 kHz at -6 dB // 3 kHz at -60 dB
Optional filters in AM Mode ONLY.
4 kHz at -6 dB // 7.5 kHz at -60 dB
6 kHz at -6 dB // 10 kHz at -60 dB
The 2-BQ Q Multiplier is a VERY effective accessory for the 2-B. It
offers a variable bandwidth, tunable IF peaking filter for CW or a
tunable IF notch filter. The Heath Q Multipliers work just about the
same, since the circuit is almost identical. The QF-1 requires power
(available from the 2-B Accy Jack).
73, Garey - K4OAH
Atlanta
Drake C-Line Service Manual
<http://www.k4oah.com>
Steve Berg wrote:
Steve Berg <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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How do the 2B selectivity curves compare with the R4B curves? I'm new
to Drake equipment and thought that the 4 series used crystal filters.
A thread here now tells me that this is not the case. Also, how well
do the 2B receivers work with Q multipliers like the 2BQ and the
Heathkit series? I use my 2B with a Gonset GSB-100 exciter, probably
heresy on this list, but they work well together on both CW and SSB
from my limited experience.
73,
Steve WA9JML
-
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