From: Garey Barrell 
Subject: Re: [drakelist] comparison of A, B and C lines


Garey Barrell  made an utterence to the drakelist gang
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The 2-B is an outstanding CW receiver, the dial calibration is a little
coarse by today's standards, but for just getting on the air and enjoying a
CW QSO it works as well as any.  It has three (L-C) filter bandwidths,
(500, 2100 and 3600 Hz,) built in along with passband tuning.  The 100 kHz
crystal calibrator was optional.  The companion 2-BQ Q Multiplier adds a
very sharp peaking filter and a nice tunable null, both at the IF.

There is no matching transmitter for the 2-B.

The R-4 is almost a 2-B, just with a linear PTO and 1 kHz dial calibration.
 All tubes.  Very similar in operation, and will
transceive with the matching T-4X for an excellent CW station.  Four filter
bandwidths, (400, 1200, 2400 and 4800 Hz,) passband tuning, noise blanker,
LC notch and 100 kHz crystal calibrator built in.

The R-4A (early 13 tube model) is an improved R-4, almost identical
specifications.  PTO and Band Oscillators converted to solid state.

The R-4A (late 11 tube model) almost identical specifications.  Product
detector, BFO, AGC and low level audio stages converted to solid state.

The R-4B (early) is very similar to the late R-4A, minor modifications and
crystal calibrator multivibrator for 25 kHz markers.

The R-4B (late) almost identical except PTO changed from bipolar to FET.

The R-4C (early) very similar, except IF filters changed to crystal
filters.  Only the 2.3 kHz filter is standard, 250, 500, 1800, 4000 and
6000 Hz BW are available as options.  The 4000 & 6000 Hz filters are
normally installed in a special socket under the chassis and is effective
on AM only.  Four position filter switch.  The noise blanker was optional. 
Entire audio chain solid state, tubes used only from RF to IF, all other
stages and oscillators solid state.

The R-4C (late) same.  Five position filter switch.

The 2-B through the R-4B used L-C filters in the IF.  This type of filter
has much gentler slopes, which means that nearby signals are still heard,
just at reduced levels.   The crystal filters are steep sided, more like
the crystal filters in today's receivers. 

Personally, I prefer the L-C filters for all except heavy duty contest use.
 I like to hear what is going on around my frequency, instead of
"listening with blinders on"...

The T-4 series transmitters are all pretty much the same, the T-4X had 4
pole crystal filters while the T-4XB and C had 8 pole filters.  The later
ones therefore had slightly better carrier and unwanted sideband
suppression, neither of which has ANY effect on CW operation. 

ANY 4 series receiver will transceive with ANY 4 series transmitter, mix
and match.  There are minor things like the B line had a neon indicator
light under the dial to show which PTO was controlling in transceive while
the C line just turned the dial lamps on or off.  The R-4 and R-4A had
neither, so you had to look at the switch!

My opinion.....  The R-4B is probably the best receiver overall.  It has
great audio, smooth AGC, all the filters and noise blanker are built in. 
The L-C filters are not quite as "drop off the table" selective,
but I prefer that for casual QSOs.

The R-4C has poorer audio, a little harsher, the "better" (?)
crystal filters are extra, and the noise blanker is extra.

The R-4 and R-4A are just earlier iterations of the R-4B, and are not quite
as refined, although some say they prefer the early R-4A to the R-4B
because the tube type product detector in the R-4A is "cleaner".

The 2-B isn't very far behind, except it will NOT transceive with anything,
and the dial calibration is not precisely linear.

73, Garey - K4OAH
Atlanta



Bruce P. Tis wrote:

> I’m just getting back into Drake ownership, after having a TR4C and 
> “C” line in the 1970’s. R-4A’s and T-4Xs are quite plentiful and 

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