Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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DW -
The primary difference between the R-4 and the R-4B is the number of
circuits that are solid-state vs tube. Functionally they are pretty
much identical.
The R-4 is very much like the 2-B with a linear PTO, all tube circuitry,
with just a couple of SS diodes. The "early" R-4A converted a few
stages to SS, most notably the PTO with a bipolar transistor, the "late"
R-4A a few more circuits went SS. The R-4B converted a few more to SS,
and the PTO to an FET. They all used a single frequency dial with 1
kHz marks on the knob skirt, the same Bandpass tuner, and the same basic
knob arrangement. The late A and all Bs used the color coded carrier
oscillator crystals to improve the "transceive align" stability with the
transmitter. Most agree that the late B is the "best", being the final
refinement of the design. It still had 10 tubes. Some claim the A has
a better (tube based) product detector and lower distortion, but I'm
hard pressed to tell the difference.
By comparison, the R-4C has only five tubes left.
The transmitters are all very similar, with similar improvements in the
PTO by going from tube, to bipolar, to FET. The only significant
change in the transmitters is the change from 4 pole crystal filters in
the T-4X to 8 pole in the T-4XB, improving the carrier and unwanted
sideband suppression. The T-4X SSB signal is a little "dirty" by
today's standards.
73, Garey - K4OAH
Atlanta
Drake R-4C Service Information CD
http://hr99.home.mindspring.com/R-4C_Servicez/
DW Holtman wrote:
Hello,
There has been quite a lot of information lately comparing the Drake
R-4C with the R-4B. Could someone please compare the performance
differences between the R-4 and the R-4A to the R-4B?
Thank you in advance.
73's
DW Holtman
WB7SSN
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