Kevin -
OK, that changes things a little. If you are not interested in hi-fi AM
audio, then the R-4, A or B would be good. Their maximum bandwidth is
4.8 kHz, which gives you reasonable bandwidth for ONE sideband. You
would zero-beat the AM carrier, and then turn the PB tuning to either
side to select which sideband you wanted to listen to. This gives you a
little more control over interference since you can pick the sideband
that is furthest from the noise! The 2-B would work the same way,
except that the max bandwidth is only 3.6 kHz, which is ok for comms,
but pretty restricted. The 2-BQ gives you a decent null or notch. The
R-4 any has an adjustable notch also.
The biggest advantage of the R-4s for you is that they are single knob
tuned, linear dials and accept a digital readout, and 10 crystal sockets
for auxiliary coverage of 500 kHz segments from 2 - 30 MHz. There is
one forbidden range, essentially from 5 to 6 MHz.
The R-4C is an entirely different receiver from the B. Major
differences between C and B are:
B has L/C IF filters, the C has crystal filters. The B has four
standard filters, the C has one (2.4 kHz) and each additional bandwidth
takes optional filters.
B has a Noise Blanker, the C does not, but one was available as an
optional accessory. Hard to find outside of a receiver today.
The biggest complaint in the comparison of the B to the C is that audio
of the C is considered a little 'harsh' compared to the B. The B has a
Class A tube AF amplifier, the C is a Class A transistor. There is a
simple mod that helps this quite a bit, but still not as 'smooth'. The
basic design of the C is the same as the B, just crystal filters instead
of L/C filters. This means that the skirts of the IF in the B are more
of a gentle slope, while the C's are much steeper.
I would still recommend a Timewave DSP-9 for AM use with just about ANY
receiver. Nothing beats its automatic notch for heterodyne suppression!
Your SX-99 would have been a good AM receiver, but suffers from the
'two-dial' tuning system.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-B, C-Line&
TR-4/C Service Supplement CDs
<www.k4oah.com>
Kevin Nathan wrote:
Hi All,
I really appreciate all the feedback I've gotten from the list so
far. It eases my mind that Collins, at least the newer models such as
the 75S series, is not the answer to what I am looking for. I would
also like to indicate here that I would like general coverage but a
few SW bands such as can be had with the crystals for the 2B or the R4
series can be equally rewarding. I am also primarily interested in
amateur AM vintage work with SW listening as a side interest.
I also need to note that size of the receiver is somewhat important
here due to the size of my operating table. It is approximately 18
inches deep, 48 inches long with a vertical operating space to the
shelf I built above it of 13 inches. and I need to set a D-104 mic
with the G type base in front of the receiver. I am also setting a
Heath HD-1410 next to the receiver on the right with the Ranger 2 on
the left. Therefore, a big receiver that is deep and over thirteen
inches high would not work. This effectively rules out something like
an R-390 or some of the later Nationals such as the NC-300 or NC-303.
The 2B fits here very well as did the Hallicrafter SX-99 I recently
sold as well as the Hammarlund HQ-110 I currently have sitting in a
corner of the shack. I have a feeling the R4 would fit quite nicely
here as well.
With this information in mind then, I do have a few more things I need
to ask the group. First, what is the major difference in performance
between the R4B and R4C models? Someone mentioned the C had a 6 kHz
filter one could use for AM but others seemed to feel the C isn't as
good. What performance factors lead to this conclusion?
Second, for those of you who have used the 2B, what is your suggested
tuning method for tuning AM? Is it better to set the band pass at
zero and then use the tuning dial to tune off on one side or the
other; or, to zero beat the signal with the main tuning knob and then
use the band pass tuning to move off to one or the other side band?
Finally, if I wish to sell or trade this 2B, is there anyone on the
list who wants one who might have a nice, working R4B or C who might
wish to trade with or without some cash involved? This 2B is in good
shape, has the 2BQ and 2AC with it and a copy of the manual. I have
crystals in it for 4.7 to 5.3, 5.7 to 6.3, 11.5 to 12.1 and have a
replacement crystal coming that will yield 9.4 to 10.0. I would be
interested in talking with anyone just to test the waters so to speak.
Thanks much all and very 73.
Kevin :)
Amateur Radio: K7RX
_______________________________________________
Drakelist mailing list
[email protected]
http://mailman.zerobeat.net/mailman/listinfo/drakelist
