[TMC] GPR-90 RXD Tuning

[Nick England]

CU-1280 manuals are hard to come by - anything associated with the
AN/FRD-10 is hard to come by.
Someone on the premium-rx list did some measurements (see below) - I was
surprised to see that it doesn't cut off below 2mc as a lot of HF mil stuff
does.

The TMC AMC-8 manual says 2-32 mc coverage (+2dB gain) with at least -30dB
rejection 0-1.4mc

Cheers,
Nick England K4NYW
www.navy-radio.com

FREQ CU-5069 CU-1280
150 kHz +5 dB +0 dB
250 kHz +7 dB +2 dB
400 kHz +7 dB +5 dB
550 kHz +7 dB +8 dB
750 kHz +7 dB +11 dB
1.0 MHz +7.5 dB +12 dB
2.0 MHz +7.5 dB +9 dB
3.0 MHz +5.5 dB +8 dB
5.0 MHz +4.0 dB +0 dB
7.5 MHz +2.0 dB -
10.0 MHz +3.0 dB +2 dB
12.5 MHz +5.0 dB -
15.0 MHz +7 dB +5 dB


On Fri, Mar 14, 2014 at 1:59 PM, W2HX <w2hx at w2hx.com> wrote:

> Hi all,
>
> Unfortunately, much of this discussion is over my head, but I wanted to
> ask the following.  I have a GPR-90/GSB-1 set up (several of them!) I am
> just now building a new shack and redesigning everything. As part of the
> redesign, I am considering putting a multicoupler in front of all of the
> receivers. I have two, one is a CU-1280/FRD-10A and the other is a TMC
> AMC-8.  I don't have the technical specs of either of these in front of me.
>  But I believe the AMC-8 has a BCB notch filter in it (again, not 100%
> sure).  If this turns out to be correct, should this improve the receiver's
> performance and would there have been any technical benefit in re-instating
> the first RF stage for this band now the overload from BCB stations should
> have been reduced? Not to say that I would attempt to modify the radio, but
> if TMC was designing the radio with the expectation of an AMC-8 in front of
> it, for example.
>
> And unrelated to this topic, does anyone have any documentation on the
> CU-1280 and whether it might have any notching in it?
>
> Thanks
> 73 Eugene W2HX
>
> -
>