[R-390] R390A / R390 help

[Helmut Usbeck]

R-390a has a better "front-end" than an r-390non a.

----- Original Message -----
From: "Roger L Ruszkowski" <rlruszkowski@west.raytheon.com>
To: <r-390@mailman.qth.net>
Sent: Thursday, January 24, 2002 12:50 PM
Subject: Re: [R-390] R390A / R390 help


>
> Hello Everyone,
> I have a question, how does the R390 and R390A compare as to sensitivity?
> 73's Lee.
> -----------------------------
> Lee,
>
> From 68 through 75 I took care of many thousands of R390/a and a few R390
> all around the Pacific Rim. I have found either species of receiver to be
> about
> equally insensitive to GI's, Sailors, Marines and Airedales. When falling
> on
> fingers and feet I have never know a receiver to apologize for the clumsy
> act.
> The receivers are prone to popping a tube filament open at the most
> inopportune
> time with out a care as to how it impacts our plans. The receivers will
> split a
> gear clamp or strip a spline screw at the though of a maintenance
> procedure.
> These receivers can be as insensitive as any other living pet. I think the
> 47 Ohm resistors in the R390 power supply circuit can treat you with even
> more contempt than any cat I have known.
>
> Text book wise the receivers are equal in receiver sensitivity.
> Having cared for and watched op's use them for years of military service
> the two are so close you can not tell them apart.
> An R390 and an R390/A set up side by side in rack and coupled to some
> of the best antenna the Military could build yields equal number of
> signals.
> One is not more hard or hearing than the other.
>
> The mechanical filters in the R390/A ring. The stock R390 sounds a
> little better on AM than the R390/A  The two stage R390 RF does
> not produce any better response in the head phones than the
> single 6DC6 in the R390/A RF amp.
>
> Ethiopia, Turkey, Berlin got the first R390's. The R390/A went to
> Viet Nam, Okinawa, Japan, Korea. I had R390's in Korea with
> 28 Volt DC power supplies that were run off the 28 Volt truck
> generators. We had gas engines and heavy duty generators
> in the 2 1/2 ton trucks. The trucks had cargo boxes (vans) mounted
> on them and filled with radio's. You could run the radio's off the
> truck generators (battries). We also had smaller engine generators
> that used a lot less gas and were much quieter than the truck
> engines.
>
> These things were mostly in retirement by 1971 in Korea.
> But hey there was a war on over there and had been since the
> early 50's so we were ready to go to the field.
>
> Worry not if its a R390 or R390/A, you do not have enough
> of them either way. Keep what you can get.
>
> Roger KC6TRU.
>
>
>
>
>
>
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