[Milsurplus] thoughts on the SRR family of radios

[John Vendely]

That's a really interesting question, Ray.  The FRR-59 (one of my 
personal favorites) was a remarkable, electrically advanced and--believe 
it or not--mechanically compact design for its day.  But oddly, though 
its long-term stability was much worse, the R-390A had much better phase 
noise than the FRR-59, due to its crystal oscillators in the first 
conversions and its narrow tuning range, low noise PTO.  In the FRR-59, 
the phase noise of the tunable LC HFO phase noise was substantially 
reduced by the action of its drift cancelling loop.  But the limiting 
factor in the FRR-59 LO chain phase noise was the relatively high jitter 
of the blocking oscillator used to generate the 1 Mc spectrum.  Manson 
Labs dispensed with blocking oscillators for this reason, and patented a 
unique, low-jitter saturable reactor harmonic generator for their 
synthesizers.  I've found that the R-390A has better front-end intermod 
performance than the FRR-59.

So I guess the question of which is better depends on the exact 
application.  If you need the ultimate in long-term frequency stability 
for suppressed-carrier ISB, the FRR-59 wins hands-down. But in a very 
level high RF environment with large close-in interferers, the R-390A 
could have certain advantages...

73,

John K9WT

On 5/9/2016 4:31 PM, Ray Fantini wrote:
>
> But what’s better? The R-390 or R-390A variant or the FRR-59???? I 
> would think that the FRR-59 is a superior receiver in terms of phase 
> noise being that all injection oscillators are synchronous to a signal 
> time base. If working properly it appears that the FRR is far superior 
> to the R-390 with several time bases that are all non-related. Not 
> that up on the CV-591 and wonder if that sampled the LO and offset 
> oscillators in the 390 but that would be a challenge with all the 
> Rupee Goldberg conversion schemes  that take place in the R-390
>
> I have seen FRR-59 receivers at Dayton for around $250 and not much 
> interest in them when compared to the R-390A receivers that sell for 
> way more although have noticed in the past couple years the beat up 
> ones have been selling at around that price. The thing is that you 
> have a cult of R-390 people who somehow claim that to be the ultimate 
> radio where no one sings about the FRR-59.
>
> RF
>
> *From:*Nick England [mailto:navy.radio at gmail.com]
> *Sent:* Monday, May 09, 2016 2:58 PM
> *To:* Ray Fantini; Military Surplus Mail List
> *Subject:* Re: [Milsurplus] thoughts on the SRR family of radios
>
> Well, I wouldn't call the SRR-13 a "direct descendent" of the RBC as 
> that implies too much genetic material. It was a functional 
> replacement. I don't know if any of the RCA engineers worked on both. 
> It's possible I suppose.
>
> Here are some personal thoughts on USN rcvr evolution. No warranty 
> express or implied and I'd love to learn more.
>
> Bear in mind that the biggest revolution for the Navy post-war was the 
> switch to RTTY. There were huge advantages to doing this given the 
> Fleet Broadcast mode of operation and on-line crypto that the Navy 
> needed. So the SRR-13 was the first attempt at a shipboard rcvr that 
> would be stable and reliable enough for 24/7 RTTY service.
>
> The next step in Navy evolution was for synthesized frequency control 
> needed for VFCT tone-pack multiplexed multi-channel RTTY (85 Hz 
> shift). We hams tend to think of SSB for voice but that was pretty 
> secondary in navy thinking.
>
> So the Navy's next real step up was to the synthesized National WRR-2 
> (aka FRR-59).
>
> The R-390A was a transition rcvr in a way. It was far better than the 
> SRR-13 for RTTY and with the CV-591 did a fine job at SSB. It could be 
> used for multi-channel RTTY but I understand not normally and not 
> without occasional retuning. With a synthesized rcvr it was set and 
> forget.
>
> The WRR-2 was pretty expensive, big, and bulky so wasn't so widely 
> deployed. The R-1051 was the real answer to the Navy's need for a 
> synthesized receiver.
>
> It is somewhat amazing that the usual petty inter-service rivalry 
> didn't keep the Navy from adopting the R-390A in huge numbers, for 
> communications as well as intercept.
>
> So far as I know the Navy never had a program to develop anything 
> comparable to the R-390A. They just skipped that generation of 
> receiver architecture. They did fund Collins to develop a PTO-based 
> receiver as part of the URC-8 prototype but this was a sideline TCS 
> replacement, not a mainline fleet comms receiver.
>
> These observations may be worth exactly what you paid for them.
>
> Cheers
>
> Nick
>
>
> On Monday, May 9, 2016, Ray Fantini <RAFANTINI at salisbury.edu 
> <mailto:RAFANTINI at salisbury.edu>> wrote:
>
> I
>

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