[R-390] wow... the R-391A does exist

[Barry Hauser]

I have a couple of '391's and had the autotuners working -- for a short 
while.  If I were to let one of them just run on (I pulled the plug), it 
would probably self-modify the 10-turn stops to infinite-turn and 
theoretically tune the RF deck to UHF, or maybe even Wi-Fi ;-)

>From what I've heard, most of the '391's never, or hardly ever, had their 
autotuners in use.  Of course, they require a heavy-duty 28 volt DC supply, 
but there's another thing.  The motor is fairly high rpm and geared down. 
Sounds like a mixmaster or an A/C (not rechargeable) drill -- and no 
wonder -- motor is courtesy of Hamilton-Beach.  The PTO, it's gearing and 
the RF deck is stock, but the R-390/URR -- "the man's radio" -- has somewhat 
heavier components.  Even so, it puts some stress on things.

In addition, it makes a racket and quite a bit of vibration -- not too kind 
to tube elements and some other components.  Not great for coils and 
trimmers, nor probably crystals, for that matter.  An even greater 
consideration with mechanical filters, in the case of an "A" rendition. 
Probably a good idea to have a few spares of those and maybe a dozen extra 
ballast tubes on hand.

I don't know if such considerations helped put the cabosh on the R-391A such 
that only 2 were made -- or did even those get fully completed?  While the 
autotune is an interesting curiosity -- and does work when it works on the 
'391 -- it isn't all that practical.

Downright scary when you fire one up.  ("Omigosh!  What's that thing doing 
to my radio!  So much for that RF deck alignment I just did!")

If you want to get an idea, just remove either or both of the MC and KC 
knobs from your R-390A or R-390, chuck up one of the shafts in your old 3/8" 
Black 'n Decker variable speed drill, and give 'er a spin.

Barry




----- Original Message ----- 
From: "Les Locklear" <leslocklear at cableone.net>
To: <paul at pdq.com>; <r-390 at mailman.qth.net>
Sent: Sunday, April 09, 2006 10:52 AM
Subject: Re: [R-390] wow... the R-391A does exist


> The existence of that particular experimental R391A has been known for a 
> while. There more than likely not a "small handful" to be found anywhere. 
> This prototype and possible one more exist.
>
> All of the R390X, R-725 were originally built with the X or XC designator. 
> Looks rough as 40 grit sandpaper to me. YMMV
>
> Les Locklear
> Monitoring Since '57
> Located On the Gulf of Mexico
> Gulfport, MS.
> http://www.hammarlund.info/homepage.html
>
> ----- Original Message ----- 
> From: "Paul H. Anderson" <paul at pdq.com>
> To: <r-390 at mailman.qth.net>
> Sent: Sunday, April 09, 2006 8:38 AM
> Subject: [R-390] wow... the R-391A does exist
>
>
>>
>> I would not normally post 'seen on ebay', but this is absolutely 
>> astounding.
>>
>> There's an R-391 XC-2 radio on eBay - item # 9710078628.
>>
>> I think I about had a heart attack when I saw it (I'm a big fan of 
>> R-391's).
>>
>> I asked the seller to list more pictures of the autotune area - hopefully 
>> we can learn more about it.
>>
>> No relationship to the seller...
>>
>> Paul
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>
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