[R-390] Stability

[wb5uom at hughes.net]

My R-390A has been ON continously now for about 3 years
being run thru a Tripp Lite 12 volt Inverter/Charger.
With a couple of exceptions where we had a power failure that lasted for 
several hours
where I turned it off.
The Tripp Lite makes a great surge protector.
The R-390A just sits there on frequency, I dont remember the last time I 
tweaked the frequency,
as I ususally leave it parked on 8903 KHZ

The power fluctuations here in the Country are numerous and have in the past 
been wild.
I run the PC , sattellite modem, other radios etc all thru the Tripp lite.

David / WB5UOM


----- Original Message ----- 
From: "Roger Ruszkowski" <flowertime01 at wmconnect.com>
To: <R-390 at mailman.qth.net>
Sent: Saturday, June 01, 2013 6:12 PM
Subject: Re: [R-390] Stability


>
> Gordon,
>
> In the day the military turned the receivers on and left them on
> for ever. I was common to come time for a 6 month preventive maintenance 
> PM
> and find the micro switch was stuck on and the receiver would not turn 
> off.
>
> The only time we experienced warm up drift was after this PM and we
> put the receiver back in the operators rack.
>
> But it is a tube radio and has a thermal mass that needs to come to
> temperature.
>
> R390 and R390/A are and were considered as stable as you
> could get with the technology.
>
> Give yours a 1/2 hour and it will warm up and settle down.
>
> If it does not, consider the tubes first. Todd's point on the
> VFO 701 is to be taken as serious. Not all tubes are
> equal and it is worth swapping tubes around not just for
> the signal to noise but for these drift problems in the
> oscillators.
>
> There is a ballast tube in the VFO and  BFO filaments.
> It is there by design.
>
> You have to ask your self, Self how stable is my
> power voltage. I lived 20 years in LA and San Diego
> counties. Brown out was common during the hours
> I wanted to operate my R390/A. So a little drift that
> would be obvious with CW was present.
>
> But it was not a problem with the receiver per say.
>
> It will be hard to judge if the drift is in the receiver tubes. In
> a ballast tube with a bright spot. Or in the power line variations.
>
> Roger AI4NI
>
>
>
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