Ron -
I wondered about that. Watching the display on Spectrogram, there is
essentially no drift when the A/C kicks on and blows cool air into the
room. There is not a vent blowing right on the receiver though. Room
temperature only varies a degree or two.
The R-7 has been running for about seven hours now, and the spectrogram
display is just slowly wandering about +/- 20 Hz. Enough to make a
difference in an SSB signal, negligible for CW. So overall it took
about an hour to settle down, about 500 Hz from cold. Not bad for an LC
oscillator with no temperature control.
There is nothing wrong with a well engineered improvement to a radio.
Personally I prefer to keep the tube (4 Series) all original since that
is the way I've used them since 1965 or so and they are perfectly
adequate for my type of operation. The B-Line is my 'daily driver', as
I think it's the best of the breed. But if I was a low band contester
I'd be more inclined to a Sherwood C-Line or a K3. If the QRM is bad
enough, (hardly ever happens these days except during a contest,) then I
can switch to the Kenwood 940 or the TR-7/R-7. I suppose if I was
interested in PSK31 or other digital mode the B-Line wouldn't work out
too well, although it's the same PTO as in the TR-7. I certainly ran a
LOT of RTTY with them.
As my Baby Sister used to say, "tweechies own"!
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-B, C-Line&
TR-4/C Service Supplement CDs
<www.k4oah.com>
Ron wrote:
FWIW, my TR7 it sensitive to the house's temperature. If the house is
about 72-73 degrees, the rig comes on and pretty well stays put but
does still move. OTOH other temperatures during the winter or summer,
and the thing drifts for about an hour before settling to a tolerable
but noticeable drift. I have never taken the time to reference/measure
the amount of drift, just that it is noticeable on QSOs (either that
or everyone else is "always" drifting). I typically have the RV7
doing frequency control as it seems to settle down sooner and run more
stable than the rig.
At some point, when I get the time, I am going to install a DAFC. I
am a semi purest, but well engineered and executed mods are designed
to make the rig better. If that offends the true purest, well I guess
you can undo my mods when you own my rig.
73
Ron WD8SBB
--- On *Wed, 9/15/10, Garey Barrell /<[email protected]>/* wrote:
From: Garey Barrell <[email protected]>
Subject: Re: [Drakelist] Drake 7 line drift
To: "drakelist" <[email protected]>
Date: Wednesday, September 15, 2010, 3:43 PM
Evan -
No WWV here with my indoor antenna, so using an Elecraft XG-1
signal generator on 7.040 MHz. Turned it on for 10 minutes,
although I don't think it moves much as the internal dissipation
is so low. Then turned on the R-7, cold start, and tuned in the
XG-1 for a ~600 Hz tone. Using Spectrogram. It's been running for
20 minutes so far and has smoothly increased a little less than
200 Hz. No sign of leveling off yet.
After an hour, it's stopped. Drifted ~600 Hz from cold start, and
the last 15 minutes it's moved 5 Hz. I don't know how to go back
on the 'strip chart' without stopping Spectrascope, so can't tell
exactly where it 'stopped'. I only have about 15 minutes
on-screen, but once I have the file, I can scan through it.
I set the 'range' from about 400 - 1100 Hz on screen.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-B, C-Line&
TR-4/C Service Supplement CDs
<www.k4oah.com>
K9sqg wrote:
> Fellow Drake Enthusiasts,
>
> The discussion of the VFO stabilizers prompted me to describe what I
> have observed about 7 line PTOs over the past 25 years or so.
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