[Johnson] Ranger adventures live on

[Jim]

I changed ALL the capacitors and a few resistors in the VFO box.
That took care of most of the problems, but it IS going to drift.

Jim

> Hi,
> 
> I haven't posted about my Ranger for a while. I have been using it on
> 160 and 80 meters. The VFO hasn't sounded good enough to use on 40 and
> higher frequencies. I started work on it again today. I examined the
> drift problem more closely. I used my digital, general coverage Ten Tec
> receiver to evaluate drift. The Ten Tec tunes in 50 Hz steps but
> displays in 100 Hz increments. Normal hearing response makes 50 Hz
> differences at zero beat pretty much indistinguishable. So I have that
> and the fact that the Ten Tec is tuning in those digital steps while the
> Ranger tunes (and drifts) continuously variable. I decided that my
> readings could be no better than +/- 75 Hz and recorded all of my
> readings at the 100 Hz steps. That could be 25 Hz of 175 Hz. Even
> listening above zero beat and below zero beat then splitting the
> difference leaves some ambiguity. Especially if the the VFO is drifting
> as much as this one on 40 meters.
> 
> First a warmup. Even though it's digital the Ten Tec had been on 48
> hours. I let the Ranger warmup a half hour. I pulled the buffer and
> doubler tubes as I have some suspicions about those on 40 meters. So it
> was just the VFO with no load. Forty meters started drifting upward
> immediately. After a half hour it was 2200 Hz high and still drifting
> upward. The rate did slow down after about ten minutes key down. It was
> 1200 Hz high at that point. And 300 Hz at 2.5 minutes. Without plotting
> the drift, the drift was about the same as the night before. Clearly
> that is completely unacceptable for on air use. It would be outside most
> ham receiver passbands at 2.5 minutes AND on top of the next QSO. I
> turned the VFO off and let it cool back down. It did not come all the
> way back to the start point after ten minutes.
> 
> Next I checked to see that the 160 meter VFO (160 and 80) worked as well
> as I thought. I set it up on 80 meters and locked it on. At 12 minutes
> it was 100 Hz high (+/- 75 Hz) and stayed there for more than a half
> hour. I believe the error was on the small side and was less than 100 Hz
> of drift with the key locked down. I almost did not notice that it had
> drifted at all. Also keying on 80 and 160 sounds very good. It's lousy
> on 40.
> 
> I have looked at the circuits and I see there are only a very few parts
> in the VFO that are in use on only 40 meters. I will order a complete
> set of those parts and take the Ranger apart far enough to work on and
> and test the VFO. I will not do that until *AFTER* I have a transmitter
> online to fill the gap it will leave (maybe the DX-100). Meanwhile, I
> have removed the VFO switch dog so I can use the 160 VFO on 40 meters
> (all bands really) and that seems to be working but with somewhat lower
> power - as expected. VFO calibration is changed for 40 meters as well -
> also expected. The 40 meter signal sounds very good and the drift is not
> noticeable in operation. That gives me 160 through 40 on the Ranger and
> it may also work on 20 but I don't go there very much. Does anybody have
> hard information regarding a reason to NOT do that. I am not using the
> Johnson VFO to determine my operating frequency as I have much better
> means in the receivers. Some of the radios I have or have used already
> operate the 40 meter band from a 160 or 80 meter oscillator. None of
> them operate 20 meters (or higher) from anything less than a 40 meter
> oscillator but I suppose that would work with even less power out. To be
> clear about the question..the bandswitch and everything from the buffer
> on is operating with it's bandswitch on 40 meters - NOT on 80 or 160.
> 
> 73,
> 
> Bill  KU8H
> 
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