EMRFD Message Archive 3244
Message Date From Subject 3244 2009-06-27 20:01:47 Paul Anderson Wobulator? My father studied for his electronics technician diploma in the
1960s, and he told me of something he remembered regarding the
earliest days of FM.
The name he remembered was "wobulator". It varied the output
frequency by having a small motor with a crank turn a variable
capacitor back and forth. Does anyone remember this device?
3245 2009-06-27 20:21:31 Graham / KE9H Re: Wobulator? Some time ago, I purchased a Korean war era airborne radar jammer
for parts, that used a "Wobulator." It was a motor driven continuous
capacitor that tuned a power oscillator up and down in frequency
as one of its several jamming modes. I am not aware of a civilian use for
3246 2009-06-27 20:31:33 David L. Foreman Re: Wobulator? ----- Original Message -----
3247 2009-06-27 22:33:20 kerrypwr Re: Wobulator? The wobbulators (note spelling) that I know were sweep generators used mostly to align IFs.
I've never seen a mechanical one but I'd heard that they existed.
Here is a nice old one;
I built one from a Practical Wireless article a long long time ago. It had a fairly narrow sweep width centred around 450kHz or so.
3248 2009-06-28 04:48:11 joe price Re: Wobulator? 3254 2009-06-28 08:36:40 Chris Trask Re: Wobulator? >In the second world war, radar jamming was overcome by way of a wobulator that consisted of a gearhead motor with a cam on the shaft. It would rub against the klystron tuning lever to vary the frequency.
>My father studied for his electronics technician diploma in the
>1960s, and he told me of something he remembered regarding the
>earliest days of FM.
>The name he remembered was "wobulator". It varied the output
>frequency by having a small motor with a crank turn a variable
>capacitor back and forth. Does anyone remember this device?
,----------------------. High Performance Mixers and
/ What's all this \ Amplifiers for RF Communications
/ extinct stuff, anyhow? /
\ _______,--------------' Chris Trask / N7ZWY
3262 2009-06-29 15:09:28 Neil Douglas Re: Wobulator? Paul,
I remember in the 1960's using wobulators to align TV's.
I have used a French Metrix unit this used a small synchronous motor
spinning a permanent magnet over a ferrite cored coil. It covered HF through
to about 200MHz, I remember using it to align my first 2M convertor made
with selected 2N3819's.
Other wobulators I used during this period were British ones made by Cossor
and Samwell and Hutton both these used electronic tuning.
The ultimate alignment aid I used during this period was a Rhode & Schwarz
Polyskop - beautifully made and a serious contender as the ultimate boat
3265 2009-06-30 06:54:50 Dave Re: Wobulator?