[R-390] Sweep Generator Alignment

[Rodney Bunt]

R-390 gurus,

I have a HP-8601a sweep generator. It uses a voltage controlled oscillator and is quite stable. It
has a "symmetric" sweep IE: it sweeps equally up and down from the center frequency.

For Xtal Filters (or others) I find the center frequency of the crystal by putting the "peak" of
the trace on the oscilloscope in the center of the sweep. Then I turn off "sweep" the resultant
center frequency is the center of the Xtal bandpass, I use this frequency to tune the rest of the
IF, I have found Xtals up to 5Khz off frequency. So using this method you end up with the IF and
the Xtal filter in alignment, and a very usefull Xtla filter/phasing combination.

For "stager tuned" IF's you use the xtal center frequency and sweep "symetricaly" and obtain the
correct bandpass shape on the scope.

Rodney
VK2KTZ

  
--- Bob Camp <ham@cq.nu> wrote:
> Hi,
> 
> You inject the signal into the front end of the radio. Say you tune it to
> 600 KHz and also set the sweeper to 600 KHz. Then hook the seeper to the
> antenna input of the radio. You hook a scope channel to the diode load
> output on the back of the radio.The sweep output of the sweeper goes to
> another scope channel or the trigger output of the sweeper goes to the
> trigger input of the sweeper. A storage scope is a good idea since you will
> be sweeping at a rate of 10 Hz or less.
> 
> An alteranate hookup would be to unplug the IF input and inject the signal
> directly into the IF deck. The disadvantage of that is you will not be able
> to properly set up the first coil on the deck and you need a cable with one
> of the weird little connectors. You can get around both problems, but why
> .....
> 
> The Wavetek's are nice little sweepers. I have several various models of
> their stuff and use them from time to time. I generaly look at them as audio
> gear rather than RF. I don't know why I do, that's just me. The oscillators
> in them are R/C based rather than L/C or crystal based. That limits the
> stability of the output. I would not recomend trying to set up the CW
> crystal filter with one :)
> 
>     Take Care!
> 
>         Bob
> 
> 
> 
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