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Old 2nd Dec 2022, 6:23 pm   #319
G0HZU_JMR
Dekatron
 
Join Date: Sep 2010
Location: Cheltenham, Gloucestershire, UK.
Posts: 3,077
Default Re: 6-gang FM stereo tuner heads

Quote:
Thanks. Sounds like a good idea. Please correct me if I misunderstand your idea:
Take tone spacing of 50khz, f1= 10.65, f2=10.75MHz. You measure the f1, f1, 2f1-f2, 2f2-f1 in four steps sequentially,
That's the idea although I spotted that you have 100kHz tone spacing in your example. That's still fine as long as you work out the correct frequencies to measure in each case.

Quote:
What do you think of the Marconi 2019 sig gen?
I've got two of them here and I've been using 2019 sig gens since the 1980s at work.

Sadly, these generators have reliability issues. They don't have any fan cooling and it's easy to block the cooling vents underneath the sig gen. They then tend to run a bit hot, and this shortens the life of the electrolytic caps inside. The PSU and transformer are weak points in the design and can fail.

When the caps start failing the sig gen will produce quite a few low-level spurious signals on the output. The output mechanical step attenuator can get sticky and intermittent if not used regularly. For these reasons this sig gen probably isn't a good purchase in 2022 unless it has been serviced or the price is very low, and you don't mind doing the work yourself.

The RF performance is quite good, with low phase noise across the 2.5-50MHz range. Above about 520MHz it uses a doubler and the phase noise is relatively poor above 520MHz. The RF levelling accuracy is very good up to about 520MHz. Above this the levelling is fairly lumpy and it gets worse above 900MHz.
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Regards, Jeremy G0HZU
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