IF Alignment using an oscilloscope and function generator as a poor man’s spectrum analyser

#003

IF Alignment using an oscilloscope and function generator as a poor man’s spectrum analyser
With grateful thanks to Dave Jones at EEVBlog, who’s video from 2012 gave me the idea to try this out .
See his original video at:-

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Other YouTube channels you may like to view:
EEVBlog - Dave’s unique style really challenges you to try things out and learn!

Mr Carlson’s Lab - Just excellent, very detailed and valuable advice and tips. From tubes (valves) to FPGA’s Paul really knows his stuff. I also have ‘lab envy’ he has so much excellent gear!

W2AEW - Lots of excellent material to keep you enthralled.

DL7MAJ Stephan - Yet more excellent content.

David Tipton - Restoration hints and tips from Australia, David does a first class job of restorations, electrically and cosmetically, well worth a watch!

Adrian’s Digital Basement - Mostly computer and monitor restorations, Adrian is a fascinating source of hints and tips. I like his fault finding style too.

[davidausterman]

Great video. Maybe you can set your scope to trigger on leading edge and set your sweeper to 1ms sweep rate. Match your scope horiz sweep rate rough, then go tweak your sweeper rate to fine tune one sweep per screen sweep.

[jeffreyyoung]

When I started out restoring my Hallicrafters SX-101, I was using a function generator and scope to look at the IF and crystal filter as well as the notch filter operation, until I had a accident with an IF transformer, which now needs to be replaced. However, when I get done replacing the IF transformer, I now have a Motorola R2001D spectrum analyzer with tracking oscillator to see the results. Hopefully, I have a good IF transformer to replace the broken one!

[jaceknowacki]

The VEF 206 has been produced in the Latvian Sovet Republic. Therefore it is a Soviet radio, but not a Russian radio. It is rather a Latvian radio.

[terryblackman]

That was very interesting. Thank you for sharing. Terry

[victorkustov]

Да, без синхронизации никак не получается. ГКЧ должен попутно выдавать синхроимпульсы или пилообразное напряжение. Тогда осциллограф начнет рисовать красивую АЧХ УПЧ.
Желательно отключать АРУ, или придется тщательно контролировать самый минимальный уровень RF.

[paulc]

I use this method Bill, but I prefer to use my CRO for alignments, nice video's

[rickeaston]

You can't afford a spectrum analyzer?? Tinysa is a very capable analyzer for $60. They have a new version out last month that is $120 with a bigger screen and more capabilities. Get one, you will like it.

[daleburrell]

...I was lucky enough to find an HP-3585A on Ebay, at a really good price.

[diego.alienigena]

nice video, that was a very interesting idea!

[ovi_]

Hi, great video. 've got a similar radio (OKEAN 205) but a little more complex in a sense that it has FM band as well (I believe that your doesn't) I could be wrong but...anyways. I wanted to say that @ 1:20 you're saying that these days you wouldn't be doing mechanical switches but rather use logic circuits Well, it so happens that for my radio in particular I'm currently searching for a practical way to achieve just that. In other words do you actually know of a certain LOGIC IC from the 74 series or ...whatever series that would do it? In my case, as you rotate the rotary wafer switch a number of "UP TO" 14 contacts are employed (depending on what band you're in at the time). So again, I'm looking for a practical hands on solution here if you happen to know one or can suggest what to try. I'm thinking, maybe there is a specialized (stand alone) IC that is purposely made for it or some large size IC style reed relays etc. One thing I'm trying to avoid here however, is using any microcontrollers in the radio simply because they are known to practically be noise generators especially for SHORT and MEDIUM wave frequencies. So the aim here is to possibly only use good old TTLs /CMOS IC's if possible. Any help or some pointers are more than welcome. Ta. PS: The idea wants to be more of a experimental achievement first and then later on (if the proof of concept work for my particular radio) to make a proper suitable PCB for it to have it implemented properly and permanently. I'm not interested in keeping the radio as original as possible but rather in achieving a vastly improved functionality for it and if successful to be able to adapt the "found" solution to other old radios (in the future) Thank You.

[beakytwitch]

Its called a turret tuner, and it contains tank circuits .

[jamescrompton]

Sorry to ask what may be dumb questions but can I ask what you set the sweep generator to? Centre Frequency, time for the sweep to take place. For an FM tuner with an IF frequency of 10.7MHz, is this the centre frequency around which the sweep takes place? How much above and below this is adequate? . And then what do you set the 'scope to?

[RockeyDAproductions]

damnit. my function generator requires an external signal to generate sweep.