Modern Superheterodyne Receiver Intermediate Frequency, Triple Conversion to 455khz , or what?

Thread Starter

Fran3

Joined Mar 28, 2019
38
Many years ago the great ham radio receivers often used triple conversion to get down to the Intermediate Frequency... if I remember it right.

And, I think they mostly converted down to 455kh as the Intermediate Frequency.

I'm wondering how modern receivers process the received RF signal until it is demodulated.

Thanks for any info.

Janis59

Joined Aug 21, 2017
1,488
Ya, I always have been braining WHY western devices have 455 kHz whilst soviet devices have 465 kHz? Or there are no idea beyound only let it be anotherhow.

RE NsaSpook - My HackRF1 is worth to pay device, but those cheap USB stich is just the crap, its sencitivity is very low, noises criminallt high, and boosting the sensitivity by softwereadjusting givs catastrophy or in the speed of computer or blast of Nyquist noise. Never buy it for 5 USD.

nsaspook

Joined Aug 27, 2009
10,427
Ya, I always have been braining WHY western devices have 455 kHz whilst soviet devices have 465 kHz? Or there are no idea beyound only let it be anotherhow.

RE NsaSpook - My HackRF1 is worth to pay device, but those cheap USB stich is just the crap, its sencitivity is very low, noises criminallt high, and boosting the sensitivity by softwereadjusting givs catastrophy or in the speed of computer or blast of Nyquist noise. Never buy it for 5 USD.
I would never use one as a professional receiver but as a general spectrum monitor (RF leakage detection using a cheap laptop) they do have a place in the field because they are low-cost and easily replaceable if lost or broken.

Janis59

Joined Aug 21, 2017
1,488
NsaSpook - Yes, me too, but there is one VERY disturbing nuance - if set the most widest screen resolution, the one screen drag by cursor means some 100kHz shift. For few MHz that is not a problem. But for many GHz its a hour to sweep say from 1 up to 2,4 GHz. Why they not programmed that all frequencies stands in the solely screen?

nsaspook

Joined Aug 27, 2009
10,427
NsaSpook - Yes, me too, but there is one VERY disturbing nuance - if set the most widest screen resolution, the one screen drag by cursor means some 100kHz shift. For few MHz that is not a problem. But for many GHz its a hour to sweep say from 1 up to 2,4 GHz. Why they not programmed that all frequencies stands in the solely screen?
There are SDR scanner programs that generate full spectrum scans much faster than that but if you want speed, it's costs money.
https://www.rtl-sdr.com/

Janis59

Joined Aug 21, 2017
1,488
Yepppsk. But my religion not allows to buy ANY software product. Any discussion against religion are fruitless. Religion`s name is Creative Commons.

Janis59

Joined Aug 21, 2017
1,488
PS: none have commented why Wild West uses 455 kHz but communists East uses 465 kHz. Or none have no an idea why?

nsaspook

Joined Aug 27, 2009
10,427
PS: none have commented why Wild West uses 455 kHz but communists East uses 465 kHz. Or none have no an idea why?
Maybe for the same reason the old Soviet bloc used 7.62x54R (.311) ammo that was slightly oversized for our .308 weapons. They could use our captured ammo in the Soviet weapons in a jam but we couldn't use their stuff.

MrChips

Joined Oct 2, 2009
27,168
Or like Spanish railway gauge was 5'6" while French gauge was 5' to prevent the French from invading Spain.