Standard IF frequencies

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Standard IF frequencies

Post by jollyrgr » Sun Sep 11, 2005 2:23 am

Does someone have a source (or know) what the standard IF frequencies are? I know AM radios normally use 455kHz, FM radios 10.7MHz, some scanners 10.8MHz, and some CBs used (I believe) 7.8MHz. In satellite systems they use 5150 MHz and 10750 MHz as the IF for the C and Ku LNBs. Cable TV "head end" systems use a 70MHz IF for a loop out.<p>What are some that I am missing?
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Re: Standard IF frequencies

Post by Robert Reed » Sun Sep 11, 2005 9:45 am

Older car radios used 262Khz, Analogue televisions used 45Mhz. All the trunked 800 Mhz systems I have seen also use 45Mhz (first conversion). Radar uses 70 Mhz. However any well designed narrow band trancievers base their conversions and subsequent IF frequencys on many aspects of their particular operating bands (image rejection being only one of many things to consider). I have seen IF frequencies from 150 Khz to 70 Mhz depending on type of use.
But I think you have covered 99% of consumer electronics with 455K & 10.7M.(radio products).

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Re: Standard IF frequencies

Post by terri » Tue Sep 13, 2005 1:53 am

Some old 1940-1950 TV sets used a 14MHz first conversion IF and it was big problem since it sat smack in the middle of the 20 Meter ham band. So every time a ham keyed up, it played hob with TV reception for owners of that brand. Of course, it was always the ham's fault, not the bonehead who chose this f for an IF.<p>Over the years, that brand of TV set fell into disrepute, probably because of the constant TVI (TeleVision Interference) issues, so the problem finally evaporated. <p>Just goes to show you. Choose your IF with care.<p>[ September 13, 2005: Message edited by: terri ]</p>
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Re: Standard IF frequencies

Post by ezpcb » Tue Sep 13, 2005 7:00 am

Old receivers use 200kHz because they use mechanical filter for the IF.<p>465k is also widely used in asia MW radio.<p>many dual convertion shortwave receivers use 58.245M and 455k(465k) as 1st and 2nd IF.
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