Jason James wrote:
> In very high RF fields, even a cavity resonator does not keep at
sufficient
> low-level, frequencies from sites such as TV and BCast transmitters
getting
> thru your RX frontend and creating a myriad of crap in the first
osc/mixer.
> Then you have the passive mixers where interfering frequencies are
generated
> in a local tower, or someone's unfiltered TX PA stage for example, are
> spewed into the atmosphere right within your operating band/s.
> If I was operating on UHF CB in my car, I would install a cavity
resonator
> between the aerial and TXRX with sufficient Q or bandpass, to handle the
> channels. They aren't cheap, but they work very well. Insertion loss is
> usually less than 2db. That'swhat we used at workforfrew multiplexing
into
> one AE all our Txs, and similarly, the RXs. Quality double ****elded
co-ax is
> also a worthwhile addition if RFInterference is a major prob.
>
> Jason
That's serious overkill for all but the most extreme QRM situations in a
mobile install. I can't say I've ever experienced anything to justify
those sorts of measures on CB, even in the Sydney CBD, but I use a radio
with a pretty good receiver (Motorola ASTRO Digital Spectra.)
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