RCM ) writes:
wrote:
On 21 Jan 2005 14:07:17 GMT, (PDRUNEN) wrote:
Hi Group,
Any one have an IF strip that they can give, trade or, swap?
Needs to be transistor type.
De KJ4UO
Ah, your request is still far from specific enough to answer.
Is the IF to be used for AM, FM, SSB, ISB or some other?
It does make a difference.
Allison
KB1GMX
Says IF strip...not detector...
No, an IF strip tends to mean including the detector. If he
meant "IF amplifier" he would have said that.
Even if the detector is not included, the modulation mode is needed to
define the solution. An FM strip will include limiter stages, which
you don't want for AM modes. Bandwidth selectivity is usually part of the IF
strip, and bandwidth depends on type of modulation, and indeed can vary
widely on the same type of mode.
The original poster sounds like he expects to find a module, and that's
not likely the case.
If someone needs an FM broadcast band IF strip, the obvious solution
is an FM broadcast receiver of some sort. A portable, a stereo receiver,
a car radio. There'll be the needed ceramic filter(s), and at this
point an IC that does the work. It won't be a module, but one could
either chop out the section, or trace it and then desolder the parts
and then rebuild it elsewhere.
Narrow deviation FM, an obvious solution is an existing two-way radio.
I've pulled actual modules out of older (and clunky) cellphones, but
they tend to have a first IF in the 45MHz range, or higher, and then
convert down to 455KHz. 49MHz superhet walkie talkies can supply
an IF strip for this, and most of them were 10.7MHz first IF and
then 455KHz. But some dropped down to 455KHz. Old cordless phones
operated at 49MHz, and again many use the same conversion scheme.
The walkie talkies, and many of the cordless phones, that I've
taken apart use one of the (now old) Motorola FM IF strip ICs,
the included the conversion stage from 10.7MHz to 455KHz. Again,
these won't be modules, but the walkie talkie boards are fairly
small and one just needs to feed the signal in around the front
end.
AM IF strips, the obvious solution is an AM broadcast radio.
For narrower selectivity, a CB set will offer up narrower filters,
and many will be double conversion with a 10.7MHz first IF and
a 455KHz second IF.
CW, well there isn't likely to be anything floating around in
consumer equipment. Either you live with wider bandwidth for
AM, and then add a BFO, or you build from scratch.
Same with SSB. While some firms over the years have offered
SSB IF strip modules, that's a rarity. And there's not much
one can extract an IF strip from where the whole unit is not
just useable to start with.
So for SSB and CW, one likely has to build from scratch.
But until we see a more detailed response, there really can't
be an answer.
Michael VE2BVW