My experience has mostly been with 300-434MHz where there are dozens of suppliers of small, inexpensive superregenerative receivers (http://davehouston.org/modules.htm ) and somewhat more costly superhet or hybrid receivers. I cascaded 3 MAR-6 amps between ANT & RCVR (w/o any filtering). This worked fine with the superhet & hybrid receivers and with most of the superregenerative receivers. However, there was one manufacturer whose superregenerative receiver had much wider bandwidth than most and it did not deal well with the higher signal levels. This was disappointing as the wider bamdwidth was a desirable trait as several devices of interest (automation & security) to me were in the 308-320MHz range. http://www.e-madeinchn.com/ReceiverModules.html And, they were dirt cheap, costing about $1 each even with some requested mods and in relatively modest (~100 pcs) quantities.Originally Posted by rayzrocket
Noise is not much of a problem as most of these receivers employ a data slicer circuit (a simple comparator) that gives an extremely noise free data output. http://davehouston.org/rf-noise.htm.
As it's against FCC rules to futz with the transmitters (or TX antenna) but not with the receiver, I always use better antennas (http://davehouston.org/eggbeater.htm) and MAR-6 based preamps on the receiver side.
Most of the superregenerative receivers also have an analog output which is merely the raw signal at the comparator input. You can measure the modulation depth and get a rough measure of the signal level (rough, because the AGC circuits also affect this amplitude) which you can use for comparing before/after (antenna, preamp) scenarios.
I have no idea what might be available at 27MHz. I did look at this briefly a few years ago as it was/is(?) used by one of the audio receiver makers for remote control. (It's been too long for my ancient gray cells to remember details.)
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