At 7/29/2010 16:52, you wrote:
>>Yes, but the NF is unpublished & unknown. I therefore assume it's poor, >>maybe 3 dB? >> >>A Chip Angle GaAsFET @ UHF has 0.5 dB NF. Put a 1/4 wave pass cavity with >>0.5 dB loops in front of it & you have a narrow 1 dB NF front-end. I'll >>take 1 dB NF over 3 dB NF any day. >> >>The Simrex unit makes a nice solution if you don't have the physical space >>for a 1/4 wave bottle. Then again, I know someone who just ordered an even >>smaller MtronPTI front-end crystal filter to solve a front-end overload >>problem from a TX over 1 MHz away from his RX. Not the best solution >>(higher loss, can't be retuned if he ever has to change freq.), but I guess >>it works for him. >> >>Bob NO6B >If you picked the UHF Simrex unit with less gain, more selectivity than >the standard model, then the noise factor should be better? I doubt it. But without any real NF numbers, it's all guesswork. > I guess it comes back to price too, a 1/4 wave can plus pre-amp will > cost more money....... GaAsFET preamp is ~$130. I don't think I've ever paid more than $50 for a pass cavity, so the total is ~$100 less than the GLB unit. Bob NO6B
