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Old 26th Apr 2021, 12:25 am   #22
majoconz's Avatar
Join Date: Jan 2008
Location: Palmerston North, New Zealand
Posts: 388
Default Re: Spectrum Comms. Active Antenna problem

Radio Wrangler said:
The NRD525 was one of the better amateur receivers of its day in terms of large signal handling, but it was not as much better as legend has it.
I have an NRD515 fed from a multicoupler - I have never suffered from cross-mod or any other artifacts - maybe because....

A Reaction Instruments 409-2 VLF/HF multicoupler feeds my HF receivers. The input amplifier is an MRF136 power MOSFET - max power rating 55 watts. You will leave your fingerprint on it if you touch it while it is on!

My Redifon R499 receiver has a push-pull RF amplifier after a preselector single channel filter. This uses four 5 watt 2N3866's and is practically bomb-proof! Unfortunately I don't have the crystals for it!

So the recipe for an RF amplifier is adequate filtering before any gain and good linearity with lots of headspace!
Cheers - Martin ZL2MC
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