Re: Norton Amplifiers

Conrad, PA5Y

Could you be referring to the HELA10B dual monolithic amplifier? I have a pair of these on my 2-channel adaptive EME system. They are there to overcome splitter losses and give a bit of extra gain for the IQ+. The path for one channel is HELA10B (11db gain 2.5dB NF on 144) then a Band pass filter, then a 3dB hybrid splitter. One side feeds the IQ+ (used for the adaptive RX) and the other my transverter which is used a linear polarisation (either +/- 45 deg) channel with the K3S. The whole system seems to work very well.

I will try one on 432 but the noise figure is significantly higher on the 4 that I built.

You need a heatsink!

Conrad PA5Y

-----Original Message-----
From: <> On Behalf Of Neil Smith G4DBN via
Sent: 19 May 2021 20:07
Subject: Re: [UKMicrowaves] Norton Amplifiers

I seem to recall seeing the layout of a Minicircuits amp that used hybrids and paired amplifier chains.  One of the benefits siuggested was that if one leg of the amp died, the other would carry one at only 6dB down, as well as being very linear and robust with a high output IP3.  I thought it was the ZRL-700+ but can't find the notes about the internal circuit of that one, so I might be wrong. NF is 2dB at 70cm and the gain is very high, so not much benefit unless it is close to the masthead. It wasn't the TAMP-72LN+ drop-in module either. Perhaps I was dreaming.

Neil G4DBN

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