Topband: Ar2 Preamp

[Tom Rauch]

Hi Milt,

>  I would be interested in the particulars of your negative experience with
> the ARR GaAsFET preamplifiers.

I just measured an AR2.

Output power 1 dB gain compression -11dBm
NF .6 dB
gain:
1.8......... 24.31 dB
7.0..........15.15
30............13.48 
50.............13.85 
400............7.98

This is a "1.8 to 2 MHz" model. I didn't measure LF cutoff, but it 
wasn't starting to roll-off much at 1 MHz!!! People might get the 
false impression this amp rejects out of band signals a worthwhile 
amount! 

This amplifier would be good on a small resonant loop antenna, but 
would be worthless on anything large and/or broad-banded. The 
accumulation of signals from some low frequency to 400 MHz and 
higher would drive this thing crazy, it also gain compresses at a 
pretty low level.

Even a four dB NF is plenty on 160, unless the antenna is super 
small and you are  in a quiet location. I have problems with 
overload (without filters) on my Beverages using preamplifiers that 
compress at +10 dBm output! I can't imagine using this amplifier 
on anything but a small resonant loop.

73, Tom W8JI
w8ji@contesting.com


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