[AMPS] Triode Amp Out/In isolation

Steve Thompson amps@txrx.demon.co.uk
Thu, 28 May 1998 07:33:16 +0100

In message <199805280414.VAA19702@server2.powernet.net>, Shawn Tayler
<stayler@powernet.net> writes
>Doing some teswting on my 8938 Stripline (K1FO) design amplifier and found the 
>output to input isolation (at 
>tuned frequency to be 14dB.  This is about the operational gain of the amp.  The 
>isolation is over 50dB andf 
>even exceeds 80dBat all other freqs from 100Khz to 1Ghz.  Is this an ok figure 
>for a GG triode amp?  Its always 
>been stable during normal use, never a snap, crackle, or pop...

You can improve the in/out isolation by tuning the grid inductance; see
the articles on 70cm amps by K1FO in the ARRL UHF/Microwave projects


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