On 2/6/19 2:37 PM, Ken M wrote:
On a related subject, I note the ARRL lab test of the FT-818 does not recommend amplifier use, which is disappointing as I suppose that reflects on the quality of it’s output signal.
This should be solvable with the appropriate output filter to knock down harmonics/spurious output.
A diplexer (such as the one at http://kw4fb.com/micro-diplexer) could be added before the amplifier on the 2m side, if that is the problem, with the 70cm port terminated in a 50 ohm load. On the 70cm path (or the 2m), one could apply a cavity filter (http://www.nx7u.net/4x3x5.html).
I don't have the ARRL test report, so I'm not sure why they don't think one should add an amplifier. If it is a transmitted phase noise problem, then, obviously, a filter won't solve the problem.
--- Zach N0ZGO