Re: Right-sided relay harmonic attempted fix for v3/4 ubitx

Gordon Gibby <ggibby@...>

Able to charge that battery significantly and proceed with tests.
All of these have a homebrew 50 dB tap on a Heathkit Cantenna, and then a 20dB attenuator at the input of the ICOM 718.   Previous measurements have suggested that between S7 and S9,   an S unit is approximately 12 DB.

Presented witll be the BEFORE/AFTER   S unit measurements where before is the relatively STOCK uBitx and the AFTER is is with my external daughterboard, with basically unshielded wiring.
All measurements are for CW (because this is where the unit had the most problems)
Power is estimated from a Micronta cheap SWR/power bridge built for CB'ers many many years ago.  

FREQ      PWR       FUNDAMENTAL       2ndHArmonic    3rdHarmonic   4thHarmonic    5thHarmonic     6thHarmonic     7thHarmonic
3.505    5 W/5+W  S9+30/S9+30           S7.5 / S7           S8.5 /  S6        S0 /   S0           S8 /  S1            S0 / S0              S8.5 / S8    
(so on 80 meters, the 3rd and 5th harmonics were greatly attenuated, and the 7th lost maybe 6 db)

7.005   2.5/3.5W   S9+30/S9+30           S0/ S0               S8.5 / S7         S5.5*/S0       *=wavering
(so on 40 meters, harmonics went  down by huge amounts

9.995   1.5/1.5 W  S9+30 /S9+30          S0 /S0               S9 / S5 or less
(so on 30 meters, the 3rd harmonic was basically demolished)  

In previous testing on 14 MHz, I cant go any farther than the 2nd harmonic and it was S0 (no reading) so not much for me to work on profitably there...and that is the filter that I damaged.

This looks overall, like a huge success.   The only oddity is the 7th harmonic of the 80 meter signal (why??)   but even it may be down 42 db.   On these bands, my crude testing indicates that even CW now either passes with flying colors or is very very close to it.   If I shield or even twist a ground around the INPUT (red in the photographs) wire it may get better.

Gordon Gibby

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