I was one of the stations on W4ZT's 3655 Wall of Shame
list. The only problem I have with his list is that it appears you
remain on it forever...even after you fix your harmonic. Here's how
I fixed mine with a shorted stub made of ~89' of polyethylene RG-8 (Vf = 0.66).
73, Bill W4ZV
"Raoul Coetzee" <raoulc@smmcape.co.za> wrote:
> I am having a bit pf a problem with a second harmonic when
operating on 160m.
> This is of course falling in the 80m band segment and causing mild
to severe
> qrm to my local 80m friends on phone.
I had a similar problem when we gained SSB access to 3600 and
above. My solution was a shorted 1/4 wave stub for 160 at the output
of my amplifier. Use (246/1.83)*Vf to determine the length in feet
and cut it a little longer if you aren't certain of the velocity
factor of your coax. I used an MFJ-259B analyzer and pruned the stub
for minimum impedance at 3.650. Just remember to switch out the stub
for other bands!
I had reports that my harmonic was S7 before I did this.
Afterwards I had W0FLS check it using his 4-Squares on both 80 and
160. On 160 I was S9+30 and on 80 I was inaudible, and I've not
received further complaints from anyone.
73, Bill W4ZV
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