Post by 2m0-silthe neighbours can go f..k themselves due to their bad attitude.
John, I had to think long and hard about how to reply to this. Please
don't take this the wrong way, but this runs so contrary to the
amateur spirit that what I'm about to say may sound pompous:
That will make you feel better for about five minutes, the pain it
will cause will last as long as they are your neighbours. You are now
the operator of a legitimate experimental radio station, representing
amateur radio to the non-amateurs around you and with those privileges
come responsibilities.
Oh sure, fine for him to say living as he has done most of his life in
small communities where everyone knows everyone else and one of his
neighbours an inactive GW6[1]. All very true, but you have to at least
try. If you really are causing the problem, you have a duty of care to
do all within your power to ensure that your activities don't spoil
the enjoyment of others, however vexatious or arrogant they appear at
first glance.
Even when it isn't you causing the problem, you *must* take the
complaint seriously, stay calm and lead the neighbour through the
diagnosis step by step, showing them your log and making notes of
actions taken. If you don't, they'll always believe it is you
regardless of any clean bill of health you may get from the
authorities. Once you have done so, you have right on your side and
any problems they cause over this can then be dealt with through the
correct channels.
Pompous lecture over.
Post by 2m0-sileverything in the shack has ferrite rings and i also use an lpf.
no interference to tvs in house there are 4 all flatscreen--no
issues.
Filtering the supply is always a good idea. However, an LPF on any
modern radio will simply be a case of adding to the ultimate
attenuation at the bottom of the skirt of the existing LPF and won't
really do much at all. If it has a single cut-off, you may as well
leave it off for anything other than 15-10m as the low pass stage in
the radio (that's what gets switched in and out with the relays as you
change band) will be doing all the work and your spurii will probably
be less than -60dBc (1/1,000,000th of the carrier power, so 50uW at
50W) on a well designed amateur set by the time that signal reaches
your external 35MHz LPF anyway.
In fact, the two extra connections and the associated potential for
poor joints, especially in PL259s, is more likely to be a liability
than a protection. Your problem is your fundamental making merry with
the set's AGC, long unbalanced conductors and a plethora of other
things it can mix with, get into or block, not harmonics or spurii.
It's a common misconception that most EMC problems are due to out of
band radiation when the reverse is actually true. You have to keep it
out of other people's equipment in the near field and that usually
means at their end for people like us with small gardens.
LCD and Plasma sets are generally more immune to EMC issues as the
image on the screen is built up digitally rather than from a scanning
electron gun or three and a load of analogue amplifiers. That means
the whole thing from decode to display is digital and is thus ignorant
of RF. It's not impossible to interfere with a digital circuit, but
it's a damned sight harder.
A CRT set, however, can be affected by RF at almost any stage. Pickup
on the braid of the feeder can find its way into any and all sections
that process an analogue waveform. You can't say just because your
sets seem immune that your signal isn't causing interference to legacy
technology.
[1] I'm working on it. He has a Baofeng on the way, we have his old
call on Buckmaster and there's a form on my desk. It took a while, but
a dual band portable for £30 was the straw that broke his apathetic
camel's back.
--
Radio glossary #16
Breadboard: A device used to prove MTBF figures of components to be
false.