[sdiy] Preventing Radio Ham Interference

Vladimir Pantelic vladoman at gmail.com
Tue Nov 29 15:51:52 CET 2016

this comes to mind:


On 29.11.2016 15:23, Mike HEQX wrote:
> I like the idea of an earth grounded mesh on the wall behind the
> recording rig. It can't hurt even on a good day. This lath screen is
> what comes to mind.
> http://thestuccoguy.com/wp-content/uploads/2013/10/Close-Up-View.jpg
> On 11/29/2016 4:55 AM, Oakley Sound wrote:
>> Wow. Thank you for all the replies and help. I got several PMs too and
>> even a phone call.
>> To answer a few questions:
>> I have done the ferrite clamps and they seem to work on the hi-fi when
>> added to the speaker and main cables. But I have yet to test this when
>> he is outputting at full power.
>> 20W causes a noticeable buzz on the Event monitors in my music area
>> even with the audio cables unplugged and ferrites on the mains cable.
>> At 60W then the buzz is so loud it's unusable and VCOs go out of tune.
>> 60W is the maximum power output of his rig. I've no idea how much ERP
>> is being developed.
>> I've not asked him to see what happens when the antenna is pointed in
>> any other direction. But when he was doing the tests it was around 45
>> degrees away from pointing directly at my house wall. Getting him to
>> test it with a dummy load sounds a good idea - although it should be
>> noted that the same rig driving a different but omnidirectional
>> antenna causes no problems.
>> We do share the same power and phase. The substation (step down
>> transformer) is up a pole just outside my back garden and I'm the
>> closest in the village to it. When pointing at my house his antenna is
>> also pointing straight at the overhead power lines that feed my house.
>> I will look into adding some capacitance across the bridge rectifier
>> diodes of the modular power supply.
>> His hi-fi is unaffected by it although it's more modern and the beam
>> was not pointed across his house at the time of testing.
>> His antenna is probably about as high as it can go on a single
>> unsupported pole. We're both in bungalows and the antenna is about as
>> high as the apex of his roof.
>> With the exception of the modular and the Event monitors everything
>> that is affected is old and was built before the letters EMC meant
>> anything. The Events are also liable to picking up mobile phone
>> interference so I think it may be worthwhile getting some more 'rad
>> hard' replacements for these.
>> I may try some grounded chicken wire to create a shield but from
>> various answers it seems that this may have little if no effect unless
>> I go for the full cage which is impractical. However, that idea I had
>> of buying an old shipping container and converting it to a home studio
>> is starting to become more and more attractive.
>> Tony
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