<HTML><HEAD>
<META content="text/html; charset=utf-8" http-equiv=content-type></HEAD>
<BODY dir=ltr>
<DIV dir=ltr>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: 'Calibri'; COLOR: #000000">
<DIV>One idea I’m wondering about that I haven’t read of doing before –
get/make/borrow a RF dummy load and replace the antenna with it.</DIV>
<DIV>If you still get interference it is a coax and/or grounding issue.</DIV>
<DIV> </DIV>
<DIV>Barry</DIV>
<DIV> </DIV>
<DIV
style='FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: "Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; DISPLAY: inline'>
<DIV style="FONT: 10pt tahoma">
<DIV> </DIV>
<DIV style="BACKGROUND: #f5f5f5">
<DIV style="font-color: black"><B>From:</B> <A title=rick.jansen@xs4all.nl>Rick
Jansen</A> </DIV>
<DIV><B>Sent:</B> Monday, November 28, 2016 11:21 AM</DIV>
<DIV><B>To:</B> <A title=timr@circuitabbey.com>Tim Ressel</A> </DIV>
<DIV><B>Cc:</B> <A title=synth-diy@synth-diy.org>synth-diy@synth-diy.org</A>
</DIV>
<DIV><B>Subject:</B> Re: [sdiy] Preventing Radio Ham
Interference</DIV></DIV></DIV>
<DIV> </DIV></DIV>
<DIV
style='FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: "Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; DISPLAY: inline'>
<DIV></DIV>
<DIV>OTOH, 20 watts RF power is a *lot* of power. You can expect you neighbour
to not direct that at your house.</DIV>
<DIV> </DIV>
<DIV>rick</DIV>
<DIV><BR>On 28 Nov 2016, at 20:03, Tim Ressel
<<A>timr@circuitabbey.com</A>> wrote:<BR><BR></DIV>
<BLOCKQUOTE type="cite">
<DIV>
<P>That can help. The mesh size needs to be significantly smaller than the
signal wavelength. In this case we're talking 2 meters, so a quarter wave is
half a meter. Chicken wire is small enough that it should work. It would not
work for something like radar or microwave ovens (yes, they do leak) where the
wavelength is about 30mm or less. <BR></P>
<P>--tr<BR></P><BR>
<DIV class=moz-cite-prefix>On 11/28/2016 10:55 AM, random variate
wrote:<BR></DIV>
<BLOCKQUOTE
cite=mid:HE1PR0701MB2028892856584356198BCCEBF58A0@HE1PR0701MB2028.eurprd07.prod.outlook.com
type="cite">
<META name=Generator content="Microsoft Exchange Server"><!-- converted from text -->
<STYLE><!-- .EmailQuote { margin-left: 1pt; padding-left: 4pt; border-left: #800000 2px solid; } --></STYLE>
<DIV>
<DIV>
<DIV style="FONT-SIZE: 11pt; FONT-FAMILY: calibri,sans-serif">Could a
faraday cage like wall of grounded chicken wire mesh help? (can you tell I'm
not an EE?)<BR><BR>Tim</DIV></DIV>
<DIV dir=ltr>
<HR>
<SPAN
style="FONT-SIZE: 11pt; FONT-FAMILY: calibri,sans-serif; FONT-WEIGHT: bold">From:
</SPAN><SPAN style="FONT-SIZE: 11pt; FONT-FAMILY: calibri,sans-serif"><A
moz-do-not-send="true">Tony K</A></SPAN><BR><SPAN
style="FONT-SIZE: 11pt; FONT-FAMILY: calibri,sans-serif; FONT-WEIGHT: bold">Sent:
</SPAN><SPAN
style="FONT-SIZE: 11pt; FONT-FAMILY: calibri,sans-serif">28/11/2016
18:28</SPAN><BR><SPAN
style="FONT-SIZE: 11pt; FONT-FAMILY: calibri,sans-serif; FONT-WEIGHT: bold">To:
</SPAN><SPAN style="FONT-SIZE: 11pt; FONT-FAMILY: calibri,sans-serif"><A
moz-do-not-send="true">Oakley Sound</A></SPAN><BR><SPAN
style="FONT-SIZE: 11pt; FONT-FAMILY: calibri,sans-serif; FONT-WEIGHT: bold">Cc:
</SPAN><SPAN style="FONT-SIZE: 11pt; FONT-FAMILY: calibri,sans-serif"><A
moz-do-not-send="true">Synth DIY</A></SPAN><BR><SPAN
style="FONT-SIZE: 11pt; FONT-FAMILY: calibri,sans-serif; FONT-WEIGHT: bold">Subject:
</SPAN><SPAN style="FONT-SIZE: 11pt; FONT-FAMILY: calibri,sans-serif">Re:
[sdiy] Preventing Radio Ham Interference</SPAN><BR><BR></DIV></DIV><FONT
size=2><SPAN style="FONT-SIZE: 10pt">
<DIV class=PlainText>Funny this should come up now, I am reading my
university textbook on analog filter design and the example I am studying is
a ham operating at 30 mhz ( impossible as it's out of band) causing
interference to tv channel 2 , the design calls for 20 db 4 pole high-pass
filter. But that's for radio or tv reception.<BR><BR>Speaking of
interference, I will shut up now;)<BR><BR>TK<BR><BR>> On Nov 28, 2016, at
11:14 AM, Oakley Sound <A
class=moz-txt-link-rfc2396E>mailto:oakleylist@btinternet.com</A>
wrote:<BR>> <BR>> Hi all,<BR>> <BR>> My next door neighbour, a
keen radio ham, has erected a new 144MHz directional beam antenna.
Unfortunately, for both of us, when it's pointing towards my house and
transmitting, it interferes with my audio set-up in both my living room and
my little music area. I get on very well with my neighbour and we've briefly
worked together on this so we know what particular combination of output
power, frequency and antenna choice causes the problem. This antenna mast is
around 5m away from the wall where my audio gear is situated. When he uses
his other non directional antennas there is no problem.<BR>> <BR>>
Anything more than 20W and the RF signal has an affect. Generally, with my
more modern gear it is not a problem, but my vintage gear (eg. my hi-fi and
older synths) are badly affected. More annoyingly, it's also the modular and
my ten year old Event active monitors.<BR>> <BR>> When transmission is
ongoing I hear what seems to be a loud buzz at 100Hz and harmonics. It's as
if the mains is being gated into the audio pathway during transmission. The
higher the RF output power the louder the buzz. The Event monitors pick up
the noise even with the audio cables unplugged and the mains additionally
filtered. Bizarrely it also makes the modular and my old SY-1 go out tune
but I can't detect any drop in power supply voltage so I think it's directly
affecting the VCO circuitry.<BR>> <BR>> I think I may have solved it
with ferrites on the loudspeaker cables on the hi-fi but the music area is
still a problem.<BR>> <BR>> At the other end of my house I haven't got
an issue but moving all my gear there isn't really practical - although I'm
thinking about it.<BR>> <BR>> Any ideas? Would some sort of earthed
wire mesh fitted to the wall directly between him and me create a suitable
RF shadow?<BR>> <BR>> Tony<BR>> <BR>> <A
href="http://www.oakleysound.com"
moz-do-not-send="true">www.oakleysound.com</A><BR>> <BR>>
_______________________________________________<BR>> Synth-diy mailing
list<BR>> <A
class=moz-txt-link-abbreviated>Synth-diy@synth-diy.org</A><BR>> <A
href="http://synth-diy.org/mailman/listinfo/synth-diy"
moz-do-not-send="true">http://synth-diy.org/mailman/listinfo/synth-diy</A><BR><BR>_______________________________________________<BR>Synth-diy
mailing list<BR><A
class=moz-txt-link-abbreviated>Synth-diy@synth-diy.org</A><BR><A
href="http://synth-diy.org/mailman/listinfo/synth-diy"
moz-do-not-send="true">http://synth-diy.org/mailman/listinfo/synth-diy</A><BR></DIV></SPAN></FONT><BR>
<FIELDSET class=mimeAttachmentHeader></FIELDSET> <BR><PRE wrap="">_______________________________________________
Synth-diy mailing list
<A class=moz-txt-link-abbreviated>Synth-diy@synth-diy.org</A>
<A class=moz-txt-link-freetext href="http://synth-diy.org/mailman/listinfo/synth-diy">http://synth-diy.org/mailman/listinfo/synth-diy</A>
</PRE></BLOCKQUOTE><BR><PRE class=moz-signature cols="72">--
--Tim Ressel
Circuit Abbey
<A class=moz-txt-link-abbreviated>timr@circuitabbey.com</A></PRE></DIV></BLOCKQUOTE>
<BLOCKQUOTE type="cite">
<DIV><SPAN>_______________________________________________</SPAN><BR><SPAN>Synth-diy
mailing list</SPAN><BR><SPAN><A>Synth-diy@synth-diy.org</A></SPAN><BR><SPAN><A
href="http://synth-diy.org/mailman/listinfo/synth-diy">http://synth-diy.org/mailman/listinfo/synth-diy</A></SPAN><BR></DIV></BLOCKQUOTE>
<P>
<HR>
_______________________________________________<BR>Synth-diy mailing
list<BR>Synth-diy@synth-diy.org<BR>http://synth-diy.org/mailman/listinfo/synth-diy<BR></DIV></DIV></DIV></BODY></HTML>