Re: LF: Re: AC Noise on RX...

[Scott Tilley <sthed475@telus.net>]

Hi Guys

Thanks for the responses.

This one has me still scratching my head.

All of the LF bands are affected.  I have tried my RF isolation 
transformer that worked rather well back in the city.  I have not tried 
the AC mains iso xfmr yet.  Yes my iso is wound like yours.  No 
computer  yet.
To answer others questions about a local noise source.  Can't be as I 
can shut off all the breakers in the house save the one feeding the 
radio and nothing else and the noise is still there.  Doesn't matter 
which PSU of the many I have I use and the noise is still there.  Switch 
to the battery and turn on everything and bang the noise is gone.
The noise is only there AFTER I connect the antenna. So it has something 
to do with the mains AC, coax run and the antenna...
73 Scott
VE7TIL

PS - The day we get the band back on 2200m is the day I'm back on the 
air...  This time with a 70' high big honking flat top about 500m from 
the ocean...

jrusgrove@comcast.net wrote:
> Scott
>
> Welcome back! Agree with previous comments on checking the power 
> supply first. What frequency range is affected?
> Is  the isolation transformer an ac mains isolation transformer or an 
> rf isolation transformer? Even if you're using an ac mains isolation 
> transformer an rf isolation transformer on the lead will probably be 
> required. For this transformer I've found that a conventional wound 
> ferrite transformer with the primary and secondary separated on the 
> core work best. Bifilar wound transformers are not the way to go here. 
> If you have a computer connected to your receiver a 600 - 600 ohm 
> isolation transformer in that connection can also improve noise pickup.
> Any hope of transmitting again?
>
> Jay  W1VD  WD2XNS  WE2XGR
>
> ----- Original Message ----- From: "Scott Tilley" <sthed475@telus.net>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Thursday, September 11, 2008 12:10 AM
> Subject: LF: AC Noise on RX...
>
>
> > Hi All
> >
> > Been awhile since I've posted to the reflector.  I'm pleased to 
> > announce I have escaped the noisy clutches of the City and bought 
> > myself a nice piece of land up the coast in a very quiet spot.
> > Presently I'm only using my passive RX loop which has a single turn 
> > 'sense' loop for coupling into the main multi turn loop...  When the 
> > RX is connected to an AC power power supply I get terrible AC 
> > growlers; however, put the RX on a battery and bang not a peep of 
> > nasty AC noise.
> > I presume this is due to some coupling between the AC mains and the 
> > RX system and my isolation transformer doesn't seem to help so I 
> > wonder if someone could set me straight on what is going on here so I 
> > can solve the problem.
> > Thanks for any support!
> >
> > 73 Scott
> > VE7TIL