Ever try using Polyphaser or similar device? Seems to help drain off static
for me.
At 09:05 PM 3/11/00 -0500, you wrote:
>I have at times had static build-up on my dipoles when there was just "dry"
>air blowing across them during the winter months. But the most common was
>when the relative humidity was low and the air was blustery and speckled
>with snowflakes.
>Mike(y)
>W3SLK
>----- Original Message -----
>From: Michael Tope <W4EF@pacbell.net>
>To: Amps Reflector <amps@contesting.com>; Carl Clawson <ws7l@arrl.net>;
><W8JI@contesting.com>
>Sent: Saturday, March 11, 2000 5:19 PM
>Subject: RE: [AMPS] Re: Static discharge caused NOISE
>
>
> >
> > As Tom points out, DC grounding doesn't make much
> > difference except in the case of electrostatic discharge.
> > This can manifest itself in the form of rain or snow
> > static. I recently saw an anecdotal account from Mike, N7MH
> > up at the Stanford Radio Club, W6YX. Seems that all their
> > KLM monobanders were wiped out by rain static in the ARRL
> > CW contest while their Mosley PRO-67 stayed quite.
> > I suspect, but I am not sure that this has something to
> > do with the fact the KLM antennas use insulated elements
> > whereas the Mosley elements are grounded to the boom.
> >
> > Mike, W4EF.................
> >
> >
> >
> > ----------
> > From: Tom Rauch[SMTP:w8ji@contesting.com]
> > Reply To: W8JI@contesting.com
> > Sent: Saturday, March 11, 2000 9:59 AM
> > To: Amps Reflector; Carl Clawson
> > Subject: Re: [AMPS] Re: Static discharge caused NOISE
> >
> >
> >
> > > > All antennas should be DC shorted to ground at the receiver input
> > > > because
> > > of
> > > > another reason: a sometimes much lower level of receiving back-ground
> > > noise.
> > > > de Hans
> >
> > DC grounded antennas are no different in noise level that DC leak
> > antennas, or DC floating antennas with one exception.
> >
> > If the antenna charges up enough to arc something over, you will
> > hear a loud POP in the receiver. Other than that, they are just as
> > "quiet".
> >
> > My lowest noise receiving antenna for 160 meters are arrays of
> > eight verticals and four verticals that are NOT dc grounded in any
> > way at all. They are quieter than my arrays of Beverages, which are
> > dc grounded.
> >
> > The reason the choke makes no difference is because the noise
> > outside the frequencies where the receiver is tuned does not make
> > it through the receiver, unless the receiver is very poorly designed.
> > At the operating frequency, the coke is a high impedance and so it
> > doesn't affect noise at that frequency at all.
> >
> > > And we certainly need to keep the choke on the tank side of the output
> > > relay. Otherwise the tank floats during receive. With HV on there are
> > > probably enough ions to charge it up and cause arcs.
> >
> > Yep, that annoying tick tic as the leakage in the blocking cap
> > allows the variables to charge until the flash over! That can be
> > shocking.
> >
> > > It makes sense to put the rf choke at the output side of the relay
> > so that
> > > it shorts anything that is not supposed to be there to ground -
> > and, as
> > > Hans has suggested, improve receiving back-ground noise.
> > There is one
> > > minor caution, though, in that the rf choke will drop in impedance
> > at some
> > > point and affect received signals. A 2.5 mh choke would be fine
> > through
> > > 160 meters when using a low impedance antenna - but suppose
> > you also use
> >
> > A 100 microhenry choke is enough for 160 meters in a 50 ohm line.
> >
> > > Sorry to digress, but it really has to do with design of power
> > amplifiers
> > > - and whether the rf choke should be hung on the output side of
> > the relay.
> >
> > A choke should always be used on the tank circuit end of the relay.
> >
> >
> > 73, Tom W8JI
> > w8ji@contesting.com
> >
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|