On Wed, 16 Jul 2008 21:15:14 -0700, Ron D'Eau Claire wrote:
In this case Eric is saying there may be a leakage path through a relay.
Right. Almost all problems have more than one component. In problems like
this one, the sum is the algebraic sum of all of the leakage paths.
Relays DO have
that is why the Top Ten AB antenna switches use two relays to gain isolation...
bill
At 02:04 PM 7/17/2008, Jim Brown wrote:
On Wed, 16 Jul 2008 21:15:14 -0700, Ron D'Eau Claire wrote:
In this case Eric is saying there may be a leakage path through a relay.
Right. Almost all problems have
David,
A very good point. Although the space is rather restricted for
RG58/U it should be possible to fit some of the smaller diameter
cable such as that used to connect between VHF/UHF PCB's.
I have some silver braided coax that would be suitable.
It would have little adverse effect over such a
As an alternative to coax, try using twisted pair - pull a couple pairs
out of a short length of CAT-5 cable. One of the pair would be grounded
at each end (will require adding a solder lug at the SO-239 jack).
73,
Don W3FPR
Stewart Baker wrote:
David,
A very good point. Although the space
I was told by Elecraft that one of the reasons for the poor isolation
between the antenna ports is this: if you don't have the subreceiver
installed, then the KAT3 subreceiver port is unterminated. So either
install the KRX3 :-) or plug a 50-ohm resistor into the port -- it's on
the top rear
Vic,
The K3 uses only a single wire to connect to the SO-239 jacks. The
return path is through the chassis metal. If one adds a direct return
path from the SO-239, that eliminates the potential for a haphazard path
for the return current. While a chassis return may be good enough in
one
On Wed, 16 Jul 2008 13:12:22 -0400, Don Wilhelm wrote:
The K3 uses only a single wire to connect to the SO-239 jacks. The
return path is through the chassis metal. If one adds a direct return
path from the SO-239, that eliminates the potential for a haphazard path
for the return current.
I had a similar isolation problem between ANT 1 and ANT 2 in my KAT100,
discovered by accident after working somebody in EU on 15m using a shielded
dummy load connected to ANT 2. Replacing the bare leads between the
switching relay and connectors with coax increased the isolation
Don Wilhelm wrote:
Vic,
The K3 uses only a single wire to connect to the SO-239 jacks. The
return path is through the chassis metal. If one adds a direct return
path from the SO-239, that eliminates the potential for a haphazard path
for the return current. While a chassis return may be
Vic,
I would not go for that solution because the insulated part of the coax
inside the cabinet would reradiate anything coming on the coax from the
outside.
Best solution is short piece of coax grounded on the inside of cabinet AND
at the antenna tuner.
That is my opinion,
humbly yours
Len
Lennart's comments fit my experience. There isn't a ground loop formed by
using coax and it does eliminate much of the RF currents floating about at
random inside the rig.
With the RF current flowing at the center pin connected to coax, the RF
energy must propagate along the *inside* of the coax,
Ron - Unfortunately theory does not always match reality. (i.e. there
are more variables than the person applying the theory is aware of..) In
this case we tried coax and it had no impact on improving isolation.
The predominant leakage path is inside the ant switching relay. Please
do not
Ron -
Don't you mean that the center conductor carries all of the RF current,
and the inside of the coaxial cable shield carries an equal amount of
current, but of opposite phase?
- Jim, KL7CC
Ron D'Eau Claire wrote:
Since the center conductor, carrying 1/2 of the RF current, is
Ahh - The dangers of cc: lists on email.
Looks like I just answered 'officially' to the list :-)
73, Eric WA6HHQ
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- Jim, KL7CC
Eric Swartz - WA6HHQ, Elecraft wrote:
Ahh - The dangers of cc: lists on email.
Looks like I just answered 'officially' to the list :-)
73, Eric WA6HHQ
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Elecraft
Sent: Wednesday, July 16, 2008 1:59 PM
To: Ron D'Eau Claire
Cc: 'Elecraft'; Wayne Burdick
Subject: Re: [Elecraft] Re: RF Coupleing
Ron - Unfortunately theory does not always match reality. (i.e. there
are more variables than the person applying the theory is aware of..) In
this case we
On Wed, 16 Jul 2008 13:59:26 -0700, Eric Swartz - WA6HHQ, Elecraft wrote:
Unfortunately theory does not always match reality.
Theory ALWAYS matches reality -- when you know enough about both. :)
(i.e. there
are more variables than the person applying the theory is aware of..)
Like I said.
Yes. Each conductor carries one phase.
Depending upon how you measure what's going on, I think it may indicate only
1/2 the total.
For example, try measuring the voltage with respect to the earth. Each side
will indicate 1/2 of the total voltage but, since they're opposite in sign,
they add
It is spelled COUPLING, NOT coupleing... hard to believe no one corrected
yet.
- Original Message -
From: Jim Brown [EMAIL PROTECTED]
To: Elecraft List elecraft@mailman.qth.net
Sent: Wednesday, July 16, 2008 8:14 PM
Subject: Re: [Elecraft] Re: RF Coupleing
On Wed, 16 Jul 2008 13:59
To: Elecraft List
Subject: Re: [Elecraft] Re: RF Coupleing
On Wed, 16 Jul 2008 13:59:26 -0700, Eric Swartz - WA6HHQ, Elecraft wrote:
Unfortunately theory does not always match reality.
Theory ALWAYS matches reality -- when you know enough about both. :)
(i.e. there
are more variables than the person
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