I use a short vertical antenna that has a low feedpoint impedance.

Would there be any advantage to running two parallel 50 ohm coax to reduce
losses to the shack tuner?

On 9/25/2015 4:31 PM, Wayne wrote:
I use a short vertical antenna that has a low feedpoint impedance.

Would there be any advantage to running two parallel 50 ohm coax to
reduce losses to the shack tuner?

Single band or multi band?
How does the feed point change with frequency.
450 ladder line is the usual low loss wire used
for multi band systems.
But what do know, I've never put up a ham frequency antenna.

Mikek

On 9/25/2015 4:31 PM, Wayne wrote:
I use a short vertical antenna that has a low feedpoint impedance.

Would there be any advantage to running two parallel 50 ohm coax to
reduce losses to the shack tuner?

If your antenna is 25+j0, paralleling two 50 ohm coax lines would reduce
the SWR from 2:1 to 1:1.

Is that what you want to know?

"John S" wrote in message ...

On 9/25/2015 4:31 PM, Wayne wrote:
I use a short vertical antenna that has a low feedpoint impedance.

Would there be any advantage to running two parallel 50 ohm coax to
reduce losses to the shack tuner?

If your antenna is 25+j0, paralleling two 50 ohm coax lines would reduce
the SWR from 2:1 to 1:1.

Is that what you want to know?

Yes, more or less. But, I wouldn't even bother trying to reduce a 2:1
unless the rig wouldn't tolerate it.

The antenna feedpoint impedance is around 20-j130 at 14 MHz, approximately a
21:1 SWR.

Some years back there was a discussion on paralleled coax, and I seem to
recall that it wasn't considered to accomplish much even under ideal
conditions.

On 9/26/2015 2:24 PM, Wayne wrote:


"John S" wrote in message ...

On 9/25/2015 4:31 PM, Wayne wrote:
I use a short vertical antenna that has a low feedpoint impedance.

Would there be any advantage to running two parallel 50 ohm coax to
reduce losses to the shack tuner?

If your antenna is 25+j0, paralleling two 50 ohm coax lines would
reduce the SWR from 2:1 to 1:1.

Is that what you want to know?

Yes, more or less. But, I wouldn't even bother trying to reduce a 2:1
unless the rig wouldn't tolerate it.

The antenna feedpoint impedance is around 20-j130 at 14 MHz,
approximately a 21:1 SWR.

Some years back there was a discussion on paralleled coax, and I seem to
recall that it wasn't considered to accomplish much even under ideal
conditions.


Oh. Well, then, it won't help. Are you opposed to putting an L and a C
up there at the base?

"John S" wrote in message ...

On 9/26/2015 2:24 PM, Wayne wrote:


"John S" wrote in message ...

On 9/25/2015 4:31 PM, Wayne wrote:
I use a short vertical antenna that has a low feedpoint impedance.

Would there be any advantage to running two parallel 50 ohm coax to
reduce losses to the shack tuner?

If your antenna is 25+j0, paralleling two 50 ohm coax lines would
reduce the SWR from 2:1 to 1:1.

Is that what you want to know?

Yes, more or less. But, I wouldn't even bother trying to reduce a 2:1
unless the rig wouldn't tolerate it.

The antenna feedpoint impedance is around 20-j130 at 14 MHz,
approximately a 21:1 SWR.

Some years back there was a discussion on paralleled coax, and I seem to
recall that it wasn't considered to accomplish much even under ideal
conditions.


# Oh. Well, then, it won't help. Are you opposed to putting an L and a C
# up there at the base?

Yes I'm opposed to that, but not for technical reasons.
It's a problem of an old man on a ladder

On 9/27/2015 10:46 AM, Wayne wrote:


"John S" wrote in message ...
On 9/26/2015 2:24 PM, Wayne wrote:


"John S" wrote in message ...

On 9/25/2015 4:31 PM, Wayne wrote:
I use a short vertical antenna that has a low feedpoint impedance.

Would there be any advantage to running two parallel 50 ohm coax to
reduce losses to the shack tuner?

If your antenna is 25+j0, paralleling two 50 ohm coax lines would
reduce the SWR from 2:1 to 1:1.

Is that what you want to know?

Yes, more or less. But, I wouldn't even bother trying to reduce a 2:1
unless the rig wouldn't tolerate it.

The antenna feedpoint impedance is around 20-j130 at 14 MHz,
approximately a 21:1 SWR.

Some years back there was a discussion on paralleled coax, and I seem to
recall that it wasn't considered to accomplish much even under ideal
conditions.


# Oh. Well, then, it won't help. Are you opposed to putting an L and a C
# up there at the base?

Yes I'm opposed to that, but not for technical reasons.
It's a problem of an old man on a ladder


In that case, how would you manage to add a parallel run of coax? Is
that somehow easier?

Doubling the number of feedlines would double the losses. Not only that
but each connector in the system inserts losses so that number
would be 4x.

Increasing the coax diameter would effectively reduce the loss.

Matching the antenna won't make the Return Loss go away but it will make
the transmitter happy.

KG7FU

On 09/25/2015 02:31 PM, Wayne wrote:
I use a short vertical antenna that has a low feedpoint impedance.

Would there be any advantage to running two parallel 50 ohm coax to
reduce losses to the shack tuner?

On 9/27/2015 10:41 AM, kg7fu wrote:

Matching the antenna won't make the Return Loss go away but it will make
the transmitter happy.

Can you explain this? I thought matching the antenna would *exactly*
make the return loss go away because it would eliminate the mismatch.

--

Rick

"rickman" wrote in message ...

On 9/27/2015 10:41 AM, kg7fu wrote:

Matching the antenna won't make the Return Loss go away but it will make
the transmitter happy.

Can you explain this? I thought matching the antenna would *exactly* make
the return loss go away because it would eliminate the mismatch.

Not wanting to put words in his mouth....
I read that to mean that the high SWR between the ATU and the antenna would
remain, but the transmitter would be happy with the SWR on the
transmitter/ATU coax.