Travel antennas - outside with rig inside

[Steve KC8QVO]

I am out of town this weekend and brought my 28' random wire/counterpoise. I have the random wire and counterpoise going out the window about 5' away. The tip of the random wire goes up in a tree about 15' up. The counterpoise goes out the window the opposite direction weaved through some bushes (to keep off the ground) about 5' up.

The antenna seems to perform a ton better in a portable set up outside. There are signals I can hear on 40, but they are much weaker than if I set up outside.

Another note is the window frame is wood and cranks open. I pulled the screen out to have clear access through the window.

Wire is #26 Silky Wire from The Wireman (my favorite).

I am thinking for this kind of set up I need to get the feedpoint OUTSIDE the window. Right now the wires come through the window and attach to the rig with a BNC-binding post adapter.

I believe getting the feedpoint outside the window requires a coax cable and external tuner. Does anyone have any ideas on running the tuner inside the rig that may work without coax?

Balanced feed lines will still detune through the window frame too, they need to be clear. Maybe it would perform better than the wires I have now though.

Steve, KC8QVO

[k6dgw]

Steve,

28 ft is close to 1/4 wave on 40, placing the current node at your rig
[low Z].  Radiation occurs primarily from the higher current portions of
the conductor(s), and with 5 ft inside, that's 18% of your physical
antenna, and perhaps 25% of the portion with significant currents, inside.

On 20, it is approaching a half-wave and will have a very high Z at the
connection to the rig, and you may or may not be able to match it with
an internal tuner.  Don't know which Elecraft rig you're using.  Other
comments interspersed below.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org

On 7/20/2012 3:54 AM, Steve KC8QVO wrote:
> I am out of town this weekend and brought my 28' random wire/counterpoise. I
> have the random wire and counterpoise going out the window about 5' away.
> The tip of the random wire goes up in a tree about 15' up. The counterpoise
> goes out the window the opposite direction weaved through some bushes (to
> keep off the ground) about 5' up.

If the counterpoise is elevated, you have basically a highly distorted
dipole ... with the portions that radiate the most inside.  On the
ground, you have a somewhat distorted 1/4 wave "vertical," highest
current section inside, with one radial. :-)  Either will work.  Getting
the high current parts outside will make it work a lot better.
>
> The antenna seems to perform a ton better in a portable set up outside.
> There are signals I can hear on 40, but they are much weaker than if I set
> up outside.

Not surprised

> Wire is #26 Silky Wire from The Wireman (my favorite).

Doesn't really matter although the non-tangle stuff is a lot easier to
deploy.
>
> I am thinking for this kind of set up I need to get the feedpoint OUTSIDE
> the window. Right now the wires come through the window and attach to the
> rig with a BNC-binding post adapter.

Yeppers.  See top post.
>
> I believe getting the feedpoint outside the window requires a coax cable and
> external tuner. Does anyone have any ideas on running the tuner inside the
> rig that may work without coax?

A 5' run of RG-58 on 40 meters is of little consequence, and a KX1 or K2
internal tuner should match it well.  It would be a real good idea to
have a current choke at the far end of the coax, similar to the coax
that comes with a Buddipole.  That will get the whole antenna outside
and minimize the imbalance and common mode currents on the outside of
the coax shield.
>
> Balanced feed lines will still detune through the window frame too,

Actually, not so much at all.  You would need a balun to get to
unbalanced coax to get into the rig.  Just 5 ft of coax is a lot easier.




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[Steve KC8QVO]

I should have been more specific on the rig - it is a KX3. I wrote that post in the morning when I was eating breakfast in a hurry to get out the door HI.

I have an LDG Z11-pro tuner. I have used it in remote situations a lot in the past, with coax to the rig. Usually I end up running a 12v battery for the tuner to run off (7Ah SLA). However, I have plans to put AA battery cases in side (8 AA cells). A friend of mine has done this and it works out great. This may be the best route for me. I do have a 1:1 balun to use with it also (the LDG version), but I am in the works on making a more compact one.

Steve, KC8QVO

[k6dgw]

OK, that will undoubtedly work.  If you're 5 ft from the window, you
don't really need to remote the tuner, but that'll work fine.  Main idea
is just to get the high current parts of the antenna outside and as
clear as possible.  I sometimes use a short [~8 ft] pigtail of RG-58
with my KX1 just to get the wire up and clear a little more.  The KX1
ATU handles it just fine.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org

On 7/20/2012 1:40 PM, Steve KC8QVO wrote:

> I should have been more specific on the rig - it is a KX3. I wrote that post
> in the morning when I was eating breakfast in a hurry to get out the door
> HI.
>
> I have an LDG Z11-pro tuner. I have used it in remote situations a lot in
> the past, with coax to the rig. Usually I end up running a 12v battery for
> the tuner to run off (7Ah SLA). However, I have plans to put AA battery
> cases in side (8 AA cells). A friend of mine has done this and it works out
> great. This may be the best route for me. I do have a 1:1 balun to use with
> it also (the LDG version), but I am in the works on making a more compact
> one.

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