Horizontal Attic Loop Feed
 

Looks like I'll have to use a horizontal loop in the attic for a few months.
Any opinions on how to best feed it?
--open wire
--coax coil balun
--ferrite bead balun
--straight coax

The loop is about 13 feet per side, and I want to operate 20 meters and up.
In the past I have simply used a coax feed without a balun. It worked OK,
but there was a lot of stray RF around the house.

TIA

Horizontal Attic Loop Feed
 

"Wayne" wrote in message
news:4EBii.3183$fw2.1666@trnddc04...
Looks like I'll have to use a horizontal loop in the attic for a few
months.
Any opinions on how to best feed it?
--open wire
--coax coil balun
--ferrite bead balun
--straight coax

The loop is about 13 feet per side, and I want to operate 20 meters and
up.
In the past I have simply used a coax feed without a balun. It worked OK,
but there was a lot of stray RF around the house.

TIA


Wayne

Personally I would try feeding the loop with open wires from the balun
output of an ATU. You don't state what sort of power you want to use, but I
would think that this method would be okay up to a miximum of 100W. It
depends on how much wiring you have running parallel to sections of the
antenna up in the attic.

If you must use coax, winding as many turns of coax as possible on an old
6-8 inch ferrite rod just before the loop will keep most of the RF off the
outer shield of the coax.

Winding coax around ferrite rods or large toroids is usually much easier and
more efficient than using loads of ferrite beads as a balun.

Straight coax is okay for powers less than 20W but a few turns around a bit
of ferrite would still be advisable.

Mike G0ULI

Horizontal Attic Loop Feed
 

"Wayne" wrote in message
news:4EBii.3183$fw2.1666@trnddc04...
Looks like I'll have to use a horizontal loop in the attic for a few
months. Any opinions on how to best feed it?
--open wire
--coax coil balun
--ferrite bead balun
--straight coax

The loop is about 13 feet per side, and I want to operate 20 meters and
up. In the past I have simply used a coax feed without a balun. It worked
OK, but there was a lot of stray RF around the house.

TIA

If the antenna is in the attic you are going to have RF in the house because
the antenna is IN the house.
Dale W4OP

Horizontal Attic Loop Feed
 

"Dale Parfitt" wrote in message
news:uQQii.2972$Np2.1287@trnddc07...

"Wayne" wrote in message
news:4EBii.3183$fw2.1666@trnddc04...
Looks like I'll have to use a horizontal loop in the attic for a few
months. Any opinions on how to best feed it?
--open wire
--coax coil balun
--ferrite bead balun
--straight coax

The loop is about 13 feet per side, and I want to operate 20 meters and
up. In the past I have simply used a coax feed without a balun. It
worked OK, but there was a lot of stray RF around the house.

TIA

If the antenna is in the attic you are going to have RF in the house
because the antenna is IN the house.
Dale W4OP

I wouldn't expect otherwise. It was just a comment about what was
previously observed. In fact, the RF got into the computerized thermostat
and burned out the computer. The new thermostat has ferrite chokes on the
leads, and it has survived nicely.

Horizontal Attic Loop Feed
 

Wayne wrote:
Looks like I'll have to use a horizontal loop in the attic for a few months.
Any opinions on how to best feed it?
--open wire
--coax coil balun
--ferrite bead balun
--straight coax

The loop is about 13 feet per side, and I want to operate 20 meters and up.
In the past I have simply used a coax feed without a balun. It worked OK,
but there was a lot of stray RF around the house.

TIA



Another option is the one that I use which is a fan dipole - it
would be simple for 20 metres up - mine is from 80m up. It's fed by
co-ax via a balun. You can see details at
http://www.radiowymsey.org/FanDipole/fandiploe.htm . The only
interference I have had was to my son's amplified computer speakers
which was easily cured by winding it's input lead on a piece of
ferrite road. If you checkout the slinky dipole page you will see
how easy it is to make co-ax balun.

Charlie.

--
M0WYM
www.radiowymsey.org

Horizontal Attic Loop Feed
 

"charlie" wrote in message
...
Wayne wrote:
Looks like I'll have to use a horizontal loop in the attic for a few
months.
Any opinions on how to best feed it?
--open wire
--coax coil balun
--ferrite bead balun
--straight coax

The loop is about 13 feet per side, and I want to operate 20 meters and
up.
In the past I have simply used a coax feed without a balun. It worked
OK,
but there was a lot of stray RF around the house.

TIA



Another option is the one that I use which is a fan dipole - it
would be simple for 20 metres up - mine is from 80m up. It's fed by
co-ax via a balun. You can see details at
http://www.radiowymsey.org/FanDipole/fandiploe.htm . The only
interference I have had was to my son's amplified computer speakers
which was easily cured by winding it's input lead on a piece of
ferrite road. If you checkout the slinky dipole page you will see
how easy it is to make co-ax balun.

Charlie.

--
M0WYM
www.radiowymsey.org

Thanks, I'll check it out.

Horizontal Attic Loop Feed
 

Wayne wrote:
Looks like I'll have to use a horizontal loop in the attic for a few months.
Any opinions on how to best feed it?
--open wire
--coax coil balun
--ferrite bead balun
--straight coax

The loop is about 13 feet per side, and I want to operate 20 meters and up.
In the past I have simply used a coax feed without a balun. It worked OK,
but there was a lot of stray RF around the house.

TIA



SWR loss is less of a headache with open/ladder line feed.
My principal DX antenna is an 8jk end-fire array cut for 20 meters.
I've fitted it in the attic of all the homes I owned, fed it with
ladder-line, and worked it with a "classic" balanced tuner on 30 through
10 meters. Yes, RF does get into the wiring (especially triggering
slightly opened lamp dimmers), even with good grounding. The array is a
gain antenna, and has given me very good results over the past 35 years
I've operated with this antenna.

W9NPI

Horizontal Attic Loop Feed
 

"afcsman" wrote in message
...
Wayne wrote:
Looks like I'll have to use a horizontal loop in the attic for a few
months. Any opinions on how to best feed it?
--open wire
--coax coil balun
--ferrite bead balun
--straight coax

The loop is about 13 feet per side, and I want to operate 20 meters and
up. In the past I have simply used a coax feed without a balun. It
worked OK, but there was a lot of stray RF around the house.

TIA

SWR loss is less of a headache with open/ladder line feed.
My principal DX antenna is an 8jk end-fire array cut for 20 meters. I've
fitted it in the attic of all the homes I owned, fed it with ladder-line,
and worked it with a "classic" balanced tuner on 30 through 10 meters.
Yes, RF does get into the wiring (especially triggering slightly opened
lamp dimmers), even with good grounding. The array is a gain antenna, and
has given me very good results over the past 35 years I've operated with
this antenna.

W9NPI

The JK sounds great, but I only have a square area of about 15 feet per
side. My previous operation has been with coax and no balun. What methods
have you used to run the open wire line from the shack up into the attic?