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Author Topic: Long Wire Antenna Questions  (Read 8125 times)

Offline K5KNT

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Long Wire Antenna Questions
« on: October 14, 2013, 1458 UTC »
Hi all,

I recently ordered an AFREDI SDR-net and following suggestions for some of you on the WUNCLUB chat Saturday I'm going to try the outdoor long wire antenna when I get the radio.  The room the radio will be in is in the southeast corner of the house with a window in the south wall. My location is San Angelo, Texas (West Texas).

1. Should I run the antenna along the south side of the house or around the corner and along the east side? Our neighbors are to the east and west and the air conditioner is also on the east side of the house.

2. What gauge of wire would be best? Stranded or solid?

3.  I'm concerned about the wire breaking when closing the window. Drilling is not an option at this time. 

Thanks for all the help and I hope to be contributing here in the near future.

Kent
K5KNT
Grand Forks, ND, USA

Offline ChrisSmolinski

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Re: Long Wire Antenna Questions
« Reply #1 on: October 14, 2013, 1702 UTC »
Hi all,

I recently ordered an AFREDI SDR-net and following suggestions for some of you on the WUNCLUB chat Saturday I'm going to try the outdoor long wire antenna when I get the radio.  The room the radio will be in is in the southeast corner of the house with a window in the south wall. My location is San Angelo, Texas (West Texas).

1. Should I run the antenna along the south side of the house or around the corner and along the east side? Our neighbors are to the east and west and the air conditioner is also on the east side of the house.

Generally, I'd try getting the antenna as far away from the house as quickly as possible, to reduce pickup of QRM generated by devices inside the house. Random wire antennas, especially short ones, are not  intended to be directional (although they can have directional characteristics).

Quote
2. What gauge of wire would be best? Stranded or solid?

Stranded for sure, solid wire will fatigue and break. #14 is the most common gauge used, but I have used #16 as well.

Quote
3.  I'm concerned about the wire breaking when closing the window. Drilling is not an option at this time. 

You may be able to run the wire under the window and still be able to close the window tightly enough.  You'll want to secure the wire outside before bringing it in, and you should think about some sort of lightning protection. There's some gas discharge type arrestors, for example.

I'd suggesting bringing in the signal via coax, rather than the actual antenna wire, to minimize pickup of QRM generated inside the house. Since you can't drill a hole, normal sized coax won't likely fit as well under the window. As this is a receive only application, you may be able to get away with using a very small diameter coax like RG-174.

Quote
Thanks for all the help and I hope to be contributing here in the near future.

Kent

Chris Smolinski
Westminster, MD
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Offline thechoat

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Re: Long Wire Antenna Questions
« Reply #2 on: October 14, 2013, 1911 UTC »
You can also drill a hole in a piece of wood run your coax through it and shut the window down onto it.
central midwest
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Offline jFarley

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Re: Long Wire Antenna Questions
« Reply #3 on: October 14, 2013, 2055 UTC »
I've used in the past to distribute CATV the EZ way through windows.  Probably would be just fine for HF.

http://www.amazon.com/Flat-Coaxial-Coax-Cable-Window/dp/B001WAPIRW
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Offline refmo

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Re: Long Wire Antenna Questions
« Reply #4 on: October 14, 2013, 2351 UTC »
1.  Chris' suggestion about using coax to get the antenna away from the house will definitely make a big difference in reducing noise, so maybe along the back of your property.  I would keep it away from power lines and away from your air conditioner.  Some kind of balun or unun will also help to keep noise from the coax shield from getting into the radio.  Also, running the coax on the ground (not suspended) to the house will help keep noise from the shield to a minimum.  Actually, having the antenna and the coax on the ground is the simplest installation (zero supports needed) and greatly reduces the chance of a lightning strike.

2.  Stranded will likely not break as easily as solid, but stranded can also get noisy if the wire oxidizes and the strands rub against each other.  I generally use solid 14AWG THHN insulated.  Use copper or copper-clad wire.
With the current cost of copper wire, I recommend using whichever you have on hand or whichever you can get the best deal on.

3.  thechoat describes what I do.  I have a spare piece of wood flooring cut to the width of the window.  Drill a hole in the board big enough to fit the coax through and close the window on the board.  
Also, MFJ makes similar metallic window entry panels.

I also must echo Chris' remark about considering some sort of lightning protection.
« Last Edit: October 15, 2013, 0015 UTC by refmo »
central Kentucky
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Offline redhat

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Re: Long Wire Antenna Questions
« Reply #5 on: October 15, 2013, 0846 UTC »
As far as cable entry is concerned, I always just added a piece of weatherstripping to the window sill and cut out a small piece of it big enough for the coax to go though.  Then, use a pair of thumb locks to keep the window closed and secure.

+-RH
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Re: Long Wire Antenna Questions
« Reply #6 on: October 15, 2013, 1154 UTC »
A short piece of neoprene fuel line from an auto parts store over the coax where it enters through the window can go a long way to protect it from wear.

Peace!

Offline K5KNT

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Re: Long Wire Antenna Questions
« Reply #7 on: October 15, 2013, 1355 UTC »
Thanks for all the good suggestions!  I have a lot to consider now.
K5KNT
Grand Forks, ND, USA

Offline desmoface

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Re: Long Wire Antenna Questions
« Reply #8 on: October 15, 2013, 1745 UTC »
Great suggestions.  I believe this is what I used for my loop: http://www.davisrf.com/antenna-wire/polystealth.php .  It's been up for a long, long time, and has survived several sizeable tree branches falling on it.  It' a little harder to work with, but it's rugged.  It doesn't have any memory, so it wants to straighten out as soon as you remove the wraps from the spool. 

Good luck.

Steve
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Full Wave 80 Meter Horizontal Loop ~ 260 Ft Long
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NE Ohio

Offline K5KNT

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Re: Long Wire Antenna Questions
« Reply #9 on: October 23, 2013, 1429 UTC »
This morning I ordered a Par EF-SWL antenna from Universal Radio. I'm looking forward to getting it up and listening.
K5KNT
Grand Forks, ND, USA

Offline Mentholyptus

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Re: Long Wire Antenna Questions
« Reply #10 on: October 27, 2013, 1835 UTC »
I have an EF-SWL antenna also and it works very well. Definitely quieter than a regular piece of wire too. Makes a great portable antenna for listening outside on the deck, etc. Got mine from Universal as well. There seems to be a big demand for them... Had to wait over a month for mine due to Universal being backordered. Hope you have better luck.
Location: Ligonier Pennsylvania area
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Antennas: Par EF-SWL -- 25 ft horizontal longwire
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