Survivalism & Self Sufficiency Topics > Amateur Radio How-To's

UnderGround HF Antenna ,40 meter Loop

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Carl:
I really did not consider it worthy of a separate thread as it is so easy to do... it is a loop of wire buried with an edger or in my case a cable "plow" /ditch digger ...you know...looks like a big chainsaw/digger. Place the wire beneath grass level and INSULATED WIRE does work a bit better. My loop was cut for 40 meters or about 154 feet long (longer than above ground loop)with a dry feed point (buried bucket with a lid) as the feed point has a 4 to 1 balun ,though a 9 to 1 may be better.

My loop shows about 1.8 to 1 SWR on 7.250 before I engage the LDG auto-tuner and that makes it match all bands ...except for 10 MHZ for some reason.The wire is left over electrical /copper  10 gauge though wire size is not too important...I have even used galvanized electric fence wire (1/4 mile for $12) but nature tends to be hard on un-protected metal.

In use the antenna loses about 2 to 3 "S" units compared to a dipole at 25 feet or my end fed half wave antenna at 8 feet above ground...but those "S" units are just NOISE ...so unless you  like full scale meter readings , this LOW KEY antenna is a winner. Though I note the GROUND MOISTURE does effect it a lot after a rain,though even when wet I was able to talk to several Canadians and Northern US while running 100 watts out with little trouble ...just low "S" meter readings.

Worms...night crawlers also tend to surface after I transmit a while when soil is wet from rain.

A bit more about it and how it is working here :

http://thesurvivalpodcast.com/forum/index.php?topic=50979.0

Alan Georges:
I must say it does work, and work well at that.  Losing 2–3 S-units is quite a hit, but with anything more than a QRP rig it can still reach out several hundred miles.  For an ultra low-profile antenna this one is awfully hard to beat.

I can think of all kinds of evil uses: an unfindable pirate shortwave site, "borrow" part of your neighbor's yard for that ginormous 160m antenna (install when they're on vacation), and of course, fish bait.  3;)

Carl:

--- Quote from: Alan Georges on August 20, 2014, 08:11:28 PM ---I must say it does work, and work well at that.  Losing 2–3 S-units is quite a hit, but with anything more than a QRP rig it can still reach out several hundred miles.  For an ultra low-profile antenna this one is awfully hard to beat.

I can think of all kinds of evil uses: an unfindable pirate shortwave site, "borrow" part of your neighbor's yard for that ginormous 160m antenna (install when they're on vacation), and of course, fish bait.  3;)

--- End quote ---

You know how low key the peppermint mine location is,even though I did find a way to put a half wave end fed antenna in the grape arbor to pass all but the closest inspection.Did you know that a TREE can also be used as an antenna, Look for TREES as ANTENNAS file in my end fed half wave folder...anyone can view and download.

https://drive.google.com/folderview?id=0B5ZIZLZV4AwIX3ZwckFUeGpEOXc&usp=sharing

backwoods_engineer:
Thanks for posting this, Carl.  I might have to give this a try, in my present rental-house situation.  I wouldn't bury the wire, you understand, just put it right on the surface.

Carl:

--- Quote from: backwoods_engineer on August 21, 2014, 03:29:30 PM ---Thanks for posting this, Carl.  I might have to give this a try, in my present rental-house situation.  I wouldn't bury the wire, you understand, just put it right on the surface.

--- End quote ---

It will surprise you at how well a wire on the ground will work,too many people just KNOW it won't work.
Maybe a GRASSWIRE ANTENNA is in your future.Or my  loop will surprise you at how well it works. I can hear BETTER
with the current LOW antennas I use now, including the end fed half wave at 8 feet.

http://f5ad.free.fr/Liens_coupes_ANT/G/K3MT%20Antenne%20gazon.htm

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