Stealth antenna

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  • Idea
  • Updated 3 years ago
Morning all,

I wanted to share something I accomplished just today.  Getting back into ham I wanted to be on HF but I live in a HOA and its pretty difficult to sell them AND my wife on big antennas.  So things need to be pretty much invisible.

Here is what I did.  I do realize it is not optimal and yes I'll not be that S+40 station you hear driving through the pile ups, but it does seem to work very well.

I made my own Jpole and put it up in a Cottonwood tree very close to my shack.  This was the test.  The antenna did fairly well.   So I went ahead and purchased a Jpole SR from Alpha Antenna.   I decided to do this because by the time I prices out matching wire and cores I was close to the cost of the pre-built antenna from Alpha.

This antenna, using a tuner works on all bands from 160 through 6 meters.  Seems to me like a perfect match for the 6300 that is supposed to arrive today.

We live in an area that can get windy as well.  My original idea was just to shoot an arrow over the tree trailing a rope and hoist one end of the jpole SR up with that rope and secure the other end.  Well this proved harder than it should have been.  The tree is tall and even with a compound bow I could not seem to get an arrow over the top of the tree.  Even from my roof it sort of tried but would get hung up on branches and I could not get to the other end.

I'm no Robin Hood and I'm sure someone with better bow skills and a better bow could have launched that thing just fine.  But I failed.

Ok plan B.  I can get the rope part way up and I did that.  But it was not enough to compensate for the full length of the Jpole SR (34 feet).  So... I went to the store and bought 40 feet of gray electrical PVC.  I used 1 inch diameter.  I glued it together fished the antenna to the end and also used hot glue and couplers to get the PVC to mate with the Alpha antenna match network.

Great idea.  It looked cool and now I had a totally weather proof antenna.  One small problem.  From the point I could get the rope the 1 inch PVC was just too flimsy and bent over.  So mounted I had an inverted J.

I'm not a radiation expert but something told me having part of the antenna drooping over would not be great.  

Back to the store.  This time with 2 inch PVC.  Much more rigid but still in sections glued to make 34 feet there was no way this was gonna stand on it's own.  But actually I didn't need it to.  I had managed to get a rope up that would leave only about 10 feet standing on it's own above the rope.

It is lucky I had this rope because there was a new problem.  34 feet of 2 inch and 1 inch PVC is HEAVY!   It took all my strength between pulling on the hoist rope and shoving the thing up into the tree to get it up.

I also had to sort of thread the thing through the branches I wanted to use as supports.  But I got it done.  I used large tiewraps at the base to secure the base pretty well and the rope hoist point about 10 feet from the top secures it there.  Beyond that it is threaded through a number of branches and I think it is unlikely it will completely come down.

So I think I overcame the obstacles and managed the goal.  I have an all band HF antenna hidden in a tree.  You really have to look to notice it.

Here is what the assembly looked like on the ground:
https://dl.dropboxusercontent.com/u/7578983/JpoleSRInPVCReadyTogoUp.jpg
https://dl.dropboxusercontent.com/u/7578983/JpoleSRFeedPoint.jpg

Here is where I wanted to put it:
https://dl.dropboxusercontent.com/u/7578983/JpoleSRGoal.jpg

After some sweat and strained muscles here it is mounted:
https://dl.dropboxusercontent.com/u/7578983/JpoleSRUp.jpg

The feed point sits in a place about 15 feet up where the first main limbs start to branch out:
https://dl.dropboxusercontent.com/u/7578983/JpoleSRFeedPointInTree.jpg

Here is what the antenna looks like looking up from the feedpoint:
https://dl.dropboxusercontent.com/u/7578983/JpoleSRLookingUp.jpg

My goal was for it not to be very visible.  Here are some views around the yard and road:
https://dl.dropboxusercontent.com/u/7578983/JpoleSRViewFromSouthRoad.jpg
https://dl.dropboxusercontent.com/u/7578983/JpoleSRViewFromWest.jpg
https://dl.dropboxusercontent.com/u/7578983/JpoleSRViewFromNorthWest.jpg

If you can't tell it's pretty hard to find the antenna in that tree.  Of course as the leaves fall it will be a little more visible but we live around a bunch of old people that probably can't see that well anyway (LOL).   

So I'm never gonna complete with you guys with your 500' towers and mega beams with 9kw of power... but on a good day with this setup and about 25 W I've worked Venezuela, Japan.  Hopefully I can get out more.

I appreciate all of you here on the Flex forums and while I realize this is NOT a post related to a flex, my flex 6300 when UPS gets here will be making use of this antenna primarily.

It was a fun project to engineer, test, build and install.  I think my total cost including the antenna is about $100.

And as I typed in this post my doorbell rang and UPS was there with my 6300.  See you guys on the air!
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Mark - WS7M

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Posted 3 years ago

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Photo of Richard McClelland, AA5S

Richard McClelland, AA5S

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One day,  after I undertook a similar exercise while getting a 250' delta loop mounted at four points up about 35', my neighbor came over to our shared fence.   He said that he watched me for over an hour and was genuinely concerned for my well being.  I can only presume that he was referring to my psychological well-being since I was obviously in good physical shape at the time.  I explained that I was installing a ham radio antenna then a light came on for him.  He was quite relieved to know that he wasn't going to have to call the men in white outfits to come take me to a safe place.  I can totally relate to your travails. 
Photo of Rob G6EIH

Rob G6EIH

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Did a similar install, just waiting for the leaves to fall now before the guys next door complain :-(

I live in hope they won't notice, no RFI yet.

Rob
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Rob N4GA

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Nice job Mark and thanks for sharing. The pics are great and good idea overall!

You've inspired me to go fix my antenna, half the dipole is hanging straight down.

Thanks!
Photo of K9APW - Dick - Verona, WI

K9APW - Dick - Verona, WI

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You did great! You need to submit a write up & pics to QST or CQ! Don't forget to seal the feed point connections with good FlexSeal or such. Waterproof all such fittings. Good luck & enjoy your great super next radio!!
Photo of Mark - WS7M

Mark - WS7M

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Hey thanks!  I have not sealed them yet as I'm waiting on RG-213 to replace the feed line with.  That is just RG58 there now.  I think that will come in tomorrow and once I fish it though I'll seal everything up.

I'm going to put a write up on my web and I will submit something.  I think it helps to see how others are solving problems.  I admit I got the PVC idea from another user of a Jpole SR.  He did it a little different and just ran his antenna on the outside of the PVC using it for some support.  I figured why not put it inside?

Mark