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Author Topic: Radials and counterpoise for very small yard area  (Read 3428 times)
KL7CW
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Posts: 609




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« Reply #15 on: March 27, 2019, 10:15:08 AM »

WW7KE makes a valid point that often reception is your biggest problem in typical urban settings.  Before spending effort and money on a transmit antenna, I would suggest that you string up a temporary wire and see if you can receive anything besides noise from all the plasma TV's, Wall warts, various lighting schemes in your house and other near (50 feet ??) houses.  Every situation is different.  For transmitting running the first 10 feet vertically directly on the wall, or probably even inches away I would guess for sure would attenuate much or most of your power.  I have never tried this myself, but have had some success with antennas further away.  You may need to experiment to see how far away from the wall is the minimum, but just a very wild guess is maybe something like at least several feet.  I have made some QRP QSO's from AZ, CA, and NV in similar homes to yours, but think the wires were mostly at least 5 feet from walls....signal reports not good, but better than nothing.  Something like your proposed 17 foot wire if it works near your house, is a good length for 15, 20, and 30 meters, and will work with reduced efficiency on 40 meters.  A remote (automatic) antenna tuner at the base of the antenna would be required for 15, 30, and 40 meters for sure, although if you have a built in ATU in your transceiver and a short run of coax, it may do the job with reduced efficiency.  When we lived in apartments, I strung up various wires made of very thin wire, probably 28 ga or smaller, however birds, wind, or whatever took it down a few times a year.  Worked with QRP power, but not sure about 100 watts.   Rick  KL7CW  Palmer, Alaska
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KF7ZFC
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Posts: 214




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« Reply #16 on: March 27, 2019, 10:26:38 AM »

Just bought on EBay 28 gauge white wire will give that a try as per WW7KE and K5LXP.

I have a have a RigExpert AA-30 so I can  tune the antenna. I have a 100 foot run of coax to the antenna.

My Yaesu FT 450D has a auto tuner that can deal with 3:1 swr

Because of how close my neighbor's child's bedroom  is I will be running 50 watts
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KF7ZFC
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Posts: 214




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« Reply #17 on: March 27, 2019, 10:50:43 AM »

Just bought on EBay 28 gauge white wire will give that a try as per WW7KE and K5LXP.

I have a have a RigExpert AA-30 so I can  tune the antenna. I have a 100 foot run of coax to the antenna.

My Yaesu FT 450D has a auto tuner that can deal with 3:1 swr

Because of how close my neighbor's child's bedroom  is I will be running 50 watts
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KL7CW
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Posts: 609




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« Reply #18 on: March 27, 2019, 11:12:09 AM »

Sounds like you are on the right track starting with 50 watts.  I say that since in my experience 5 watts will only rarely cause trouble to consumer devices, but even 100 watts will sometimes cause trouble.  Also I agree with your concern about RF exposure to your neighbor is justified.  My guess is that 28 ga wire will probably handle the power, but this depends upon many factors.         Rick  KL7CW
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W1VT
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« Reply #19 on: March 28, 2019, 07:36:46 AM »

https://krupniklaw.com/chapter-3-american-flag-display/
In addition to the federal law on flying the American flag, Arizona has a specific law that requires an association to allow the flying of certain flags on flagpoles on the lot:  the American flag, military flags, the POW/MIA flag, the Arizona state flag, an Arizona Indian nations flag, and the Gadsden flag.  The association shall adopt rules governing the flying of the flag, which may include limiting the member to flying no more than two flags at once and the limiting the height of the flagpole to no more than the height of the rooftop of the member’s home.  However, the association cannot prohibit the installation of a flagpole on a member’s property.
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KF7ZFC
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« Reply #20 on: March 28, 2019, 12:52:19 PM »

Zack

The house is owned by my daughter and son-law and I am not sure they would like a flagpole.

Additionally the front yard is not big enough to lay down radials long enough for 20m operation

Steve

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W1VT
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« Reply #21 on: March 28, 2019, 04:38:13 PM »

There may be other hams in Arizona that may not be aware of that flagpole law.
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KL7CW
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Posts: 609




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« Reply #22 on: March 28, 2019, 04:55:09 PM »

Just a quick note about on ground or buried radials.  They do not need to be a quarter wavelength long.  In fact it is better and more cost effective to install more, but shorter radials, than a few 17 foot radials which is 1/4 wavelength on 20 meters.  Something like a dozen 8 or 10 foot radials would yield fair results on 20 meters and higher frequencies, and may even work to a certain extent on 40 meters if longer radials are not possible. I am not necessarily recommending a flagpole antenna but we are just trying to have you explore all options.  If you have plastic rain gutters, possibly you could just lay a wire inside the gutter.  I have also just tossed a wire up on roofs and tuned it against ground with an antenna tuner.  However I understand that tile roofs which are common in your area and some composite shingles tend to absorb RF.  I guess you could just try various options.     Good Luck   KL7CW
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W1BR
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Posts: 4196




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« Reply #23 on: March 29, 2019, 07:51:59 AM »

The flagpole antennas may be some sort of OCF design similar to a Cushcraft R7.  Although I have a tower and a six band Navassa  JK beam, the backup R7 will work DX.  But again, they are expensive.
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KF5KWO
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Posts: 66




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« Reply #24 on: March 31, 2019, 03:10:44 PM »

Hi Steve,

You and I are in the same boat, my friend.  Stealth ham radio is a reality for many of us. 

I looked up your QTH on Google maps and noted that the current “street view” pic shows some Christmas lights strung up on the eaves of the roof.  I had a wire strung up as a horizontal loop, very much in the same location as those lights and at the same approximate height, all around my house, and could work 40m and 80m quite nicely with it. Quite easy to do. You’d just need to run some twin-lead or similar feedline out through a wall or window and up to the feedpoint. And instead of following the eave to the front door then back out to the garage, just run it above the sidewalk across to the garage. Use a beige-colored insulated wire and it blends right in. I hung mine with little hooks screwed into the wood above it.  Using this method doesn’t require radials.  One thing though: when using it on 20m, it would trip my house alarm!  But 40 and 80 were fine (TS-520SE, 100 watts, MFJ manual tuner).

Granted this is a compromise antenna due to low height and your wish to keep the power output down, but given the lack of trees to provide concealment, this might one of your only alternatives.  And depending on what mode/s you wish to work, 50 watts may be more than enough. You might be in for some QRP operation, or CW and other data modes, rather than SSB or AM.

I also have the MFJ-1786 Magnetic Loop for 30-10m, and use it in conjunction with my current 40m stealth vertical. I’ve had it for about 15 years, can’t complain at all because of what it gives me.

Very best of luck!

73 de Jeff, KF5KWO
Helotes, TX
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KL7CW
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Posts: 609




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« Reply #25 on: March 31, 2019, 05:16:29 PM »

Here are two other ideas to consider, probably neither is a great idea, but should work.  How about installing a good mobile antenna on one of your cars.  If your subdivision does not prevent this.  Then run a small stealth coax out to the car.  Configure it with some type of break away connection, so if the car accidently gets driven, no problem.  Install something better and bigger than a ham stick.  Performance on 20, and 17 should be good, 15, 12, and 10 meters should be excellent, and 40 and 30 meters should be useable, especially if the antenna is at least something like 8 feet or longer and has a low loss loading coil, preferably at least several feet above the base.  Another idea I have considered if I ever need to live in civilization rather than out here in rural Alaska is to buy one of the "portable" basketball hoop supports which I seem to see at about every third house in HOA developments in AZ, CA, etc.  Put it in the driveway, install some hidden radials and an automatic antenna tuner beside your driveway where you have the basketball thing.  I have not measured or modeled them, but if you electrically tied everything in the structure might be equivalent to say a 10 or 12 foot wire, which is probably long enough to work moderately OK on 20 through 10 meters with any good tuner.  I have not tried either of these schemes.  Please do consider going to a local park instead.  Often when we travel or visit outside of Alaska, I just send the girls (wife, daughter, and granddaughter) off on a shopping expedition or visit to a spa for the day while I sit a picnic bench in a park and operate my portable equipment.  It does get a bit rough at times like north of the Arctic circle in Norway in the winter, or on a hot summer day in AZ. Also many parks close at sundown or before 10 PM.  Even a typical urban city park only a hundred meters or so from houses, usually has low or very low receive noise levels. Low power (probably CW) outdoor operation does not appeal to everyone.  When my grandkids were young, often we took them to the park where they would play on the playground or skateboard while I played radio and my wife would knit, read, or play with the grandkids.  Warning, with the present sunspot cycle status being what it is, my park expeditions over the last 5 years have not been as productive as in past decades, both in the "lower 48" and in the UK and Europe, so do not expect a 100 percent success rate.       Cheers,   KL7CW
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N4NYY
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Posts: 5224




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« Reply #26 on: April 01, 2019, 05:56:04 AM »

You do not need a solid conductive surface.  Your plan to use chicken wire has a lot of merit.  Check out this web page:

 http://www.sherweng.com/documents/GroundScreen-sm.pdf

Personally, I would opt for a different radiator system, if possible.  How much vertical wire can you run?  There are remote antenna tuners that can handle the matching--not the cheapest solution, I know.

Pete

I'm glad someone asked this as this was something I have always thought about, but never complimented. The question is, if you use chicken wire, how much grid do you need?
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KD0REQ
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Posts: 2406




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« Reply #27 on: April 01, 2019, 02:26:01 PM »

how much space you got? Wink

if you think of it as a straight radial field, X*Y. for your favorite bands.  there might be one of those EE "infinite grid of 1 ohm resistors, with one diagonal 1 ohm in the middle. calculate resistance points A and B" issues that makes it look like a perfect counterpoise to everything. this one would not be a washout question for freshmen... but an opportunity to see how good your tuner is.
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K6PCW
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Posts: 27




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« Reply #28 on: April 29, 2019, 08:20:36 AM »

I see it's been nearly a month since anybody's posted on this thread, but the OP and others might enjoy perusing this ham's blog on stealth antennas.  http://www.n6cc.com/tactical-antenna-systems

Some neat ideas, good advice, and enjoyable reading throughout his website.

Good luck!


73 Pete
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K6PCW
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Posts: 27




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« Reply #29 on: April 30, 2019, 11:18:31 AM »

And some more great ideas.  This Florida ham club has does a wonderful job with this antenna publication.
https://www.hamfesters.org/main/wp-content/uploads/2012/07/Stealth-Antenna-Guide.pdf
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