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Author Topic: What's your take on this antenna idea?  (Read 16397 times)

WA4SE

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What's your take on this antenna idea?
« on: August 25, 2000, 03:02:22 PM »

I have been following the topics on this forum with great interest.  Though I have been an Advanced class operator for 3 years now, I have not had much of a chance to operate on HF due mainly to deed restrictions in my former apartment and here in our townhome.  

I was thinking about good ways to get out on HF without climbing around in our small attic, and this is what I came up with:  Diamond makes a 5 band antenna that is about 16' tall.  For a base, I thought about getting a 5 gallon bucket and filling it with concrete with a 1.5 or 2 inch pipe in the center that sticks out maybe a foot or two.  When I want to operate, drag out the bucket and mount the antenna to it.  When I am done, bring both back onto the porch.  I also thought about driving a stake into the ground to use to ground the antenna.

Any comments on the feasability of this arrangement would be appreciated.  I considered dipoles in the attic and all that, but then I need an external tuner for my TS-440S/AT and I need to be in the attic and it is about 4000 degrees up there.

Happy Hamming!

Scott - WA4SE
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WA4CNG

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What's your take on this antenna idea?
« Reply #1 on: August 27, 2000, 12:06:27 PM »

Check out the Outreach Antenna from Outbacker at about $350.  It is 12 ft tall assembled, 4 ft stored.  Does 160-10 including WARC.  Alpha Delta makes a ground coupler mounting system that folds up also that will let you do just what you described.  You should be able to get the whole deal for $550. There is a picture of it in HRO's Current catalog on page 95. A second option would be the Vectronics (MFJ) VEC-896 that is a shortened full feed vertical that is 12 feet high that requires NO ground under it.  It costs $199 at 1-800-363-2922 I'm currently looking into this unit to put in my attic to go along with my two DX-EE's and two square loops.
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K1TWH

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What's your take on this antenna idea?
« Reply #2 on: September 18, 2000, 10:49:35 PM »

WA4ASE,
_____If you do decide to go into the attic consider using
one of the small loop antennas (MFJ Superloop or AEA
Isoloop) for 30 thru 10M.  On 80 & 40M you can use the
braid of RG58 or RG59 as the wire and stretch it accross
the highest portion of the attic and then make the turn
at the end and go about halfway down, then mount a piece
of plexiglass and on it mount a Hustler 40M and 80M mobile
resonator (on each end).  Keep the ends of the resonators
a few inches away from objects. The open loop (circumference
equal to 1/2 wave and open on the side opposite the feed
line) works good in many attics also.  You might want to
do something like this just for times when you don't
setup the outdoors antenna.  
_____There are many other ways to go, these are just a
few I've tried and have worked fairly well.  Every indoor
antenna is a little different because of objects nearby
the antenna.  Some attics are terrible, and others are
seemingly as good as having an outdoor antenna.  In any
case, indoor antennas mean a little consultation to
look up and figure out the RF Exposure levels that are
permitted now.
_____73 and hope you get something up & running.  
Tom Howey  WB1FPA
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WB6BYU

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What's your take on this antenna idea?
« Reply #3 on: December 11, 2000, 01:02:11 PM »

There was an article - perhaps in QST - a few years ago where
someone used a plastic dishpan filled with concrete to mount a
tribander on an apartment roof.  (Actually, I think there was one
under each foot of the tripod, and some guy wires as well.)

One suggestion:  most verticals will require radials for reasonable
efficiency.  A simple ground rod is not adequate.  However, the
radials don't have to be straight or of any particular length.

Also, if you are willing to do some experimenting, you can make
your own vertical using 16' to 20' of aluminum tubing or rod.  (Look
for the smallest sizes which nest properly at the local home supply
store.)  Use a piece of PVC pipe for an insulator at the base and
wind a loading coil.  If one end of the coil is grounded, then you
can tap the feedline and antenna radiator onto the coil with clips
and adjust them for the best match on each band.

(Actually, you should be able to install dipoles in the attic which
are within the matching range of the tuner in your TS440S/AT.  But
I understand the heat problem!)

Good luck! - Dale WB6BYU

RobertKoernerExAE7G

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What's your take on this antenna idea?
« Reply #4 on: December 19, 2000, 12:48:13 AM »

For quite a while now, I have been wondering if it wouldn't make more sense to rent space where antenna(s)
can be erected, and operate remotely?  I honestly don't have any idea if remote operation can be done via "off the shelf" equipment.

Where I am, southern AZ, there is land with utilities, but no water; I don't imagine it would be expensive to buy, or to rent.

There must be rather secure roof tops, in commercial parts of towns, where antennas can be put up?

Is it feasable for a few hams to build a remote controlled club station?

With the advent of the internet, remote controll of station put on inexpensive land would seem to be an attractive option; especailly if the antenna site stays fixed while the operator moves from apartment or condo, or CCr house to CCr house?
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WT8Y

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What's your take on this antenna idea?
« Reply #5 on: December 19, 2000, 06:56:16 AM »

A vertical without a RF ground makes for a good dummy load. A ground rod just won't do if you really want a signal. The dipole in the attic, feed with 300 or 450 ohm ribbon would be the way I would go. Your only going to spend a half hour putting the element up, so
let's not  cry about the heat. This antenna would be balanced (not ground dependent) and able to be tuned on more than one band.
Make the flat top as long (longer the better) as you can and let the tuner take care of the rest. Denny
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KA3VVV

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What's your take on this antenna idea?
« Reply #6 on: December 24, 2000, 11:52:47 PM »

Get you a Don Johnson DK3 screwdriver it for a mobile but it work good in apt. Give Don johnson a call Phone #530-787-3905. He sale lot of them to ham that live in apt in rv parks.
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W9ZIM

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What's your take on this antenna idea?
« Reply #7 on: December 28, 2000, 01:30:26 PM »

I'm pretty much in the same boat as you, but there is a danger of "nickle and diming" yourself to death trying to make hairbrained antenna schemes work.  I've tried one or two and each time the results have been disappointing.

That said, there is an article in the January 2001 QST on how to build a portable antenna for 10 through 40 meters.  It's a well written article and the antenna design seems sound (it uses an innovative ground system) so you may want to look into that.  One caveate about a portable antennna: unless you're planning on leaving it "permanently" mounted you will spend quite a bit of time setting it up and tearing it down every time you want to operate.  This can really take the enjoyment out of ham radio and makes casual operating a pain in the neck.  There's nothing like the convience of being able to sit down, switch on the rig, and start playing radio.

Another idea for a more permanent solution is something called a Droopy Loop (another QST antenna article, but I can't remember what issue).  Basically, it's a loop antenna that sort of droops over the roof of your house.  You secure the antenna at the corners of your roof and run some twinlead into your shack.  Its low profile makes it virtually invisible and will not raise the ire of deed-restriction conscious neighbors.  Of course, you'll have to run conservative power if you don't want to cook your family.

If all else fails, get yourself a good mobile antenna and mount it to your car.  Then whenever you want to operate just pull your car out to the driveway and run some coax to your shack.  The neighbors would be none the wiser and nobody is going to complain about an antenna on your car!

Whatever you do, make sure your idea is sound before investing time and money into something that will either not work or will not work to your satisfaction.
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K1IR

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What's your take on this antenna idea?
« Reply #8 on: January 04, 2001, 01:01:40 PM »

Thin, invisible wire is your best solution, for sure. Keep the feed line very short and close to the building. Run that invisible wire out away from the building to any reasonable support. Use a tuner. Run 100 watts or less. Apply good rf grounding/counterpoise techniques. You'll do a whole lot better with 30-50 feet of skinny wire than that little vertical would allow - and spend less, too.
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KC5VDJ

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What's your take on this antenna idea?
« Reply #9 on: January 16, 2001, 03:38:11 AM »

I've lived in apartments ever since I became a ham, and I have found the following to work extremely well:

40-15M  MFJ-1788 High-Q loop

30-10M  MFJ-1786 High-Q loop

2M - Jpole

General Coverage RX - MacKay-Dymek DA-100E Active antenna with a Rat Shack 102 inch stainless whip.

Both loops are mounted vertiaclly about 3 feet above the ground on the back porch, and i usually get as good reports or better reports on 30m and up than most local hams using low inverted vees, longwires, or quarterwave verticals.

I think the key performance factor on the reports i get are because my antennas are actually tuned to the frequnecy in use.  Most other hams are using tuners and such that only tune the feedline, but do nothing to get all of the energy out of their antennas.

The MFJ loops are small, and unobtrusive, and are far more efficient than the AEA IsoLoop.

One other benefit of the loops is that they exhibit a high impedance to all but the frequency in use.  This means no TVI other than direct TVI.  Harmonics just show up as SWR and never leave the antenna.  In an apartment, this helps temendously to reduce complaints.

The worst complaint i've heard involved computer speakers, and that was fixed with a $2.00 common-mode choke.
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KC5VDJ

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What's your take on this antenna idea?
« Reply #10 on: January 16, 2001, 03:43:29 AM »

Concerning the MacKay-Dymek DA-100E active antenna, I have found that it works quite well from VLF through 30MHz.

My only complaint is that local AM MW stations tend to overload it a little, and a post-selector is of great help in eliminating this, but it would be nice to come up with a modification for a remote-head-mounted preselector.  Maybe using varactor diodes or something...

If I come up with something for this, i'll post it.
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