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Author Topic: Advice sought on attic antenna for MARS  (Read 4339 times)

W0QU

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Advice sought on attic antenna for MARS
« on: May 09, 2006, 03:38:03 PM »

I recently joined Navy Marine Corps MARS but have had a terrible time hearing other stations with my MFJ 10-band vertical.

Does anyone have any suggestions about a wire antenna which could be hidden in the attic which might work better?  My landlord won't permit wire antennas outside.
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W3LK

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Advice sought on attic antenna for MARS
« Reply #1 on: May 09, 2006, 07:54:41 PM »

If you are talking about 4-meg frequencies, you are going to have a very difficult time with an attic antenna, not to mention the increased possibility of RF getting into the home electronics.

I am not familiar with that antenna you are using, but if it is a 1/4 wave vertical, it will need a good set of radials, not matter what MFJ might say.

Lon - NNN0OOR / NNN0GAW THREE
MDE Navy-Marine Corps MARS
Proudly Serving Those Who Serve
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K2TL

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Advice sought on attic antenna for MARS
« Reply #2 on: May 25, 2006, 02:15:18 AM »

Build this antenna:

http://www.hamuniverse.com/cobraantenna.html

I built one for a friend who lives in a Townhouse.  I built the 40 meter version and it works FB on 80 meters !

In fact, its hard to believe how well it works.  I wish I knew about this 40 years ago..it would have come in handy many times!
There is a commercial version as well, but this is easy to build.  DX Engineering makes one.  You can download the details of their antenna in PDF.  I'm thinking of putting one up to replace my 40 meter twinlead fed dipole so I get better performance on 80 and 160.
Oh, BTW, make sure you don't use a shielded 3 conductor wire. That is a very common type of cable, so beware!
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N5UOA

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Advice sought on attic antenna for MARS
« Reply #3 on: May 29, 2006, 02:14:29 AM »

What you can do is build a loop antenna with small ties and eye rings. Take some ties and eye rings and put it up and make a semi loop  like a Squared off U  that should make a decent antenna.
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N5ILN

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Advice sought on attic antenna for MARS
« Reply #4 on: January 12, 2007, 02:22:48 PM »

Another possible solution...I built a Field Day antenna for 20m (and I'm having a hard time finding a link for the plans I used now), which seems to load up well on the area net frequencies using a manual MFJ tuner.  

The basic construction:  a 3/4" (ID) schedule 40 PVC pipe, 4-5' in length (I used 5' because I could get a section that long without cutting and it fit in the back of my car), with the top 4' wound by 30' of 16ga insulated stranded copper wire.  Then on the upper end of the winding, attach a 3' brass brazing rod as a "stinger".  At the bottom, connect your feedline and add a 15' counterpoise of suitable weight for your conditions.  Total cost, including splurging on a SO-239 connector for the base and having to get a small bag of 8-32 hardware, was $9 plus tax.  

It took me all of 45 minutes to build, and with absolutely no adjustments other than matching it through my tuner I was able to check into the Maritime Services Net on 14300 with the antenna lashed to a porch roof pole using fish line.  The only obvious sign of there being an antenna there (from a distance, anyway) is the section of coax leading from the base of the antenna to the apartment.

Another option, if your landlord can be convinced to let you try it, is a "Cliffdweller" antenna.  Here's a link for one:  http://usa2way.homestead.com/CliffDweller.html
I have one, but I never was able to get good transmission from it...too much metal in the construction of the apartment.  Received very well, though.

Hope this helps...
NNN0PEU / N5ILN
Alan
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