[Scan-DC] antenna question

[Rick]

Congrats on the idea of using another magnet inside the car - very creative!
If you're just going to be receiving you might get "good enough" reception
without doing anything else. 

You could do an experiment to see if a ground plane helps your reception.
You could use very thin magnet wire in 1/4 wavelength lengths (#30 or less,
spray-painted black so as to be not very visible) and use clear silicon
seal/RTV to hold it down - it works great on glass. Use 3 or 4 radials and
one end of each under the mag mount. If you listen to VHF-Hi (140MHz and up)
make the radials about 17-18" If you only listen to UHF (450MHz and 800MHz)
you can get  away with  3-4" radials and longer is always better. 

It would be interesting to see if some of the weak signals, like far-away
weather band stations, came in more clearly with the radials. I have magnet
wire if you'd like to try the idea. 

Best wishes for Happy Monitoring,

Rick

-----Original Message-----
From: Scan-DC [mailto:scan-dc-bounces at mailman.qth.net] On Behalf Of Scott,
KB3JQQ via Scan-DC
Sent: Sunday, September 14, 2014 10:58 PM
To: Scan DC
Subject: Re: [Scan-DC] antenna question

A magnet mount antenna uses capacitive coupling to "attach itself" to the
ground image. In order to be effective, it has to be at least 1/4 wavelength
at your frequency of interest. You can't magnetically couple to aluminum, it
has to be a ferric material.


HTH 


==
Have scanner, will listen.




________________________________
 From: Doorgunner <doorgunner666 at msn.com>

 

or by definition does it have to touch/be grounded/ etc? 

From: Doorgunner 
Sent: Sunday, September 14, 2014 10:01 PM
To: DC-Scan 
Subject: antenna question

So I am slowly working my way back into scanning....setting up my very new
car.
My car is mostly glass on the top, I found a way to put a humble 3dp or less
mag mount antenna by putting another magnet under the glass inside.
Here is my question to the group of guys that know more than I do...
---I have no ground plane for the antenna, if I adhered a 12x12 square under
the 1/8 inch glass would that work? Would aluminum be ok? What would be
best?

I am enjoying the group...still in the process of getting my home attic beam
hooked up..

Thanks, Paul/aka Doorgunner
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