Topband: Re Small lot antenna idea (steve d)

M0VEY at M0VEY at
Fri Feb 9 11:26:52 EST 2007

>Hello, I want to get some suggestions about this before I try it. I was  
going to do something >similar to it earlier but I just havent got around to  it 
yet. Anyway, a buddy of mine was >telling me that I really need to get  back 
on Top Band as conditions are at their peak. So I >think I am going to  take 
his suggestion and throw something up - quite literally HI.

>My buddy, KA1VHF, said to get a piece of wire as long as I could  get up and 
then make a >loading coil to match it. The only problem with this  approach 
is it would be a VERY limited >bandwidth. So instead of making a  loading coil 
I started thinking of using my screwdriver >antenna as the  loading coil 
instead - after all, thats all it is, right? Only its motorized.  

>The plan is to use insulated wire and drape it  over the house (no trees to 
speak of so >unless I erect a mast or tower, or  go into the neihbors yard I 
dont have any other support). >The screwdriver  would be at one end of the wire 
to load it. 

>The  question now becomes how to I ground it? I could tap into the plumbing 
in the  house, >but then the wire would be laying right on top of the 
counterpoise. I  dont know how that >would affect the signal. 

>  The other option would be to just string out a longwire from my room and 
use my  tuner to >load it. Then, use the plumbing as a counterpose. But again, 
the  wire would have to go over >the house. 

>I  could go AROUND the house, but the antenna would be at the most 6 feet 
off the  ground >(accept where it would slope up to my second story shack) and 
10 feet  from the house. 

>Any ideas? Something that  radiates is better than nothing, and something 
that radiates >better is..  well, even better! But I have to make due with what 
I have.

>Steve, KC8QVO
Hi Steve, 
              This worked for me & the top loading wire can be zig zagged. 
After you have  read this you can check out my yahoo group.
 In early 2005 I spoke with Andy, G7LRR about homebrewing an  antenna for 
Topband that I could fit in my garden.Andy suggested using a design  by Alan, 
G4ERZ that I could fit in the 60' space I had. I had a head start,  because Paul, 
G6AXW had already made one which just needed altering so it could  be coax 
fed instead of being fed with a length of wire.
This antenna is space  wound on a 6' length of 1 1/2" plastic pipe. It is 
fixed to the pipe using a hot  glue gun. Total length of wire is approx 130' with 
half the wire helically wound  on the pipe & the other half of the wire left 
as a top loading wire. For  this mk1 antenna a hole was drilled in the side of 
the antenna, 2" from the  bottom. I fed the coax in here & joined the centre 
part of the coax to the  Helical wire, using a choc-block. The braid side of 
the coax was also connected  to a choc-block so a wire could be attached & 
returned to the ground system  once the antenna was in the air. I will describe in 
my next posting how to use  an S0-239 connector as on the mk2. 
I made a mounting loop at the top of the  antenna so that I could pull the 
antenna to the top of my 40' flagpole I use as  a mast. I will describe how to 
base mount this antenna in another posting. I use  2 counterpoises connected to 
my ground system. One is 125' long & runs under  the top loading wire. The 
other is a very long wire running thru the bottom of a  wooden fence alongside 
my garden.
I also buried a 3' copper hot water tank,  4' in the ground. This took 2 s 
points off my background noise level &  improved my TX signal. After trimming 
the antenna wire the overall length of my  Helical is approx 125'
My antenna is 40' in the air with the top loading wire  sloping to 20' above 
ground. I have had some good dx results & inter G  contacts with the Helical. 
Please post any messages to this group if you have  any questions to be 
Details of any of your homebrew Topband, base  or mobile antennas would be 
appreciated. Regards, Phil. m0vey 
_Click here:  Topband helical yahoo_ 
_Click here:  M0VEY_ (  
_Click here: Welcome to  G7LRR Amateur Radio Site_ 


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