[Lowfer] Final design for new antenna at Beacon " XR "

[Paul Daulton]

Andy, capacatance is the key to sucess of a lowfer verticle. The more 
cap you have the less coil needed and thus the more efficent the ant is. 

I was suprised at the cap of my lowfer ant, 330pf, and I originally 
attributed it to the base. Look at pictures of my antenna on Dex's site 
or on Part15 files. My top hat is a wire  cage formed by pvc cross 
arms. the skeleton forms a cube or approximates a sphere. In the Arrl 
ant book the formula for cap on a top hat says the sphere has 1.6 times 
the cap of a disk of the  same dimensions. Also look at running 
multiple verticle wires. The tower looks like a cylinder and has more 
cap than a single wire. I built  mine out of what I had, but it looks 
like I lucked into a good combination. 

Good luck. 

Paul k5wms

Quoting Andy - KU4XR <ku4xr at yahoo.com>:
> Hello fellow LF'ers:
>
> After quite a bit of deliberation, I have finally decided on the final
> design for the new antenna for Beacon " XR ". The new antenna is a
> necessity because it must be self supporting with the exception of the
> guy ropes. I started running into some problems with the utility Co. by using
> the power poles to tie my twine to , to be able to hold the top
> hat up. They told me I can't use their poles due to liability issues. 
> Makes sense... and I had some of the twine running over pine branches,
> and so I was constantly having to put lines back up because of breaks. 
> The sun wasn't very kind to the twine either. Using all the advice, and
> available info. I could get, I have finally decided to go with a 40 foot
> mast, made of wood, and schedule 40 PVC. Stuff that I either had on hand,
> or could be bought very inexpensively. The vertical part of the radiator
> will be 35 feet in length, with 5 feet turning horizontal, and coming into
> the window to the loading coil. The horizontal section will 5 feet above
> the ground. For the time being, I have opted to stay with the base mounted
> loading coil/variometer. The elevated coil, if done right, presents many
> constructional, and tuning difficulties. I won't rule out the possibility
> of an elevated coil at a later time though..... The top hat will be a
> 9 foot in length " semi - circle " similar to the old antenna I had,
> only half the size. The old top hat was 18 1/2 feet in length and had
> 13 wires in it. On the 9 foot top hat, I will be using most likely number
> 18 insulated wire from a bunch of rotator cable I have on hand, and will
> put as many wires in the perimeter as I possibly can to try and get the
> capacitance to ground as high as possible. I'm going to try for 32 wires. 
> I will use a # 10 bare wire for the perimeter wire. It will be easy to
> solder the smaller wires to. 
> I will use 3 - 10 foot lengths of 1/2 inch schedule 40 PVC to hold up the
> top hat, and a 3 foot vertical pipe with tensioning wires to help keep
> wire sag to a minimum. It will look like a big fan standing up there. 
> That is, If I can get it stood up there to begin with. I plan to guy it
> at about 36 feet, that is where a pipe joint will be at, and I hope this
> will help to minimize shaking at the joint from wind. The wooden " A "
> frame will be secured to the side of my mobile home. 
> So, in comparison, The old antenna was 30 feet AGL, the new one will be
> 40 feet AGL. The old top hat was 18 - 1/2 feet long, and the new one
> will be 9 feet long. So, I am gaining 10 feet in height, but loosing
> 9 - 1/2 feet in top hat. The overall antenna length will still be the
> same 49 feet, +/- an inch or two. The new antenna will be a little less
> obtrusive to the surroundings, and thus hopefully draw less attention. 
> I have all the materials on hand, and now comes the slow process of
> working in the heat, and putting it together in small portions. I will
> not be able to attach the top hat, and the radiator wire until I am
> ready to raise the antenna into position. I hope to put this antenna
> together in such a manner that it will be able to stay up for a few
> years, but that may be wishful thinking though. Wind, and weather do
> take their toll.  I hope everyone has a great day; 73 to all :
>
>
> Andy - KU4XR - EM75xr - Friendsville, TN. USA
> LOWfer Beacon " XR " @ 185.29875 KHz ( QRSS-60 )
>
> *** Temporarily OFF, while constructing a new antenna ***
>
> Coordinates:  N:  35º 43' 54" - W:  84º 3' 16"
> http://www.myspace.com/beaconxr
> ______________________________________________________________
> Lowfer mailing list
> Home: http://mailman.qth.net/mailman/listinfo/lowfer
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Lowfer at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

Paul Daulton K5WMS
beacon WMS 185.302 khz qrss30/slow 24/7
Jacksonville,Ar 72076
em34wu