[TowerTalk] Converting a vee to a top-loaded vertical

[Michael Tope]

Hi Dick,

I used an interesting variation on this idea at my QTH in Florida. I put the center
of an 80/40 meter parallel dipole in the top of a 60' pine tree. Near the base of the
tree, I placed a modified  Dentron "Super Tuner" about 8 feet off the ground. The 
Super Tuner was outfitted with a couple of relays which would bypass the tuner 
for 40 and 80 meters. For 160 meter operations, the relays would short the antenna 
coax lead's center conductor and shield together and route the signal thru the T 
network (the output SO-239 on the tuner was floated on a piece of G-10 PCB material). 
Originally I fed this against a couple of 1/4 wave elevated radials (about 10' feet high). 
Performance was mediocre at best.  I then acquired about 3000' of #14 stranded 
copper from Home Depot. I laid out around 25 ~1/4 wave radials along the ground 
under the "T" antenna - performance improved dramatically. After the change I finally 
managed a QSO with 4X4NJ for worked all continents on 160 with 100 watts. 

BTW, the relay was switched from the shack thru the coax to the tuner using a 
couple of RF chokes I picked up from RadioWare. 

Mike, W4EF......................................



----- Original Message ----- 
From: "Dick Green" <dick.green@valley.net>
To: "Tower" <towertalk@contesting.com>
Sent: Thursday, October 05, 2000 5:32 PM
Subject: [TowerTalk] Converting a vee to a top-loaded vertical


> 
> Hello TowerTalkians,
> 
> I'm decommissioning an 80M vee that I have mounted 65' up a tree (I just put
> up an 80M delta loop elsewhere on the property.) I would like to use the 80M
> vee pulley mount to put up something decent for 160M. I could use the mount
> for an inverted-L, but would need to suspend the far end of the horizontal
> portion from another tree (that, ahem, happens to be slightly over the
> property line...)
> 
> It occurs to me that converting the vee to a top-loaded vertical might be
> easier. In his section on the "T" antenna, ON4UN says the length of the T
> should be about twice as long as the missing portion of the 1/4-wave
> vertical. If the T wires are sloping, they have to be a little longer. If I
> use a 65' vertical wire, it seems to me that the existing legs of the 80M
> vee ought to be just about the perfect length (68' each) for the sloping
> top-loading wires. Why not take out the coax and center insulator and
> replace it with a vertical wire connected to the two existing sloping wires?
> Has anyone tried a conversion like this or set up a top-loaded 160M vertical
> with similar dimensions? How can I determine the correct length for each
> wire? I don't know the first thing about antenna modeling software!
> 
> BTW, my plan is to use two elevated radials, about 130 feet each. I figured
> I'd slope them up at 45 degrees from the ground to about 10 feet. Would it
> be better to elevate the vertical element (i.e., make it 55' long instead of
> 65') and not slope the radials? Another issue is that the radials would be
> in the same plane as the sloping elements. Any problem with this?
> 
> Any help I can get with this idea will be much appreciated.
> 
> Thanks & 73,
> Dick WC1M
> 
> 
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