yeh, a chain link fence with a metal top rail definitely wouldn't work too 
well as an antenna.
but, it would work reasonably well as a paracytic element to a horizontal 
wire placed above it.
or, as a ground plane for a vertical.
468 feet of chain link fence is an awful lot...does that go all the way 
around your property or along the front or something?
73
Colin, V A6BKX
----- Original Message ----- 
From: "Michael Thurman" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, November 23, 2010 12:14 AM
Subject: Re: nvis antenna


> if ou are thinking of using your fence as an antenna you have one issue =
> that may or may not be a real problem. because the chain and associated =
> hardware isn't electrically bonded, you can get poor contacts, or even =
> semi conductive contacts with corrosion and can generate rfi . having =
> coorsion and semiconductors, the signal you transmit can excite the =
> those areas and cause them to re adioate and generate harmonics. you =
> also have the issue that most fences of this type are grounded as well, =
> so matching it would be very difficult
> so be careful  and if you decide to use the fence as an antenna, make =
> sure you check for harmonics and tvi or rfi   good luck
> kb7nla
> On Nov 22, 2010, at 5:07 PM, Junior Lolley wrote:
>
>> Colin, that is an idea I have a 6 foot chain link fence.
>> It is 468 foot long.
>> Thanks much.
>>=20
>>=20
>> Junior Lolley KG4ITD Liberty County E. C.
>>=20
>>=20
>> -----Original Message-----
>> From: For blind ham radio operators =
> [mailto:[log in to unmask]]
>> On Behalf Of colin McDonald
>> Sent: Monday, November 22, 2010 4:00 PM
>> To: [log in to unmask]
>> Subject: Re: nvis antenna
>>=20
>> try getting the antenna say 5 feet above the top rail of the fence.  =
> the=20
>> metal top pipe rail will act as a paracytic element and may give you =
> even=20
>> better results with an NVIS antenna.
>> as long as you can get a good 65, or better, 130 feet out of it.
>> 73
>> Colin, V A6BKX
>> ----- Original Message -----=20
>> From: "Gerry Leary" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Monday, November 22, 2010 6:07 AM
>> Subject: Re: nvis antenna
>>=20
>>=20
>>> This is new information for me.  I haven't been following this =
> thread, but
>>=20
>>> I
>>> might actually try it.  My fence is a Metal chain link kind, but I =
> could
>>> clamp plastic pipe on the support poles and hang the antenna from =
> that.=20
>>> Do
>>> you think the fence will absorb the RF, and How far above the Fence =
> do you
>>> think I should keep it? Gerry
>>> ----- Original Message -----=20
>>> From: "Junior Lolley" <[log in to unmask]>
>>> To: <[log in to unmask]>
>>> Sent: Saturday, November 20, 2010 2:21 PM
>>> Subject: Re: nvis antenna
>>>=20
>>>=20
>>>> Colin, thanks much well it looks like I will have to lower the =
> antenna a
>>>> little bit.
>>>>=20
>>>>=20
>>>> Junior Lolley KG4ITD Liberty County E. C.
>>>>=20
>>>> -----Original Message-----
>>>> From: For blind ham radio operators=20
>>>> [mailto:[log in to unmask]]
>>>> On Behalf Of colin McDonald
>>>> Sent: Saturday, November 20, 2010 4:05 PM
>>>> To: [log in to unmask]
>>>> Subject: Re: nvis antenna
>>>>=20
>>>> it'll depend on which bands you wish to work NVIS on.
>>>> Typically, 160 and 80/75M are the usable NVIS bands.
>>>> You want your main radiating wire down pretty low, say between 5 and =
> 15
>>>> feet
>>>>=20
>>>> off the ground.  It has to be in a horizontal configuration.  Some =
> guys
>>>> will
>>>>=20
>>>> put another wire along the ground as a paracytic element.  A dipole =
> at
>>>> 30FT
>>>> will have some NVIS properties, but not like something that is 8 or =
> 10
>>>> feet
>>>> off the ground.
>>>> One of the best antennas I ever built was an 80M NVIS wire.  =
> essentially
>>>> just a piece of 14 gage copper wire strung in a large U shape around =
> a
>>>> fence
>>>>=20
>>>> line.  I made the wire about 68 feet long, connected the center =
> conducter
>>>> of
>>>>=20
>>>> a coax to one end, and the ground of the coax to a cold water pipe =
> that
>>>> went
>>>>=20
>>>> straight into the ground near the feed point.  The antenna was no =
> more
>>>> than
>>>> 5 feet off the ground.  I cut about 6 inches at a time off the far =
> end
>>>> from
>>>> the feed point until I obtained a 1 to 1 match at 3.750.  The final=20=
>
>>>> length
>>>> was probably around 65 feet.  The U was approximately 20 feet per =
> side,
>>>> with
>>>>=20
>>>> the longer leg being 25 feet long...the one that came back towards =
> the
>>>> feed
>>>> point was the long side, that is, on the opposite side of the =
> you...so=20
>>>> the
>>>> end of the antenna was actually about 5 feet back past the feet =
> point,=20
>>>> but
>>>> 20 feet across the yard...this was a duplex back yard so there =
> wasn't=20
>>>> much
>>>> room for an antenna.  I just layed the wire on the top rail of the =
> wooden
>>>> fence and used large staples to keep it from blowing off.
>>>> That antenna would consistently perform very well out to about 1200 =
> miles
>>>> in
>>>>=20
>>>> any direction, and more often than not could talk and hear into =
> ontario,
>>>> about 2500 miles to the east.  It was a great NVIS antenna and the=20=
>
>>>> signals
>>>> within that 1200 miles were almost always S9 and above...that is 
>>>> the=20=
>
>>>> great
>>>> thing about NVIS antennas.  they perform extremely well for what =
> they are
>>>> designed to do.
>>>> Now, if that antenna had been up at 30FT, I don't think it would =
> have
>>>> performed as well.
>>>> regards
>>>> Colin
>>>>=20
>>>> ----- Original Message -----=20
>>>> From: "Junior Lolley" <[log in to unmask]>
>>>> To: <[log in to unmask]>
>>>> Sent: Saturday, November 20, 2010 4:39 AM
>>>> Subject: nvis antenna
>>>>=20
>>>>=20
>>>>> I have a 132 foot dipole I want to use for NVIS.
>>>>> I have sandy soil here in Florida.
>>>>> What is the best height off the ground to have each end?
>>>>> It is 30 foot center on the tower.
>>>>> I now have each end about 10 foot off the ground.
>>>>> I am trying to mess around with NVIS a little bit.
>>>>> if anyone can give me a little info it would help.
>>>>> Thanks very much.
>>>>>=20
>>>>>=20
>>>>>=20
>>>>> Junior Lolley KG4ITD Liberty County E. C.
>>>>=20