I am not gonna use the chain link fence as an antenna.
I am thinking of using the top rail as a paracytic element.
Thanks for the info it is greatly appreciated.
Junior Lolley KG4ITD Liberty County E. C.
-----Original Message-----
From: For blind ham radio operators [mailto:[log in to unmask]]
On Behalf Of Michael Thurman
Sent: Tuesday, November 23, 2010 2:14 AM
To: [log in to unmask]
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
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