Ground plane antenna
 

I'm planning on building a 10 meter ground plane antenna out of PVC pipe and #12 wire radials drooping about 40 degrees. This will be mounted on my roof on a tripod and mast, with the radials also serving as guy wires. The ARRL antenna book mentions that a ground plane antenna should be mounted at least one half wavelength above "ground". I know that this sounds like a stupid question but I have to ask: for this example do I consider the roof, which is more than 5 meters above ground level as "ground" or do I need to be at least 5 meters above the roof. I would like to secure the radials, (guy wires) to my roof, but with the antenna at 5 meters high my droop angle will be off and then I can't guarantee a 50 ohm match. The house is wood frame, no foil backed insulation and a non metallic roof. Thanks for any advice.. Lenny

Ground plane antenna
 

Ground plane antenna
 

wrote in message
...
I'm planning on building a 10 meter ground plane antenna out of PVC pipe
and #12 wire radials drooping about 40 degrees. This will be mounted on my
roof on a tripod and mast, with the radials also serving as guy wires. The
ARRL antenna book mentions that a ground plane antenna should be mounted at
least one half wavelength above "ground". I know that this sounds like a
stupid question but I have to ask: for this example do I consider the roof,
which is more than 5 meters above ground level as "ground" or do I need to
be at least 5 meters above the roof. I would like to secure the radials,
(guy wires) to my roof, but with the antenna at 5 meters high my droop
angle will be off and then I can't guarantee a 50 ohm match. The house is
wood frame, no foil backed insulation and a non metallic roof. Thanks for
any advice. Lenny

You can think of the ground as being the actual ground for your case. Even
if the roof was a conductor it would not be large enough to actually be
called the ground. Unless there conductors for several wavelenghts around
the antenna they usually have little effect on the antenna. if they are
below the radials.



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Ground plane antenna
 

On Thursday, November 6, 2014 3:15:23 PM UTC-5, wrote:
I'm planning on building a 10 meter ground plane antenna out of PVC pipe and #12 wire radials drooping about 40 degrees. This will be mounted on my roof on a tripod and mast, with the radials also serving as guy wires. The ARRL antenna book mentions that a ground plane antenna should be mounted at least one half wavelength above "ground". I know that this sounds like a stupid question but I have to ask: for this example do I consider the roof, which is more than 5 meters above ground level as "ground" or do I need to be at least 5 meters above the roof. I would like to secure the radials, (guy wires) to my roof, but with the antenna at 5 meters high my droop angle will be off and then I can't guarantee a 50 ohm match. The house is wood frame, no foil backed insulation and a non metallic roof. Thanks for any advice. Lenny

To build this antenna I plan on using an SO239 inside a length of 1.50 or 2 inch PVC pipe, and bringing the 4 radials, which are cut to 1.05 wavelength,(as per the ARRL Antenna book) out through four drilled holes up toward the top of it. Then I'll use an adapter to convert to half inch pipe, cap the top end of the half inch and run the # 12 wire radiator straight up into that. I'll bring my 213 up inside the pipe, connect to the SO 239 and seal the whole thing up with silicone. The thing will be mounted on a tripod and the radials will have insulators on them so that they'll double as guy wires as well.

I built another ground plane years ago and it's still up there and in use using this method for my business band radio. That unit operates in the 40 MHZ band and I recall that I came up with a very good SWR on that one. I'm nowhere near half wavelength above the roof with that one either but I had to ask.

So now I have to ask another stupid question. I'm stripping old Romex for the wire and I mentioned this to a local friend the other day. He asked me if I was using bare wire for the radiator. I said that I didn't think that it mattered. He assured me that it did. I would think that either in free space or inside a plastic pipe that it wouldn't matter. Am I correct or is he? Lenny

Ground plane antenna
 

wrote in message
...
On Thursday, November 6, 2014 3:15:23 PM UTC-5,
wrote:
I'm planning on building a 10 meter ground plane antenna out of PVC pipe
and #12 wire radials drooping about 40 degrees. This will be mounted on my
roof on a tripod and mast, with the radials also serving as guy wires. The
ARRL antenna book mentions that a ground plane antenna should be mounted
at least one half wavelength above "ground". I know that this sounds like
a stupid question but I have to ask: for this example do I consider the
roof, which is more than 5 meters above ground level as "ground" or do I
need to be at least 5 meters above the roof. I would like to secure the
radials, (guy wires) to my roof, but with the antenna at 5 meters high my
droop angle will be off and then I can't guarantee a 50 ohm match. The
house is wood frame, no foil backed insulation and a non metallic roof.
Thanks for any advice. Lenny

To build this antenna I plan on using an SO239 inside a length of 1.50 or 2
inch PVC pipe, and bringing the 4 radials, which are cut to 1.05
wavelength,(as per the ARRL Antenna book) out through four drilled holes up
toward the top of it. Then I'll use an adapter to convert to half inch pipe,
cap the top end of the half inch and run the # 12 wire radiator straight up
into that. I'll bring my 213 up inside the pipe, connect to the SO 239 and
seal the whole thing up with silicone. The thing will be mounted on a tripod
and the radials will have insulators on them so that they'll double as guy
wires as well.

I built another ground plane years ago and it's still up there and in use
using this method for my business band radio. That unit operates in the 40
MHZ band and I recall that I came up with a very good SWR on that one. I'm
nowhere near half wavelength above the roof with that one either but I had
to ask.

So now I have to ask another stupid question. I'm stripping old Romex for
the wire and I mentioned this to a local friend the other day. He asked me
if I was using bare wire for the radiator. I said that I didn't think that
it mattered. He assured me that it did. I would think that either in free
space or inside a plastic pipe that it wouldn't matter. Am I correct or is
he? Lenny



Any material around the wire will make some differance. At 10 meters it
will only make an inch or two worth of differance. The PVC pipe you put it
in will make about the same ammount of differance. The angle of the radials
will make more differance than the insulation in your case.

If this was at two meters and above then you will notice a larger ammount of
differance. The higher the frequency the more th differance will be noticed
in any material around the bare wire.

The insulation tends to make the antenna look longer so you can cut some off
the ends if it is too low in frequency.








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Ground plane antenna
 

On Thursday, November 6, 2014 3:15:23 PM UTC-5, wrote:
I'm planning on building a 10 meter ground plane antenna out of PVC pipe and #12 wire radials drooping about 40 degrees. This will be mounted on my roof on a tripod and mast, with the radials also serving as guy wires. The ARRL antenna book mentions that a ground plane antenna should be mounted at least one half wavelength above "ground". I know that this sounds like a stupid question but I have to ask: for this example do I consider the roof, which is more than 5 meters above ground level as "ground" or do I need to be at least 5 meters above the roof. I would like to secure the radials, (guy wires) to my roof, but with the antenna at 5 meters high my droop angle will be off and then I can't guarantee a 50 ohm match. The house is wood frame, no foil backed insulation and a non metallic roof. Thanks for any advice. Lenny

I never would have figured. Maybe I can come up with a way to transition from PVC to .5 inch copper pipe for the radiator. Thanks, Lenny

You can buy a decent 10 / 11 meter ground plane antenna for about $69.00 - why in the heck would you want to build one out of plastic pipe?

Ground plane antenna
 

"Channel Jumper" wrote in message
...

You can buy a decent 10 / 11 meter ground plane antenna for about $69.00
- why in the heck would you want to build one out of plastic pipe?


Because he is a ham.



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Ground plane antenna
 

Channel Jumper wrote:

You can buy a decent 10 / 11 meter ground plane antenna for about $69.00
- why in the heck would you want to build one out of plastic pipe?

Because you can make on for about $20 even if you have to buy everything
new and even less if you have some extra wire and pipe.


--
Jim Pennino

Ground plane antenna
 

On Fri, 7 Nov 2014, Ralph Mowery wrote:


"Channel Jumper" wrote in message
...

You can buy a decent 10 / 11 meter ground plane antenna for about $69.00
- why in the heck would you want to build one out of plastic pipe?


Because he is a ham.

I would have said "Because he's not a CB'er".

Michael

Ground plane antenna
 

On Sat, 8 Nov 2014, wrote:

Channel Jumper wrote:

You can buy a decent 10 / 11 meter ground plane antenna for about $69.00
- why in the heck would you want to build one out of plastic pipe?

Because you can make on for about $20 even if you have to buy everything
new and even less if you have some extra wire and pipe.

On the other hand, I once bought a CB set at a garage sale (I had
intentions for reusing it) for all of five dollars, and they threw in an
SWR meter and the whip antenna. I couldn't be bothered carrying the whip,
so I left it, but at that price, it probably could have formed a good
basis of a 10M antenna. And back in the day, I remember various projects
that used CB whips for other bands, simply because as a mass produced
item, they were cheap and easy to find.

But no, if you have to pay $70, scrounging will always be cheaper.

Michael

Ground plane antenna
 

On Thursday, November 6, 2014 3:15:23 PM UTC-5, wrote:
I'm planning on building a 10 meter ground plane antenna out of PVC pipe and #12 wire radials drooping about 40 degrees. This will be mounted on my roof on a tripod and mast, with the radials also serving as guy wires. The ARRL antenna book mentions that a ground plane antenna should be mounted at least one half wavelength above "ground". I know that this sounds like a stupid question but I have to ask: for this example do I consider the roof, which is more than 5 meters above ground level as "ground" or do I need to be at least 5 meters above the roof. I would like to secure the radials, (guy wires) to my roof, but with the antenna at 5 meters high my droop angle will be off and then I can't guarantee a 50 ohm match. The house is wood frame, no foil backed insulation and a non metallic roof. Thanks for any advice. Lenny

Thanks for the encouragement guys. When I was 15 (53 years ago) I built my second kit, an Eico CB transceiver. I was really proud of the finished product. I had built a Lafayette short wave receiver two years prior.

Back then, when CB was in it's infancy CB'ers were kind of like many Hams today. For the most part we were a technical group and a whole lot more professional than many of the morons on CB today. I lived in an apartment house in the Bronx. I built a quarter wave dipole and strung it between two water towers. As soon as I got on the air I found a group of guys that would get together every night and chew the rag.

At 15 some of these guys could have been my grandfather, but I was accepted without issue. And at 15 I was not yet an electronics technician either but I guess I was guilty by association. I learned so much from these guys and I truly believe that it paved the way for my ultimate career choice.

Back then we built our own stuff and that's just how it was. I just always loved to experiment. And I still do so. So yeah 69.00 for an antenna isn't much, but when you compare it to the satisfaction gained from building your own and seeing it perform, as the commercial says, "priceless". Lenny

Ground plane antenna
 

On 11/6/2014 3:15 PM, wrote:
I'm planning on building a 10 meter ground plane antenna out of PVC pipe and #12 wire radials drooping about 40 degrees. This will be mounted on my roof on a tripod and mast, with the radials also serving as guy wires. The ARRL antenna book mentions that a ground plane antenna should be mounted at least one half wavelength above "ground". I know that this sounds like a stupid question but I have to ask: for this example do I consider the roof, which is more than 5 meters above ground level as "ground" or do I need to be at least 5 meters above the roof. I would like to secure the radials, (guy wires) to my roof, but with the antenna at 5 meters high my droop angle will be off and then I can't guarantee a 50 ohm match. The house is wood frame, no foil backed insulation and a non metallic roof. Thanks for any advice. Lenny

The ground is that muddy stuff your wife calls DIRT when you track it
indoors.

He's Older than dirt!
(Well yes he is cause he watched the building being built and it was
EARTH or GROUND before the building was built, it did not become DIRT
till it was tracked indoors).

The office I retired from.... Well,, See above. I watched' em buldoze
the building that used to be there and build the new one so I was, in
that office, older than dirt.

--
Home, is where I park it.

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