"Tom" wrote in message
...
Thanks for the advice.

The 2m 70cm old antenna someone gave me is a Diamond X200 I believe. It is
about 2.4 meters long with a connection in the middle. It was full of
water and for many years, I took it apart yesterday and emptied the water
and green stuff out and sanded the entier top part of the element and
coils. I will de-oxit it and put it back together and seal it better. I
cannot get the bottom length of antenna out of the fiberglass shell so I
will leave that greenish but I noticed there was continuity between the
outside shield of the S0239 connector and the antenna and not continuity
between the center of the Coax connector and the antenna. I thought the
center coax would connect with the antenna and the shield would connect
with the gnd planes. Is that normal?

From the center of the SO239 connector on the antenna there is no
continuity between anything. Only continuity between the threads of the
SO239 and the antenna length. After I put it all together I will use the
AV600 meter to tests its SWR with the 2m70cm rig to see if it is ok.

That bottom fiberglass piece looks glued in there pretty good I don't want
to break the seal , I think the water might be getting in from that half
way connector.

Can this antenna be modified for broader band scanner use? Most of my
interests in the scanning will be the marine bands (156 ish megs) and VHF
and UHF ham bands anyway.

I don't know about how this antenna is made. Some antennas have a coil
between the center of the coax and shield or radials. They may also have a
capacitor in series with the center of the coax and the vertical part of the
antenna. This will show up as an open circuit with a simple ohmmeter.

As you are going to just use it as a receiving antenna, I would prop it up
outside a few feet off the ground and see what you can hear. It may be
broad enough to pick up what you want. Most any antenna a foot to 6 feet
long or so will pick up plenty of strong signals in the vhf and up
ranges.While some are much beter , if it picks up what you want ,then all is
fine. If not, then you will have to look for a beter antenna.

I have a scanner with just the short antenna on it. I can pick up a 6 meter
repeater about 10 miles away, several local 2 meter and 440 repeaters, the
WX frequency and the emergency around 152 mhz. I also have antennas up
outside that will pick up lots more than the scanner, but the scaner picks
up what I am most interisted in with the short whip.

I was thinking the same that there is some sort of cap or resister or
lightning protection shorting component between the center and threads on
that S0239 female connector. But why wouldn't there be continuity between
the center and the main 2.5m copper system that is inside that antenna? I
suppose once I check the SWR it will tell me that it was designed or
engineered that way if there is a suitable reading on the SWR. And my ohm
meter is simply a basic one. This antenna is old and seen a lot of years in
the air, so not worried and am wondering if there are any modifications I
can do to this antenna to make it more of a receiving antenna only for the
scanner. Thanks again,,,

73s






"Ralph Mowery" wrote in message
news

"Tom" wrote in message
...
Thanks for the advice.

The 2m 70cm old antenna someone gave me is a Diamond X200 I believe. It
is about 2.4 meters long with a connection in the middle. It was full of
water and for many years, I took it apart yesterday and emptied the water
and green stuff out and sanded the entier top part of the element and
coils. I will de-oxit it and put it back together and seal it better. I
cannot get the bottom length of antenna out of the fiberglass shell so I
will leave that greenish but I noticed there was continuity between the
outside shield of the S0239 connector and the antenna and not continuity
between the center of the Coax connector and the antenna. I thought the
center coax would connect with the antenna and the shield would connect
with the gnd planes. Is that normal?

From the center of the SO239 connector on the antenna there is no
continuity between anything. Only continuity between the threads of the
SO239 and the antenna length. After I put it all together I will use the
AV600 meter to tests its SWR with the 2m70cm rig to see if it is ok.

That bottom fiberglass piece looks glued in there pretty good I don't
want to break the seal , I think the water might be getting in from that
half way connector.

Can this antenna be modified for broader band scanner use? Most of my
interests in the scanning will be the marine bands (156 ish megs) and VHF
and UHF ham bands anyway.

I don't know about how this antenna is made. Some antennas have a coil
between the center of the coax and shield or radials. They may also have
a capacitor in series with the center of the coax and the vertical part of
the antenna. This will show up as an open circuit with a simple ohmmeter.

As you are going to just use it as a receiving antenna, I would prop it up
outside a few feet off the ground and see what you can hear. It may be
broad enough to pick up what you want. Most any antenna a foot to 6 feet
long or so will pick up plenty of strong signals in the vhf and up
ranges.While some are much beter , if it picks up what you want ,then all
is fine. If not, then you will have to look for a beter antenna.

I have a scanner with just the short antenna on it. I can pick up a 6
meter repeater about 10 miles away, several local 2 meter and 440
repeaters, the WX frequency and the emergency around 152 mhz. I also have
antennas up outside that will pick up lots more than the scanner, but the
scaner picks up what I am most interisted in with the short whip.

"Tom" wrote in message
...
I was thinking the same that there is some sort of cap or resister or
lightning protection shorting component between the center and threads on
that S0239 female connector. But why wouldn't there be continuity between
the center and the main 2.5m copper system that is inside that antenna? I
suppose once I check the SWR it will tell me that it was designed or
engineered that way if there is a suitable reading on the SWR. And my ohm
meter is simply a basic one. This antenna is old and seen a lot of years in
the air, so not worried and am wondering if there are any modifications I
can do to this antenna to make it more of a receiving antenna only for the
scanner. Thanks again,,,


Tom if you go here you will see why the ohmmeter shows what it does.
http://xoomer.virgilio.it/ham-radio-manuals/a99.pdf

Notice the coils between the shield and center of the coax, and then the
capacitors between the coax and actual antenna element.

This may or may not be the case of the antenna you have as I do not know
what is acutually inside it.