Scanner antenna ???
 

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
m...

"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.

Scanner antenna ???
 

"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.

Scanner antenna ???
 

El 05-05-13 13:57, Tom escribió:
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.

Thanks gents for the advice,,,

73s


Hello Tom,

I don't know the internal construction of your antenna, but when SWR
turns out to be good on 2m and 70cm, the antenna is very likely good
and can be used for reception, but on 2m and 70 cm only. As Jeff also
said, these antenna are narrow band and performance on VHF marine band
will be well below that of a simple halve wave dipole tuned for VHF
marine. It does not mean it receives nothing, but you only hear
nearby stations on the 2m/70cm antenna when tuning your scanner to VHF
air or VHF marine.

If you want one antenna that fits all, go for the discone, or even
better, go for the biconical antenna. I fully agree with Jeff, the
biconical dipole has better radiation pattern for your application.

When you enter biconical cebik into a search engine you may find
useful info on biconical antennas if you plan to construct your own
antenna. As your VHF and UHF bands of interest have around 3:1 ratio,
VSWR will be good enough for reception.

Wim
PA3DJS
don't forget to remove abc in case of PM





"Ralph Mowery" wrote in message
m...

"Tom" wrote in message
...
Hi

I have the Realistic Programmable scanner with 200 programable
channels. A lot of range there like 6 m, 2 m, 70 cm, marine, etc
etc etc, wide range.

I want to put up an external antenna that I can hook it up to its
own BNC connection for external antenna. I believe the higher the
better.

Which is better to run a bare copper wire longest and highest to
connect it to the BNC center? Or should I use coax and splice the
center copper feed to

You will not receive much with a long bare copper wire.

Get some coax, rg8x is good, the rg 6 type is also good and usually
cheap. Don't worry about the 70 ohm impedance of the rg-6 as the
impedance is not going to be 50 ohms anyway over much of the
frequecny range. The lmr400 type is beter, but I doubt that you will
notice the differance if the length is around 100 feet or less. Not
worth the big price differance for a scanner in many cases. The only
problem with the rg6 may be the connectors as the shield is usually
aluminum or a material that will not take solder. The crimp
connectors are fine.

For the outside antenna, a discone type is often used. Really for a
broad band reception any ground plane or colinear will probably give
you good reception over a wide band. After all, the short antenna
that usually comes with the scanners often pick up many signals.






--
Wim
PA3DJS
www.tetech.nl
Please remove abc first in case of PM

Scanner antenna ???
 

Hi
I got the base out. An old ham buddy stopped by and we cranked and hammered
that end out. The bottom section of the X200a antenna that is connected to
the whip. The bottom half of the antenna out of that bottom piece of
fiberglass tube. Very green as there was water sitting in there. Ok so at
the base is a coil that is tapped at about 75% through it and that tapping
(there are two) one to the shield part of the S0239 and one to the center of
the S0239 connector. Both are broken and both look like there is a capacitor
there that split apart.

Any idea what those two caps are? I think if I just clean the element up
with sand paper, deoxit it and replace those caps (if that is what is there)
looks like two small caps were supposed to be there or what is there could
be corroded up broken caps.

Or is that little piece available online anywhere?

Or could I simply connect everything to the gnd planes or even lengthen
those gnd planes and connect short everything as I only want to use as
receive for the scanner. I am probably at about 3 or 4 hours cleaning this
old antenna up, compared to the costs of a new one.

Thanks for your thoughts

73s





"Wimpie" wrote in message
abel.net...
El 05-05-13 13:57, Tom escribió:
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.

Thanks gents for the advice,,,

73s


Hello Tom,

I don't know the internal construction of your antenna, but when SWR turns
out to be good on 2m and 70cm, the antenna is very likely good and can be
used for reception, but on 2m and 70 cm only. As Jeff also said, these
antenna are narrow band and performance on VHF marine band will be well
below that of a simple halve wave dipole tuned for VHF marine. It does
not mean it receives nothing, but you only hear nearby stations on the
2m/70cm antenna when tuning your scanner to VHF air or VHF marine.

If you want one antenna that fits all, go for the discone, or even better,
go for the biconical antenna. I fully agree with Jeff, the biconical
dipole has better radiation pattern for your application.

When you enter biconical cebik into a search engine you may find useful
info on biconical antennas if you plan to construct your own antenna. As
your VHF and UHF bands of interest have around 3:1 ratio, VSWR will be
good enough for reception.

Wim
PA3DJS
don't forget to remove abc in case of PM





"Ralph Mowery" wrote in message
m...

"Tom" wrote in message
...
Hi

I have the Realistic Programmable scanner with 200 programable
channels. A lot of range there like 6 m, 2 m, 70 cm, marine, etc
etc etc, wide range.

I want to put up an external antenna that I can hook it up to its
own BNC connection for external antenna. I believe the higher the
better.

Which is better to run a bare copper wire longest and highest to
connect it to the BNC center? Or should I use coax and splice the
center copper feed to

You will not receive much with a long bare copper wire.

Get some coax, rg8x is good, the rg 6 type is also good and usually
cheap. Don't worry about the 70 ohm impedance of the rg-6 as the
impedance is not going to be 50 ohms anyway over much of the
frequecny range. The lmr400 type is beter, but I doubt that you will
notice the differance if the length is around 100 feet or less. Not
worth the big price differance for a scanner in many cases. The only
problem with the rg6 may be the connectors as the shield is usually
aluminum or a material that will not take solder. The crimp
connectors are fine.

For the outside antenna, a discone type is often used. Really for a
broad band reception any ground plane or colinear will probably give
you good reception over a wide band. After all, the short antenna
that usually comes with the scanners often pick up many signals.






--
Wim
PA3DJS
www.tetech.nl
Please remove abc first in case of PM

Scanner antenna ???
 

On Sun, 5 May 2013 07:57:59 -0400, "Tom" wrote:

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.

Here is my lousy photos of the inside of a Diamond X50 antenna after
the former owner backed over it with his pickup truck:
http://802.11junk.com/jeffl/antennas/Misc/slides/x50-01.html
http://802.11junk.com/jeffl/antennas/Misc/slides/x50.html
My guess(tm) is that the X200 base structure is similar. As I recall,
there should be continuity between the center conductor and the lower
element. However, the crumpled brass phasing section(?) in the middle
of the antenna has no continuity through the center conductor. The
end wires go in about 2" and stop. This may be the lack of continuity
that you're seeing.

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.

Don't try to remove it. The fiberglass radome extends into the cast
aluminum base and is glued with something I couldn't soften. I had to
use a hack saw at the point of entry to remove the radome, which also
shortened it about an inch. No loss for me since the X50 was already
destroyed, but I woudln't do it with a potentially good antenna.

Can this antenna be modified for broader band scanner use?

No. The design is not inherently broadband and everything you change
affects everything else.

Most of my
interests in the scanning will be the marine bands (156 ish megs) and VHF
and UHF ham bands anyway.

The X200 will work on 2m and 440MHz. Marine band (156-163MHz) is a
bit of a stretch from 144-148MHz) but may work. VSWR will be high,
but since you're not transmitting, that shouldn't be a huge problem.
Try it and see what happens.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Scanner antenna ???
 

El 05-05-13 18:12, Tom escribió:
Hi
I got the base out. An old ham buddy stopped by and we cranked and
hammered that end out. The bottom section of the X200a antenna that is
connected to the whip. The bottom half of the antenna out of that
bottom piece of fiberglass tube. Very green as there was water sitting
in there. Ok so at the base is a coil that is tapped at about 75%
through it and that tapping (there are two) one to the shield part of
the S0239 and one to the center of the S0239 connector. Both are
broken and both look like there is a capacitor there that split apart.

Any idea what those two caps are? I think if I just clean the element
up with sand paper, deoxit it and replace those caps (if that is what
is there) looks like two small caps were supposed to be there or what
is there could be corroded up broken caps.

Or is that little piece available online anywhere?

Or could I simply connect everything to the gnd planes or even
lengthen those gnd planes and connect short everything as I only want
to use as receive for the scanner. I am probably at about 3 or 4 hours
cleaning this old antenna up, compared to the costs of a new one.

Thanks for your thoughts

73s





"Wimpie" wrote in message
abel.net...
El 05-05-13 13:57, Tom escribió:
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.

Thanks gents for the advice,,,

73s


Hello Tom,

I don't know the internal construction of your antenna, but when SWR
turns out to be good on 2m and 70cm, the antenna is very likely good
and can be used for reception, but on 2m and 70 cm only. As Jeff
also said, these antenna are narrow band and performance on VHF
marine band will be well below that of a simple halve wave dipole
tuned for VHF marine. It does not mean it receives nothing, but you
only hear nearby stations on the 2m/70cm antenna when tuning your
scanner to VHF air or VHF marine.

If you want one antenna that fits all, go for the discone, or even
better, go for the biconical antenna. I fully agree with Jeff, the
biconical dipole has better radiation pattern for your application.

When you enter biconical cebik into a search engine you may find
useful info on biconical antennas if you plan to construct your own
antenna. As your VHF and UHF bands of interest have around 3:1
ratio, VSWR will be good enough for reception.

Wim
PA3DJS
don't forget to remove abc in case of PM





"Ralph Mowery" wrote in message
m...

"Tom" wrote in message
...
Hi

I have the Realistic Programmable scanner with 200 programable
channels. A lot of range there like 6 m, 2 m, 70 cm, marine, etc
etc etc, wide range.

I want to put up an external antenna that I can hook it up to its
own BNC connection for external antenna. I believe the higher the
better.

Which is better to run a bare copper wire longest and highest to
connect it to the BNC center? Or should I use coax and splice the
center copper feed to

You will not receive much with a long bare copper wire.

Get some coax, rg8x is good, the rg 6 type is also good and usually
cheap. Don't worry about the 70 ohm impedance of the rg-6 as the
impedance is not going to be 50 ohms anyway over much of the
frequecny range. The lmr400 type is beter, but I doubt that you will
notice the differance if the length is around 100 feet or less. Not
worth the big price differance for a scanner in many cases. The only
problem with the rg6 may be the connectors as the shield is usually
aluminum or a material that will not take solder. The crimp
connectors are fine.

For the outside antenna, a discone type is often used. Really for a
broad band reception any ground plane or colinear will probably give
you good reception over a wide band. After all, the short antenna
that usually comes with the scanners often pick up many signals.






--
Wim
PA3DJS
www.tetech.nl
Please remove abc first in case of PM


Hello Tom,

This maybe helpful to you:
http://on3jt.byze.be/repair-a-diamon...vhfuhf-antenna.

You are right, the brown disc type components are capacitors.

--
Wim
PA3DJS
www.tetech.nl
Please remove abc first in case of PM

Scanner antenna ???
 

Hi Jeff

That base you show is exactly the same as the base matching coupler on the
diamond x200a , mine was completely green and corroded and cleaned up ok.
Those capacitors are crumbled and no way of reading them, do you know their
value? I can order some and replace them.

thanks

73s




"Jeff Liebermann" wrote in message
...
On Sun, 5 May 2013 07:57:59 -0400, "Tom" wrote:

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.

Here is my lousy photos of the inside of a Diamond X50 antenna after
the former owner backed over it with his pickup truck:
http://802.11junk.com/jeffl/antennas/Misc/slides/x50-01.html
http://802.11junk.com/jeffl/antennas/Misc/slides/x50.html
My guess(tm) is that the X200 base structure is similar. As I recall,
there should be continuity between the center conductor and the lower
element. However, the crumpled brass phasing section(?) in the middle
of the antenna has no continuity through the center conductor. The
end wires go in about 2" and stop. This may be the lack of continuity
that you're seeing.

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.

Don't try to remove it. The fiberglass radome extends into the cast
aluminum base and is glued with something I couldn't soften. I had to
use a hack saw at the point of entry to remove the radome, which also
shortened it about an inch. No loss for me since the X50 was already
destroyed, but I woudln't do it with a potentially good antenna.

Can this antenna be modified for broader band scanner use?

No. The design is not inherently broadband and everything you change
affects everything else.

Most of my
interests in the scanning will be the marine bands (156 ish megs) and VHF
and UHF ham bands anyway.

The X200 will work on 2m and 440MHz. Marine band (156-163MHz) is a
bit of a stretch from 144-148MHz) but may work. VSWR will be high,
but since you're not transmitting, that shouldn't be a huge problem.
Try it and see what happens.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Scanner antenna ???
 

On Mon, 6 May 2013 16:23:44 -0400, "Tom" wrote:

That base you show is exactly the same as the base matching coupler on the
diamond x200a , mine was completely green and corroded and cleaned up ok.
Those capacitors are crumbled and no way of reading them, do you know their
value? I can order some and replace them.

My Diamond X50 shows 1pf and 7.5pf.

However, I think it best that you use the values from an X200 antenna,
and not an X50.
http://on3jt.byze.be/repair-a-diamond-x200-vhfuhf-antenna
Looks like 9pf and 1pf.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Scanner antenna ???
 

On Tue, 07 May 2013 11:32:57 -0700, Jeff Liebermann
wrote:

Incidentally, you might find the modifications and analysis of the
Diamond X510 antenna of interest:
http://pa0fri.home.xs4all.nl/Ant/X510N/Diamond%20X510N%20modification.htm
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Scanner antenna ???
 

Nice, Thanks Jeff and all for your expertise again and again.

Best regards

73s







"Jeff Liebermann" wrote in message
...
On Tue, 07 May 2013 11:32:57 -0700, Jeff Liebermann
wrote:

Incidentally, you might find the modifications and analysis of the
Diamond X510 antenna of interest:
http://pa0fri.home.xs4all.nl/Ant/X510N/Diamond%20X510N%20modification.htm
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558