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
a certain length from its shield and just get that piece of the antenna the
highest possible? Would it make better receive sense to simply use one leg
of the 16ga copper wire with jacket that I have and use for dipoles?

If I use an adapter (SO239 x BNC) and hook the scanner up to my Alpha Delta
DX-CC which has a lot of exposed copper very high and very long and
available, Is that a better receive antenna than would be another piece of
coax spliced at a certain length and get that up there higher?

Simply for scanner of course, nothing transmit,

Appreciate any comments on this, cheap or otherwise,

thanks

73s

Tom wrote:
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
a certain length from its shield and just get that piece of the antenna the
highest possible? Would it make better receive sense to simply use one leg
of the 16ga copper wire with jacket that I have and use for dipoles?

If I use an adapter (SO239 x BNC) and hook the scanner up to my Alpha Delta
DX-CC which has a lot of exposed copper very high and very long and
available, Is that a better receive antenna than would be another piece of
coax spliced at a certain length and get that up there higher?

Simply for scanner of course, nothing transmit,

Appreciate any comments on this, cheap or otherwise,

For VHF use it is not a good idea to connect a very long bare wire to
the antenna connector, because only a short part of the wire close
to the receiver will be active and thus you have an indoor antenna
even when the wire runs outside.

As you write, the higher the better. So it is better to run a decent
quality coax to outside and construct a simple antenna connected to
the end of it. Generally, the thicker the coax the better, but no
need to over-spend on this.

For receive only, a random length (in the ballpark of 1/2 wavelength)
vertical dipole is good enough. You can make it a true dipole
or you can use some "groundplane" configuration (one quarter wavelength
pointing upward and connected to the coax center, and three or four
quarter wavelength rods slanting downward and connected to the braid).
The latter may be more convenient when you want to put it on top of
a short pole.

Indeed, you can also just strip the end of the coax and fold back the
braid over the end of the coax to form a halfwave dipole, and put
the whole thing in a plastic tube.

When looking inside commercially available scanner antennas, you
will often find just a copper wire inside the plastic stick. Often
there has been an attempt to make it more wideband by winding it
in the form of a couple of coils (3 turns or so) every 10 inch or
so, but if that really makes any difference in the results is to
be seen.

On Sat, 4 May 2013 08:26:09 -0400, "Tom" wrote:

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.

Realistic scanners have model numbers. Could I trouble you to
disclose the exact model number? Do you have a tower?

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.

Forget about using long wire antennas as a scanner antenna. At
VHF/UHF, long wires look more like big RF chokes. It's unlikely to
hear much connected to an HF antenna.

There are numerous scanner antennas on the market. If you have a
tower for your HF antenna, you also should have room for a discone,
"spider", trapped vertical, or something similar. I don't know
exactly what to recommend as broadband antennas are always a
compromise between gain, bandwidth, vertical radiation takeoff angle,
size, etc. Something on this list should work (except for the
handheld and mobile scanner antennas).
http://www.universal-radio.com/catalog/scanants.html
RG-58a/u or RG-58c/u to between the scanner and antenna will probably
need to purchases seperately. Attach your own BNC or UFH connectors.


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

Yes, I have the tower and have a bracket that extends to the side about 4 ft
and this antenna will be at the end of that extension.

Realistic 2037.

I see those links for those scanner antennas and think that one from 25 mhz
to 1000 ish is suitable.

I see a lot of them have ground planes or are all those elements part of the
center wire in the bnc?

I have an old 2m 70cm diamond antenna with gnd planes, Suppose that would
work also? But someone gave it to me because it didn't work so might take a
closer look at it.

thx
73s




"Jeff Liebermann" wrote in message
...
On Sat, 4 May 2013 08:26:09 -0400, "Tom" wrote:

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.

Realistic scanners have model numbers. Could I trouble you to
disclose the exact model number? Do you have a tower?

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.

Forget about using long wire antennas as a scanner antenna. At
VHF/UHF, long wires look more like big RF chokes. It's unlikely to
hear much connected to an HF antenna.

There are numerous scanner antennas on the market. If you have a
tower for your HF antenna, you also should have room for a discone,
"spider", trapped vertical, or something similar. I don't know
exactly what to recommend as broadband antennas are always a
compromise between gain, bandwidth, vertical radiation takeoff angle,
size, etc. Something on this list should work (except for the
handheld and mobile scanner antennas).
http://www.universal-radio.com/catalog/scanants.html
RG-58a/u or RG-58c/u to between the scanner and antenna will probably
need to purchases seperately. Attach your own BNC or UFH connectors.


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

On Saturday, May 4, 2013 2:26:09 PM UTC+2, Tom wrote:
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
a certain length from its shield and just get that piece of the antenna the

highest possible? Would it make better receive sense to simply use one leg
of the 16ga copper wire with jacket that I have and use for dipoles?



If I use an adapter (SO239 x BNC) and hook the scanner up to my Alpha Delta
DX-CC which has a lot of exposed copper very high and very long and
available, Is that a better receive antenna than would be another piece of
coax spliced at a certain length and get that up there higher?

Simply for scanner of course, nothing transmit,

Appreciate any comments on this, cheap or otherwise,


thanks


73s

If you want to receive from say 145 MHz to 500 MHz, I would go for a descent cable (foam dielectric) if the length exceeds say 5m. Below this length I would just use standard RG 58. A bare or insulated wire into the center of the antenna input will not work well.

I would not recommend any thin wire antennas (including whips) as these are narrow band, so it will only work well on a single frequency band (for example VHF airband, but not together with VHF Marine) . When you want to buy something, I would go for the discone antenna if you really want to receive from 145 MHz up to around 500 MHz.

A wide band antenna in combination with strong signals nearby may result in overload to the RF input circuitry of your scanner. You may arrive into a situation that a better antenna will give worse results due to overloading the RF input circuitry. If you have limited or no experience, you may not recognize this.

There are other solutions: If you want to receive a limited amount of frequency bands (for example 2 m and 70 cm), you can buy dual-band antennas for certain frequency bands. Other option is to use separate antennas for each band, but you cannot connect them all together to one cable without a special frequency selective combiner.

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

Tom wrote:
I have an old 2m 70cm diamond antenna with gnd planes, Suppose that would
work also? But someone gave it to me because it didn't work so might take a
closer look at it.

A dualband transmit antenna may work less well as a wideband receive
antenna than a plain dipole, as it is constructed to match well and
even provide gain at two distinct bands, and the methods used to achieve
this may result in nulls at other frequencies. But you can always
try it and find out how it works at the bands you are interested in.

"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.

On Sat, 4 May 2013 15:48:22 -0400, "Tom" wrote:

Yes, I have the tower and have a bracket that extends to the side about 4 ft
and this antenna will be at the end of that extension.

Perfect, but not for the obvious reason. Retail discone antennas cost
$25 to $150, which seems a bit high. Mostly, it's because of the
large number of parts involved. If you have a tower and yard-arm, you
can hang a center fed vertical biconical antenna off the end, which in
my never humble opinion will work better than a discone (due to the
reduced up tilt of the vertical radiation pattern) than a discone.
Discones are good for broadband, and listening to airplanes, but if
you want distance, the radiation pattern should point to the horizon,
not the sky. Something like one of these:
https://www.google.com/search?q=biconical+antenna&tbm=isch

Realistic 2037.

http://www.rigpix.com/rs-realistic/realistic_pro2037.htm
Made by GRE starting in about 1996. It has a marginal front end
design that is easily overloaded by strong signals and will produce
intermod mixes with little effort. The "ATT" for attenuation switch
is an obvious clue. If you hear obvious intermod, you may want to
insert a 1/4 wave stub notch filter between the antenna and receiver
to get rid of strong paging junk and such.
http://dl4xav.sysve.de/coax.filter/coax-filter.html

The more strange looking and ugly the antenna, the better it works.

I see a lot of them have ground planes or are all those elements part of the
center wire in the bnc?

The bottom angled elements are at ground potential. The flat top
"hat' is connected to the center wire of the UHF connector. If you
replace the flat top hat, with a mirror image of the ground elements,
you have an instant biconical antenna.

I have an old 2m 70cm diamond antenna with gnd planes, Suppose that would
work also? But someone gave it to me because it didn't work so might take a
closer look at it.

A dual band antenna will work on 2m and 70cm, and little else. You
can probably hear something on the adjacent frequencies, but at more
than a few MHz away, such an antenna is going to be comatose. If you
use your scanner mostly for these ham bands, put a ground plane under
it, as if it were mounted on a vehicle, and attach it to your
yard-arm. If that's too messy, several 1/4 wave at 2m horizontal
ground radials will probably suffice.

Incidentally, don't toss the antenna. Diamond make good antennas and
it's probably worth your time to determining why it didn't work.

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

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





"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.

"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.