How to make antenna for a Weather Radio

I got a Midland WR-100 weather radio. Because I live in a metal sided
house, the reception is poor. On the back there is a RCA jack for
external antenna. I can easily make up a piece of coax with a RCA
jack on the end, but what should I use for an antenna. I'd prefer to
make something simple out of wire, such a a straight piece of wire or
dipole type wire, strung under the roof of my deck, or a piece of
stiff wire pointing upward. I do have some old CB car antennas that I
could modify too, and mount them on the deck or rain gutter. I know I
could likely buy something, but I'd like to keep the cost down. I'm
not needing to boost the signal as much as to just get the signal from
the outside into the house due to the metal siding.

Simple and cheap are what I want.
And redardless of that I use, can I use common TV antenna type coax,
or do I need the stuff that was used for CB radios. (I dont recall
the numbers used on them, but know they were not the same).

Thanks in advance.

 

[Geoffrey S. Mendelson]

JoseGomez@dotcom.com wrote:

I got a Midland WR-100 weather radio. Because I live in a metal sided
house, the reception is poor. On the back there is a RCA jack for
external antenna.

Simple and cheap are what I want.
And redardless of that I use, can I use common TV antenna type coax,
or do I need the stuff that was used for CB radios. (I dont recall
the numbers used on them, but know they were not the same).

Use RG-6 (TV coax). If you have any left over, you can make a large (12")
loop out of it, anywhere along the way, so you might as well get a length
already cut with connectors attached. The connectors will be "F" connectors
for TV's etc.

Buy an F to RCA adaptor, but I doubt that it's an RCA connector. It's probably
a MOTOROLA connector that looks like a long RCA one. A Motorola connector
will fit in (and stick out) of an RCA jack, but not vice versa.

My experience with places like radio shack is that you will have to buy
an F to UHF adapter and then a UHF to Motorola. Maybe not, ask. Radio Shack
has lots of motorola plugs and adaptors, but their web site is not indexed
well and I don't feel like paging through them all.

As for the antenna, you can buy one, or make a simple ground plane or
dipole antenna. For example, a simple dipole would be two 18 inch aluminum
tubes, separated with about an inch of plastic rod. Connect each side of
the coax to one rod, and stack them vertically. You can put plastic caps
on the ends of them to prevent water getting in, but don't paint them.

You can play around with the location, orientation (horizontal or vertical)
and direction of the antenna for best results.

Geoff.

--
Geoffrey S. Mendelson N3OWJ/4X1GM
Occam's Razor does not apply to electronics. If something won't turn on, it's
not likely to be the power switch.

 

[Michael A. Terrell]

"Geoffrey S. Mendelson" wrote:

JoseGomez@dotcom.com wrote:
I got a Midland WR-100 weather radio. Because I live in a metal sided
house, the reception is poor. On the back there is a RCA jack for
external antenna.

Simple and cheap are what I want.
And redardless of that I use, can I use common TV antenna type coax,
or do I need the stuff that was used for CB radios. (I dont recall
the numbers used on them, but know they were not the same).

Here is a link to the owner's manual:

http://www.midlandradio.com/Resource_/OwnerManual/122/WR-100B.pdf

Use RG-6 (TV coax). If you have any left over, you can make a large (12")
loop out of it, anywhere along the way, so you might as well get a length
already cut with connectors attached. The connectors will be "F" connectors
for TV's etc.

It is 50 ohm, not 75.

Buy an F to RCA adaptor, but I doubt that it's an RCA connector. It's probably
a MOTOROLA connector that looks like a long RCA one. A Motorola connector
will fit in (and stick out) of an RCA jack, but not vice versa.

It is a RCA/Phono connector. I have the same unit. Use the right
connector if you want good reception. You can see it in the photo of
the rear panel on page 5.

My experience with places like radio shack is that you will have to buy
an F to UHF adapter and then a UHF to Motorola. Maybe not, ask. Radio Shack
has lots of motorola plugs and adaptors, but their web site is not indexed
well and I don't feel like paging through them all.

You don't need any adapters.

As for the antenna, you can buy one, or make a simple ground plane or
dipole antenna. For example, a simple dipole would be two 18 inch aluminum
tubes, separated with about an inch of plastic rod. Connect each side of
the coax to one rod, and stack them vertically. You can put plastic caps
on the ends of them to prevent water getting in, but don't paint them.

A VHF ground plane cut for 162.475 MHz will cover the VHF frequencies
used by NOAA: 162.40, 162.425, 162.45, 162.475, 162.50, 162.525, 162.55
MHz

There is a sketch on the NOAA website showing the proper dimensions:
http://www.erh.noaa.gov/cae/images/antenna.gif

You can play around with the location, orientation (horizontal or vertical)
and direction of the antenna for best results.

The NOAA transmitters use vertical polarization.


--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.

 

[Phil Allison]

<JoseGomez@dotcom.com>

I got a Midland WR-100 weather radio. Because I live in a metal sided
house, the reception is poor. On the back there is a RCA jack for
external antenna. I can easily make up a piece of coax with a RCA
jack on the end, but what should I use for an antenna. I'd prefer to
make something simple out of wire, such a a straight piece of wire or
dipole type wire, strung under the roof of my deck, or a piece of
stiff wire pointing upward. I do have some old CB car antennas that I
could modify too, and mount them on the deck or rain gutter. I know I
could likely buy something, but I'd like to keep the cost down. I'm
not needing to boost the signal as much as to just get the signal from
the outside into the house due to the metal siding.

Simple and cheap are what I want.

** Use an indoor TV antenna - the kind with a pair of telescopic rods for
VHF reception.

Spread the rods wide apart and set each to about 18 inches long - get an
extension antenna lead if you need to and an adaptor for the plug to go to
RCA.

Should all be fine if kept out of the rain.


..... Phil

 

[Dave Platt]

In article <68qts6tdknihtdh3t7sj6o56oafvhi7553@4ax.com>,
<JoseGomez@dotcom.com> wrote:

I got a Midland WR-100 weather radio. Because I live in a metal sided
house, the reception is poor. On the back there is a RCA jack for
external antenna. I can easily make up a piece of coax with a RCA
jack on the end, but what should I use for an antenna. I'd prefer to
make something simple out of wire, such a a straight piece of wire or
dipole type wire, strung under the roof of my deck, or a piece of
stiff wire pointing upward.

Something very like the latter should work fine, as long as you have
one or two ground-plane radials as well.

One example is at

http://www.hamuniverse.com/2metergp.html

You don't have to use a socket-and-plug arrangement if you don't want
to - simply soldering wires to the center and braid of the coax will
work. Might not be as rugged, though.

Another thing you could do is use a piece of flat plastic a few inches
on a side as a junction point... fasten the vertical element, radials,
and coax to it with twists of wire or plastic zip-ties run through
holes drilled in the plastic.

Weather radio is around 162.5 MHz - plug that into the formula on the
page above to determine the lengths of the elements needed. You can
get away with just 2 radials of you wish, and don't need to be
excessively accurate in the measurements.

The type of wire you use to the make the antenna itself won't matter
much. Any copper wire (e.g. appliance wire from the hardware store)
should work fine... odds are you have something in your
spares-and-junk collection which will work perfectly well. If you
bend a loop at the top of the vertical element you can even hang the
antenna from it!

Simple and cheap are what I want.
And redardless of that I use, can I use common TV antenna type coax,
or do I need the stuff that was used for CB radios. (I dont recall
the numbers used on them, but know they were not the same).

Depends to some extend on the length. If you need a couple of hundred
feet of coax, using a lower-loss type such as RG-6 or RG-8 will give
you more signal strength. For lengths of 20' or so, ordinary
TV-antenna coax should do just fine.

Some coaxes have a 50-ohm characteristic impedance (used for CB and
ham and other transceiving applications). TV coax usually has a
75-ohm characteristic impedance. The ground-plane antennas shown
above are designed for 50-ohm operation, but (once again) in a
non-critical receiving application like this you should be able to use
either type and get acceptable results.

--
Dave Platt <dplatt@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

 

[Jeff Liebermann]

On Sun, 15 May 2011 05:04:05 +0000 (UTC), "Geoffrey S. Mendelson"
<gsm@mendelson.com> wrote:

Michael A. Terrell wrote:

It is 50 ohm, not 75.

Doesn't matter. RG-6 has taken over the low end coax market, it's well made,
cheap, easy to find and can be gotten in regular, direct burial and
long distance hanging (with attched steel wire) versions.

The steel wire is called a messenger wire. I live in a forest, and
such coax is really handy for preventing cable breakage when a big
branch fall on the coax.

For reception, the difference in impedance is meaningless and many hams are
using it for transmitting. Most hams use it for transmitters of 100 watts or
less, but some have reported using it for 500. (ouch).

I agree. 75 ohm coax is cheaper, generally better made, lower loss,
and nice and stiff for building a coaxial antenna (by slipping the
braid back over the outer jacket). The loss of typical 75 ohm coax is
less than the equivalent 50 ohm coax thus compensating nicely for any
mismatch losses.
<http://www.qsl.net/n9zia/wireless/75_ohm_hardline.html>
For what it's worth, I have rolls and rolls of 75 ohm coax, that I use
for literally everything from HF antennas to WX satellite. The only
time I would consider demanding 50 ohms is when the mismatch is
guaranteed to cause a problem, such as detuning a repeater cavity
duplexer, when I need the absolute lowest loss as in satellite work,
or when running high power.

See the max power versus impedance graph:
<http://www.microwaves101.com/encyclopedia/why50ohms.cfm>


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

 

[Geoffrey S. Mendelson]

Michael A. Terrell wrote:

It is 50 ohm, not 75.

Doesn't matter. RG-6 has taken over the low end coax market, it's well made,
cheap, easy to find and can be gotten in regular, direct burial and
long distance hanging (with attched steel wire) versions.

For reception, the difference in impedance is meaningless and many hams are
using it for transmitting. Most hams use it for transmitters of 100 watts or
less, but some have reported using it for 500. (ouch).

It is a RCA/Phono connector. I have the same unit. Use the right
connector if you want good reception. You can see it in the photo of
the rear panel on page 5.

That's a lot easier. I have RG-6 compression RCA connectors. Strip the
coax with simple tool, trim the center conductor and squeeze. I bought
50 of them off of ebay including the compression tool for $50.

F to RCA adapators are easy to get an cheap.

A VHF ground plane cut for 162.475 MHz will cover the VHF frequencies
used by NOAA: 162.40, 162.425, 162.45, 162.475, 162.50, 162.525, 162.55
MHz

There is a sketch on the NOAA website showing the proper dimensions:
http://www.erh.noaa.gov/cae/images/antenna.gif

Ground planes are more difficult to make, he asked for cheap and simple
and a dipole will do it. Almost anything from 15 to 20 inches a leg
will do. I picked 18 as it's a foot and half and simple to measure and make.
Making it out of tubing instead of wire makes broadband enough that it will
cover all of his VHF scanning needs.

Two meter ham band antennas, of which I've made many, need to be 19 inches,
so 18 is close enough for 162mHz, and is simple. If the person building
it buys 3 feet of tubing, and cuts it in half, it will work well.

The NOAA transmitters use vertical polarization.

Good to konw, and it probably will be what he needs, but he may have
reflections, hills, buildings, etc in the way so it always is better to
try than not.

Geoff.


--
Geoffrey S. Mendelson N3OWJ/4X1GM
Occam's Razor does not apply to electronics. If something won't turn on, it's
not likely to be the power switch.

 

[Michael A. Terrell]

"Geoffrey S. Mendelson" wrote:

Michael A. Terrell wrote:

It is 50 ohm, not 75.

Doesn't matter. RG-6 has taken over the low end coax market, it's well made,
cheap, easy to find and can be gotten in regular, direct burial and
long distance hanging (with attched steel wire) versions.

Yes, it's dirt cheap, but I still use the right cable. If you looked
at that NOAA sketch you will see that the connector was a SO-238 UHF
connector. You can get an adapter for RG-59 for the PL-259 mating
connector, but I haven't looked for any for the newer RG-6 Double
braid/double shielded coax. Hams around here prefer RG-8X.

For reception, the difference in impedance is meaningless and many hams are
using it for transmitting. Most hams use it for transmitters of 100 watts or
less, but some have reported using it for 500. (ouch).

It is a RCA/Phono connector. I have the same unit. Use the right
connector if you want good reception. You can see it in the photo of
the rear panel on page 5.

That's a lot easier. I have RG-6 compression RCA connectors. Strip the
coax with simple tool, trim the center conductor and squeeze. I bought
50 of them off of ebay including the compression tool for $50.

F to RCA adapators are easy to get an cheap.

A VHF ground plane cut for 162.475 MHz will cover the VHF frequencies
used by NOAA: 162.40, 162.425, 162.45, 162.475, 162.50, 162.525, 162.55
MHz

There is a sketch on the NOAA website showing the proper dimensions:
http://www.erh.noaa.gov/cae/images/antenna.gif

Ground planes are more difficult to make, he asked for cheap and simple
and a dipole will do it. Almost anything from 15 to 20 inches a leg
will do. I picked 18 as it's a foot and half and simple to measure and make.
Making it out of tubing instead of wire makes broadband enough that it will
cover all of his VHF scanning needs.

Difficult? I've made them in less than 15 minutes with a 1/4
electric drill and hand tools. It would be less than 10 if you have
access to a drill press and a drill vise.

How are you going to keep dirt and water out of the top end of the
coax with a dipole?

Two meter ham band antennas, of which I've made many, need to be 19 inches,
so 18 is close enough for 162mHz, and is simple. If the person building
it buys 3 feet of tubing, and cuts it in half, it will work well.


The NOAA transmitters use vertical polarization.

Good to konw, and it probably will be what he needs, but he may have
reflections, hills, buildings, etc in the way so it always is better to
try than not.

I have always had good results with a ground plane antenna, and poor
with anything else. A Yagi could be used, but less than 1% of the US is
in an area that needs the gain. Most areas can pick up two or three
different transmitters, but you want to use the closest, because of
NOAA's S.A.M.E that can tailor the alerts to a single area.

I have used a weather radio or scanner on NOAA for decades.


--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.