BUILDING A NOOA ANTENNA?

[MikeinBaja]

I'm a satellite guy - not a radio guy - but I need to build an outdoor antenna for NOOA broadcast reception (162.400-162.550MHZ) for a weather warning station I recently acquired.

The existing unit has a telescoping antenna and an external antenna RCA type jack. If I take the unit outside about 35' away I can lock on with no problem - but no lock where the unit needs to sit inside (or anywhere else inside).

Any recommendations for sites? Google search wasn't much help. Dimensions? Material? Any hints?

HELP!

 

[turbosat]

Mike, sounds like a simple 1/4 ground plane antenna would do the trick for you, if it works simply by going outside. If you can handle some easy soldering, you can build yourself one for probably less than 10 dollars, and stick it on a short mast on your roof or eave.
If you want ready made, you can buy one already built at the radioshack but they recently upped the price of theirs by about 8-9 dollars, its the 20-176, also called the sputnik by scanner fans. I've built a bunch of them and they work fine.
If you want to really get into antenna building, google for the plans for a super-j-pole, works great also.

edit: heres a link to one of many project pages covering home made ground plane antennas:
http://www.pbase.com/dickh/image/27104369
Use #12 wire, that 10guage stuff is too big to solder into the top of the SO-239 connector~!

 

[turbosat]

Here's the link to the ready-built model :
Outdoor VHF-Hi/UHF Scanner Antenna - RadioShack.com
And you can use RG6 to connect it, you'll need a couple of adapters to connect antenna to radio, a PL-259/RG6 from the antenna, and RG6-whatever on the radio end. And some coax-seal.

 

[Pepper]

Google can't help if you search for the wrong thing. It's NOAA not NOOA.

 

[MikeinBaja]

Mike, sounds like a simple 1/4 ground plane antenna would do the trick for you, if it works simply by going outside. If you can handle some easy soldering, you can build yourself one for probably less than 10 dollars, and stick it on a short mast on your roof or eave.
If you want ready made, you can buy one already built at the radioshack but they recently upped the price of theirs by about 8-9 dollars, its the 20-176, also called the sputnik by scanner fans. I've built a bunch of them and they work fine.
If you want to really get into antenna building, google for the plans for a super-j-pole, works great also.

edit: heres a link to one of many project pages covering home made ground plane antennas:
Ground Plane photo - Dick Harris photos at pbase.com
Use #12 wire, that 10guage stuff is too big to solder into the top of the SO-239 connector~!

That looks intersting and doable. What length does each "arm" need to be?

 

[MikeinBaja]

Google can't help if you search for the wrong thing. It's NOAA not NOOA.

Fat fingered it, but thanks for your helpful technical post.

 

[Pepper]

Unfortunately that's as far as my technical knowledge goes on this particular subject. Since you did it twice I thought it just might be a legitimate case of not knowing what it was.

 

[turbosat]

Here's a link to one of many online calculators:
BUILD A GROUND PLANE ANTENNA FOR 2 METERS AND MORE - SIMPLE AND EASY!
Just put 162 mhz in the search box and it'll figure it for you. You can make them with coathangers too, but you need to sandpaper the ends where the bolts hold them onto the so239. I've made a bunch of them cut to the 108=136mhz aircraft band, If you need some pictures let me know, I'm in the middle of putting another one together right now. I use a 1 1/2" pvc pipe 'male adapter' to mount them in, fill in the spaces with hotglue to help weather proof, and a stub of 1 1/2" pvc to hold it to a mast.

 

[MikeinBaja]

Here's a link to one of many online calculators:
BUILD A GROUND PLANE ANTENNA FOR 2 METERS AND MORE - SIMPLE AND EASY!
Just put 162 mhz in the search box and it'll figure it for you. You can make them with coathangers too, but you need to sandpaper the ends where the bolts hold them onto the so239. I've made a bunch of them cut to the 108=136mhz aircraft band, If you need some pictures let me know, I'm in the middle of putting another one together right now. I use a 1 1/2" pvc pipe 'male adapter' to mount them in, fill in the spaces with hotglue to help weather proof, and a stub of 1 1/2" pvc to hold it to a mast.

I tried to download and the only thing that downloads is the images - no calculator. If yours is working, could you input 162MHZ and give me the lengths?

 

[turbosat]

Sorry for the bum steer~! I forgot that that one is a downloadable program, for windows only, so I couldn't use it myself, forgot to delete it.
17 & 11/32" for the vertical, and just make the lower radials 2" longer. The lower ones aren't that critical on length, as long as they are longer than the vertical (they form the ground plane part of the antenna).
Just cut 'em close and it'll work fine, it'll have a good chunk of VHF spectrum covered.

edit: Here's one that works in java:
http://bfn.org/~bn589/antenna.html
click 1/4 button after inputting the freq...

 

[turbosat]

some pictures

Maybe these will help a little in the project...I use #6-32 x 3/4" long bolts and nuts to hold the radials to the SO-239, some people just loop the wires thru the holes and solder. The idea for the pvc thing to hold it came to me in the hardware store while looking at all the various parts. Just take a hacksaw and saw across the top threads of the thing, and once the wires all attached to it, it'll drop right down in place, and a 1 1/2" pvc cap, with a hole drilled through the top for the vertical wire, will drop right down onto the whole thing. Then just pvc-glue it or hot glue up the holes to keep out the moisture. The coax came down through the bottom, and I just use those big shiny steel pipe clamps to hold it to the top part of a tv mast. Some tie-wraps will hold the coax in place and give it some strain relief.

 

[MikeinBaja]

Maybe these will help a little in the project...I use #6-32 x 3/4" long bolts and nuts to hold the radials to the SO-239, some people just loop the wires thru the holes and solder. The idea for the pvc thing to hold it came to me in the hardware store while looking at all the various parts. Just take a hacksaw and saw across the top threads of the thing, and once the wires all attached to it, it'll drop right down in place, and a 1 1/2" pvc cap, with a hole drilled through the top for the vertical wire, will drop right down onto the whole thing. Then just pvc-glue it or hot glue up the holes to keep out the moisture. The coax came down through the bottom, and I just use those big shiny steel pipe clamps to hold it to the top part of a tv mast. Some tie-wraps will hold the coax in place and give it some strain relief.

Thanks - the pictures really help.

Instead of using the wire - I have access to an old busted up TV antenna (at a neighbors) to scrounge for parts. If I could salvage enough of the aluminum rod would that maybe make something more wind durable?

 

[turbosat]

Hard to solder aluminum, of course you could make a simple dipole antenna out of it. Coat hangers or 12guage house wire works better , in my experience with ground plane constructions. Main reason being, the tiny little hole in the top of the connector that you have to solder the vertical rod into, anything bigger than a coathanger won't fit in it. I made a yagi out of an old antenna though, 12' long! You could make that 3 element yagi, from that link I sent you, from old tv antenna parts. In fact, for vhf-hi band, which that is, an old vhf tv antenna would probably work for it too.

 

[MikeinBaja]

Hard to solder aluminum, of course you could make a simple dipole antenna out of it. Coat hangers or 12guage house wire works better , in my experience with ground plane constructions. Main reason being, the tiny little hole in the top of the connector that you have to solder the vertical rod into, anything bigger than a coathanger won't fit in it. I made a yagi out of an old antenna though, 12' long! You could make that 3 element yagi, from that link I sent you, from old tv antenna parts. In fact, for vhf-hi band, which that is, an old vhf tv antenna would probably work for it too.

Great - now you got my "McGuiver" side going.

Need to spend some time in my scrounge pile today - will post back.

Thanks for all the help!

 

[turbosat]

I suppose your local weather radio station is close by, if you can get it by avoiding some walls. The little ground plane will bring in the closest 2 or 3, most likely. I can get one thats about 60miles away, plus my local one, and 2 more that are in the 25-30mile range.
I took a shot of that little 3 element yagi today, I'll post it later. Really easy to build, especially if you have an old tv antenna lying around.

 

[MikeinBaja]

I suppose your local weather radio station is close by, if you can get it by avoiding some walls. The little ground plane will bring in the closest 2 or 3, most likely. I can get one thats about 60miles away, plus my local one, and 2 more that are in the 25-30mile range.
I took a shot of that little 3 element yagi today, I'll post it later. Really easy to build, especially if you have an old tv antenna lying around.

I actually want this for the beach house in Mexico - the unit has a warning function that alarms when there are warnings/watches posted.

I'm probably 35 miles +/- as the crow flies from the transmitter in San Diego. Funny thing, I've gotten a strange signal "blip" the other day while trying with the unit's telescopic antenna outside - but that blip was from LA - probably a good 75-80 miles! It actually came in stronger than the closer one in San Diego.

Go figure.

 

[turbosat]

That was some skip, I guess. I've picked up the Chattanooga station before, which is about 110 miles from me , when the conditions are just right.

 

[MikeinBaja]

ANTENNA-STEIN; TAKE 1






Spent the afternoon going through my and a neighbor's scrounge pile and built this for proof of concept. Can't hook it up yet until I come up with the right RCA adapter plug and figure out the transition from the coax to the plug.

This dog have any chance of hunting? So far, $ investment = $0.00.

Once I get the concept down I plan to build a good one.

 

[turbosat]

Interesting, kinda looks like a robotic alien grasshopper, lol. If you got the so-239 in there, with the center radial soldered in, and the legs of the antenna insulated from that, and attached to the outside of the connecter, it might just work. As far as the connection to the coax, some people don't even worry with one at the antenna-they just solder the center conductor of the coax to the upright , and twist the shield of the coax together and fasten it to one of the lower radials. It's really a simple thing to make, and so far, all of them I've made work great. Well, except that first one, and it was because I didn't seal it good enough to keep the rain out, it all corroded inside. One question: how are you going to mount it to a mast? Attach to roof maybe, like a big bug?

 

[MikeinBaja]

Interesting, kinda looks like a robotic alien grasshopper, lol. If you got the so-239 in there, with the center radial soldered in, and the legs of the antenna insulated from that, and attached to the outside of the connecter, it might just work. As far as the connection to the coax, some people don't even worry with one at the antenna-they just solder the center conductor of the coax to the upright , and twist the shield of the coax together and fasten it to one of the lower radials. It's really a simple thing to make, and so far, all of them I've made work great. Well, except that first one, and it was because I didn't seal it good enough to keep the rain out, it all corroded inside. One question: how are you going to mount it to a mast? Attach to roof maybe, like a big bug?

Thanks for not laughing - actually, I called it a LEM for a really small alien! My much better half got a good laugh out of that.

I did solder a 239 in scrounged from a 70's CB radio and filled the whole thing with silicone. Found an old 259 on a pigtail RG58 and fitted an OLD RG58 connector to make a transition to cable I can work with.

The RCA type plug to the unit is strange - has me stumped - nothing in my scrounge pile fits?

Had a good time today fabricating though.

I'm retired - time is my ally!

This is version 1.0 - if I can figure out the transition to RCA to the radio and it works, then I will build 2.0. Mount plan is a straight out piece transitioning to a 90 degree piece & either clamp or sheet metal screw to mount.