Scanner Antenna for Campground?

[ctcamper]

I have a diamond rh77ca portable antenna for my gre 500 scanner.
Since it didn't receive that great when on the road, I ended up with a larsen multiband on a magnetic mount which seems to do much better when moving.
Larsen does ok if I am at a higher elevation ( class c rv with magnetic mount on hood) but I have trouble picking up noaa with it fading in a and out or not coming in strong enough to hear. I was thinking that getting it above the roofline might be helpful?
I did buy a rs sputnik which I am thinking about mounting on arrival to a campground maybe on the top of the ladder.
Not sure how to attach to ladder yet.
I was also debating a couple of yagis instead as sometimes I get far away from transmitters. I figure I can turn them by hand if I use a section of pvc pipe on the back or something like that. I mainly listen to 160-170 for my noaa and 450-470 freq. for public safety rr, etc.
I just found a preamp that is available also but am not sure if they are any good.
Does anyone have any helpful hints.

[hamguy]

Quote:

Originally Posted by ctcamper I have a diamond rh77ca portable antenna for my gre 500 scanner. Since it didn't receive that great when on the road, I ended up with a larsen multiband on a magnetic mount which seems to do much better when moving. Larsen does ok if I am at a higher elevation ( class c rv with magnetic mount on hood) but I have trouble picking up noaa with it fading in a and out or not coming in strong enough to hear. I was thinking that getting it above the roofline might be helpful? I did buy a rs sputnik which I am thinking about mounting on arrival to a campground maybe on the top of the ladder. Not sure how to attach to ladder yet. I was also debating a couple of yagis instead as sometimes I get far away from transmitters. I figure I can turn them by hand if I use a section of pvc pipe on the back or something like that. I mainly listen to 160-170 for my noaa and 450-470 freq. for public safety rr, etc. I just found a preamp that is available also but am not sure if they are any good. Does anyone have any helpful hints.

We have a couple cheapie hand held transceivers which include NOAA. I can hear them anywhere we have been. I suspect you have a receiver problem, not antenna. You are aware there a more than 1 NOAA freqs ans you need to scan fot the strongest (=closest) transmitter. I searched that radio and it should hear ALL NOAAs with a 5' length of wire!

[John-D]

Well I design and build my own antennas much of the time.. The problem is.. to test it I need to feed it power, and that's not easy to do if you don't have a license (I do not have a receive type antenna analyzer

But most any 2-mtr Ham Radio antenna sold in a store will work on 162.xxx MHZ just fine (That's the weather band) Using my Diamond no-ground-plane 2m/70cm antenna I can get two different weather stations where I am now and in some places 3.. IN other places.. NONE both in the car and the MH

My favorite design is a "J"-pole antenna.. basically it is a length of TV twin lead

To make one you need to know the wave length (300/162 meters) and cut a piece of twin lead 3/4 that length, At the 1/2 wavelength point you cut JUST ONE WIRE. This will give you a "Short End" and a "long End" we are done with the long end.

On the short end short the wires together at the end, Now you tap your coax in (Traditionally the shield is hooked to the short side) a short distance up from the shorted end, about 1.5 inches as I recall without taking measurements.

I would use straight pins and move up/down a bit for best result.

You can getmore precise designs from here Now these are normally cut for the 144-148 MHZ band but Google search page lists a bunch of 'em

Most of the designs there use copper tubing

Just take any 2-mtr design and shorten by a factor of 146/162 and you got it

[ctcamper]

Thanks
The reciever is good. I can pull in transmissions usually 10 miles distant with the diamond rh77 and the larsen does a bit better. It is those times when I am in a valley with very weak noaa signals that I was hoping to improve reception on. Diamond does not do so well on 800 but that is another story.
I was camping three quarters of the way up a mountain in vt last yr and was pulling in towns 40 miles distant for public service. noaa came in good there on the gre. My cheap small table am/fm radio does weather also and on the mountain I have to maneuver the antenna around just right to get noaa. I do have all the noaa freq programmed into the gre and it scans thru them automatically for the strongest signal. I can also get more than one noaa most of the time If I manually select through the weather frequencies.

I was thinking along the lines of, If I can make something like a yagi I might be able to pull in those weak signals when I am camped inbetween mountains and I'll be able to get it higher up off the rear ladder which I'm sure will help

[John-D]

By the way,, ON 162 MHZ Height is MIGHT.. True story follows.

I was trapped at work (I worked in Downtown Detroit Got off about 30 minutes after the final out in a Tiger Ball game, could not exit the parking lot as the road was wall to wall bumpers to bumpers)

So I decided to see how my new toy worked

It worked right good I'm not sure how far it is from DETROIT, MI to ADRIAN, MI but I found myself listing to a ham radio repeater in Adrian, I was able to access it too, just fine.. From Downtown Detroit

Well, we heard another station try to join in, a VE3??? (Could not get his full call) I listened for him on the repeater input, Got him clear. Well after we signed with the folks in Toledo he and I switched to a "Simplex" (Direct) frequency and chatted.. I ask him what he was running

I forget the transcever, the antenna was a Ringo Ranger at around 30 feet The effective Radiated power was on the order of 40 watts as I recall.

I"m running a Wilson WE-800, 1 watt into a "Rubber Duck" antenna, Effective radiated power.. Somewhere around a quarter watt.

I CAN SEE HIS HOUSE FROM WHERE I"M STANDING

And he could not make it

Of course.. I was standing... around 250 feet above ground (21's floor observation deck in a office building)

HEIGHT IS MIGHT

But frankly for RV use I'd go with one of the J-Poles

And 10 miles is nothign.. Sitting on the ground at that same downtown Detroit Location I coudl easily work repeaters in Ann Arbor and one day I drove from Downtown Detroit to Grass Lake Michigan, meanwhile another ham drove from Flint to Detroit, We were chatting all the way, Made a couple of phone calls using the repeater's phone patch (Fire reports, it was after all July 4) and all the while had good communications.

That's mile marker That is about 68 miles for me. Not sure of his distance

And my transmitter is only 10 watts (Well was only 10 watts) then

[ctcamper]

I alway thought of 10 miles as pretty good around here, I am in a area with very large hills/mountain type terrian. CB, back in the old days, was useless at 10 miles even with my radio which is peaked at ~8 watts.

I know cell phones in the mountains are almost useless but I'm guessing that is even more of a line of sight problem


Thanks for the good ideas , I'll see if I can work on that j pole this weekend.

[John-D]

OF course with a J-Pole of the TV-Twin lead type (Which I have) and a pneumatic launcher to send a weighted tennis ball 50 feet up a tree, and enough coax and fish line (monofiliment) you can get some SERIOUS height.

(Google Pneumatic Antenna Launcher)

I got to build one of those