ham radio antenna...cheapgreenspun.com : LUSENET : TimeBomb 2000 (Y2000) : One Thread
Howdy folks. Something I posted in a newgroup, somebody might find it useful. Oh, death to trolls as well. Regards, Art
Cory, some Ham notes:
I told you about the Radio Shack HTX202 handheld 2 meter TXers on sale at $129.00? That sale SHOULD run to the end of this month. I THINK it will. That radio comes with a rechargeable Ni-Cad pack, a standard 6 cell AA battery pack, and a 120V charge adapter for the NiCad pack. It is not a wide band receiver, but limited to 2 meter ham band. It can put out 1 watt on low power no matter what power source it has, but on high it varies from about 3.5 all the way up to maybe 6 watts depending on power supply. It can be hooked DIRECTLY to a 12V source, like a car battery (max output)! It does scan both open and memory freqs. It does PLL and tones to work autopatch.
Antenna notes......some ham on the local repeater told me making your own antenna was a waste of time for 2 meter cause you would have more money in it than just buying a new one.
People will never learn....you should NEVER tell me I shouldn't do something.
Let me tell you....(and whoever you want to pass it on to)...............
This week I made a 2 meter TX antenna. I chose a 1/4 wave ground plane design as it's efficient and small in 2 meter. The whole sheebang would easily fit in the crawl space of most homes and has a such a small visible signature few people would notice it outside a building, like on a deck rail.
I started with a 5"x5" sheet of scrap aluminum. I drilled a hole in the center big enough to mount a Radio Shack PL-239 chassis mount (pn# 278-201). The chassis mount is attached to the sheet with four small machine screws. So far, thats one 3/4" hole surrounded by four 1/16" holes . Go ahead and bolt on the chassis mount. Now bend the four corners of the aluminum sheet down at a 45 degree angle for the last 1" of each corner. Down/bottom is defined as the side of the plate on which you screw the coax to the chassis mount. Now drill a small hole in each bent down corner. Should I mention you'll need a drill and perhaps a round file to enlarge the center hole?
Next, attack the closet monster and wage war till it gives up 5 uncoated wire clothes hangers. By uncoated I mean ones without the blue stuff or the rough section that keeps your pants from puddling on the floor. You know, the cheap ones the dry cleaner gives you, they breed in your closet till the monster comes to life and refuses to let you have your clothes any more without a struggle.
Take these hangers and cut/straighten them till your have five pieces at least 22 inches long. Here you need a pair of wire cutters. (WHY is it called a 'pair' when it's one tool?). Now take your handy dandy needle nose pliers and grab the end on one and turn it till it's a tight loop. Do that with one end of four wires total. Attach these wires with the loops to the bent down corners of the aluminum plate using four small bolts and nuts (also available from Radio Shack). On my antenna I soldered the wires and bolts together just for luck. These four down turned wires might make it look like a Martian spider, but are really ground radials. Measure from the bolt that holds each wire down the wire to 19" and cut it off there. ('pair' of wire cutters again). The wires should continue the same 45 degree angle that the plate corners have.
Now, take your last remaining wire and clean a few inches of one end till it's shiny polished steel. Stick this end in the center tube of the Chassis mount and solder it in place with rosin core solder. Be careful to have it fairly straight as you do cause that joint will be delicate and breakable till reinforced. Be generous with the solder but don't let it touch the metal body of the chassis mount. Also, do not heat it to the point that the plastic insulator melts out of the chassis mount.
Congrats, that upright piece is now the driven element of your antenna. I chose to reinforce mine with a bead of silicone sealer around the base of the wire and the chassis mount. After that bead dried I clipped the driven wire off at exactly 19 inches from the top of the mount. I rounded the end of the driven element with a file till it was smooth. As a final touch I shot the whole thing with a light coat of clear spray paint to hold down corrosion. About four PHHUTTT's of the paint can was enough.
As a way to mount it later, I left a small tab of aluminum on one side of the plate which I bent down and will simply clamp to a 8 foot 1x2 board off my back deck.
After action report: I used a PL-239 to BNC adapter to hook that antenna to my HTX202, using a 36" piece of RG58 CoAx. From my back deck on a clear night, with the HT set at 1 watt and holding the antenna up using the Co-Ax as a handle, I worked a repeater about 30 miles away. I got a signal report of 85%, in other words just a bit of white noise. On five watts the report was 599, perfect. I was able, on five watts, to trigger repeaters I know are over 60 miles away. The nearest repeater, about 8 miles away by air, reported me as perfect with 1 watt, better than my truck mounted mobile set at 10 watts and using a mag mount 5/8 wave ground plane antenna.
Total costs involved: between the PL-239 chassis mount, the 36" CoAx, and the adapter, I have about $12 in the whole rig. Everything else was scrounged. I did not have to buy the CoAx or adapter in that configuration, I could have knocked another $5 off the price by doing it differently. In the antenna itself I have $2 invested. That's it, TWO BUCKS, and about 45 minutes total. For $2 and 45 minutes I get an antenna that rivals $100 store bought models and probably works better.
My point is....long lost I know, but.............ANYBODY can do this. It aint complicated or difficult. This antenna uses one store bought part and a bunch of scrap. With this antenna and a $129 on sale Radio Shack HTX202 I have great local communications. You don't need a $1800 base station, (although I am not going to give mine up!). You don't need a $$499 walletscraper antenna. You don't even need to be real smart (LOOK, *I* made one, didn't I?)
2 meter is not world wide, it's just local stuff. Build a beam antenna and get it real high up, maybe you gets hundreds of miles. It's local, but it will get you in touch with hams that ARE worldwide. From my home with my HTX202 and my $2 antenna I can reach everything within 30 or so miles, and that includes six repeaters, one of which crosses to 10 meters and lets me reach literally thousands of miles when fate smiles. Most hams that work world wide HF rigs also use 2 meter radios. Most local ham nets use 2 meter radios. Most RACES emergency nets use 2 meter radios locally.
Anyway, Cory I know this stuff is basic to you, but maybe someone else will find it useful.
-- Art Welling (email@example.com), December 19, 1998
Used to make antennas out of heavy gauge wire glued, tied or otherwise affixed to bamboo or cpcv pipe as a support. Works OK. And working with copper makes it a lot easier to get a good solder joint. Had a shortwave antenna for a while that I stepped off at 1257 feet or thereabouts. I could hook a neon bulb between the antenna and my ground (a nine foot steel fence post with about 20 inches still showing above ground - got some blisters using the twelve pound sledge on that sucker) and use it for lightening storm detection - the bulb would flash if lightening was striking within a hundred miles or so.
-- Paul Davis (firstname.lastname@example.org), December 19, 1998.
THANKS for the heads-up on the HTX-202! Most of the RS stores in my area were sold out, but I found a display unit and got it. They couldn't find the instructions, but will have a set shipped to me.
I got an advanced ticket in high school, and mostly worked CW & SSB on 40 thru 10 meters. Let it expire 5 years later in '74 when I was busy with other things. DUH! I hear license requirements have changed a lot since then, but will probably test for technician or general in the near future. Any recommended websites with study info?
Like your 2 meter antenna -- will probably make something similar. Most of my first gear was homebrew using scrounged TV tubes, hand- wound coils, etc.
Are you the Art Welling who used to be on the CIS CARS Forum? I was very active there in its early days, but was fading into lurker mode around the time you were becoming active (assuming that was you -- heh, heh).
Thanks again for taking the time to post that information. I had my HTX-202 in hand within an hour of reading it, and certainly would have missed out on this good opportunity without your timely message.
Randy Jones, Anaheim CA
-- Randy Jones (email@example.com), December 20, 1998.
Thanks for detailed info. Copied notes..plan to follow up
-- More Dinty Moore (Not @this time.com), December 21, 1998.