Today's project, a dual band 2M/70Cms aerial for your handy.
Nothing more than an SO239 and a couple of pieces of brass rod or whatever rod you may have. In this example, a length of threaded rod was used for the short element but of course you can simply use a length of brass rod or strong stiff wire for the elements. I like brass and brazing rod cause it solders nice, is cheap and can be had but if you put one of these in a length of sink waste with a couple of stop ends it makes for a very sturdy outdoor aerial.
Cut the rods a little but oversize and trim them back to the correct length afterwards. You *know* it makes sense!
If you go down the PVC sink waste route, you'll find the PVC pipe 'radome' will shift the resonant frequency downwards a bit and you may want to trim for best VSWR. Most folks don't bother.
I've even made these aerials from heavy duty mains cable, the sort you use for cookers and the like, and stuffed them in a bit of sink waste with some styrofoam spacers for the 'elephants' made from old packing foam to keep the wires spaced apart.
Just use whatever you have, but DO get the lengths and spacings right.
If you use a PVC RADOME, don't forget to drill a couple of tiny 'drip holes' in the bottom bung to let out moisture. If you don't, you will be sorry later!
You'll never buy a cheaper dual band 2/70 aerial for your handy for less than the price of an SO-239 and some scrap material!
This aerial 'design' is as old as the hills, perhaps even older than me.
Take care, Stay safe,
Be kind to your neighbours.
Make soup, not war!
No comments:
Post a Comment