Sent from my iPhone
On Mar 28, 2012, at 5:21 AM, "Rick - DJ0IP / NJ0IP" <Rick@DJ0IP.de> wrote:
> John,
>
> The lynchpin to having a good signal when operating low power portable, is a
> good antenna.
> Some people take a great rig, run it at reduced power on a crappy antenna
> (i.e., mobil whip mounted to a ground stake), and wonder why they don't work
> anybody.
>
> Wire can be a wonderful antenna, but you have to get it up high in the air.
> That's why I always took a telescoping fiberglass pole with me.
> In the early days they were just 8m long.
> Later there were some purpose-built poles for ham radio that were 10m long.
> Today you can get them in even stronger quality in lengths of 12m or 18m.
> In fact they even come as long as 26m but that's a bit overkill for a
> one-man expedition.
>
> For Field Day I always ran a doublet, with each leg 13m long, and fed with
> 300 Ohm Openwire.
> I had a tiny little MFJ Matchbox (T-filter), with a built in Balun.
> The Balun was great for 5w QRP or 20w, etc., but I burned it up running
> 100w.
> Had to re-build it, then never tried 100w with it again.
>
> For my normal excursions I had a special lightweight 3-band dipole:
>
> - made of thin Teflon-insulated stranded copper wire (I guess about AWG 22
> or so)
> - cut for 20m, insulator, more wire for 40m
> - 2x short jumpers for jumping the insulator between 20m and 40m segments,
> for 40m operation
> - 2x short stubs with alligator clips to extend the antenna for 15m
> operation (6 inches on each end)
> - fed with about 50' of RG-174 (YES, THE THIN STUFF).
> - A ball of twine for tying off the ends
>
> Twine was cheap and disposable if it got too tangled. Ends tied off to
> trees, or if nothing else, simply to stakes in the ground.
>
> The thin RG-174 is sufficient and loss is really not bad for short runs at
> those frequencies. The loss is worse if you use heavier coax, and then fail
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