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Old April 20th 07, 07:12 PM posted to rec.radio.amateur.antenna
[email protected] nm5k@wt.net is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 757
Default Multi-band dipole question

On Apr 19, 4:28 pm, Roy Lewallen wrote:
wrote:
So would a 80/40/20 be the thing to make? For whats it's worth, I
don't have a tuner right now.
I just want to cut each for the middle of the band for General phone,
and accept whatever bandwidth
I get.


That'll get you on those three bands and, as I mentioned, you can
probably get a reasonable impedance on 15 as well by fiddling the 40
meter antenna a bit. It won't be quite resonant on 40, but probably
close enough so your rig won't shut down.

Roy Lewallen, W7EL



He may notice a resonant point around 27-28-29 mhz also..
If you use a length a coax to feed, that will add a 1/4 wave
of length to the 80 legs, IE: about 60-70 feet, you can feed
the shorted coax end from the shack, and run it on 160m as
a vertical. When I use the 40 legs for 15m, I usually slap a
tuner inline as a line flattener to keep the radio happy, and
also increase the usable bandwidth. I usually don't trim the
40 antenna to get a match on 15, as I prefer the 40 legs to
be tuned where I cut it, which is usually in the middle of the
band, so I can work both phone and CW. Any cheap tuner
will easily give a good match for 15m, and the loss is going
to be low, being the match isn't bad to begin with.
In the old days with tube rigs, I never worried about tuning 15.
The rigs would tune it no problem, with no tuner required.
But the newer solid state radios are a bit pickier.. So I'll
put the tuner on. I have a 989c which is always inline, but
rarely actually used in most cases, except for the meter,
and in rare cases like 15m, 30m, and maybe 160m where
I want to tweak the match a bit.
MK