On Sat, Feb 7, 2009 at 12:53 AM, Roger (K8RI) <K8RI-on-TowerTalk@tm.net>wrote:
>
> >
> > Postulate: Full legal limit effective radiated power is basically
> > requirement to make lots of 160m contacts
> >
> What's ERP have to do with the legal limit?
Nothing... I probably should have said 1500W ERP instead of full legal limit
ERP, because of course, there's no such thing as the latter. I'm just
saying that I think people expect they need to *RADIATE* 1500W to work DX
and do well in general on 160m. They don't have to do that. A dozen watts
EiRP will do OK, and yield a "useable" station. and a couple hundred watts
EiRP will do great.
I feel like there are a lot of people who just wouldn't believe me if I told
them you could work 160m DXCC from the East Coast with 10W or 20W radiated
power. Midwestern and West Coast stations will just get cross with me, but
that's a somewhat different issue :-)
A lot of people need to run full legal limit on 160m, but it's not because
they need to radiate 1500W. The people that actually manage to radiate 1kW
or more of their 1.5kW on Topband are the really big guns.
My point is that running 1500W to a -20dBi antenna, equivalent to running
15W to a 0dBi antenna, is enough to do a LOT of fun stuff on Topband, given
the strong domestic signal strengths. It's even enough for DXCC from good
locations, given the stellar ears of DX ops around the world. That makes
it a problem to conclude that an antenna system is working "well" on Topband
if your measuring stick is to be able to work around the country and work
some DX while running a full legal limit amp. To *NOT* be able to do that,
you'd probably need a -30dBi antenna system.
I briefly dropped in on the Stew Perry warmup contest in October and ran 5W
to my antenna, for at most 1W or so out, maybe more like 500mW, and I did OK
in closer than about 700 miles. Further than that, I couldn't really get
anyone's attention. (though I have logged a couple of big gun EU with 5W
output too) But you need a massively bad antenna system to burn 1499W and
get to that point.
With 13dB more signal strength than what it takes to work easily in a 700
mile circle, I've got 102 countries worked on TB. Doesn't really matter
if that (estimated) 20W is from the application of 100W to a -7dBi antenna
system or 1500W to a -19dBi antenna system... it does the same job, but I
wouldn't call a -19dBi antenna "good." Honestly, I don't really call the
-7dBi antenna "good" either. I have fun with it.
I'm not here to disparage anyone's choices, just trying to paint the picture
of what a "workable" antenna system may mean at 1.8MHz if you run full legal
limit power into the input end.
73
Dan
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