[RTTY] 160

[Bill Coleman]

On Feb 22, 2007, at 7:35 AM, Anthony (N2KI) wrote:

> I think the biggest obstacle to overcome is the antenna.  Many,  
> including
> myself do not have a 160 antenna.  You could load the 80 meter  
> dipole but
> NVIS would be your working conditions to some extent.  Most already  
> are
> aware that to REALLY work DX on 160(or any band for that matter)  
> with good
> results is to be at least a quarter wave up. On 160 that's about  
> 130 feet.

W8JI has done a number of experiments with full size 1/4 wave  
verticals (130 feet) as well as full-size 1/2 wave dipoles at 300 feet.

In Tom's experience, the verticals are equal or more effective than  
the dipole for DX in 95+% of the time. There's just a few instances  
where the dipoles are more effective, and these are unusual  
propagation conditions that occasionally occur around sunrise / sunset.

> That's a big tree.  The higher you are the lower the take off angle.

Practically speaking, most hams cannot get a horizontal 160m antenna  
high enough to be effective for DX. Tom's 300 foot high dipole is the  
exception. That's equivalent to a 20m dipole at 38 feet -- which  
would be close to the minimum reasonable height.

For 160m, and for the most part 80m, vertical antennas rule. You do  
not need super-high supports to put up a reasonably effective  
vertical antenna. Many operators are using inverted-Ls with either  
elevated or ground-mounted radials.

I've had reasonable success shunt-feeding my 15m (50 foot) tower  
topped with a tribander. This vertical isn't even 1/10 wavelength  
tall, although the tribander does offer a bit of top-loading. I had  
to build one heck of a matching network to get this to work reliably  
on 160m. I worked 370 Qs in the recent ARRL 160m contest, and that  
with only 6 hours on. And this was with 100 watts.

If I had more supports (read trees), I would probably go with an  
inverted-L.

> It's
> certainly worth a shot, if you have an 80 meter dipole, to see how  
> it will
> play out.  My guess is you'll have about a 700 to 1000 mile  
> radius.  I'm in
> for trying.

160m is a really neat band.

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901