On 9/16/2010 2:01 PM, Bill Ogden wrote:
> Concerning the SteppIR on top of the tower and its effects on the
> half-sloper and inverted V. I can see very little interaction. The beam
> elements are not connected to the boom, so any "top hat" effect is due to
> right-angle coupling (which I expect is very little). Both the inverted V
> and half-sloper have SWRs mostly in the 2:1 to 3:1 range where I operate
> (which is fine for me) and any changes due to SteppIR manipulation are very
> minor.
>
> Unless very long coax runs are involved, I always wonder why so many people
> are chasing 1:1 matches on the low bands.
It depends on your equipment. When I had the solid state KW you could
see the power falling off by the time the SWR hit 1.2:1, by 1.3:1 it
would be down by 200 to 300 watts. With the present tube amp, it's more
a matter of how far I can move without having to retune. On 40 I can
cover 7.150 to 7.185 without having to touch the tuning with the half
wave sloper.
Typically I use a line tuner/antenna tuner, tune into a dummy load,
match the antenna analyzer into the antenna, then switch over to the
antenna with the station. I run the legal limit, but even with the AT5K
tuner, I can cover over 35 KHz without having to touch the tuning at the
antenna tuner or amp. I could probably make it up to at least 50 or 75
KHz but I've not tried it.
I forgot to save the figures from the 75 meter sloper, but IIRC it was
good for about 30 KHz.
160 gets pretty narrow so I want to try the fan approach, or a remote
tuner as a last resort.
73
Roger (K8RI)
> My "high power" is only about
> 700-800 watts, so I may be avoiding some of the effects of a poorer match.
>
> Bill - W2WO
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