Nate Duehr wrote:
> I am not an expert, but most of the Sinclair stuff I've used had the
> elements welded in place.
>
> These are the "HD" models (heavy-duty)
> They also make
> them welded in the "Low PIM" models... no moving parts to make noise...
Interesting. I was wondering what was different about the low PIM
models. I should have guessed they would be welded construction. I
wonder if they also use different types of coax in the harness? I
have often wondered if "single copper braid" cables weren't a
potential source of noise, especially as they get older?
> I think you're right in the lower-end Sinclair line, there are elements
> that are just bolted to a mast
Correct. I am not an expert either, but have seen quite a few of
these in various configurations and spent some time perusing the
product line, wishing I could buy a new one.
Some have the dipoles just a few inches from the mast, and are field
adjustable for offset or omni pattern. For offset, all dipoles go on
one side of the mast. For omni they go on opposite sides or spiral
around the mast. These models generally seem to have a bandwidth of
about 10 MHz, eg. they come in 142-152, 152-162 MHz models, etc.
Some have the dipoles roughly a quarter wavelength from the mast,
all on one side, and are intended to provide an offset pattern only.
These usually cover 138-174 MHz.
Some have the dipoles roughly a half wavelength from the mast, all
on one side, and are intended to provide and elliptical pattern.
These usually cover 138-174 MHz.
There are also a few that have "pairs" of dipoles side by side, with
spacing somewhat less than a quarter wavelength. These are field
adjustable for elliptical or omni, and the ones I've seen (and
owned) were 138-174 MHz.
There very likely may be others that I am not familiar with, these
are just some observations I have made.
> I'll take the expensive antenna, any day...
> over farting around with a lower quality one!
I would if I could! Maintaining a repeater is becoming a full time
job. Much of the time that goes into it is directly related to
farting around trying to keep something on the air and working
reasonably well with a zero budget. But one does what one can. If it
was just another repeater "serving" an area that already had several
repeaters sitting idle, I'd have walked away from it in frustration
long ago!
Paul N1BUG
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