|[AMRadio] new antenna and matchbox a bust.|
jpl15 at panix.com
Mon Jan 29 13:00:04 EST 2007
On Mon, 29 Jan 2007, Brett gazdzinski wrote:
>> Probably. W/out going into a lot of math - 50' is quite
>> short, and not
>> near a multiple or fraction, of the bands you mention.
> 50 feet is all I got...
> If I let some dangle, it will be inside the trees...
Ok - this is not the major problem
>> "Fed with open wire line": Fed in the center? What Z is
>> the feedline?
>> What Z is the feedPOINT of the antenna at the height and ground
> Home made #14 about 4 inches apart.
What is it's characteristic impedance? What is the exact spread of
Basically it's best for the feedLINE impedance to match the feedPOINT
impedance at the frequency of interest.
>> Then you mention RG214 - how does the balanced(?) 'open
>> wire line' make
>> the transition to the coax? if the feedline is 450 ohms, you
>> need a 4:1
>> Balun at that point in your System.
>> Oooh, wait - do you mean you ran *two parallel runs of coax*
>> side-by-side, "with the shields tied together at the ends"...?
>> Umm - that just won't work at all, I don't theenk.....
> That is what wa1hlr told me to try.
> Not sure if that was the problem or not.
guaranteed it was 80% of it....
> Brick house, antenna tuner in a 6 foot rack cabinet
> in the center of the basement. No easy way to get the
> open wire line into the tuner...
drill two 3/16" holes thru the brick (with a masonry bit) spaced the
width of your feedline apart. Get a couple of #8 through-bolts (or
all-thread) long enough to allow connecting the wires on the outside and
inside of the shack. Glob on a bit of RTV or bathtub caulk to seal stuff
up. If you ever move it, then RTV or caulk the two holes, with something
the color of the brick - done.
> As a G5RV type antenna into the heathkit tuner, it
> seems to work real well for what it is.
As long as it works - problem over. HOWEVER: does it work 'well'? are
you getting 600 watts worth of signal out? Is the antenna as 'quiet' as it
can be on recieve?
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