Gee I spent not more than 2 hours with my MFJ259, my MFJ Tuner (I think it
cost me 129.95 and is good for 300 watts, which is three times the power I
will ever need, and 600 times the power that I used most of the time), and
a pencil and paper. I am old fashioned and maintain a log. In the log I
have recorded tuner settings for each of the ham bands. (75 and 80 are
separate bands) QSY is a matter of referring to log, presetting dials, and
changing bands. If I feel the burning need a quick touch up of the
capacitor and I am matched. My transceiver, and the DIP unit sit side by
side on top of the tuner, so there is no significant footprint problem at
the operating position.
You failed to mention the only major drawback to the ladder line fed
doublet that I am aware of. It develops some strange lobes as it gets
longer. I have heard that the 44' length of the NorCal "Crappie" dipole
was chosen as a compromise between 80 meter efficiency and 10 meter lobes.
I have been scared of "fan" dipoles for years. I worry that given a
reasonable radiator I put enough 7.810 signal on the air to upset the FCC
when I was on 3.905. Of course the tuner you seem to refuse to run would
help with that somewhat, but I still do not like having the nearly resonate
antenna connected to the transmitter any way. I have found out just how
far I can talk with a couple of watts (halfway around the world, after that
it is shorter going the other way). I never have run an amplifier, there
was a time I put 225 plus watts out on 80, and 40 (TR4) but since I got my
first ICOM never more than 100, seldom that much. Still worried about
harmonics where I have no business radiating, and the FT817 has
dramatically demonstrated just how little power is required for a QSO.
Amplify the harmonic, and couple it to a nearly resonate antenna, no thank
you, I like my license to much, and do not have all that much money for
fines laying around the house.
--
73 es cul
wb3fup
a Salty Bear
"Ed Senior" wrote in message
nk.net...
Hi Bill -
I tried to find the specific antenna you are considering using your
links,
but I wasn't able to do so with a reasonable amount of effort.
However, there is no doubt at all that a well-designed trap antenna
could do a good job for you.
I am rather bemused by the responses you got suggesting a
one-size-fits-all
ladder-line doublet instead. I'm sure these can be good antennas; but
they usually seem to be presented by their advocates as having no draw-
backs at all. That would be an incorrect view, as those antennas have
their own tradeoffs--just like other antennas.
The biggest tradeoff is the tuner, of course. If you're planning on
running
power, this is about a $600 +/- item (commercial models), and it takes
up space at your operating position. But you're not done when you buy
it and find a space for it... you also have to TUNE it every time you
make
a significant QSY. (I won't mention tuner losses unless someone brings
up trap losses.)
I friend of mine took a look at my array of two W9INN trap/fan dipoles
(6-band coverage); but he decided that he wanted to go with the
ubiquitous
135-foot doublet-plus-tuner. (He bought the tuner from me, which was
great... I don't need it!)
When I asked him how he was doing with his new setup, he reported
that it gets out fine on 80m and 40m, but is such a pain in the a*s to
tune on the higher bands that he doesn't bother with them. (That's just
his experience, other users seem to have less trouble.) Oh, and if he
ever decides to run power, he'll have to buy a BIGGER tuner, and
probably re-sell the low-power tuner he bought from me.
Meanwhile, I'm enjoying six bands, instant QSY, no tuner needed, and
I run power when I want to. Because of the loading effects of the traps,
my antennas fit in a very compact space... which is all the space I've
got.
I hear well,and my reports are excellent. Not bad, not bad at all.
All I really want that I haven't got is the ability to get these antennas
straighter and HIGHER.
Good luck with your selection, and I hope whatever you choose works
great for you.
73,
Ed W6LOL
"Bill" wrote in message
...
Anybody tried to build this trap antenna yet?
http://www.nerc.com/~jdegood/coaxtrap/
http://members.shaw.ca/ve6yp/
http://members.fortunecity.com/xe1bef/hf-antennas.htm
Need some help on where to tune the traps for the bands of operation,
and
pruning the connection wiring. Can this be done with out a major test
equipment investment?