On Wed, 26 Jan 2005 15:05:39 -0600, Ken Bessler wrote:

My 160/80m trap dipole can be operated without a tuner from 1.800 to
1.930. I mainly operate in that range (usually on 1.893) and I have a
tuner for operating above 1.930. Easy.

My question is this - is it better to resonate high and use a tuner to
go lower or do it the way I'm doing now (resonate low and use a tuner to
go higher)?

Or will it even matter enough to notice??? My guess is (at these freqs)
no......

How about a compromise? Split the difference.

1. Tune low, measure the length.
2. Tune high by trimming, measure the new length.
3. Solder a piece of wire equal to the difference in leg lengths to one
leg only.

On Wed, 26 Jan 2005 15:05:39 -0600, "Ken Bessler"
wrote:

My 160/80m trap dipole can be operated without
a tuner from 1.800 to 1.930. I mainly operate in
that range (usually on 1.893) and I have a tuner for
operating above 1.930. Easy.

My question is this - is it better to resonate high and
use a tuner to go lower or do it the way I'm doing now
(resonate low and use a tuner to go higher)?

Or will it even matter enough to notice??? My guess
is (at these freqs) no......


Not enough info to tell. You need to measure or calculate the input Z
of your transmission line with the two (or more) wire lengths and then
calculate the tuner loss for each case. This will depend of the
topology of the tuner.

Remember that as a general rule, the tuner capacitors are lower loss
than the inductors. I think that you will find that over this
restricted frequency range there will be little difference, although
with some weird line length, you might create a condition where the
tuner is quite lossy.

On Wed, 26 Jan 2005 15:05:39 -0600, "Ken Bessler"
wrote:

My 160/80m trap dipole can be operated without
a tuner from 1.800 to 1.930. I mainly operate in
that range (usually on 1.893) and I have a tuner for
operating above 1.930. Easy.

My question is this - is it better to resonate high and
use a tuner to go lower or do it the way I'm doing now
(resonate low and use a tuner to go higher)?

Or will it even matter enough to notice??? My guess
is (at these freqs) no......


I use a multi-band dipole, but it is full length. I have about 130
feet of 75 meter dipole and 67 feet for 40 meters (the lengths may
vary, but they are tuned to the SSB portions I use.) I feed them into
the house via 75 ohm coax. The 40 meter elements hang about 6 inches
below the 75 meter element. No tuner or other matching is necessary
and the 75 meters band width is increased because of the 40 meter
hanging below it.

This is the same style antenna I used for the first time as a novice.
I have continued to use it over the last 26 years.

If you are going to use a tuner for tuning the antenna to all bands, I
would eliminate the traps altogether and tune down the 75/80 meter
elements. There are several places on the Web that explain what
lengths actually work best for all-band operation.

Someone has an Off-center Fed Dipole that they claim works really well
for all bands and it is a bit shorter than the 1/2 wave 80 meter
dipole. Look for Off center fed dipole and doublets in a search
engine. I am sure you will keep yourself occupied for many hours
reading various solutions. I am sure one of them will fit your need
perfectly.

Good luck.

Buck
N4PGW
Buck
--
For what it's worth.

Thanks to everyone for the info. For the record, I'm
going to leave the antenna tuned for 1.875 and use
the tuner for those rare times when I go above 1.930.

Since I operate on 1.893 about 75% of the time (not
using the tuner at all), I figure I'll be OK.

--
73's es gd dx de Ken KGØWX
Grid EM17ip, Flying Pigs #1055,
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