In article , "BFoelsch"
writes:

Well, seeing that it is cut to be an 80 meter dipole, I would expect success
on 80 meters. It is very difficult to make a dipole work on even harmonics,
so I would expect trouble on 40, 20 and 10 meters. 15 should be usable
however.

This is all true for a center-fed dipole. You might want to try the "Fritzel"
trick, which is to move the feed point from cetner to a 1/3 - 2/3 point
(whichever side is closer to your shack). This feedpoint will give you about
600 ohms on the even-harmonic bands as well as the 80m fundamental. In fact, I
think the only band that my dipole won't load is 18 (aw shucks).

If you really want to do this, I would abandon the balun and coax and use
ladder feeders instead, but you will need a tuner that can feed a very high
impedance balanced load on 40, 20 and 10.

Unless you can find or make a 600:50 or 600:75 balun (like the one that came
with my Fritzel dipole), you can just feed it with 600-ohm ladder line. Your
tuner will need to feed that balanced load, but at only 600 ohms, not that high
an impdenance.


73 es best wishes on your ant -- Mike K. AA1UK




Oscar loves trash, but hates Spam! Delete him to reply to me.

Bob wrote:

Hi all

I have it back up without the balun, and still have to use the coax for now.
I am able to tune it now on all bands but I am sure there is a lot of power
loss from the tuner. I grounded out all devices in the shack but still
receiving a lot of RF interferrence on tv, computer, and home alarm.
Thanks for all the advice, really appreciate it.

You probably have a lot of feedline radiation.

Some suggestions:

Although I ordinarily don't care much for crossposting, you are going
to get so many different answers that your head will spin since you are
single posting your message to so many groups.

You should also take a look at some of these pages:

http://www.electronics-tutorials.com...nna-basics.htm

http://w1.859.telia.com/~u85920178/antennas/anten.htm


Your antenna is simply not the right length for the other bands. If you
even *can* tune with a coax setup, remember that you aren't changing the
impedence of the antenna, you are only providing a match between the
tuner and the radio. You will still have the coax/antenna mismatch to
deal with.

- Mike KB3EIA -

....[snip]....
However, if you change the feed line to a balanced line, ie: 450 ohm PVC
covered ladder line, (readily available from any ham store), and use an
antenna tuner capable of matching "balanced line" (ie: the tuner has a built
in balun), you will be able to match that antenna very nicely on any
....[snip]....

Everything he said is true, but, from years of acting like a Hardly Any
Money kinds of HAM, I know that you can get quite-useable results WITHOUT
a balun.

For years, my main antenna was an "unbalanced dipole" (sounds like a good
name to me) with one leg about 250 feet long and the other leg about 275
feet long fed with an unknown length of "true" 450-ohn open-wire feeder
(two wires separated an inch with pencil-diameter spreaders about every
six inches, not the more-common almost-looks-like-TV-leadin-with-holes-
in-it feeders, but probably will make little difference) and using the
simplest tuner I could build: _____
\ | / antenna
\|/
|
| open-wire feeder
|
X (see below)
|
antenna +----------+ v alligator clip
+------+ output | optional | +-------+--+
| xmtr +-----------+ VSWR +---X-+ inductor +-- (no connection)
| xcvr | | meter | +---+------+
+--+---+ +----------+ ^ alligator clip
| ground |
| lead +-----+-----+
| | capacitor |
| +-----+-----+
| |
+------------------------------------+
|
Ground

and it worked fine.

I even have a tuner like this in my pick-up truck, with just a slight
modification: small capacitors mounted on the ends of the inductor
wired at each X in the above sketch. For perfect matching, you need
to be able to adjust the inductance ANYWHERE around every turn, but
that's hard to do in the constricted space of a truck cab, so I use the
eXtra capacitors to "subtract out" a little inductance in either or
both of the two "windings" (between the input and the first alligator
clip and between the first and second alligator clips). Overkill,
perhaps, and looks like an early version of the Starship Enterprise's
FTL engine, but it works.

--Myron.
--
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448
NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol)

William Warren wrote:

4. Verticals: if you put in a good counterpoise, verticals can outperform
dipoles, especially those fed with long lengths of coax. The work is
in the
ground system: you'll need to dig up a lot of yard, but you'll only do it
once.


If you want to avoid the expense and digging of a conventional
radial system, go to the hardware store and buy several 50-foot
rolls of galvinized chicken wire fencing.
The cheap, "big hole" stuff works fine.
Put a ground rod at the center
below your vertical and connect the fencing.
Make a big "X" with it under your vertical.
If you really want to do it up right, make a "*" with it.
Use rocks or whatever to hold the stuff down flat.
The grass will grow over it and you can cut (using a
high blade setting, of course).
No digging, no miles of wire and it works very well,
as long as you secure it flat to the ground
so you don't snag a foot on it.
If you're in a wet environment
you'll have to replace it every couple of years,
but it's easy to do.

73 DE Dave AB5S

4. Verticals: if you put in a good counterpoise, verticals can
outperform
The work is
in the
ground system: you'll need to dig up a lot of yard, but you'll only do
it
once.
=========================
Agreed. But there's too much emphasis placed on the number and length of
radials needed for a satisfactory ground electrode system for verticals of
moderate height.

Much depends, of course, on the quality of the soil under the antenna but in
general the number of radials, or other electrodes, in the ground needed for
satisfactory operation is fewer than usually recommended in the handbooks
and magazine articles and by the plagiarists and the old wives on newsgroups
who play things far too safely.

1. Forget all about Marzipan the Magician's magic number of 118.5 radials of
1/2-wavelength radials.

2. Don't bother with ground plates or rods if you have space to lay
shallow-buried radials. They are hardly better than a shallow buried radial
of length equal to their longest dimension. Generally they are a waste of
effort and material.

2. In ordinary garden soil begin by laying one shallow-buried radial of
1/10th or 1/12 wavelengths long at the lowest frequency of interest.
There's not much point in increasing length of radials longer than the
height of the vertical antenna they are associated with. In good soil much
shorter lengths are satisfactory.

3. On receive, using your S-meter, measure signal strength of a number of
stable radio transmissions. These will usually be found at MF and LF but
include HF if there are any to be found. Take averages over time periods at
the same time of day or night.

4. Now double the number of radials. Roughly of the same length. Spread them
around over the space available. Carefully record the improvement in signal
strenghts. Guess at fractions of an S-unit. Keep your receiver stable.

5. Roughly double the number of radials again. Record signal strengths as
before.

6. Keep doubling the number of radials until there is no significant
increase in received signal strengths. Add one or two more for luck. Then
STOP!

7. For extremely poor, arid, sandy, rocky, infertile soil, start with
1/8-wavelength radials at the lowest frequency of interest.

8. For highly fertile, moist, agricultural soil, start with 1/16th
wavelength radials at the lowest frequency of interest.

9. At 10 or 20 MHz and above, the minimum length of buried radials is not of
great practical importance. Most backyards will accommodate them. A length
of 4 metres or 12 feet will suffice in reasonable soil.

10. If there's any wire left over after laying radials then use it to
increase the number of radials rather than their length.

I am reluctant to use a personal example to ullustrate the foregoing
philosophy but I will say that for many years I have used an inverted-L on
160m and higher frequencies with only 8 radials of varying lengths up to 6
feet, each terminated with an earth rod of 0.5 inches diameter, 30 inches
long. The garden soil is of the order of 70 ohm-metres. I have used the
system in the knowledge that if I had doubled the length of the radials, or
doubled their number, there would have been no detectable increase in signal
strength on either transmit or receive.

Reciprocity Rules !
----
Reg, G4FGQ

David Stinson wrote in message ...

If you want to avoid the expense and digging of a conventional
radial system, go to the hardware store and buy several 50-foot
rolls of galvinized chicken wire fencing.

C'mon Dave, tell him how to feed the raingutter. :-)

wrote:



C'mon Dave, tell him how to feed the raingutter. :-)

Hey- when you live in a ground-floor apartment,
you gotta make a way!