Hi Gary, ok, glad that some of the numbers agree. I used NEC-Win Pro to
calculate the antenna input Z.

In real terms there is only 4 dB between our numbers for transmission line
loss, so not really a great amount. I am familiar with some of Reg's
programs, and have found them in reasonable agreement with other methods,
but have not tried his transmission line program.

The fact is, whatever the loss, the use of an open wire transmission line
would reduce the losses to near zero -- then he would probably find his
tuner could not match it!

73,

Frank
(VE6CB)

"JGBOYLES" wrote in message
...
Gary, since your data are so different from mine, you have to tell me
where
I went wrong.


Hi Frank, I used one of Reg Edwards Dipole programs to get the line loss.
At
the time that was the fastest way I could think of to get some numbers.
His
program lets you describe the antenna, feedline, and frequency of interest
and
it gives a number of operating conditions including line loss.
As far as where you went wrong? May have been me that was wrong. I
think I
have TL program somewhere, but don't have time to look at the moment. I
checked the impedance of the antenna a couple of ways, and it agrees with
your
calculation about 300+j700. The difference must be in the way the line
loss is
calculated?
73 Gary N4AST

You know, Gary, there is another option which no one mentioned. Add a 30M dipole under the 40M job and use the same
feedline. You will likely have to adjust the length of the 40M wire slightly to return the VSWR to the present value,
but you will then have a good antenna for both bands. See any number of references about actual mechanical
construction.

--
Crazy George
Remove N O and S P A M imbedded in return address
"Gary" wrote in message ...
On 10 Dec 2004 06:30:32 -0800, "
wrote:

The loss on coax with that kind of a mismatch is around 90%. You are
better off with open wire feeds, especially since you have a tuner
available..even if it is MFJ ( Hi ).
grin
An open wire fed 40 meter dipole will produce a fine multiband
antenna..take that to the bank!
Jim

Thanks to all that replied. I knew it was probably somewhat lossy but
I didn't know it was as bad as has been pointed out. I'll have to
think about feeding it with open wire or twinlead when the weather is
more suitable here in Michigan.

73 and Thanks again.

Gary K8IQ

On Sat, 11 Dec 2004 10:14:26 -0600, "Crazy George"
wrote:

You know, Gary, there is another option which no one mentioned. Add a 30M dipole under the 40M job and use the same
feedline. You will likely have to adjust the length of the 40M wire slightly to return the VSWR to the present value,
but you will then have a good antenna for both bands. See any number of references about actual mechanical
construction.

Thanks for the idea George, I hadn't thought of that one. I knew the
30M into the 40 dipole wasn't the best in the world as I didn't hear
the signals on 30 that I would expect to hear but I didn't know it was
as lossy as pointed out. I'll have to give it a go this spring or
summer.

73 Gary K8IQ