88 ft. Doublet Question
 

Does an 88 ft. doublet have any advantage over a conventional 67 ft.
doublet? In either case, feedline would be approx. 50 ft. of 450 Ohm ladder
line to a 4:1 current balun, then a short length of coax into the shack.

My usual band of choice is 40, but I'd like to become more active on 20 and
30.

--
Vy 73 de Bert
WA2SI
FISTS #9384
QRP ARCI #11782

On Sun, 26 Sep 2004 13:22:15 GMT, "Bert Craig"
wrote:

Does an 88 ft. doublet have any advantage over a conventional 67 ft.
doublet? In either case, feedline would be approx. 50 ft. of 450 Ohm ladder
line to a 4:1 current balun, then a short length of coax into the shack.

My usual band of choice is 40, but I'd like to become more active on 20 and
30.

Hi Bert,

Short answer: No. [could be Yes]

Long answer: Yes. [could be No]

More details are needed to lengthen the short answer or shorten the
long answer. Are you pointed in the right direction? A longer
antenna can invalidate that. Can you load the antenna? A longer
antenna can invalidate that. Going to higher bands makes these
questions even more meaningful.

Advice: Leave it alone, or put it up higher.

73's
Richard Clark, KB7QHC

Bert Craig wrote:
Does an 88 ft. doublet have any advantage over a conventional 67 ft.
doublet? In either case, feedline would be approx. 50 ft. of 450 Ohm ladder
line to a 4:1 current balun, then a short length of coax into the shack.

My usual band of choice is 40, but I'd like to become more active on 20 and
30.


Hi Burt,

W4RNl , Cebik gives a good write up on this and some Ideas on other
antennas as will ( you'll need a PDF reader though) You can find his
article at
http://www.cebik.com/fdim/fdim9.pdf

Hope this is of some help.
73 Dave KC1DI

"Richard Clark" wrote in message
...
On Sun, 26 Sep 2004 13:22:15 GMT, "Bert Craig"
wrote:

Does an 88 ft. doublet have any advantage over a conventional 67 ft.
doublet? In either case, feedline would be approx. 50 ft. of 450 Ohm
ladder
line to a 4:1 current balun, then a short length of coax into the shack.

My usual band of choice is 40, but I'd like to become more active on 20
and
30.

Hi Bert,

Short answer: No. [could be Yes]

Long answer: Yes. [could be No]

More details are needed to lengthen the short answer or shorten the
long answer. Are you pointed in the right direction? A longer
antenna can invalidate that. Can you load the antenna? A longer
antenna can invalidate that. Going to higher bands makes these
questions even more meaningful.

Advice: Leave it alone, or put it up higher.

73's
Richard Clark, KB7QHC

Advice taken, thanks Richard. :-)

--
Vy 73 de Bert
WA2SI
FISTS #9384
QRP ARCI #11782

"KC1DI" wrote in message
...
Bert Craig wrote:
Does an 88 ft. doublet have any advantage over a conventional 67 ft.
doublet? In either case, feedline would be approx. 50 ft. of 450 Ohm
ladder line to a 4:1 current balun, then a short length of coax into the
shack.

My usual band of choice is 40, but I'd like to become more active on 20
and 30.


Hi Burt,

W4RNl , Cebik gives a good write up on this and some Ideas on other
antennas as will ( you'll need a PDF reader though) You can find his
article at
http://www.cebik.com/fdim/fdim9.pdf

Hope this is of some help.
73 Dave KC1DI

Sure is, DAve. I now have the page saved offline, thanks so much. :-)

--
Vy 73 de Bert
WA2SI
FISTS #9384
QRP ARCI #11782

"Bert Craig" wrote in message .net...
Does an 88 ft. doublet have any advantage over a conventional 67 ft.
doublet?

It depends! One big consideration is "on which band"?

On 80 meters, the 88 footer will do a better job than the 67 footer
because the feedpoint Z is higher and less reactive. If you can get to
132 feet, things get really good on 80 - but that's a lot of space to
find.

The 88 footer will theoretically have some gain broadside to the wire
on 40 through 20 meters because it's longer than a half wave but
shorter than a 1.28 wave (think of two 5/8 wave verticals back to
back..) Above 20 you theoretically get a cloverleaf pattern.

W4RNL explains it better than I can but you already know that...

In either case, feedline would be approx. 50 ft. of 450 Ohm ladder
line to a 4:1 current balun, then a short length of coax into the shack.

That's the rub - feeding the beast.

Model the thing with Reg Edwards' DIPOLE3 freeware and see what you
can expect on the various bands.

My usual band of choice is 40, but I'd like to become more active on 20 and
30.

If you can get the feed figured out, it might be worth doing. Be aware
that the gain isn't more than a few dB, and an inefficient feed system
can eat a lot of it up.

Ideally, you'd eliminate the balun and run straight to a balanced
tuner. All depends on your house/shack situation. Some family members
take a dim view of new holes in new walls - can't understand why...

73 de Jim, N2EY