I have an old (but very good) W9INN 40/80 dipole. The only problem is
it is cut for the upper phone band (centered at ~7.200) for 40 meters
and I now do most operating in the lower portion of the band and would
like to move the center to about 7.100 MHz. The 40 meter portion of the
antenna is all soldered so I cannot just unwrap and extend it bit.

Any suggestions on the best way to add a extension and how much to add?

I have been thinking about cutting it and soldering in an X?-inch
splice. Does the extension wire have to really match?

Dick AA5VU

I am not familiar with your 40/80 dipole, I assume it is a trap
arrangement.

The 1/2 wave difference on 40M of 7.2 and 7.1mhz is only about a foot.
The change in a DIPOLE at 40M would be difficult to measure.

I would not change it.
Do you have an indication that it needs adjustment?

On Fri, 10 Mar 2006 12:55:55 GMT, "Dick, AA5VU"
wrote:

I have an old (but very good) W9INN 40/80 dipole. The only problem is
it is cut for the upper phone band (centered at ~7.200) for 40 meters
and I now do most operating in the lower portion of the band and would
like to move the center to about 7.100 MHz. The 40 meter portion of the
antenna is all soldered so I cannot just unwrap and extend it bit.

Any suggestions on the best way to add a extension and how much to add?

I have been thinking about cutting it and soldering in an X?-inch
splice. Does the extension wire have to really match?

Dick AA5VU
John Ferrell W8CCW

On Fri, 10 Mar 2006 12:55:55 GMT, "Dick, AA5VU"
wrote:

I have an old (but very good) W9INN 40/80 dipole. The only problem is
it is cut for the upper phone band (centered at ~7.200) for 40 meters
and I now do most operating in the lower portion of the band and would
like to move the center to about 7.100 MHz. The 40 meter portion of the
antenna is all soldered so I cannot just unwrap and extend it bit.

Any suggestions on the best way to add a extension and how much to add?

I have been thinking about cutting it and soldering in an X?-inch
splice. Does the extension wire have to really match?

Dick AA5VU

I've added extensions via an alligator clip with a piece of wire
attached, and then shorten that wire until you get a good match.

bob
k5qwg

In article ,
John Ferrell wrote:

The 1/2 wave difference on 40M of 7.2 and 7.1mhz is only about a foot.
The change in a DIPOLE at 40M would be difficult to measure.

I would not change it.
Do you have an indication that it needs adjustment?

John,

When i trimmed it the first time (years ago) I was working mostly SSB so
it is great in phone band and okay in the old Novice portion. I am now
working mostly 40 meter RTTY and PSK and these are at 7.070 and 7.035.

The current antenna shows SWR of about 1:8 at 7.100 and goes up to
2:0 at 7.050. My TS-570S tuner makes the rig smile but I feel it would
be better if I could extend it a bit.

The problem is there is no wrapped back wire that I could let out and
hate to use a jumper extender at the loading coil.

I may have to just bit the bullet and cut some wire per the formulas by
Steve, K9DCI, and solder it in the middle some place.

Still thinking about it. The WX in South Texas is too nice for antenna
work. I will probably put it off until the WX is bad.

73, Dick AA5VU

Dick, AA5VU wrote:
The current antenna shows SWR of about 1:8 at 7.100 and goes up to
2:0 at 7.050. My TS-570S tuner makes the rig smile but I feel it would
be better if I could extend it a bit.

If you enjoy lowering your SWR below 2:1, go for it. If you
think it will help the ham on the other end copy you better,
you are, as someone has said before, picking fly spots out
of black pepper.
--
73, Cecil http://www.qsl.net/w5dxp

"Dick, AA5VU" wrote in message
...
In article ,
John Ferrell wrote:

The 1/2 wave difference on 40M of 7.2 and 7.1mhz is only about a foot.
The change in a DIPOLE at 40M would be difficult to measure.

I would not change it.
Do you have an indication that it needs adjustment?

John,

When i trimmed it the first time (years ago) I was working mostly SSB so
it is great in phone band and okay in the old Novice portion. I am now
working mostly 40 meter RTTY and PSK and these are at 7.070 and 7.035.

The current antenna shows SWR of about 1:8 at 7.100 and goes up to
2:0 at 7.050. My TS-570S tuner makes the rig smile but I feel it would
be better if I could extend it a bit.

The problem is there is no wrapped back wire that I could let out and
hate to use a jumper extender at the loading coil.

I may have to just bit the bullet and cut some wire per the formulas by
Steve, K9DCI, and solder it in the middle some place.

Still thinking about it. The WX in South Texas is too nice for antenna
work. I will probably put it off until the WX is bad.

73, Dick AA5VU

I am not familair with this antenna, but if it has a choke/trap for 40M,
just add a foot of wire on the side of the choke/trap that is closest to the
center insulator- let it hang down and dangle. You can clip it on as one
poster said- this is a high Z point and contact resistance is a non-issue.
But as others have said, the on-air difference is zero.

Dale W4OP

I agree on the part about the wx.
I doubt the antenna is really centered on 7.2 if it is up to 2:1 at
7.050. IF I were going to try to change anything, I would go to the
hardware store electrical department and get a couple of screw type
wire splices that are intended to splice about 12 ga. wire. Get the
type that come apart so that you don't have to cut the antenna to
string them on the wire. Alligator clips don't weather well here. You
can add a foot on each end of the 40M section and trim from there. I
hope the antenna goes up & down easy!

I would keep tabs on what is happening to the 80M operation as I went.
The environment around the antenna (height above ground, quality of
ground) may lead to erratic measurements. 2:1 is not a bad SWR. Your
ability to tune it out fixes everything except the losses in the tuner
and I doubt if they are high enough to consider!

Before you take any advice from me remember I consider myself an
antenna student, not an expert!

On Fri, 10 Mar 2006 20:24:41 GMT, "Dick, AA5VU"
wrote:

In article ,
John Ferrell wrote:

The 1/2 wave difference on 40M of 7.2 and 7.1mhz is only about a foot.
The change in a DIPOLE at 40M would be difficult to measure.

I would not change it.
Do you have an indication that it needs adjustment?

John,

When i trimmed it the first time (years ago) I was working mostly SSB so
it is great in phone band and okay in the old Novice portion. I am now
working mostly 40 meter RTTY and PSK and these are at 7.070 and 7.035.

The current antenna shows SWR of about 1:8 at 7.100 and goes up to
2:0 at 7.050. My TS-570S tuner makes the rig smile but I feel it would
be better if I could extend it a bit.

The problem is there is no wrapped back wire that I could let out and
hate to use a jumper extender at the loading coil.

I may have to just bit the bullet and cut some wire per the formulas by
Steve, K9DCI, and solder it in the middle some place.

Still thinking about it. The WX in South Texas is too nice for antenna
work. I will probably put it off until the WX is bad.

73, Dick AA5VU
John Ferrell W8CCW

In article T8mQf.913$_f4.191@trnddc03,
"Dale Parfitt" wrote:

I am not familair with this antenna, but if it has a choke/trap for 40M,
just add a foot of wire on the side of the choke/trap that is closest to the
center insulator- let it hang down and dangle. You can clip it on as one
poster said- this is a high Z point and contact resistance is a non-issue.
But as others have said, the on-air difference is zero.

Dale W4OP

Late yesterday afternoon I decided to try the two alligator clips and
some wire to run a test to see what would happen. Sounds easy but I
made it very hard. To make a long shaggy-dog story short I added the
wire and the SWR went out of sight. It acted like a dead short. I then
lowered he antenna and cut the wire in half and it was still terrible.
I then trashed he alligator clips and wire to and it was still
terrible. After two hours of screwing around, I found some dummy (me)
had the coax switch on the old Ringo Ranger rather than the W9INN
antenna. By this time it was too dark to mess with anything.

Going to start over when the sun comes up but this time I plan to ditch
the alligator clips and attach a one foot wire using the connection nuts
on the coil/trap or whatever w9inn used to call that thing between the
40 and 80 wires and will have the coax switch on the right antenna this
time.

Dick AA5VU (red-faced)

In article ,
Cecil Moore wrote:

Dick, AA5VU wrote:
The current antenna shows SWR of about 1:8 at 7.100 and goes up to
2:0 at 7.050. My TS-570S tuner makes the rig smile but I feel it would
be better if I could extend it a bit.

If you enjoy lowering your SWR below 2:1, go for it. If you
think it will help the ham on the other end copy you better,
you are, as someone has said before, picking fly spots out
of black pepper.

Cecil,

You are correct but many of us tend to get obsessive about SWR. The
enemy of good is better and many of us have wasted hours trying to make
a good antenna better. It is part of being a ham.

Dick AA5VU

"Dick, AA5VU" wrote:


Late yesterday afternoon I decided to try the two alligator clips and
some wire to run a test to see what would happen. Sounds easy but I
made it very hard.

Dick AA5VU (red-faced)

Atta Ham! :-) I'm pretty sure we've all done things like that! At
least I have -- more than once too!

Irv VE6BP
--
--------------------------------------
Diagnosed Type II Diabetes March 5 2001
Beating it with diet and exercise!
297/215/210 (to be revised lower)
58"/43"(!)/44" (already lower too!)
--------------------------------------
Visit my HomePage at http://members.shaw.ca/finkirv/index.html
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--------------------
Irv Finkleman,
Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP
Calgary, Alberta, Canada