On Fri, 28 Apr 2006 10:52:54 -0700, Richard Clark
wrote:


You must have some idea of what band you are going to use it on, what
is it?

73's
Richard Clark, KB7QHC


Thanks, Richard for the comments. I would like to use it for 75-6
meters as I am not worried about 160 meters. I would like to use it
on 75 meters, as it is the band most likely to meet the coverage I am
interested in, but also to operate all bands as I would like not to
change antennas all the time. I have loaded the 20 meter and 40 meter
antennas with it to see how it works on other bands, but they really
suck!. I don't know if it is the way they are wound or what, but
tuning the 20 for six works well, but not with other bands. Going
lower doesn't help.

As for the mobile vs base antennas, there may be some difference. The
problem occurs when using a quarter wave or shorter dipole. However,
a quarter wave vertical is a match! This is part of my questioning.
Also, the fact that the tuner will be virtually at the antenna rather
than the coax, may make some difference, although, technically, I
think the coax would lower the reflected power to the tuner.

The theory i was hearing was that the loading coil takes all the
missing length of antenna and heats up. I can't imagine auto-tuners
having as large a coil as this manual tuner. (It uses a wire wrapped
around a toroid of some sort. ) I imagine an autotuner uses much
smaller inductors tied together thru relays.

I am trying to think of a type thurmometer that I could use that
wouldn't interact with the tuner to see if it heats up.

I will probably test the antenna this weekend if I can get the parts
and time....


--
73 for now
Buck
N4PGW

On Fri, 28 Apr 2006 22:57:40 -0400, Buck wrote:
I would like to use it for 75-6
meters as I am not worried about 160 meters. I would like to use it
on 75 meters, as it is the band most likely to meet the coverage I am
interested in,

Hi Buck,

All reports of short, mobile antennas on 80M generally cry crippled.
That is, unless, they are augmented by center loads under top hats a
dozen feet high or more. Even then, hardly remarkable unless you can
stand to be down 2 S-Units out the gate. For some, this knowledge is
a killer. For others who ignore it, they simply work those who can
hear them.

but also to operate all bands as I would like not to
change antennas all the time. I have loaded the 20 meter and 40 meter
antennas with it to see how it works on other bands, but they really
suck!.

Well, again, you are short on details. These two antennas (I presume
you have introduced two more to the discussion) may be air cooled
resistors for all their qualities you suggest. You might find an
object lesson here.

I don't know if it is the way they are wound or what, but
tuning the 20 for six works well, but not with other bands. Going
lower doesn't help.

Barring details....

As for the mobile vs base antennas, there may be some difference. The
problem occurs when using a quarter wave or shorter dipole.

Mobile quarterwave dipole?

However,
a quarter wave vertical is a match! This is part of my questioning.

Aside from this being natural, what could the question be?

Also, the fact that the tuner will be virtually at the antenna rather
than the coax, may make some difference, although, technically, I
think the coax would lower the reflected power to the tuner.

Many antennas are designed with a match external to them, but quite
close by. Why would this be detrimental? Even more, many antennas
are built with the match as part of them. They go by many names,
Gamma being one. Certainly nothing is lost in their use.

The theory i was hearing was that the loading coil takes all the
missing length of antenna and heats up.

Dare I say you can't trust everything you hear (read here)?

Myself, I taught RF communications in the Navy and had no trouble
whatever with the concept that a coil replaces the electrical length
missing in a short antenna. However, the Navy was never a slave to
fashion nor strict interpretation in this matter, and it was enough to
observe this quid-pro-quo as symbolic, and not literal.

I can't imagine auto-tuners
having as large a coil as this manual tuner. (It uses a wire wrapped
around a toroid of some sort. ) I imagine an autotuner uses much
smaller inductors tied together thru relays.

Indeed.

I am trying to think of a type thurmometer that I could use that
wouldn't interact with the tuner to see if it heats up.

Yuri might suggest aquarium thermometers (Liquid Crystal) - but you
would have to make sure the entire surface fit the entire strip (or
versa vice). If you have a very old digital camera, then they were
sensitive to IR. You could take a picture in the dark and resolve hot
spots.

I will probably test the antenna this weekend if I can get the parts
and time....

Further reports would be interesting.

73's
Richard Clark, KB7QHC

On Fri, 28 Apr 2006 22:07:00 -0700, Richard Clark
wrote:

On Fri, 28 Apr 2006 22:57:40 -0400, Buck wrote:
I would like to use it for 75-6
meters as I am not worried about 160 meters. I would like to use it
on 75 meters, as it is the band most likely to meet the coverage I am
interested in,

Hi Buck,

All reports of short, mobile antennas on 80M generally cry crippled.
That is, unless, they are augmented by center loads under top hats a
dozen feet high or more. Even then, hardly remarkable unless you can
stand to be down 2 S-Units out the gate. For some, this knowledge is
a killer. For others who ignore it, they simply work those who can
hear them.

I realize this. I have used a Hustler on 75 before. I was definitely
a weak signal station. I can only imagine that a tuned whip would
generate similar results, or more likely, poorer results.

but also to operate all bands as I would like not to
change antennas all the time. I have loaded the 20 meter and 40 meter
antennas with it to see how it works on other bands, but they really
suck!.

Well, again, you are short on details. These two antennas (I presume
you have introduced two more to the discussion) may be air cooled
resistors for all their qualities you suggest. You might find an
object lesson here.

There are a total of four antennas I have mentioned in here for
comparison sake. The Hustler, just mentioned above, the 102 whip with
a possible 2 foot extension, and two Antenna Specialists (AS) (look
exactly like HamSticks). I haven't had the Hustler for over a decade.
I will introduce another antenna in this message later.

The AS antennas are thin fiberglass poles with long stingers on the
top. The fiberglass poles, of course, have copper wound around them
from bottom to top, above which is a whip (stinger) about the same
length as the pole. The hustler was a center loaded trap that was
several inches in diameter and about 10-12 inches tall (the trap part)
with a stinger on top. (You are probably familiar with the Hustler.)
I also have a Volvo brand CB whip. It is a thin fiberglass whip
similar to the bottom portions of the AS antennas, but it does not
have a stinger. Like the AS antennas, the fiberglass has copper wire
wound from bottom to top with the top tightly wound and the bottom
section loosely wound. There is no stinger on top of the CB antenna.

I previously did a little experimenting with the two AS antennas and
the Volvo CB antenna (I don't have the 102 whip yet.) I used the tuner
to compare receive signals on various active bands. the results
weren't very good. Basically, each antenna performed best on the
frequencies for which they were designed (no big surprise here) but
they performed terribly on any other band. In fact, they were not
even acceptable for use on other bands. The signal strength on 20
meters, for example went from s-9 on the 20 AS antenna to less than
s-2 on the other antennas. I know others who have used the 102 steel
whip/auto-tuner combination that I have talked to never complained
that they only received s-2 signals with the system. Therefore, my
theory is that the winding of the coil on the fiberglass poles is
adversely affecting the radiation on out-of-band operation. I am
hoping that the steel whip, with or without the extension, will
perform better on all bands than any of these antennas tested. I
realize it is a compromise but the loss of an s-unit or two in
exchange for all band coverage for my mobile without having to switch
antennas or get out of the car and change taps is an acceptable
trade-off.

Remember, too, that in the original post, money is a big issue. The
purchase of a screwdriver (the best known mobile antenna design for
all band coverage) is not an option at this time. My theory is that I
should be able to mimic the 102 whip/auto-tuner results using a manual
tuner. My question is whether or not the tuner itself can hold up to
the task without being damaged.





I don't know if it is the way they are wound or what, but
tuning the 20 for six works well, but not with other bands. Going
lower doesn't help.

Barring details....

I think I addressed that above, the fiberglass poles are wrapped
tightly at the top and then loosely to the bottom, a stinger extends
from the tops of the AS antennas, and the Volvo antenna doesn't have a
stinger.


As for the mobile vs base antennas, there may be some difference. The
problem occurs when using a quarter wave or shorter dipole.

Mobile quarterwave dipole?
base. The suggestion I was given was not to use the antenna tuner on
a 20 meter dipole to tune a 40 meter frequency. This would be a 1/4
wave dipole on 40 meters. I don't know what the impedance of such an
antenna would be, but I do know that a 1/4 wave vertical is a
reasonable match. We never discussed the use of the tuner in the
mobile.



However,
a quarter wave vertical is a match! This is part of my questioning.

Aside from this being natural, what could the question be?

Also, the fact that the tuner will be virtually at the antenna rather
than the coax, may make some difference, although, technically, I
think the coax would lower the reflected power to the tuner.

Many antennas are designed with a match external to them, but quite
close by. Why would this be detrimental? Even more, many antennas
are built with the match as part of them. They go by many names,
Gamma being one. Certainly nothing is lost in their use.

The theory i was hearing was that the loading coil takes all the
missing length of antenna and heats up.

I should have clarified that this statement. The internal inductor of
the tuner makes up the missing length of the antenna and heats up
which can cause damage to the antenna tuner's inductor. This is how
it was presented to me, or how I understood it. Again, the discussion
was using the tuner to tune short dipoles to transmit on lower
frequencies.


Dare I say you can't trust everything you hear (read here)?

Myself, I taught RF communications in the Navy and had no trouble
whatever with the concept that a coil replaces the electrical length
missing in a short antenna. However, the Navy was never a slave to
fashion nor strict interpretation in this matter, and it was enough to
observe this quid-pro-quo as symbolic, and not literal.

I can't imagine auto-tuners
having as large a coil as this manual tuner. (It uses a wire wrapped
around a toroid of some sort. ) I imagine an autotuner uses much
smaller inductors tied together thru relays.

Indeed.

I am trying to think of a type thurmometer that I could use that
wouldn't interact with the tuner to see if it heats up.

Yuri might suggest aquarium thermometers (Liquid Crystal) - but you
would have to make sure the entire surface fit the entire strip (or
versa vice). If you have a very old digital camera, then they were
sensitive to IR. You could take a picture in the dark and resolve hot
spots.

I will probably test the antenna this weekend if I can get the parts
and time....

Further reports would be interesting.



I have been scheduled to work this weekend. I hope to be off Sunday,
If I can, I will try testing the whip idea using the side mount on the
van and if it appears to be promising, I will drill the holes in the
roof to mount the whip there near the radio and tuner.


73's
Richard Clark, KB7QHC
73 for now

--
73 for now
Buck
N4PGW

Buck wrote:
I have used a Hustler on 75 before. I was definitely
a weak signal station. I can only imagine that a tuned whip would
generate similar results, or more likely, poorer results.

Following are the summarized normalized combined results
of three 75m mobile antenna shootouts held in California
during the 1980's.

0 dB - (Reference) Bugcatcher or Screwdriver with large top hat

-2 dB - Bugcatcher or Screwdriver with no top hat

-5 dB - 8.5' whip with bugcatcher base loading coil

-6 dB - Bugcatcher with Stainless Steel Loading Coil

-8 dB - Hustler High Power system

-9 dB - Outbacker

-12 dB - Hamstick

-12 dB - 11.5' whip with SGC-230 autotuner

-14 dB - 8.5' whip with SGC-230 autotuner (estimated, not measured)
--
73, Cecil http://www.qsl.net/w5dxp

On Sat, 29 Apr 2006 14:19:33 GMT, Cecil Moore
wrote:

Buck wrote:
I have used a Hustler on 75 before. I was definitely
a weak signal station. I can only imagine that a tuned whip would
generate similar results, or more likely, poorer results.

Following are the summarized normalized combined results
of three 75m mobile antenna shootouts held in California
during the 1980's.

0 dB - (Reference) Bugcatcher or Screwdriver with large top hat

-2 dB - Bugcatcher or Screwdriver with no top hat

-5 dB - 8.5' whip with bugcatcher base loading coil

-6 dB - Bugcatcher with Stainless Steel Loading Coil

-8 dB - Hustler High Power system

-9 dB - Outbacker

-12 dB - Hamstick

-12 dB - 11.5' whip with SGC-230 autotuner

-14 dB - 8.5' whip with SGC-230 autotuner (estimated, not measured)


Thank you, that is good to see.

--
73 for now
Buck
N4PGW

On Sat, 29 Apr 2006 07:55:47 -0400, Buck wrote:
There are a total of four antennas I have mentioned in here for
comparison sake.

Hi Buck,

They are by degrees poor, poorer and poorest.

The Hustler
You probably walked away from the best of the group here.
the 102 whip with a possible 2 foot extension
which isn't extension enough.
and two Antenna Specialists (AS)
the air-cooled resistors.

The fiberglass poles, of course, have copper wound around them
from bottom to top, above which is a whip (stinger) about the same
length as the pole.

These on something like 4 foot or longer extension poles would help
you for a cheap solution to the lower bands. Adding a top hat to the
stinger (yeah, impossible) would go further.

(I don't have the 102 whip yet.)

Get one, at hamfests they are cheaper than toilet paper.

I know others who have used the 102 steel
whip/auto-tuner combination that I have talked to never complained
that they only received s-2 signals with the system.

They would never notice on receive. The tuner made the difference.

Therefore, my
theory is that the winding of the coil on the fiberglass poles is
adversely affecting the radiation on out-of-band operation. I am
hoping that the steel whip, with or without the extension, will
perform better on all bands than any of these antennas tested.

A coil loading it halfway up would go further (AKA Bugcatcher).

I realize it is a compromise but the loss of an s-unit or two in
exchange for all band coverage for my mobile without having to switch
antennas or get out of the car and change taps is an acceptable
trade-off.

Then using a cheap tuner (with a loaded antenna), by all means, is
part of the solution.

My question is whether or not the tuner itself can hold up to
the task without being damaged.

As an all band solution, you do stand the risk of one of them being a
fire-breather. Just which is hardly predictable with any accuracy
given the vast number of variables. There is certainly a strong
correlation with longer wavelengths and short antennas. So, you might
design two systems - cheaply, of course.

Mobile quarterwave dipole?
base. The suggestion I was given was not to use the antenna tuner on
a 20 meter dipole to tune a 40 meter frequency. This would be a 1/4
wave dipole on 40 meters. I don't know what the impedance of such an
antenna would be, but I do know that a 1/4 wave vertical is a
reasonable match.

Again, you should never believe everything you hear.

A quarter wave dipole should be a snap to tune. On the other hand,
using an 80M antenna on 40M could be a bear. Also, a quarterwave
dipole is only vaguely related to a quarterwave vertical - um, let's
just say that relationship is too strained to be compared.

We never discussed the use of the tuner in the mobile.

That was the first thing you said, it would be quite close to the
proposed mount. Anyway, I have always considered it part of your
cheap solution and it has a place there.

I should have clarified that this statement. The internal inductor of
the tuner makes up the missing length of the antenna and heats up
which can cause damage to the antenna tuner's inductor. This is how
it was presented to me, or how I understood it. Again, the discussion
was using the tuner to tune short dipoles to transmit on lower
frequencies.

This is another instance of not believing everything - but it at least
this time it offers a nugget of truth. This is the spin of the wheel
of chance I mentioned above. Don't fret so much and simply try it in
the driveway. Open the tuner, fire up the rig and tune for lowest
SWR. Let go of the key and touch components to see how hot it's
gotten. You don't need infra-red analysis and toolkit of thermocouple
probes to obtain a good understanding of the situation. Repeat on all
bands.

73's
Richard Clark, KB7QHC

SNIP

This is another instance of not believing everything - but it at least
this time it offers a nugget of truth. This is the spin of the wheel
of chance I mentioned above. Don't fret so much and simply try it in
the driveway. Open the tuner, fire up the rig and tune for lowest
SWR. Let go of the key and touch components to see how hot it's
gotten. You don't need infra-red analysis and toolkit of thermocouple
probes to obtain a good understanding of the situation. Repeat on all
bands.

73's
Richard Clark, KB7QHC
Thanks, After reading all this, I will be going to get the antenna. I
have a mount on side of the van. i will re-wire it so it goes to an
SO-239 connector so I can mount the tuner next to the antenna for the
test. if all is well, I will get a hole kit and set it up on the roof.

I like the bug-catcher idea, but I don't have the parts .

Thanks, again,
Buck

--
73 for now
Buck
N4PGW

On Sat, 29 Apr 2006 18:37:46 -0400, Buck wrote:

I like the bug-catcher idea, but I don't have the parts .

You don't have any WIRE? This is preposterous.

You split the vertical rise with an insulator and wind WIRE to fill
the gap. End of story. Your job is to make it mechanically sound at
70MPH and thumb your nose at what may be called Q here.

You want a bigger coil? Have dreams of that Q that marks status here?

Wrap a coffee can with several many wraps of paper so it clears all
seams and beads. Wrap turns of wire around the can/paper. Add epoxy
in nice neat lines along six lengths around the circumference (use
modeling or florist clay to build dams). Wait a couple of days for it
to cure. Take out the can and paper. Clean off the clay. Paint it
red, white, and blue!

What can 40 or 50 feet of wire, clay, three colors of paint, and an
ounce of epoxy cost? $5?

73's
Richard Clark, KB7QHC

On Sat, 29 Apr 2006 16:32:50 -0700, Richard Clark
wrote:

On Sat, 29 Apr 2006 18:37:46 -0400, Buck wrote:

I like the bug-catcher idea, but I don't have the parts .

You don't have any WIRE? This is preposterous.

You split the vertical rise with an insulator and wind WIRE to fill
the gap. End of story. Your job is to make it mechanically sound at
70MPH and thumb your nose at what may be called Q here.

You want a bigger coil? Have dreams of that Q that marks status here?

Wrap a coffee can with several many wraps of paper so it clears all
seams and beads. Wrap turns of wire around the can/paper. Add epoxy
in nice neat lines along six lengths around the circumference (use
modeling or florist clay to build dams). Wait a couple of days for it
to cure. Take out the can and paper. Clean off the clay. Paint it
red, white, and blue!

What can 40 or 50 feet of wire, clay, three colors of paint, and an
ounce of epoxy cost? $5?

73's
Richard Clark, KB7QHC


LOL I haven't looked into that yet. I will. Thanks.


--
73 for now
Buck
N4PGW