Hi folks, I'm in the process of building myself a screwdriver antenna
for my truck. Being the vain sort, I'd like it to end up being black
as that matches nicely with the other bitties sticking out of the
vehicle.

Q.- Does anodyzing negatively impact aluminum's ability to efficiently
radiate? I seem to recall reading somewheres that anodyzing leaves a
non-conductive surface, but on the other hand aluminum oxide ain't
supposed to be that great a conductor either & that whats on the
surface of any piece of aluminum thats seen air for more than a few
minutes.

Enquiring Minds want To Know-

Howard.

The radiating surface don't care. Just make sure all mechanical contacts which need to conduct penetrate the anodizing.
Like where the coax connects, or where the coil is connected.

--
Crazy George
The attglobal.net address is a SPAM trap. Please change that part to: attdotbiz properly formatted.
"Howard Eisenhauer" wrote in message
...
Hi folks, I'm in the process of building myself a screwdriver antenna
for my truck. Being the vain sort, I'd like it to end up being black
as that matches nicely with the other bitties sticking out of the
vehicle.

Q.- Does anodyzing negatively impact aluminum's ability to efficiently
radiate? I seem to recall reading somewheres that anodyzing leaves a
non-conductive surface, but on the other hand aluminum oxide ain't
supposed to be that great a conductor either & that whats on the
surface of any piece of aluminum thats seen air for more than a few
minutes.

Enquiring Minds want To Know-

Howard.

Hello Sir George and Howard:

Anodizing the aluminum is kind of over kill as I have measured new
antennas and old antennas with 30 plus years of exposure to the
elements. No difference measured.

What did throw me a curve was buying Anodized Surplus Aluminum Tubing in
Burbank Ca, and making a vertical for the VHF Low Band. Ok no problem
getting it together and should have tuned in a few minutes.

But no it was responding to a much higher frequency than the 31 Mc I
wanted it to tune to. After checking and double checking everything and
replacing the coax and antenna analyzer it still measured a way high
frequency SWR null.

Now faced with the strong reality that this thing was gonna kick my a$$,
after a hole day of going nutzoid. I got my old Simspon 260 VOM and
measured continuity from all the elements. I found that one of the
vertical elements had been anodized on the inside causing a no
connection condition.

Cutting off a metal wire brush and putting the shank in Mr. 1/2 inch
chuck, drill motor, and the 100 foot cord (I have given up on battery
operated drill motors) the inside of the tubing was now nice and shinny
bright aluminum.

The antenna tuned up as designed. So keep your eyes open when using
anodized aluminum tubing. And I think this is why some antenna
manufactures do not anodize their aluminum tubing. Plus the added
manufacturing costs.

Jay in the Mojave

Crazy George wrote:

The radiating surface don't care. Just make sure all mechanical contacts which need to conduct penetrate the anodizing.
Like where the coax connects, or where the coil is connected.

--
Crazy George
The attglobal.net address is a SPAM trap. Please change that part to: attdotbiz properly formatted.
"Howard Eisenhauer" wrote in message
...

Hi folks, I'm in the process of building myself a screwdriver antenna
for my truck. Being the vain sort, I'd like it to end up being black
as that matches nicely with the other bitties sticking out of the
vehicle.

Q.- Does anodyzing negatively impact aluminum's ability to efficiently
radiate? I seem to recall reading somewheres that anodyzing leaves a
non-conductive surface, but on the other hand aluminum oxide ain't
supposed to be that great a conductor either & that whats on the
surface of any piece of aluminum thats seen air for more than a few
minutes.

Enquiring Minds want To Know-

Howard.

On Sat, 09 Apr 2005 15:38:23 -0700, Jay in the Mojave
wrote:

Anodizing the aluminum is kind of over kill as I have measured new
antennas and old antennas with 30 plus years of exposure to the
elements. No difference measured.

That might be ture in the Mojave but come up here on the norhern
California coast - on the ocean - and you 30+ aluminum antenna will be
noting more that a memory.

Danny, K6MHE

Jay in the Mojave wrote:
... a much higher frequency
than the 31 Mc ...
^^
Showing our age, are we Jay? :-)
--
73, Cecil http://www.qsl.net/w5dxp

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Jay in the Mojave wrote:

Hello Sir George and Howard:

Anodizing the aluminum is kind of over kill as I have measured new
antennas and old antennas with 30 plus years of exposure to the
elements. No difference measured.

Interesting, as I have measured antennas with only 2 years exposure that
had .5 dB measured difference. A 432 MHz antenna scrubbed with a
ScotchBrite showed a .6 dB gain increase.

So B as in B, S as in S, as we say here in Minnesota.

tom
K0TAR

On Sat, 09 Apr 2005 21:12:47 -0500, Tom Ring
wrote:
A 432 MHz antenna scrubbed with a
ScotchBrite showed a .6 dB gain increase.
So B as in B, S as in S, as we say here in Minnesota.

Hi Tom,

You could measure to the accuracy of better than 0.2dB between two
separate tests? And at UHF too? Care to share how?

73's
Richard Clark, KB7QHC

Hello Cecil:

Ok well thats two of us then, .... hehhehe

Jay in the Mojave

Cecil Moore wrote:
Jay in the Mojave wrote:

... a much higher frequency

than the 31 Mc ...
^^
Showing our age, are we Jay? :-)

Hello Dan:

So what do you use for being near the ocean?

Do you have to anodize all the aluminum tubing to keep the antennas up?

Jay in the Mojave


Dan Richardson wrote:

On Sat, 09 Apr 2005 15:38:23 -0700, Jay in the Mojave
wrote:


Anodizing the aluminum is kind of over kill as I have measured new
antennas and old antennas with 30 plus years of exposure to the
elements. No difference measured.


That might be ture in the Mojave but come up here on the norhern
California coast - on the ocean - and you 30+ aluminum antenna will be
noting more that a memory.

Danny, K6MHE

Jay,

We just replace them more frequently than dry desert dwellers. After
about five years (sometime sooner) they are about shot.

My two-meter omni is incased in a fiberglass radome and my wire
antennas are made with insulated wire with ends sealed.

Danny, K6MHE



On Sun, 10 Apr 2005 02:08:57 -0700, Jay in the Mojave
wrote:

Hello Dan:

So what do you use for being near the ocean?

Do you have to anodize all the aluminum tubing to keep the antennas up?

Jay in the Mojave


Dan Richardson wrote:

On Sat, 09 Apr 2005 15:38:23 -0700, Jay in the Mojave
wrote:


Anodizing the aluminum is kind of over kill as I have measured new
antennas and old antennas with 30 plus years of exposure to the
elements. No difference measured.


That might be ture in the Mojave but come up here on the norhern
California coast - on the ocean - and you 30+ aluminum antenna will be
noting more that a memory.

Danny, K6MHE

Richard Clark wrote:

On Sat, 09 Apr 2005 21:12:47 -0500, Tom Ring
wrote:

A 432 MHz antenna scrubbed with a
ScotchBrite showed a .6 dB gain increase.
So B as in B, S as in S, as we say here in Minnesota.


Hi Tom,

You could measure to the accuracy of better than 0.2dB between two
separate tests? And at UHF too? Care to share how?

73's
Richard Clark, KB7QHC

Well, you'd have to ask Mark Thorsen, WB0TEM, what equipment was used,
but the range is checked several times against the reference antenna
during each band we run, and is generally within .1 dB between checks.
Except that one day in KS. Boy was it hot.

I wouldn't bet absolute values are on the mark, but an antenna measured
against itself was reproducable. So I do believe the antenna improved
due to having the oxide scrubbed off.

tom
K0TAR

Cecil Moore wrote:
Jay in the Mojave wrote:

... a much higher frequency

than the 31 Mc ...
^^
Showing our age, are we Jay? :-)

You know I didn't even notice that when I read it. :-)
...lew... ( ex W3SLX circa. 1950 )

On Sun, 10 Apr 2005 09:23:19 -0500, Tom Ring
wrote:

I wouldn't bet absolute values are on the mark, but an antenna measured
against itself was reproducable.

Hi Tom,

But the point of accuracy, even reproducible accuracy, requires a very
absolute source to compare against. Sometimes that absolute is quite
simple to achieve, but now you have upped the ante to 0.1dB. This
implies a measurement accuracy of at least three times better; which,
in turn, means you have access to a standard that can discern 0.8%.

To say you test the antenna "against itself" does not really say much
when it comes to power and gain. That is no benchmark. The
presumption here is that you have an external source of power that is
constant. This then raises the same question. Over a span of time,
what guarantees this degree of accuracy? By what method is it
confirmed? That source's "absolute" power level needn't be an issue,
but there is no way to escape casting that "absolute" requirement into
another standard to confirm the fact of its stability.

73's
Richard Clark, KB7QHC

Based on some of the other responses you received it may not be worth
it but there is another type of coating for aluminum called alodyne
which protects the same way as anodizing but is electrically
conductive.

jtm

Jim Miller wrote:
there is another type of coating for aluminum called alodyne
which protects the same way as anodizing but is electrically
conductive.


Alodine (R) coatings are not conductive. You can specify a "type 3"
coating that is thin enough that fasteners will usually punch through
the coating layer.

See MIL-C-5541 chromate conversion coatings.

Kevin Gallimore

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Another corrosion-inhibiting coating for aluminum is iridite. There are
conductive and non-conductive versions, something I learned the hard way
long ago.

Roy Lewallen, W7EL

axolotl wrote:
Jim Miller wrote:
there is another type of coating for aluminum called alodyne

which protects the same way as anodizing but is electrically
conductive.



Alodine (R) coatings are not conductive. You can specify a "type 3"
coating that is thin enough that fasteners will usually punch through
the coating layer.

See MIL-C-5541 chromate conversion coatings.

Kevin Gallimore

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On Sun, 10 Apr 2005 14:30:04 -0700, Roy Lewallen
wrote:

Another corrosion-inhibiting coating for aluminum is iridite. There are
conductive and non-conductive versions, something I learned the hard way
long ago.

Tell me about it [g].

I was the engineer responsible for transferring the design of the then
new Phoenix Missile IMPATT diode transmitter from the development lab
to the production floor.

The transmitter had three stages: a single diode driven by a
phase-locked Gunn oscillator fed a three diode cavity that drove a 16
diode cavity.

The development hardware used aluminum cavities that were comprised of
two pieces, with third copper piece that mounted the sixteen diodes.
So there was one aluminum-to-aluminum and one aluminum-to-copper
interface in each sandwich. Since this was a product for the U.S.
military, "passivation" was required for all aluminum parts.

I won't go into the considerable amount of detective work that it took
to decide that despite being "conductive" Alodine and its ilk are not
suitable coatings for rf components.

Gold is your friend, if of course, it's thicker than a few skin
depths, which is another long story. [g]


Roy Lewallen, W7EL

axolotl wrote:
Jim Miller wrote:
there is another type of coating for aluminum called alodyne

which protects the same way as anodizing but is electrically
conductive.



Alodine (R) coatings are not conductive. You can specify a "type 3"
coating that is thin enough that fasteners will usually punch through
the coating layer.

See MIL-C-5541 chromate conversion coatings.

Kevin Gallimore

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Amen! If gold did not exist, it would need to be invented just for EE
purposes. 73 Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Wes Stewart" wrote in message
...
snip


I won't go into the considerable amount of detective work that it took
to decide that despite being "conductive" Alodine and its ilk are not
suitable coatings for rf components.

Gold is your friend, if of course, it's thicker than a few skin
depths, which is another long story. [g]

"J. Mc Laughlin" wrote in message
...
Amen! If gold did not exist, it would need to be invented just for EE
purposes. 73 Mac N8TT

I've often entertained thoughts about the utility of gold in my other
hobby. I reload ammunition and cast lead bullets. Anything over 1200 to
1500 fps leads to leading from friction and gas cutting. Gold shares with
lead a high mass and malleability. Its higher melting point should allow
considerably higher velocities. Unfortunately I've not found suffient
quantities at economically feasible acquiral rates. Once Oklahoma gets its
lottery running and I win I'll get myself 4 or 5 pounds and find out if my
theory about gold bullets proves out. Another complication stems from the
high melting point which may prove damaging to my bullet molds. If that
should occur, I'll have to get someone to extrude me some gold rod and
lathe cut my gold bullets. Hmm, with gold rods, can gold ground plane
antennas for 2 and 6 meters be far behind? So many fun homebrew projects,
so little time, sigh.

Harold
KD5SAK

On Sun, 10 Apr 2005 18:17:42 -0500, Tom Ring
wrote:

Hi Tom,

The number of variables in the description of your (Mark's) method is
rather considerable, so I will remark by the parts you offer:

The range has a source yagi for each band, that yagi has a low power AM
modulated signal on it (as I remeber, might be wrong on this).

So far, fine.

The other end has a reference yagi off to the side from the test position.

Commendable.

A yagi with "known gain" is run against the reference yagi, and the
relative signal strength is measured.

I might slyly point out how do you know the gain? It visits the age
old logical knot offered:
In a town of clean shaven men,
there is a barber who shaves everybody who does not shave himself;
who shaves the barber?

That gives us a known gain point
on the meter. A yagi is then placed in the test position and the
relative gain or loss is recorded. The "known gain" yagi can be put
back into the test position at intervals to check the calibration.

This method is called using a "transfer standard." As I offered, that
requires an absolute knowledge somewhere, and you have identified it
in this "known gain" yagi. However, the gain is actually immaterial
until you begin making claims of absolute gain. That is, most of this
correspondence is satisfied with relative gain comparisons as you
point out:

Obviously the absolute values may be suspect, but relative measurements
work well.

Quite true, however, you having once acknowledged suspicions you then
plunge back into the murky pool of absolutes:

The results also agree very well with YO predictions, with a
yagi in the 18.4 dBd predicted range being low by .3 as measured, which
is roughly what he expected to happen. Most more normal gain, 14 to 15
dBd for 432, were within .1 of predicted. Bands tested on this range
were 144, 220, and 432.

Well, here we run counter to my experience with real life components.
They varied by several times your 0.1dB, and this was often times for
the same item tested repeatedly (I never measured any item less than
five times and never five times repeatedly, in a row).

Multiple prototype 2M and 70cm EME antennas that my partner and I built,
stored safe from corrosion, tested the same +- .1dB with a several year
gap between the tests.

OK, the method is good and robust, but your sudden departure from
expected results are on the scale of 5 to 6 times the range of your
typical error.

If this is to be attributed to oxidation on the elements, that still
seems suspect. The oxidation is not lossy, and certainly is not
sufficiently thick enough to shift the resonance. Oxidation is one of
the charms of aluminum, it is self sealing.

I would offer that if the elements oxidized, so did the connectors (or
connections). Simple, repeated connector matings (like swapping in
and out for the range test) were sufficient to break bad contacts and
make the difference which was attributed to scrubbing the elements.
In the normal course of my calibration of various items with
connectors, I always inspected and cleaned them first. N connectors
have erosion problems that will give rise to variations outside of
0.1dB - comes from those threads. The "standard gain" antenna should
be suffering from this erosion by now, but you don't report it.

This raises suspicions for me - you have too much fulfillment of
expectations which is truly extraordinary. I have made thousands of
calibrations of isolators, pads, couplers, meters and so on that have
shown a gaussian distribution of results for premium equipment. Your
range experience shows very little variation - much too little when we
are talking about being within 0.1dB.

What equipment he uses for the ratio measurement, and precisely how it
is done, I don't know. I will attempt to contact him and find out if I
can get this damn sinus infection under control in the next few days.

Well I hope you shake the infection off. Further details are unlikely
to resolve this corrosion as it is too much a matter of "you had to
have been there" kind of thing.

73's
Richard Clark, KB7QHC

On Sun, 10 Apr 2005 20:27:55 -0500, Tom Ring
wrote:

HP ratio meter, 1kHz tone on AM. He thinks the HP is a model 340, but
would have to go out in the garage to look.

Hi Tom,

Not one of their numbers against the characteristics. However, I am
familiar with what you describe as the characteristics.

It is a tuned AC voltmeter, commonly used for SWR measurement in
slotted lines connected to a the detector where the source is
modulated at 1KHz. The meter is tuned to 1KHz and has a very high
gain and selectivity. This allows it to employ a variable gain, by
10dB switch steps (and a variable knob to set zero, or the reference).
The scale is read in combination with the attenuator (gain) switch and
thus the scale offers considerable resolution, easily 0.1dB and
better. It is probably an HP-415.

I've calibrated these too (Boonton, I think, also built them, but as
Boonton was acquired by HP, it isn't a remarkable difference).

73's
Richard Clark, KB7QHC

Richard Clark wrote:

On Sun, 10 Apr 2005 20:27:55 -0500, Tom Ring
wrote:


HP ratio meter, 1kHz tone on AM. He thinks the HP is a model 340, but
would have to go out in the garage to look.


Hi Tom,

Not one of their numbers against the characteristics. However, I am
familiar with what you describe as the characteristics.

It is a tuned AC voltmeter, commonly used for SWR measurement in
slotted lines connected to a the detector where the source is
modulated at 1KHz. The meter is tuned to 1KHz and has a very high
gain and selectivity. This allows it to employ a variable gain, by
10dB switch steps (and a variable knob to set zero, or the reference).
The scale is read in combination with the attenuator (gain) switch and
thus the scale offers considerable resolution, easily 0.1dB and
better. It is probably an HP-415.

So for relative gain it's possible, in your opinion, to measure +- .1dB
with this, if properly used?

tom
K0TAR

On Sun, 10 Apr 2005 21:42:21 -0500, Tom Ring
wrote:

So for relative gain it's possible, in your opinion, to measure +- .1dB
with this, if properly used?

Hi Tom,

Quite easily.

73's
Richard Clark, KB7QHC

Richard Clark wrote:

On Sun, 10 Apr 2005 21:42:21 -0500, Tom Ring
wrote:


So for relative gain it's possible, in your opinion, to measure +- .1dB
with this, if properly used?


Hi Tom,

Quite easily.

73's
Richard Clark, KB7QHC

So he's using decent equipment. Whether it's used correctly is another
matter. I'm betting he did a good job, given the results I've seen, and
what I know of him.

But you are correct to be be skeptical on the results.

tom
K0TAR

Dan Richardson wrote:

Jay,

We just replace them more frequently than dry desert dwellers. After
about five years (sometime sooner) they are about shot.

My two-meter omni is incased in a fiberglass radome and my wire
antennas are made with insulated wire with ends sealed.

How close to the ocean are you? It sounds like you are right in the spray!


- Mike KB3EIA -

On Sun, 10 Apr 2005 21:54:26 -0500, Tom Ring
wrote:

So he's using decent equipment. Whether it's used correctly is another
matter. I'm betting he did a good job, given the results I've seen, and
what I know of him.

Hi Tom,

As I've offered, the test protocol is very precise, and the
instrumentation (as far as has been discussed or inferred) is up to
the resolution. However, many mistake what accuracy, precision, and
resolution mean.

Resolution is the number of digits in your reading. It usually
implies that you can read more digits than you report. So, to say you
have measured a voltage to be 1.5V means that you have an instrument
that can read in hundredths of volts.

Precision is the repetition of readings. High precision means your
measurements all can be reported as 1.5V because they vary no more
than 4 hundredths of a volt in readings around the reported value (or
by more fancy regression techniques).

Accuracy is how far from actual your report is. It is enough to say
that resolution and precision are not accuracy, but that they are
necessary components of accuracy.

Insofar as the range goes, it remains to be seen if it has been
calibrated in its own right. The test is not necessarily found in
absolutes, but rather in its response to perturbations. In other
words, inject a known variable and measure its ability to support a
report that faithfully records the value of that variable as evidence
of its robustness. You have to perturb the system with small changes
as well as large changes to see if it is linear in its response. This
is not easy and makes great demands upon not only the instrumentation,
but the ingenuity of the tester. Then you repeat the tests from a
different angle to see if it is symmetric. Then you test for
background contributions - noise (actually this is probably best done
first as it sets the boundaries of your low end and defines part of
the dynamic range).

You do all the above, and then some, pool the results and describe
your limits of error. Test results that are reported without knowing
the limits of error are not very informative. Hence, when I hear that
readings are repeatable to 0.1dB for UHF and I hear nothing of the
range of error (I must presume that it is no greater than 0.033dB);
then I am more than skeptical because 1% accuracy in power
determination is the extreme of very tightly controlled laboratory
conditions.

That there are repeated measurements in the field to this level of
precision is suspect because there is very little instrumentation AND
combinations of many pieces of gear that come close. It takes only
two pieces of 1% gear to create a situation that is at best 1.4%
accurate and you are already crossing the 0.1dB threshold. For those
trying to balance the ledger, a 1% accurate determination requires a
method that is at least 3 times more accurate. The usual aggregation
of error arrives through RSS (root sum square); some may like to gild
their prospects and compute RMS (root mean square) and if they are
lucky, this is not far off. Given enough results, luck washes out to
sea and RSS dominates. Given enough results that conform to RMS, then
you find you have qualified your methods and instrumentation to
superlative standards.

73's
Richard Clark, KB7QHC

On Sun, 10 Apr 2005 23:58:12 -0400, Mike Coslo
wrote:


How close to the ocean are you? It sounds like you are right in the spray!


About a half mile. I live in the northern California "Mendocino"
coast. We have a lot of rain too and that combination is a killer for
aluminum exposed to the elements.

Danny

Richard Clark wrote:

On Sun, 10 Apr 2005 21:42:21 -0500, Tom Ring
wrote:


So for relative gain it's possible, in your opinion, to measure +- .1dB
with this, if properly used?


Hi Tom,

Quite easily.

73's
Richard Clark, KB7QHC

HP416A.

tom
K0TAR

On Mon, 11 Apr 2005 09:48:17 -0500, Tom Ring
wrote:

HP416A.

Hi Tom,

By description and application, probably, but I need a picture or
manual to be able to confirm. I've calibrated and used so much
different gear that the numbers blur.

73's
Richard Clark, KB7QHC

On Mon, 11 Apr 2005 09:08:54 -0700, Richard Clark
wrote:

On Mon, 11 Apr 2005 09:48:17 -0500, Tom Ring
wrote:

HP416A.

Hi Tom,

By description and application, probably, but I need a picture or
manual to be able to confirm. I've calibrated and used so much
different gear that the numbers blur.


http://www.qsl.net/n7ws/HP416.pdf

The (inappropriately named) Pacific coast where Danny lives has
fair-sized waves almost constantly, particularly in the winter. When
they break along the shore, a very fine mist of salt water droplets is
created, and those drift for a long distance. In the winter, the
prevailing wind direction is from the west, so the salt water mist is
blown farther yet. The result is that the air itself contains a
suspension of salt water. Aluminum corrodes fairly quickly, and good
sized bare copper wire turns into a blue powder in a year or less. Where
I live, in the Willamette valley of Oregon which is about 70 miles
inland, it rains pretty constantly from about October through June --
not an extraordinary amount, but everything outside stays wet for the
whole winter because of the lack of direct sunshine and the frequent
rain. But aluminum lasts forever and so does copper, which only gets a
thin, dark oxide coating. It's the salt water suspension that's the
killer on the coast.

Roy Lewallen, W7EL

Dan Richardson wrote:
On Sun, 10 Apr 2005 23:58:12 -0400, Mike Coslo
wrote:



How close to the ocean are you? It sounds like you are right in the spray!



About a half mile. I live in the northern California "Mendocino"
coast. We have a lot of rain too and that combination is a killer for
aluminum exposed to the elements.

Danny

On Mon, 11 Apr 2005 10:48:54 -0700, Roy Lewallen
wrote:

It's the salt water suspension that's the
killer on the coast.

Yea, but those launch angles to the west. G

Danny, K6MHE

On Mon, 11 Apr 2005 10:40:56 -0700, Wes Stewart
wrote:

On Mon, 11 Apr 2005 09:08:54 -0700, Richard Clark
wrote:

On Mon, 11 Apr 2005 09:48:17 -0500, Tom Ring
wrote:

HP416A.

Hi Tom,

By description and application, probably, but I need a picture or
manual to be able to confirm. I've calibrated and used so much
different gear that the numbers blur.


http://www.qsl.net/n7ws/HP416.pdf


GAD!

I had forgotten that white elephant. Thanx Wes.

Tom,

It is pretty much in the same class of expanded range, 1KHz tuned AC
Voltmeters. As long as you reference and return to a Cardinal point
on the scale, accuracy you describe can be supported.

In fact, this class of instrumentation is probably the best leverage
to building a very good RF lab. You can spend more, you could even
find equipment that does most of the grunt work for you, but it is
still a long shot that you will obtain more accuracy.

Accuracy is steadfastly bound to method and this style of
instrumentation reveals an example of method thought out and polished
with the best of engineering thought.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
....

I've calibrated these too (Boonton, I think, also built them, but as
Boonton was acquired by HP, it isn't a remarkable difference).


Errrk?? From Boonton's web site:

"In July 2000 we became a member of a larger family as we were acquired
by Wireless Telecom Group, Inc. (doing business as Noise Com). Being a
wholly owned subsidiary of Wireless Telecom Group, Inc. has enabled us
to further our product development and customer service initiatives."

See http://www.boonton.com/2002/about-history.html

Since you're wanting to make it black to match other accouterments on
your vehicle, consider that most, if not all, black-dyed anodization
will fade in the sunlight, and it doesn't take all that long. In
addition, depending on the aluminum alloy, the "black" may not be all
that black to begin with. Why not instead give the antenna a coat of
automotive enamel or lacquer? You can either mask off areas that need
to have electrical contact, or scrape them after painting. Perhaps you
can paint after the antenna is assembled. That way, you can get a
color that really matches other items.

Cheers,
Tom

On 11 Apr 2005 11:52:53 -0700, "K7ITM" wrote:


Richard Clark wrote:
...

I've calibrated these too (Boonton, I think, also built them, but as
Boonton was acquired by HP, it isn't a remarkable difference).


Errrk?? From Boonton's web site:

"In July 2000 we became a member of a larger family as we were acquired
by Wireless Telecom Group, Inc. (doing business as Noise Com). Being a
wholly owned subsidiary of Wireless Telecom Group, Inc. has enabled us
to further our product development and customer service initiatives."

See http://www.boonton.com/2002/about-history.html

They left out part of their history.

H-P *did* acquire Boonton at one time. I have both a black crackle
Boonton 250 RX meter and an H-P gray HP 250 RX meter out in my storage
building.

Once long ago I was driving down highway 101 in my VW squareback,
operating mobile CW late at night on 40 meters. Rig was homebrew, about
8-9 watts output (10 watts input). Antenna was a CB mobile whip on a
bumper mount, base loaded with a coil wound on a powdered iron toroid
core, Q about 200 - 250. Worked JA, solid copy. Yea, that salt water
does wonders for a vertical.

Roy Lewallen, W7EL

Dan Richardson wrote:
On Mon, 11 Apr 2005 10:48:54 -0700, Roy Lewallen
wrote:


It's the salt water suspension that's the
killer on the coast.


Yea, but those launch angles to the west. G

Danny, K6MHE

Thanks Tom (& everybody else). The problem is that I'm planing on
having an 8' two section whip on the top that will power extend &
retract through the loading coil into the bottom mast.

Why?

Call it a combination of lazyness & a prepondarence towards low
ceilings in parking garages. Also (bonus), with the coil retracted
I'll be able to vary the height of the whip for the upper bands.

So what I was really looking (hoping) for is a black coating that
maintains electrical contact between the inner & outer whip sections
as one slides in & out of the other.

Don't look like I'm gonna get it .

Maybe it would be easier just to build a test range insted .

H.

On 11 Apr 2005 12:01:05 -0700, "K7ITM" wrote:

Since you're wanting to make it black to match other accouterments on
your vehicle, consider that most, if not all, black-dyed anodization
will fade in the sunlight, and it doesn't take all that long. In
addition, depending on the aluminum alloy, the "black" may not be all
that black to begin with. Why not instead give the antenna a coat of
automotive enamel or lacquer? You can either mask off areas that need
to have electrical contact, or scrape them after painting. Perhaps you
can paint after the antenna is assembled. That way, you can get a
color that really matches other items.

Cheers,
Tom

On Mon, 11 Apr 2005 06:47:14 -0700, Dan Richardson
wrote:
On Sun, 10 Apr 2005 23:58:12 -0400, Mike Coslo
wrote:

How close to the ocean are you? It sounds like you are right in the spray!

About a half mile. I live in the northern California "Mendocino"
coast. We have a lot of rain too and that combination is a killer for
aluminum exposed to the elements.

Has anyone done any testing (RF resistance) on squirting some NOALOX
compound (or other anti-corrosion sealants) between the aluminum
elements and scrubbing them clean to remove the oxide film before
bolting them together? Should help a lot, especially along the coast.

Works great on AL power wire at 60Hz...

-- Bruce --

(KBPY-8540 - wait, they discontinued those calls. Oh well...) ;-)
--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

On Mon, 11 Apr 2005 12:25:26 -0700, Wes Stewart
wrote:
On 11 Apr 2005 11:52:53 -0700, "K7ITM" wrote:
Richard Clark wrote:

I've calibrated these too (Boonton, I think, also built them, but as
Boonton was acquired by HP, it isn't a remarkable difference).

Errrk?? From Boonton's web site:
"In July 2000 we became a member of a larger family as we were acquired
by Wireless Telecom Group, Inc. (doing business as Noise Com). Being a
wholly owned subsidiary of Wireless Telecom Group, Inc. has enabled us
to further our product development and customer service initiatives."

See http://www.boonton.com/2002/about-history.html

They left out part of their history.

H-P *did* acquire Boonton at one time. I have both a black crackle
Boonton 250 RX meter and an H-P gray HP 250 RX meter out in my storage
building.

Another rec.crafts.metalworking crosspost kibbitz: Double check
that - they could have been owned for a while, but it's far more
likely H-P ordered some made by Boonton in gray cases with the H-P
name on them. Far cheaper than H-P duplicating them from scratch, and
doing a total redesign so they don't infringe on any patents.

Happens all the time - for one example, Sears doesn't build power or
hand tools themselves, but they have the OEM suppliers put their name
on tons of them. Sometimes they're customer specific designs, others
are only 'badge engineered' from an existing design and change the
plastic feedstock color in the case molding machine.

In the past I've saved an average 20% by going to the OEM (like
Skil-Bosch) for parts when you can identify them, rather than the
Sears Parts Center.

-- Bruce --

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.