Richard Clark wrote:
On 9 Feb 2005 02:16:27 -0800, wrote:
So basically, i sell bed-warmers
I'm sure some of your customers agree - the population that has
survived the first self thinning of the genetic pool :-)

And your antennas? I suppose they are probes for warming delicate
tissues?


No, they just look BEAUTIFUL on
top of a roof!

:)


S,

On 9 Feb 2005 09:42:47 -0800, wrote:

What brand and model # field strength
meter do you have? Or did you build a
homemade RF rectifying "sniffer" amplified
with an Op-amp? Not saying the later
couldn't be calibrated correctly...

An older lampkin, and also a tuned RF sniffer
with gain (at RF) so I only need milliwatts.

Doesn't matter much as it can be performed with uncalibrated
instruments and a simple field reference by using a simple dipole
as a reference antenna first and do A:B comparisons. You don't need
absolute levels, only ratios for good accuracy.

Yeah, but you need a serious tower
to put 4 bays on, esp. at VHF, which we don't have
the money for.

The first tower was built for repeater site using EMT stacked one on
another with sleeve joints (poor mans swage) to 30 ft. Then I put the
4 stack dipole on that (its height was also 22ft VHF). It was done
for a commercial site that was to be temporary and cheap. Worked well
for nearly a year before we planted a DB products commercial 4 bay and
a telephone pole at that site when they decided to make it permanent.
Its about 10$ per ten feet to build and guy that arrangement.

Also, solder has VERY little
mechanical strength. Almost none.

It's a bad idea.

If the connector is holding weight then something else is wrong
as you would normally secure the cable to the supports. Strength
is not an issue then. Also most cut a small slot so the corner is
acutally in a grove, adds imensely to strength.

So then use a brass plate, and
stainless-steel 4-40 bolts and nuts.

Don't forget locking hardware as vibration and themal creep are
problems. You still get galvanic effects. Also drilling holes in the
structure to support the plate detracts from the structures strength.

This is under 12 pounds and is self supporting to that height.
Plenty light enough for this girl. You could use Aluminum tube
to build this and really cut the weight.


Opps! I meant to say 1" copper. 1/2" copper
is not strong enough for a VHF super J-pole.

But for the multibay dipole the 1/2 insections are only 19 iches and
very robust for that. The dipole portion could also be done with 1/4"
refrigeration tube as the structre is small.

Aluminum is not solderable.

Again your wrong. It's solderable but, you do have to know how and
use a decent heat source. Though bolted connections would work.

The Super J-pole at VHF is big, and
it's worse depending on how high you want
to get it.

Yes it is.

Since the super-j doesnt offer the same performance your
claim is specious. As to structural, The super-J often fails
badly at the center insulator and the phasing loop as descrbed often
rarely makes the winter here in the east due to ice, wind and
snow. New England winters are harsh on antennas.


We used a length of Delrin rod for the center
conductor, it's slightly flexible but ultra strong.
Don't use a wooden dowel coated w/epoxy, it will break.

Delrin works, not easily obtained and often not the right size
meaning a machine shop may be needed. Doesnt solve
the problem of the phasing loop sagging and failing.

The phasing loop was something like AWG#4
solid copper wire. Hasn't failed for 3 years,
but Ca. is a bit less harsh, indeed!

CA is timid save maybe for wind and mountain weather. The use of #4
CU is very heavy and adds to the problems. The problem in that case
is #4 has a low strength to weight ratio. Most use hard drawn 1/4"
copper or brass tube which is far more satisfactory.

Allison

In article .com,
wrote:

We serve the San Jose/Milpitas area now.

Just because i build transmitters, don't mean
i encourage people to use radiating loads with them!
Dummy loads are a wonderful thing, and you can learn
so much about RF circuit design and the phase-locked-loop!

Do the transmitters and/or amplifiers that you advertise and/or sell,
comply with the current FCC rules regarding certification? If so,
under which Part number are they certificated?

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Wed, 09 Feb 2005 19:20:47 -0000, (Dave Platt)
wrote:

Do the transmitters and/or amplifiers that you advertise and/or sell,
comply with the current FCC rules regarding certification? If so,
under which Part number are they certificated?

Nah, thats not the effective path.

Do the play lists get recorded and is RIAA paid? Seems they
are far nastier than the FCC.

Allison

wrote:



Also, solder has VERY little
mechanical strength. Almost none.

It's a bad idea.

If the connector is holding weight then something else is wrong
as you would normally secure the cable to the supports. Strength
is not an issue then. Also most cut a small slot so the corner is
acutally in a grove, adds imensely to strength.


Sure you better have strain relief, but i
still wouldn't rely on the soldered corner of
an SO-239.







Aluminum is not solderable.

Again your wrong. It's solderable but, you do have to know how and
use a decent heat source. Though bolted connections would work.


Ok, you can solder aluminum, but most
people don't know how, and it's not done often.






We used a length of Delrin rod for the center
conductor, it's slightly flexible but ultra strong.
Don't use a wooden dowel coated w/epoxy, it will break.

Delrin works, not easily obtained and often not the right size
meaning a machine shop may be needed. Doesnt solve
the problem of the phasing loop sagging and failing.


Wrong. Tap Plastics. In sizes that fit
3/4" or 1/2" or 1" copper perfectly.

Delrin is perfect for the Super J.

Don't use wood.

Our phasing loop doesn't sag and
hasn't failed yet.




The phasing loop was something like AWG#4
solid copper wire. Hasn't failed for 3 years,
but Ca. is a bit less harsh, indeed!

CA is timid save maybe for wind and mountain weather. The use of #4
CU is very heavy and adds to the problems. The problem in that case
is #4 has a low strength to weight ratio. Most use hard drawn 1/4"
copper or brass tube which is far more satisfactory.


It may have been #6, but it was fine
for our purposes.



Slick

On 9 Feb 2005 18:24:44 -0800, wrote:

Sure you better have strain relief, but i
still wouldn't rely on the soldered corner of
an SO-239.

Try it someday.

Ok, you can solder aluminum, but most
people don't know how, and it's not done often.

There are fluxes and solders for this at every local hardware.

Delrin is perfect for the Super J.

Don't use wood.

Wood is poor.

Our phasing loop doesn't sag and
hasn't failed yet.

Wouldnt last through the 30 inches of snow we got here.

It may have been #6, but it was fine
for our purposes.

Marginal.

Wanna try a real broadcast FM antenna, try a dual cycloid. Not to
hard to build but has both vertical and horizontal polarization. good
gain too.


Allison

wrote:
On 9 Feb 2005 18:24:44 -0800, wrote:

Sure you better have strain relief, but i
still wouldn't rely on the soldered corner of
an SO-239.

Try it someday.


I did. The SO-239 broke, and
we had to haul the antenna down
just to replace it....pain in the
ass.



Ok, you can solder aluminum, but most
people don't know how, and it's not done often.

There are fluxes and solders for this at every local hardware.


But few people ever solder aluminum.



Delrin is perfect for the Super J.

Don't use wood.

Wood is poor.


Wood sucks. Delrin is great,
and it carves and shapes very easily,
yet is extremely strong.



Our phasing loop doesn't sag and
hasn't failed yet.

Wouldnt last through the 30 inches of snow we got here.


Oh yes it would. Snow ain't THAT
heavy!



It may have been #6, but it was fine
for our purposes.

Marginal.


In what way? Hollow tubing would have been
too weak.



Wanna try a real broadcast FM antenna, try a dual cycloid. Not to
hard to build but has both vertical and horizontal polarization.
good
gain too.


Yeah, this one is our next one:

http://members.tripod.com/AMN92/cp_ant.htm


A full report when we get it together!



Slick