"Jeff Liebermann" wrote in message
...

Yes, I know. A clean workbench is a sign of a sick mind.
http://802.11junk.com/jeffl/pics/home/slides/chain-saw-repair.html
It's currently not quite as messy, but it's close.


Looks like you have an antenna harness for phasing 2 meter antennas. Is the
chain saw apart to put the co-phased antennas on ? hihi..

On Sun, 12 May 2013 16:34:53 -0400, "Ralph Mowery"
wrote:

"Jeff Liebermann" wrote in message
.. .

Yes, I know. A clean workbench is a sign of a sick mind.
http://802.11junk.com/jeffl/pics/home/slides/chain-saw-repair.html
It's currently not quite as messy, but it's close.

Looks like you have an antenna harness for phasing 2 meter antennas.

I guess you mean the Wilkinson power divider/splitter in the lower
left. It's not for phasing antennas, but for combining the signals
from two receive only 1090MHz antennas for ADS-B reception. The lines
are 3/4 electrical wavelengths long RG-6a/u because I couldn't find
any small diameter 75 ohm coax. That was a prototype I just threw
together to see if I really needed the 100 ohm resistor for receive
only. With low gain antennas, it's not needed. For high gain, where
impedance matching is more important, it's needed.

Is the
chain saw apart to put the co-phased antennas on ? hihi..

The chain saw has nothing to do with RF, unless you include using the
trees as supports for various HF antennas. In this case, the only
thing wrong with the saw was that the fuel line split and started
leaking. In order to replace a simple fuel line, I had to tear down
the saw completely. I used the occasion to also clean out the
accumulated crud, clean the carb, replace various filters, clean the
carbon out of the exhaust port, and do the usual tuneup. Right now,
the bench has two weed whackers torn apart. Since I took them apart
about 2 weeks ago, I don't remember which parts belong to which
engine. This should be interesting...




--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Jeff Liebermann" wrote in message
...
On Sun, 12 May 2013 16:34:53 -0400, "Ralph Mowery"
wrote:

"Jeff Liebermann" wrote in message
. ..

Yes, I know. A clean workbench is a sign of a sick mind.
http://802.11junk.com/jeffl/pics/home/slides/chain-saw-repair.html
It's currently not quite as messy, but it's close.

Looks like you have an antenna harness for phasing 2 meter antennas.

I guess you mean the Wilkinson power divider/splitter in the lower
left. It's not for phasing antennas, but for combining the signals
from two receive only 1090MHz antennas for ADS-B reception. The lines
are 3/4 electrical wavelengths long RG-6a/u because I couldn't find
any small diameter 75 ohm coax. That was a prototype I just threw
together to see if I really needed the 100 ohm resistor for receive
only. With low gain antennas, it's not needed. For high gain, where
impedance matching is more important, it's needed.


I know about the Wilkinsson devider. Not sure if it is done now, but the
CBers would put two antennas on their cars and especially the big trucks.
Feed them with a T and 1/4 wavelengths of coax if I recall corectly.
Thought you were going to do that to the chain saw for 2 meters to help out
your handy talkey while sawing wood. As if you could hear it over the
noise.

I have not looked over the power devider in a long time. I was thinking the
100 ohm resistor was mainly to absorbe the unballanced power. If everything
was matched you could leave it out, but as you well know, nothing is perfect
in the RF world.

What are you using for a receiver for the ADS-B ? I have one of the dongles
that plugs into the usb of a computer on order. Should be here Monday. It
tunes from about 25 MHz to over 1 Ghz from the writeups. Off ebay here is
the item number.
310655269457

I don' t see how they can make and ship a device like that for only $ 11.00.

On Sun, 12 May 2013 17:56:21 -0400, "Ralph Mowery"
wrote:


"Jeff Liebermann" wrote in message
.. .
On Sun, 12 May 2013 16:34:53 -0400, "Ralph Mowery"
wrote:

"Jeff Liebermann" wrote in message
...

Yes, I know. A clean workbench is a sign of a sick mind.
http://802.11junk.com/jeffl/pics/home/slides/chain-saw-repair.html
It's currently not quite as messy, but it's close.

Looks like you have an antenna harness for phasing 2 meter antennas.

I guess you mean the Wilkinson power divider/splitter in the lower
left. It's not for phasing antennas, but for combining the signals
from two receive only 1090MHz antennas for ADS-B reception. The lines
are 3/4 electrical wavelengths long RG-6a/u because I couldn't find
any small diameter 75 ohm coax. That was a prototype I just threw
together to see if I really needed the 100 ohm resistor for receive
only. With low gain antennas, it's not needed. For high gain, where
impedance matching is more important, it's needed.

I know about the Wilkinsson devider. Not sure if it is done now, but the
CBers would put two antennas on their cars and especially the big trucks.
Feed them with a T and 1/4 wavelengths of coax if I recall corectly.

Yep. It was called a "co-phasing harness". Basically, the same thing
as a Wilkinson power divider. The original purpose was to deal with
the problem that the truckers were having with mounting antennas on
their big rigs. The antenna could not be mounted on top of the
tractor or trailer because the weight scale operators did not like
antennas smashing into the overhead clearance gauges. However, one
antenna on the side of the tractor didn't work very well because it
blocked signals on the other side. Two antennas were just fine. The
only problem was that while in receive, there was little loss from
either antenna, in transmit, the power was split equally between
sides. To compensate, doubling the transmit power was deemed
necessary. It worked.

At the time 1973(?), I was working on an ill fated CB related project
that would eventually have Antenna Specialists' name on it. I
discussed the co-phasing harness problem with one of their engineers.
He mumbled something about it being a great way to double antenna
sales. The rest you can guess.

Thought you were going to do that to the chain saw for 2 meters to help out
your handy talkey while sawing wood. As if you could hear it over the
noise.

Yacking on the radio while operating a rather dangerous piece of
machinery is not a great idea. If someone wants to yell at me, they
can wait until I'm done sawing.

I have not looked over the power devider in a long time. I was thinking the
100 ohm resistor was mainly to absorbe the unballanced power. If everything
was matched you could leave it out, but as you well know, nothing is perfect
in the RF world.

True for a splitter. Not quite so true for a combiner. It's main
purpose it to provide the best possible isolation between input ports.
The phase shift through the *TWO* 1/4 wave lines, combined through the
100 ohm resistor, exactly cancel, which provides the necessary
isolation. If you look at the specs for a combiner, you'll see the
isolation specification.

What are you using for a receiver for the ADS-B ?

One of the receive stations for one of the aircraft monitoring
networks.
http://planefinder.net
http://my.pinkfroot.com
http://Flightradar24.com

I have one of the dongles
that plugs into the usb of a computer on order. Should be here Monday. It
tunes from about 25 MHz to over 1 Ghz from the writeups. Off ebay here is
the item number.
310655269457
I don' t see how they can make and ship a device like that for only $ 11.00.

Yep, very cheap. I couldn't afford to ship an empty box for that
price.
http://www.ebay.com/itm/310655269457
There are numerous projects on the web for turning it into everything
from a spectrum analyzer to a radio scanner.
http://www.hamradioscience.com/building-an-inexpensive-ads-b-receiving-and-sharing-station/
http://panteltje.com/panteltje/xpsa/index.html
I could use one of those RTL8232U dongles, but I have a different
problem to solve. 1090MHz is in the middle of the frequencies used by
DME (distance measuring equip) which provides a challenge in
interference reduction using DSP. The receivers will probably be
located in the middle of transmitter infested mountain tops, which
means they need a really good IM tolerant front end. The antenna
problem is also unique in that it requires maximum gain toward the
horizon in order to maximize range, but also must still have some gain
overhead to hear closer aircraft. I combine two antennas for the
purpose.
http://802.11junk.com/jeffl/antennas/AMOS-3-INV-1090Mhz/index.html


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Jeff Liebermann" wrote in message
...
Yep. It was called a "co-phasing harness". Basically, the same thing
as a Wilkinson power divider. The original purpose was to deal with
the problem that the truckers were having with mounting antennas on
their big rigs. The antenna could not be mounted on top of the
tractor or trailer because the weight scale operators did not like
antennas smashing into the overhead clearance gauges. However, one
antenna on the side of the tractor didn't work very well because it
blocked signals on the other side. Two antennas were just fine. The
only problem was that while in receive, there was little loss from
either antenna, in transmit, the power was split equally between
sides. To compensate, doubling the transmit power was deemed
necessary. It worked.

At the time 1973(?), I was working on an ill fated CB related project
that would eventually have Antenna Specialists' name on it. I
discussed the co-phasing harness problem with one of their engineers.
He mumbled something about it being a great way to double antenna
sales. The rest you can guess.


During that period of time I repaired things for the CBers to pick up some
extra spending money. I was thinking there was a mobile antenna system that
you mounted two antennas and had a switch box that phased them for differant
directions. Don't believe it worked too well as the antennas were usually
too close together. The the base station 'scanner' antenna was devoloped
using 3 verticals in a triangle patern several feet apart. Seemed to work
ok for what it was.

During that period of time, I think Antenna Specialists' made up much of the
CB antenna sales.

Only double the power,, many of the ones I knew ran 50 to 100 watts in the
mobiles back in the 70's . During those years you could sell almost
anything to the CB. Much like for the last number of years you can sell to
the audio/hifi people. Best scam I know of is the wire going from the hifi
to the wall socket. For about $ 120 you get 6 to 8 feet of 'special wire'
Even if it was special that would not account for the wire going from the
outlet to the breaker box and then to th epole transformer..

On Sun, 12 May 2013 20:36:26 -0400, "Ralph Mowery"
wrote:

I was thinking there was a mobile antenna system that
you mounted two antennas and had a switch box that phased them for differant
directions. Don't believe it worked too well as the antennas were usually
too close together.

Chuckle. That's because the co-phasing harness combiner would produce
a giant null in the fore and aft directions. The box had a 3 position
switch, that selected antenna 1, 2, or both. The problem was that
there was no way to use a real Wilkinson splitter with the switch, so
the both position was simply both antennas in parallel. That didn't
work.

The the base station 'scanner' antenna was devoloped
using 3 verticals in a triangle patern several feet apart. Seemed to work
ok for what it was.

It's still being sold and it actually works fairly well. It's just a
VHF/UHF version of an HF "fan" antenna, where each band has its own
dipole. Well, for the scanner antenna, a monopole.

The stranger looking the antenna, the better is works (and sells).

During that period of time, I think Antenna Specialists' made up much of the
CB antenna sales.

Yep. I wasn't involved in antenna design at the time, but I did meet
with some of the designers. The RF part of the design was minimal.
The aesthetics, cosmetics, packaging, and sales pitch were the major
considerations.

Only double the power,, many of the ones I knew ran 50 to 100 watts in the
mobiles back in the 70's.

It started with doubling the power, again for good reason caused by
the power divider. Radios had such features on the schematic as
"Don't short this resistor or you will transmit at illegal power
levels". That would usually get the typical 23 channel CB up to about
12 watts in. Linears came later.

Incidentally, in about 1979, I worked on a marine 2-30MHz HF SSB
transmitter. The 150 watt power amplifier was my design. Sales of
"replacement" power amplifiers were rather high until management found
out what the dealers were doing with them. Oh well.

During those years you could sell almost
anything to the CB. Much like for the last number of years you can sell to
the audio/hifi people. Best scam I know of is the wire going from the hifi
to the wall socket. For about $ 120 you get 6 to 8 feet of 'special wire'
Even if it was special that would not account for the wire going from the
outlet to the breaker box and then to th epole transformer..

Got $10,000?
http://www.amazon.com/Denon-AKDL1-Dedicated-Link-Cable/dp/B000I1X6PM
There probably should be a law against this, but on the other hand,
the purchase of such an overpriced cable is probably its own
punishment.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

I am noticing a lot of fuel lines up here in Ontario are failing because of
the newly introduced or mandated or shoved down our throats Alcohol or
Ethenol they are putting 15% in the fuels. One dealer around here actually
doubled that amount and was caught and fined now is paying for everyone's
fuel lines, gaskets, seals that were eaten by the ethenol they mix in the
fuels. We are seeing this happen around here and boat owners and chainsaw
owners etc etc are squacking.

Thanks for all the great advice on batteries gents, I appreciate it all and
thank you.



"Jeff Liebermann" wrote in message
...
On Sun, 12 May 2013 16:34:53 -0400, "Ralph Mowery"
wrote:

"Jeff Liebermann" wrote in message
. ..

Yes, I know. A clean workbench is a sign of a sick mind.
http://802.11junk.com/jeffl/pics/home/slides/chain-saw-repair.html
It's currently not quite as messy, but it's close.

Looks like you have an antenna harness for phasing 2 meter antennas.

I guess you mean the Wilkinson power divider/splitter in the lower
left. It's not for phasing antennas, but for combining the signals
from two receive only 1090MHz antennas for ADS-B reception. The lines
are 3/4 electrical wavelengths long RG-6a/u because I couldn't find
any small diameter 75 ohm coax. That was a prototype I just threw
together to see if I really needed the 100 ohm resistor for receive
only. With low gain antennas, it's not needed. For high gain, where
impedance matching is more important, it's needed.

Is the
chain saw apart to put the co-phased antennas on ? hihi..

The chain saw has nothing to do with RF, unless you include using the
trees as supports for various HF antennas. In this case, the only
thing wrong with the saw was that the fuel line split and started
leaking. In order to replace a simple fuel line, I had to tear down
the saw completely. I used the occasion to also clean out the
accumulated crud, clean the carb, replace various filters, clean the
carbon out of the exhaust port, and do the usual tuneup. Right now,
the bench has two weed whackers torn apart. Since I took them apart
about 2 weeks ago, I don't remember which parts belong to which
engine. This should be interesting...




--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558