[Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer
I built a paint can 6 meter helical coil duplexer, and also built an 8 stub heliax 6 meter duplexer. The mechanics don't seem all that complicated, but getting the rejection and insertion loss you want can take a lot of messing with it. The heliax was difficult to find. Traded a large tray of donuts to a local electrical contractor for 6 pieces of 8 foot long scrap heliax. I found a partial tray of 3-30 pf trimmer caps at a hamfest. The paint cans didn't hold up to temp changes at all.- Drift all over the place like others said. I cut the heliax cable, drilled and installed BNC connectors, selected stubs resonant at the higher frequency then used ceramic piston trimmers to couple the coax to the stub, then a duplicate trimmer to tune stub down to desired freq. I have built a 1/4 wave heliax stub filter using same technique with a 1/4 wave phase line to a T connector to make a band pass filter for 2 meter APRS. I suspect heliax will make a more stable and smaller duplexer then oil cans. Happy tinkering! Ed N3SDO
Re: [Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer
As I recall, an early ARRL VHF manual had a brief chapter on repeaters, and I believe there were two articles that were of interest. One was the duplexer and another was a four bay folded dipole antenna for repeater use. If you know where the four vertical bay antenna article is located, you may find the duplexer article also. I think it also was a QST article. I remember one fellow who built the duplexer complained that when it was hit by lightning, it disassembled itself. He had made the outside tube out of individual sheets of copper soldered together, and the solder joints let go when it took the strike. 73 - Jim W5ZIT --- On Tue, 4/28/09, cruizzer77 atlant...@gmx.ch wrote: From: cruizzer77 atlant...@gmx.ch Subject: [Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer To: Repeater-Builder@yahoogroups.com Date: Tuesday, April 28, 2009, 5:18 AM It's interesting to hear about your projects! I would be interested in knowing which VHF manual you're referring to, Jim.
Re: [Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer
--- On Tue, 4/28/09, cruizzer77 atlant...@gmx.ch wrote: From: cruizzer77 atlant...@gmx.ch Subject: [Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer To: Repeater-Builder@yahoogroups.com Date: Tuesday, April 28, 2009, 5:18 AM It's interesting to hear about your projects! I would be interested in knowing which VHF manual you're referring to, Jim. At 08:32 AM 04/29/09, you wrote: As I recall, an early ARRL VHF manual had a brief chapter on repeaters, and I believe there were two articles that were of interest. One was the duplexer and another was a four bay folded dipole antenna for repeater use. The duplexer article is on the antennas page at repeater-builder.com A Homemade Duplexer for 2-Meter Repeaters by John Bilodeau, W1GAN (from the July 1972 QST magazine) http://www.repeater-builder.com/antenna/w1gan-duplexer.pdf I'd like to get a scan of that ARRL antenna article for the antennas page (repeater-builder has permission from the ARRL to post PDFs of any articles in QST or their books). If you know where the four vertical bay antenna article is located, you may find the duplexer article also. I think it also was a QST article. You may be thinking of the 73 Magazine article that is on the antennas page... 440 MHz Folded Dipole Repeater Antenna (222kb PDF file) This is a two page PDF file of the classic 73 Magazine construction article by Chuck Kelsey WB2EDV - Yes, you can build yourself a DB-224 folded dipole array. http://www.repeater-builder.com/antenna/440fdipl.pdf I remember one fellow who built the duplexer complained that when it was hit by lightning, it disassembled itself. He had made the outside tube out of individual sheets of copper soldered together, and the solder joints let go when it took the strike. That's what the PolyPhaser is for... mounted to the grounded copper plate in the building wall... 73 - Jim W5ZIT Mike WA6ILQ
Re: [Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer
Mike Morris WA6ILQ wrote: As I recall, an early ARRL VHF manual had a brief chapter on repeaters, and I believe there were two articles that were of interest. One was the duplexer and another was a four bay folded dipole antenna for repeater use. I'd like to get a scan of that ARRL antenna article for the antennas page (repeater-builder has permission from the ARRL to post PDFs of any articles in QST or their books). I think this may be the one he was referring to: http://www.repeater-builder.com/projects/exposeddipole.html 73, Paul N1BUG
RE: [Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer
We have 3 sets of the W1GAN duplexers here in San Antonio that I know of (San Antonio Repeater Organization), 2 on the air and one in a backup cabinet. I'm curious how many others are out there in service. I wasn't around when they were built but I was told ours were silver plated. Don Kirchner W5DK From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Mike Morris WA6ILQ Sent: Wednesday, April 29, 2009 2:33 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer --- On Tue, 4/28/09, cruizzer77 atlant...@gmx.ch wrote: From: cruizzer77 atlant...@gmx.ch Subject: [Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer To: Repeater-Builder@yahoogroups.com Date: Tuesday, April 28, 2009, 5:18 AM It's interesting to hear about your projects! I would be interested in knowing which VHF manual you're referring to, Jim. At 08:32 AM 04/29/09, you wrote: As I recall, an early ARRL VHF manual had a brief chapter on repeaters, and I believe there were two articles that were of interest. One was the duplexer and another was a four bay folded dipole antenna for repeater use. The duplexer article is on the antennas page at repeater-builder.com A Homemade Duplexer for 2-Meter Repeaters by John Bilodeau, W1GAN (from the July 1972 QST magazine) http://www.repeater-builder.com/antenna/w1gan-duplexer.pdf http://www.repeater-builder.com/antenna/w1gan-duplexer.pdf I'd like to get a scan of that ARRL antenna article for the antennas page (repeater-builder has permission from the ARRL to post PDFs of any articles in QST or their books). If you know where the four vertical bay antenna article is located, you may find the duplexer article also. I think it also was a QST article. You may be thinking of the 73 Magazine article that is on the antennas page... 440 MHz Folded Dipole Repeater Antenna (222kb PDF file) This is a two page PDF file of the classic 73 Magazine construction article by Chuck Kelsey WB2EDV - Yes, you can build yourself a DB-224 folded dipole array. http://www.repeater-builder.com/antenna/440fdipl.pdf http://www.repeater-builder.com/antenna/440fdipl.pdf I remember one fellow who built the duplexer complained that when it was hit by lightning, it disassembled itself. He had made the outside tube out of individual sheets of copper soldered together, and the solder joints let go when it took the strike. That's what the PolyPhaser is for... mounted to the grounded copper plate in the building wall... 73 - Jim W5ZIT Mike WA6ILQ
Re: [Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer
At 12:52 PM 04/29/09, you wrote: Mike Morris WA6ILQ wrote: As I recall, an early ARRL VHF manual had a brief chapter on repeaters, and I believe there were two articles that were of interest. One was the duplexer and another was a four bay folded dipole antenna for repeater use. I'd like to get a scan of that ARRL antenna article for the antennas page (repeater-builder has permission from the ARRL to post PDFs of any articles in QST or their books). I think this may be the one he was referring to: http://www.repeater-builder.com/projects/exposeddipole.html 73, Paul N1BUG OK, I'd forgotten about that I'll add it to the Antenna Systems page. Mike
[Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer
It's interesting to hear about your projects! I would be interested in knowing
which VHF manual you're referring to, Jim.
While the original barrels used by Aerial Facilities Ltd. are pretty big I had
the idea to try the beer kegs that are common here in Switzerland. These are 20
litre kegs so less than half the capacity of the original 11 imperial gallons.
The diameter is 23cm (about 9) and measured from the outside the height could
be just about sufficient to mount the plunger. But the overall size of 4
cavities would still be ok. I'll see if I can get some scrap barrels of this
kind...
Regards
Martin
--- In Repeater-Builder@yahoogroups.com, Jim Brown w5...@... wrote:
We built a duplexer back in the late '70s using sections cut from the
refueling boom from a KC-135 tanker. After cutting the six sections to
length, the inside of the top end had to be machined to be able to insert a
cap with the center tube and coupling loops inside with a tight fit. The
other end of the tubing had a square piece welded to the bottom to close out
the tube.
The tubing was about six inches in diameter and about a quarter inch thick,
as I recall. We used the design in the repeater section of the VHF manual
and used two connectors with a cap between the connectors on one side and an
inductor between the connectors on the other side.
The thing worked as long as the temp was constant, but with varying
temperature, it was all over the place in tuning. When we finally got the
money together we bought a 4 can 8 inch DB duplexer and it is still in
service.
73 - Jim W5ZIT
--- On Sun, 4/26/09, cruizzer77 atlant...@... wrote:
From: cruizzer77 atlant...@...
Subject: [Repeater-Builder] Re: W1GAN and square duplexers aka homebrew
duplexer
To: Repeater-Builder@yahoogroups.com
Date: Sunday, April 26, 2009, 3:03 PM
Since your post I've been googling like hell and found one Dutch design
of a copper clad duplexer by PA0NHC, but this also has two loops per cavity
and uses 8 cavities. However it answers the question about square enclosures
and could be a reference design.
Furthermore I found a design by WB3AYW which uses 16 gallon transmission
fluid barrels as cavities in BPBR configuration using 4 cavities. This one
looks easy to build and is somewhat similar to the beer keg duplexer which
has been made professionally in the seventies afaik. The problem with these
is that a 4 cavity duplexer gets pretty big and will hardly fit into a 19
cabinet.
Does anyone know of any other particular homebrew design, especially one
which uses some kind of available enclosure similar to the barrels but more
space-saving?
I also found some notice that the heliax duplexer, which is well-known for 6
meters, could also be built for 2 meters, but no detailed info was given. If
anyone knows more about this, please tell...
--- In Repeater-Builder@ yahoogroups. com, DCFluX dcflux@ wrote:
There were a couple of designs that used copper circuit boards to form
square boxes for the outer jacket of the duplexer.
Size maters as the inner to outer diameter ratio effects the impedance
of the cavity. It is my understanding that the optimum impedance for
a cavity is approx 70 ohms. Not sure if this is true for cavities, but
with helical resonators square shields have higher Q than round ones.
You would also probably be better off using a BpBr style design, as I
remember W1GANs was for pass cavities which would require 6, BpBr can
get away with use 4, they would be similar but only have 1 coupling
loop that has a high quality trimmer capacitor such as a johansen or a
coaxial gimmic in the ground leg of the loop to set the notch
frequency.
On Fri, Apr 24, 2009 at 4:19 AM, cruizzer77 atlantis7@ .. wrote:
Hi
Most of you who are into duplexers will know W1GAN's old QST-article A
Homemade Duplexer for 2-Meter Repeaters.
His design uses 4 copper tubes, but today many duplexer manufacturers
use square aluminium profile as duplexer bodies, i.e. Sinclair but others
as well. Now I wondered if W1GAN's design could be used for building such
an aluminium square tube duplexer as well and if it would work equally
well. Does anybody know?
Instead of the 4 round tube, would a 4 square tube be used, or does the
circumference matter?
Kind regards
Martin
- - --
Yahoo! Groups Links
__
Re: [Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer
That would be the design I was thinking of, You would only build half of the enclosure in a 1x4 configuration. To convert to BpBr you would only have one coupling loop per cavity and on the ground leg of the loop you would have a high quality variable capacitor or a N or BNC connector to come out to a gimmic style capacitor like the Wacom cavities use. Sinclair has some VHF and 220 duplexers that are rack mount friendly made of aluminum extrusions which could be used for a size reference. I would think 4 square inner dimension and .125 or .25 thick walls. Aerial facilities limited was the company that made the beer keg cavities. See: http://www.ingenia.org.uk/ingenia/issues/issue18/david.pdf They also produced a 8 or so band pass cavity that was rack mount friendly, I converted 4 of these from an ACSSB combiner to be a BpBr duplexer by removing the one loop and adding a johansen capacitor and cutting RG-214 coax the right length. got about -1.4dB loss and -84 dB rejection per leg On Sun, Apr 26, 2009 at 1:03 PM, cruizzer77 atlant...@gmx.ch wrote: Since your post I've been googling like hell and found one Dutch design of a copper clad duplexer by PA0NHC, but this also has two loops per cavity and uses 8 cavities. However it answers the question about square enclosures and could be a reference design. Furthermore I found a design by WB3AYW which uses 16 gallon transmission fluid barrels as cavities in BPBR configuration using 4 cavities. This one looks easy to build and is somewhat similar to the beer keg duplexer which has been made professionally in the seventies afaik. The problem with these is that a 4 cavity duplexer gets pretty big and will hardly fit into a 19 cabinet. Does anyone know of any other particular homebrew design, especially one which uses some kind of available enclosure similar to the barrels but more space-saving? I also found some notice that the heliax duplexer, which is well-known for 6 meters, could also be built for 2 meters, but no detailed info was given. If anyone knows more about this, please tell...
Re: [Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer
We built a duplexer back in the late '70s using sections cut from the refueling boom from a KC-135 tanker. After cutting the six sections to length, the inside of the top end had to be machined to be able to insert a cap with the center tube and coupling loops inside with a tight fit. The other end of the tubing had a square piece welded to the bottom to close out the tube. The tubing was about six inches in diameter and about a quarter inch thick, as I recall. We used the design in the repeater section of the VHF manual and used two connectors with a cap between the connectors on one side and an inductor between the connectors on the other side. The thing worked as long as the temp was constant, but with varying temperature, it was all over the place in tuning. When we finally got the money together we bought a 4 can 8 inch DB duplexer and it is still in service. 73 - Jim W5ZIT --- On Sun, 4/26/09, cruizzer77 atlant...@gmx.ch wrote: From: cruizzer77 atlant...@gmx.ch Subject: [Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer To: Repeater-Builder@yahoogroups.com Date: Sunday, April 26, 2009, 3:03 PM Since your post I've been googling like hell and found one Dutch design of a copper clad duplexer by PA0NHC, but this also has two loops per cavity and uses 8 cavities. However it answers the question about square enclosures and could be a reference design. Furthermore I found a design by WB3AYW which uses 16 gallon transmission fluid barrels as cavities in BPBR configuration using 4 cavities. This one looks easy to build and is somewhat similar to the beer keg duplexer which has been made professionally in the seventies afaik. The problem with these is that a 4 cavity duplexer gets pretty big and will hardly fit into a 19 cabinet. Does anyone know of any other particular homebrew design, especially one which uses some kind of available enclosure similar to the barrels but more space-saving? I also found some notice that the heliax duplexer, which is well-known for 6 meters, could also be built for 2 meters, but no detailed info was given. If anyone knows more about this, please tell... --- In Repeater-Builder@ yahoogroups. com, DCFluX dcf...@... wrote: There were a couple of designs that used copper circuit boards to form square boxes for the outer jacket of the duplexer. Size maters as the inner to outer diameter ratio effects the impedance of the cavity. It is my understanding that the optimum impedance for a cavity is approx 70 ohms. Not sure if this is true for cavities, but with helical resonators square shields have higher Q than round ones. You would also probably be better off using a BpBr style design, as I remember W1GANs was for pass cavities which would require 6, BpBr can get away with use 4, they would be similar but only have 1 coupling loop that has a high quality trimmer capacitor such as a johansen or a coaxial gimmic in the ground leg of the loop to set the notch frequency. On Fri, Apr 24, 2009 at 4:19 AM, cruizzer77 atlant...@. .. wrote: Hi Most of you who are into duplexers will know W1GAN's old QST-article A Homemade Duplexer for 2-Meter Repeaters. His design uses 4 copper tubes, but today many duplexer manufacturers use square aluminium profile as duplexer bodies, i.e. Sinclair but others as well. Now I wondered if W1GAN's design could be used for building such an aluminium square tube duplexer as well and if it would work equally well. Does anybody know? Instead of the 4 round tube, would a 4 square tube be used, or does the circumference matter? Kind regards Martin - - -- Yahoo! Groups Links __
[Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer
Since your post I've been googling like hell and found one Dutch design of a copper clad duplexer by PA0NHC, but this also has two loops per cavity and uses 8 cavities. However it answers the question about square enclosures and could be a reference design. Furthermore I found a design by WB3AYW which uses 16 gallon transmission fluid barrels as cavities in BPBR configuration using 4 cavities. This one looks easy to build and is somewhat similar to the beer keg duplexer which has been made professionally in the seventies afaik. The problem with these is that a 4 cavity duplexer gets pretty big and will hardly fit into a 19 cabinet. Does anyone know of any other particular homebrew design, especially one which uses some kind of available enclosure similar to the barrels but more space-saving? I also found some notice that the heliax duplexer, which is well-known for 6 meters, could also be built for 2 meters, but no detailed info was given. If anyone knows more about this, please tell... --- In Repeater-Builder@yahoogroups.com, DCFluX dcf...@... wrote: There were a couple of designs that used copper circuit boards to form square boxes for the outer jacket of the duplexer. Size maters as the inner to outer diameter ratio effects the impedance of the cavity. It is my understanding that the optimum impedance for a cavity is approx 70 ohms. Not sure if this is true for cavities, but with helical resonators square shields have higher Q than round ones. You would also probably be better off using a BpBr style design, as I remember W1GANs was for pass cavities which would require 6, BpBr can get away with use 4, they would be similar but only have 1 coupling loop that has a high quality trimmer capacitor such as a johansen or a coaxial gimmic in the ground leg of the loop to set the notch frequency. On Fri, Apr 24, 2009 at 4:19 AM, cruizzer77 atlant...@... wrote: Hi Most of you who are into duplexers will know W1GAN's old QST-article A Homemade Duplexer for 2-Meter Repeaters. His design uses 4 copper tubes, but today many duplexer manufacturers use square aluminium profile as duplexer bodies, i.e. Sinclair but others as well. Now I wondered if W1GAN's design could be used for building such an aluminium square tube duplexer as well and if it would work equally well. Does anybody know? Instead of the 4 round tube, would a 4 square tube be used, or does the circumference matter? Kind regards Martin Yahoo! Groups Links
