On 8/31/2010 2:05 PM, ka9qjg wrote:
OK Great , Thanks to Everyone who answered , I will sleep better now
one less thing to worry about
Don KA9QJG
Not the same thing, but something else to remember: Mount them
vertically! If you mount them horizontally, you run the risk of the
rods warping
Wow this must of Really been a Dumb question , No one answered it
Don KA9QJG
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of ka9qjg
Sent: Monday, August 30, 2010 9:07 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder
No problem. Most are in non-climate controlled environments.
Chuck
WB2EDV
- Original Message -
From: ka9qjg
To: Repeater-Builder@yahoogroups.com
Sent: Tuesday, August 31, 2010 1:42 PM
Subject: RE: [Repeater-Builder] Duplexers
Wow this must of Really been a Dumb
this must of Really been a Dumb question , No one answered it
Don KA9QJG
*From:* Repeater-Builder@yahoogroups.com [mailto:
repeater-buil...@yahoogroups.com] *On Behalf Of *ka9qjg
*Sent:* Monday, August 30, 2010 9:07 PM
*To:* Repeater-Builder@yahoogroups.com
*Subject:* RE: [Repeater
...@yahoogroups.com] On Behalf Of ka9qjg
Sent: Monday, August 30, 2010 9:07 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Duplexers
Since We are on the Topic of Duplexers, And some claim there is no such
thing as a Dumb Question but at the Risk of Asking one I will take a
chance
@yahoogroups.com
Subject: RE: [Repeater-Builder] Duplexers
I have a set of Wacoms on 2-meters in a totally uncompensated shack, running
from the teens in the winter to probably 150 in the summer. I've never had an
issued. I have another set in a similar shack, but it it air conditioned
@yahoogroups.com
Subject: RE: [Repeater-Builder] Duplexers
Since We are on the Topic of Duplexers, And some claim there is no
such thing as a Dumb Question but at the Risk of Asking one I will
take a chance , I have the Wacom 4 can on My 220 System,
The Question I have
')
Subject: RE: [Repeater-Builder] Duplexers
Since We are on the Topic of Duplexers, And some claim there is no
such thing as a Dumb Question but at the Risk of Asking one I will
take a chance , I have the Wacom 4 can on My 220 System,
The Question I have in a non controlled
: Tuesday, August 31, 2010 11:08 AM
Subject: RE: [Repeater-Builder] Duplexers
For there to be condensation there must be humidity in the air. The
more humidity, the more condensation.
Duplexers are in harsh environments now and I don't think it has been
a problem. Condensation on the outside
Sent: Tue, August 31, 2010 1:42:32 PM
Subject: RE: [Repeater-Builder] Duplexers
Wow this must of Really been a Dumb question , No one answered it
Don KA9QJG
From:Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com]
On Behalf Of ka9qjg
Sent: Monday, August 30, 2010 9
I've never had a problem. I would say that if the duplexers are out
of tune on the transmit side there is a possibility that they might get
hot, then cool off. This may cause them to take in moist air and cause
condensation. I've never seen it happen, but I can see how it could.
73, Jow,
Has anyone mentioned band-pass cavities? One on the RX side could be
enough and one more on the TX would do it for sure. There're some for
220 for less then a $100 on ebay right now. This might sound off the
wall but I once saw a DB4021 UHF band-pass cavity tune up quite well on
2 meters!!! Only
, No one answered it
Don KA9QJG
*From:* Repeater-Builder@yahoogroups.com [mailto:
repeater-buil...@yahoogroups.com] *On Behalf Of *ka9qjg
*Sent:* Monday, August 30, 2010 9:07 PM
*To:* Repeater-Builder@yahoogroups.com
*Subject:* RE: [Repeater-Builder] Duplexers
Since We
- Original Message -
From: Chris Fowler k...@k4fh.com k4fh%40k4fh.com
To: Repeater-Builder@yahoogroups.com Repeater-Builder%40yahoogroups.com
Cc: ka9qjg ka9...@wowway.com KA9QJG%40WOWWAY.COM
Sent: Tuesday, August 31, 2010 11:08 AM
Subject: RE: [Repeater-Builder] Duplexers
of staying a little warm in a repeater shack,
within reason.
73,
Paul, AE4KR
- Original Message -
From: ka9qjg
To: Repeater-Builder@yahoogroups.com
Sent: Tuesday, August 31, 2010 11:42 AM
Subject: RE: [Repeater-Builder] Duplexers
Wow this must of Really been a Dumb
If the transmiter is sometimes desensitizing the receiver,then re tune the or
readjust the duplexeur.
--- On Tue, 8/31/10, cmcclel...@aol.com cmcclel...@aol.com wrote:
From: cmcclel...@aol.com cmcclel...@aol.com
Subject: Re: [Repeater-Builder] Duplexers
To: Repeater-Builder@yahoogroups.com
Chris,
You do not have to use a duplexer, but it makes building a repeater SO much
easier! Keep in mind that antenna separation usually means vertical
separation, not horizontal separation. Moreover, the same isolation
provided by 1000 feet of horizontal separation might be provided by 10 feet
Thank you for your response.
The problem is that the repeater is located on top of a building and the
tower on that building is only about 20 feet tall. We can move the two
antennas apart horizontally, but only 20 feet vertically. Duplexers are way
too
expensive and hard to find for the
if you keep your eyes open you can find 220 duplexers at a good price ..
Email Bob Morton and I am sure he can find you one at a good price .. I had
2 from him and love his work
and the shipping cost of a 220 duplexer is not that bad either
On Mon, Aug 30, 2010 at 8:44 PM, cmcclel...@aol.com
- Original Message -
From: cmcclel...@aol.com
To: Repeater-Builder@yahoogroups.com
Sent: Monday, August 30, 2010 6:44 PM
Subject: Re: [Repeater-Builder] Duplexers
Thank you for your response.
The problem is that the repeater is located on top of a building
:
www.telewave.com/pdf/TWDS-6026.pdf
73, Eric Lemmon WB6FLY
-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of cmcclel...@aol.com
Sent: Monday, August 30, 2010 5:45 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater
Since We are on the Topic of Duplexers, And some claim there is no such
thing as a Dumb Question but at the Risk of Asking one I will take a
chance , I have the Wacom 4 can on My 220 System,
The Question I have in a non controlled environment such as No Heat or Air
Will the
Theory: http://www.repeater-builder.com/antenna/thoughts-on-isolation.html
Applications: http://www.repeater-builder.com/antenna/separation.html
Mike WA6ILQ
At 05:36 PM 08/30/10, you wrote:
Chris,
You do not have to use a duplexer, but it makes building a repeater SO much
easier! Keep in
The 4 WaCom UHF 10 cavities I believe were designed to be
part of a simple duplexer for a UHF-Lo repeater. They
*should* tune up to the 440 ham band based on what Telewave
has listed for specs on the current modern day model number.
Current config is Pass RX Reject TX on 3 cans and Pass
The cavities in this particular case are BpBr. Pics below:
http://vwreact.org/sale/Item%2031-34.jpg
http://vwreact.org/sale/Item%2031.1.jpg
http://vwreact.org/sale/Item%2031.2.jpg
On Sat, Feb 20, 2010 at 1:33 PM, Jeff DePolo j...@broadsci.com wrote:
The 4 WaCom UHF 10 cavities I believe
Hi Jeff,
I wouldn't worry about being a member of the Batboard Discussion Forum, it's
quite impossible to sign up as the captcha security device (jumbled
letters and numbers) is the most fascist I've EVER encountered.
There's no way that someone with minor visual impairment could ever sign up
to
Oddly enough, that's my ad ;) Thanks for the bump.
The 4 WaCom UHF 10 cavities I believe were designed to be part of a simple
duplexer for a UHF-Lo repeater. They *should* tune up to the 440 ham band
based on what Telewave has listed for specs on the current modern day model
number. Current
I would think that at the least you would want to build a small building, even
something close to a large dog house, 3'D X 4'W x 4'H. Leaves at least a
little room to breath and work around, heat may be a factor depending on the
cans you use and may send them a bit out of tune from the
: [Repeater-Builder] Duplexers
I would think that at the least you would want to build a small building,
even something close to a large dog house, 3'D X 4'W x 4'H. Leaves at least
a little room to breath and work around, heat may be a factor depending on
the cans you use and may send them
-world was around
$100 or so.
Scott
Scott Zimmerman
Amateur Radio Call N3XCC
474 Barnett Rd
Boswell, PA 15531
- Original Message -
From: Mung Bungholio
To: Repeater-Builder@yahoogroups.com
Sent: Monday, October 27, 2008 10:40 AM
Subject: RE: [Repeater-Builder] Duplexers
Yes I agree, something designed to be out in the elements a bit more.
From: Scott Zimmerman [EMAIL PROTECTED]
To: Repeater-Builder@yahoogroups.com
Sent: Monday, October 27, 2008 10:59:24 AM
Subject: Re: [Repeater-Builder] Duplexers
I often thought about using
That is what I was thinking of too.
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Scott Zimmerman
Sent: Monday, October 27, 2008 10:59 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Duplexers
I often thought about using a Rubbermaid
[mailto:[EMAIL PROTECTED] On Behalf Of Scott Zimmerman
Sent: Monday, October 27, 2008 10:59 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Duplexers
I often thought about using a Rubbermaid product.
Here is a deck box:
Rubbermaid item #3743
or a vertical
Vern,
This will probably raise some eyebrows, but I put up a ham repeater on the top
of an 18-story office building in Orlando, and will tell you what i did.
I used a very stout, steel rack box, cast off from the computer industry,
sealed the few holes in it, weatherstripped the door and
Are you seeking U.S. distribution?
Please contact [EMAIL PROTECTED] directly.
Thanks
ua3ahm [EMAIL PROTECTED] wrote: I wish to take
an interest at American HAM's how much actually now to
sell new duplexers in the USA. My company makes antennas and duplexers
for
Ralph,
Contact Telewave at www.telewave.com for both Telewave and Wacom duplexer
tuning information.
73, Eric Lemmon WB6FLY
-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Thursday, December 20, 2007 6:17 PM
To:
This makes sense.
I guess what might help is to find a single VHF bandpass
can to put in front of the receive side of the duplexer.
How much does the power output effect the required filter
attinuation? Right now I am running about 70w out would
turning it down make much of a difference?
Thanks for the great info as soon as we get the service
monitor back we are going to try these things.
I have already seperated the 2 sides and have seen much
improvement so I think that this is really my problem.
I do have a question about duplexers in general. I am
sure that this is a dumb
A transmitter may have broadband noise with considerable noise content
at the receive frequency. The notch in the transmit side removes
transmitter noise that may impair your receiver's capability. In an
earlier post there was mention of a solid state transmitter.
Traditionally tube
At 11:12 AM 9/26/2007, Steve wrote:
A transmitter may have broadband noise with considerable noise content
at the receive frequency. The notch in the transmit side removes
transmitter noise that may impair your receiver's capability.
In my day job 99% of the problems I have with noise floor is
Our local club recently installed a 2 meter repeater on a water tank adjacent
to a cell site. Two cell towers are serviced by four buildings housing
equipement, and we are having some desense due to noise pickup on the antenna.
Running an iso-tee we found that our GE Mastr II receiver with GE
The duplexer is a DB-4048.
I have had this repeater for a couple of months and it has
always had problems. I don't have access to a service
monitor or anything like that right now but I have a
friend that has one however someone is borrowing it right
now.
From what I can tell the desense
Of Jim Brown
Sent: Tuesday, September 25, 2007 8:20 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Duplexers
Our local club recently installed a 2 meter repeater on a water tank
adjacent to a cell site. Two cell towers are serviced by four buildings
housing equipement
At 9/25/2007 05:20, you wrote:
Our local club recently installed a 2 meter repeater on a water tank
adjacent to a cell site. Two cell towers are serviced by four buildings
housing equipement, and we are having some desense due to noise pickup on
the antenna. Running an iso-tee we found that
The noise floor is really decreasing the utility of the new
repeater. The noise source seems to come and go as a quiet signal
on the repeater input can become suddenly noisey, and vice versa - a
noisey signal can become suddenly quiet.
It looks like you have a 10dB degradation. Many times
The 10dBd Yagi I mentioned is for 900MHz, something smaller would
have to be used for VHF :)
73,
Mark N5RFX
At 9/25/2007 07:59, you wrote:
The noise floor is really decreasing the utility of the new
repeater. The noise source seems to come and go as a quiet signal
on the repeater input can become suddenly noisey, and vice versa - a
noisey signal can become suddenly quiet.
It looks like you have a
[EMAIL PROTECTED] wrote:
I had them tuned because I had just bought them and didn't
really trust that they were right. They were very far out
so it's good that I got them tuned. I was having the same
problem as now though very poor receive. Right now I have
a radio on there for receive
Time for an isolated TEE test with a dummy load. Why did you have the
duplexers tuned ? Was there a problem prior?
You should be able to split the duplexer without any trouble - just mark
things so you can go back as it was.
Best luck and 73, Steve NU5D
[EMAIL PROTECTED] wrote:
I am having
I would be quite surprised if you are NOT having desense with a Mastr
II and a 6 can notch only duplexer at 600 khz
Typically a 6 can reject only duplexer is not sufficient isolation at
600khz for 2 meters with a solid state PA.. Vertical separation or a
pass/reject duplexer will be
I had them tuned because I had just bought them and didn't
really trust that they were right. They were very far out
so it's good that I got them tuned. I was having the same
problem as now though very poor receive. Right now I have
a radio on there for receive that was getting about 30
Vern,
Did this problem exist before you had the duplexer tuned? Was anything at
all done to your repeater system just before the problem was noticed?
A band reject (notch) duplexer may be incapable of performing even
satisfactorily at 2m. Please advise the model number of your duplexer, so
we
Decibel did make a 6 cavity notch duplexer - 4 full sized cavities -
that would work nicely on a 110 Watt M2 station @ 600 kHz. Isolated
TEE test into a dummy load - how bad is the receiver desense ? If you
don't have some test equipment - signal gen, dummy load, and a TEE
fitting with the
Adding or removing cable lengths between the transmitter and duplexer also
does not change the VSWR as seen by the transmitter (minimal cable loss
effects notwithstanding).
--- Jeff
True but only if everything (tx out, cable and duplexer) is matched
problem.
Milt
N3LTQ
- Original Message -
From: Eric Lemmon [EMAIL PROTECTED]
To: Repeater-Builder@yahoogroups.com
Sent: Saturday, August 25, 2007 1:38 AM
Subject: RE: [Repeater-Builder] Duplexers
My statement regarding tuning did not explicitly refer to the actual
tuning of the duplexer
Adding or removing cable lengths between the transmitter and
duplexer also
does not change the VSWR as seen by the transmitter (minimal
cable loss
effects notwithstanding).
--- Jeff
True but only if everything (tx out, cable and duplexer) is
At 8/29/2007 06:40 PM, you wrote:
If you have two watt meters and an antenna matching device you can put
one
wattmeter between the transmitter and the matching device and tune it for
minimum reflected power on the first meter. Then with a second meter
between the tuner and the
]
Date: 2007/08/30 Thu PM 12:53:11 CDT
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Duplexers
OK, after talking to a senior RF engineer at lunch here at work I think I
understand what's going on. The part that threw me was having the matching
circuit
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
[EMAIL PROTECTED] On Behalf Of Bob Dengler
Sent: Thursday, August 30, 2007 12:53 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Duplexers
At 8/29/2007 06:40 PM, you wrote
or World
Radio...def not QST.
73, ron, n9ee/r
From: Jeff DePolo [EMAIL PROTECTED]
Date: 2007/08/27 Mon PM 05:11:42 CDT
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Duplexers
As a side note for this discussion, I think Jeff's doing a
great job
It doesn t matter where the min and max are on the line. The
same amount
of reflected power will be seen at any point. Reflected
power does NOT get
back into the transmitter. It gets re-reflected back towards
the antenna
when it reaches the transmitter circuits.
I don't buy into
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Tuesday, August 28, 2007 10:54 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Duplexers
At 8/27/2007 20:52, you wrote
@yahoogroups.com
Subject: Re: RE: [Repeater-Builder] Duplexers
I think he quote needs little correction...âWhen you are using a VSWR
meter you are measuring voltageS, not just one voltage, hi.
You are measuring voltage ratios.
The SWR reading due to losses changes when one moves closer
, but
not sure.
73, ron, n9ee/r
From: Gary Schafer [EMAIL PROTECTED]
Date: 2007/08/27 Mon PM 10:52:11 CDT
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Duplexers
Â
Â
From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of
Jesse
If your coax is the same impedance as your transmitter, but
different than your load, can it still be a transformer
though?
It will ALWAYS act as a transformer when the cable's Z does not match the
LOAD Z. The SOURCE device (transmitter) plays NO part in the transformation
that happens.
Jeff DePolo wrote:
NO. VSWR on a transmission line doesn't directly manifest as heat in a
transmitter. The whole notion of high VSWR creating heat in a transmitter
is likely based on a drop in efficiency in SOME transmitters when they are
not properly matched to the feedline.
Or worse, a
At 8/27/2007 20:52, you wrote:
Yes your right VSWR is the ratio between Vmax and Vmin, node and anodes,
of the interference pattern caused by standing waves. Even still there is
a point where the voltage is at a minimum on the line. What happens if
that point is at the transmitters output...
12:30 AM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Duplexers
When you put the Bird between the TX and the duplexer, you
have changed the
length of the jumper cable, which upset the tuning.
Adding a wattmeter or any other length of cable between the transmitter
:* RE: [Repeater-Builder] Duplexers
When you put the Bird between the TX and the duplexer, you
have changed the
length of the jumper cable, which upset the tuning.
Adding a wattmeter or any other length of cable between the transmitter
and
the duplexer Tx input port has no effect
One can also use 1/4- and 1/2- λ stubs of coaxial cable of the same
impedance as matching networks in conjunction with a Tee connector.
Shorting or Opening the end of the matching stub also makes a
difference, based upon the length being employed.
I believe that VSWR is *one* reason that cabling
Sent: Monday, August 27, 2007 12:48 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Duplexers
The length of coax doesn't effect impedance. Trimming the coax effects what
is read on the VSWR meter because what is actually happening is that there
is an interference pattern
Subject: Re: [Repeater-Builder] Duplexers
The length of coax doesn't effect impedance. Trimming the coax effects what
is read on the VSWR meter because what is actually happening is that there
is an interference pattern created when you have a mismatch on the end of
feedline. This pattern
The length of coax doesn't effect impedance.
That statement is misleading, if not totally wrong. If there is anything
other than a perfect match at the load (in other words, if the VSWR on the
line is not a perfect 1:1), the coax behaves as a transformer. The
resulting Z, as measured at the
I have heard this point argued for years. Does trimming the
coax affect the SWR?
The answer is NO!!
If the length of coax has an affect on
impedance, then how could it not affect power out?
Changing the length of the line changes IMPEDANCE at the source end
(assuming the VSWR isn't
As a side note for this discussion, I think Jeff's doing a great job of
explaining how transmission line theory works...
For those that want to dive in a lot further (e.g. Do the math), the
ARRL Antenna Book has a whole section dedicated to this topic, and it's
written well enough that a
As a side note for this discussion, I think Jeff's doing a
great job of
explaining how transmission line theory works...
I try...
For those that want to dive in a lot further (e.g. Do the math), the
ARRL Antenna Book has a whole section dedicated to this
topic, and it's
written well
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Duplexers
The length of coax doesn't effect impedance. Trimming the coax effects what
is read on the VSWR meter because what is actually happening is that there
is an interference pattern created when you have a mismatch
Lloyd
*Sent:* Monday, August 27, 2007 11:48 AM
*To:* Repeater-Builder@yahoogroups.com
*Subject:* Re: [Repeater-Builder] Duplexers
The length of coax doesn't effect impedance. Trimming the coax effects
what is read on the VSWR meter because what is actually happening
_
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jesse Lloyd
Sent: Monday, August 27, 2007 9:39 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Duplexers
If your coax is the same impedance as your transmitter, but different
Ya you should be able to trim your coax so the transmitter
sees 50 ohms, which should be every 1/2 wave. All this
does it protect the transmitter, the standing waves are still
there, they just gets dissipated/radiated by the coax.
No, no, no, no, no (thumping head on desk).
If the VSWR
Jeff you have just made two statements that are the
exect opposit of each other. If changing the length
of cable makes a differance, then the swr as seen by
the transmitter must change.
Re-read what I said. Changing the cable length changes the *Z*, but it
doesn't change the *VSWR*. As you
--- Jeff DePolo [EMAIL PROTECTED] wrote:
When you put the Bird between the TX and the
duplexer, you
have changed the
length of the jumper cable, which upset the
tuning.
Adding a wattmeter or any other length of cable
between the transmitter and
the duplexer Tx input port has no
Ya you should be able to trim your coax so the transmitter sees 50 ohms,
which should be every 1/2 wave. All this does it protect the transmitter,
the standing waves are still there, they just gets dissipated/radiated by
the coax.
Also with cans usually, if I have enough time on my hands, I tune
Generally the duplexer only makes a slight contribution to the reflected
power. How doe the reflected power between the transmitter and antenna,
without the duplexer in line look? Steve NU5D
dallasreact112 wrote:
Anyone one know what to expect SWR wise with a duplexer?
I have a DB products 2
If the duplexer is correctly tuned, there will be NO measurable SWR into it. If
you have 25/60 watts, it is way off frequency.
- Original Message -
From: dallasreact112
To: Repeater-Builder@yahoogroups.com
Sent: Friday, August 24, 2007 7:16 PM
Subject: [Repeater-Builder]
From the Dup. to the Ant. is ok. But the Dup. is out of tune or no good. Might
even be a bad jumper on the Dup.
dallasreact112 [EMAIL PROTECTED] wrote: Anyone one know what to expect SWR
wise with a duplexer?
I have a DB products 2 meter duplexer on an amateur repeater.
Measuring with a Bird
Bernie,
A typical VSWR for a duplexer would be 1.5:1 or less, more like less. Will not
be 1:1 most times, but low. A lot lower than your 65/25W which is more like a
4.5:1 VSWR.
Really sounds as the duplexer is out of tune or has an internal problem.
Wonder if you tuned these from another
Bernie,
When you put the Bird between the TX and the duplexer, you have changed the
length of the jumper cable, which upset the tuning. But, really, you need
not worry about what the SWR is, if the forward power to the antenna is
appropriate.
Let's say you have a 4-can duplexer, which might
--- Eric Lemmon [EMAIL PROTECTED] wrote:
Bernie,
When you put the Bird between the TX and the
duplexer, you have changed the
length of the jumper cable, which upset the tuning.
But, really, you need
not worry about what the SWR is, if the forward
power to the antenna is
appropriate.
-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo
Sent: Friday, August 24, 2007 9:30 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Duplexers
When you put the Bird between the TX and the duplexer, you
have changed the
length
Sent: Monday, March 15, 2004 2:42 PM
Subject: RE: [Repeater-Builder] duplexers
I have it on good advice from Lloyd Alcorn at Wacom Products (RIP Wacom)
that Black Magic is involved.
Steve
In a nutshell, the cavities are either 1/4 or 3/4 wavelength with
coupling loops oriented for a particular
Best bet is to pick up a used can and duplicate it times the number you
need. After you've done that and poured tons of hours into your project, you
decide whether you want to document in detail and share the info with the
rest of the world.
Chuck
WB2EDV
- Original Message -
From:
This site explains some of the basics:
http://www.xs4all.nl/~pa0nhc/repeater/duplexfilter/English/duplexfilter.htm
Here are some plans:
http://www.vacsew.com/435/dup.htm
http://www.dalek.org/srg/cavity.html
http://www.repeater-builder.com/rbtip/2mduplexer.html
Found this site too:
http://www.amalgamate2000.com/radio-hobbies/radio/coaxial_resonators.htm
- Original Message -
From: David Schornak [EMAIL PROTECTED]
To: Repeater-Builder@yahoogroups.com
Sent: Monday, March 15, 2004 4:25 PM
Subject: [Repeater-Builder] duplexers
has anyone or does
I suspect when you add the coupling loop length that the interstage cables
will be on the order of 3/4 wave length, or around 10 or so.
I ran into the 3/4 wavelength business taking some 10 Sinclair VHF
cavities, and building a 5 channel UHF combiner with cavities and dual
junction isolators.
Steve I am beginning to believe that with as much info as I have found.
I have it on good advice from Lloyd Alcorn at Wacom Products (RIP Wacom)
that Black Magic is involved.
Steve
In a nutshell, the cavities are either 1/4 or 3/4 wavelength with
coupling loops oriented for a particular
I have it on good advice from Lloyd Alcorn at Wacom Products (RIP Wacom)
that Black Magic is involved.
Steve
In a nutshell, the cavities are either 1/4 or 3/4 wavelength with
coupling loops oriented for a particular degree of coupling, and also
the length affects coupling. Some cavities use 2
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