RG-8 is not good for duplex. The braid will make TX noise and get into the
receiver. Cheap antennas can make the same problem. Test into a dummy load
right at the duplexer. If no noise then you know it's the feed line and/or
antenna.
6.5 inch dia cans are big ones so you should have plenty of
Hi
have you put a spectrum analyser on the rx port and fed, from a signal
generator, the tx freq into the aerial input making sure that the tx port
is terminated at 50 ohms. What freqs, what split. You need to know
just what level is getting to the rx port, it has to be around 70dB
rejection or
and got 80dB and it worked
Steve
- Original Message -
From: Tim Sawyer
To: Repeater-Builder@yahoogroups.com
Sent: Friday, May 21, 2010 3:47 PM
Subject: Re: [Repeater-Builder] Duplexer on the cheap worries
RG-8 is not good for duplex. The braid will make TX noise and get
PM
*Subject:* Re: [Repeater-Builder] Duplexer on the cheap worries
RG-8 is not good for duplex. The braid will make TX noise and get into the
receiver. Cheap antennas can make the same problem. Test into a dummy load
right at the duplexer. If no noise then you know it's the feed line
Yes you do need to use good coax and decent connectors
73
Steve
- Original Message -
From: Tim Sawyer
To: Repeater-Builder@yahoogroups.com
Sent: Friday, May 21, 2010 4:17 PM
Subject: Re: [Repeater-Builder] Duplexer on the cheap worries
Yep, low isolation in the duplexer
On 5/21/2010 10:28 AM, kc0mlt wrote:
Hello all.
I am trying to figure out if the duplexer we have put together is up
to the task or not. Here is the situation. We have four cavities 6.5
dia. one is a vari-notch the others are simple reject cans. Two
rejects are on the TX side and one reject
-62 does seem a tad high. Describe the duplexer...
On Wed, May 19, 2010 at 6:29 PM, Atlantis atlant...@gmx.ch wrote:
Hi
In the attached picture you see the notch of the 70cm duplexer I built
according to W4NFR's description in QEX, those who can't receive attachments
find it here:
You are seeing the noise floor of the spectrum analyzer
Either increase the generator strength or decrease the REF level, (Try
-40dBm)
On Wed, May 19, 2010 at 3:49 PM, Larry Horlick llhorl...@gmail.com wrote:
-62 does seem a tad high. Describe the duplexer...
On Wed, May 19, 2010 at 6:29
Narrow the resolution bandwidth and slow the sweep to remain within the
units calibration requirements. Seems you are simply seeing the noise
of the spectrum analyzer or network analyzer being many dBs below the
reference line. If the unit can tolerate it, increase the RF input
level to
At 5/19/2010 15:29, you wrote:
Hi
In the attached picture you see the notch of the 70cm duplexer I built
according to W4NFR's description in QEX, those who can't receive
attachments find it here:
http://conturafm.mine.nu/_fh/438.95_notch.bmphttp://conturafm.mine.nu/_fh/438.95_notch.bmp
The
Hi,
It looks like the filter over couple,under couple between each other.
If the case caused by the interlink coaxial cable .
Please try difference cable length .
e.g + or - 0.5 cm in step... etc
And then return the filters .
Good luck 73s
de VR2XVD
On Thu, May 20, 2010 at 6:57 AM, Curt
http://www.surplussales.com/Variables/ButterflyCapacitors/ButCap1.html
(CAV) 167-205-71 sounds close to it.
On Thu, Apr 15, 2010 at 11:59 AM, Gary Hoff k7ney...@q.com wrote:
I have an old Phelps Dodge VHF Duplexer that has a
frozen air variable. The Duplexer is a part# 499-509 and
covers
I already found that one, thanks anyway, the 167-205 is close but not enough
plates, mine has 6 rotor and 6 stator. Physical size is right though,
maybe this
cap was made by Johnson also since the numbers are close.
Gary
On 4/15/2010 1:59 PM, DCFluX wrote:
crites wa9...@arrl.net
Subject: Re: [Repeater-Builder] Duplexer vs Split Level Antennas
To: Repeater-Builder@yahoogroups.com
Date: Friday, January 29, 2010, 5:13 AM
Jim
That's a very interesting posting of the repeater(s) you were aware of and
worked reliably
Have chance to install a DB 224 at 450' and another one
anywhere below it. Using LDF6 on both runs. RF solid state
110 watts out. Wanting to know the pros or cons of running
both antenna close together for more height with duplexer or
spacing antennas for isolation without duplexer?
All
I'll chime in.
I would definitely mount the 2nd ant low enough below the 450 ft one to
provide enough vertical separation to run without the duplexers. That way
you always have the option. 60 plus feet on vhf. Somebody can run you the
numbers if you provide station specs.
It's a trade off. DB
One of the best working repeaters I have run across was located on the
outskirts of Ft Worth Texas on a 1000 ft tower. It used a single receive
antenna at 1000 ft into a down converter that output on 10 meters. Several 10
meter receivers were connected to the RG-58 downlead in the radio room
Phil;
Check with KA1RCI, Steve (st...@ka1rci ) He bought a couple of sets of 220 mc.
duplexers from me and retuned them to our band. He has all the equipment.
Clay W 8 J V V
- Original Message
The number TDF6980A is a Motorola number, for a PD5134-18BK duplexer made by
Celwave. Insertion loss is specified as 1.2 dB per side, isolation is 75 dB
minimum, and it can handle 400 watts.
73, Eric Lemmon WB6FLY
-Original Message-
From: Repeater-Builder@yahoogroups.com
I plan on using LMR-400 as I have it readily available - Is this a good
choice?
NO
The answer for whomever asks next week is the same - NO.
@yahoogroups.com
Subject: Re: [Repeater-Builder] Duplexer Cable Length / Recomendations
I plan on using LMR-400 as I have it readily available - Is this a good
choice?
NO
The answer for whomever asks next week is the same - NO.
Yahoo! Groups Links
@yahoogroups.com
Sent: Sun Feb 15 15:52:36 2009
Subject: RE: [Repeater-Builder] Duplexer Cable Length / Recomendations
Well what would be a good choice? Just saying its bad is really useless
information.
Trevor
-Original Message-
From: Repeater-Builder@yahoogroups.com
mailto:Repeater-Builder
...@monkeywireless.net
To: Repeater-Builder@yahoogroups.com
Sent: Sunday, February 15, 2009 4:52 PM
Subject: RE: [Repeater-Builder] Duplexer Cable Length / Recomendations
Well what would be a good choice? Just saying its bad is really useless
information.
Sent: Sunday, February 15, 2009 3:52 PM
Subject: RE: [Repeater-Builder] Duplexer Cable Length / Recomendations
Well what would be a good choice? Just saying its bad is really useless
information.
Trevor
-Original Message-
From: Repeater-Builder@yahoogroups.com
PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Duplexer Cable Length / Recomendations
Take a look at the message archives. You'll see that this same question
comes up VERY regularly, and gets answered VERY regularly.
I'm not trying to be difficult, but a little looking
http://www.repeater-builder.com/antenna/double-shielded-coax.html
- Original Message -
From: Trevor Raty tr...@monkeywireless.net
To: Repeater-Builder@yahoogroups.com
Sent: Sunday, February 15, 2009 5:32 PM
Subject: RE: [Repeater-Builder] Duplexer Cable Length / Recomendations
I have
An archive search for LMR-400 on this Yahoo group came up with over 290
posts on the subject.
Chuck
- Original Message -
From: Trevor Raty tr...@monkeywireless.net
To: Repeater-Builder@yahoogroups.com
Sent: Sunday, February 15, 2009 5:32 PM
Subject: RE: [Repeater-Builder] Duplexer
Subject: RE: [Repeater-Builder] Duplexer Cable Length / Recomendations
I have been digging through archives and the site for the last week and
haven't found anything. Thank-you for the information.
-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil
Trevor,
A few comments, as the List Owner.
First, you didn't ask what is/was a good choice - you asked if LMR-400
is a good choice, and the answer is NO; so don't get an attitude because
you think someone should have expounded upon a yes/no question.
LMR type cable is not a good choice in
To:
mailto:Repeater-Builder%40yahoogroups.comRepeater-Builder@yahoogroups.com
Sent: Sunday, February 15, 2009 5:32 PM
Subject: RE: [Repeater-Builder] Duplexer Cable Length / Recomendations
I have been digging through archives and the site for the last week and
haven't found anything. Thank-you
Lou,
I doubt that you can use this band-reject (notch) duplexer at 70 cm without
factory rework. The coupling loops were designed and positioned
specifically for the 450-512 MHz band, and they are not externally
adjustable. The lengths of the jumper cables are unique to the band for
which the
At 2/10/2009 17:31, you wrote:
Lou,
I doubt that you can use this band-reject (notch) duplexer at 70 cm without
factory rework. The coupling loops were designed and positioned
specifically for the 450-512 MHz band, and they are not externally
adjustable. The lengths of the jumper cables are
If I remember right, it's four notches and two passes. The normal
configuration was one pass and one notch on the Rx leg, and two pass and two
notch on the Tx leg.
--- Jeff WN3A
-Original Message-
From: Repeater-Builder@yahoogroups.com
FROM THE LOOKS OF SIMILAR PHELPS DODGE MODELS, BAND REJECT ONLY.
DAVID N1ROA
From: Ron Wright mcc...@verizon.net
To: Repeater-Builder@yahoogroups.com
Sent: Tuesday, February 3, 2009 12:29:14 PM
Subject: [Repeater-Builder] duplexer
hi all,
I have a Phelps
_
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jeff DePolo
Sent: Tuesday, February 03, 2009 9:31 AM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] duplexer
If I remember right, it's four notches and two passes. The normal
You can't beat TX-RX systems. www.txrx.com
Custom made just for you .
Robert / KD4PBC
-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Don Spivey
Sent: Friday, August 08, 2008 8:27 AM
To: Repeater-Builder@yahoogroups.com
Subject:
Don, I have 2 Wacom duplexers used but in excellent shape. One is a WP-639 (2
meter) and a WP-652A (220). Also have 3 TX-RX new in original boxes models
28-37-11E (6 can 2meter), 28-52-02A (220) and a 28-52-04319-A (220) and 1 new
220 pass cavity 11-54-01. I will tune to your frequency. If
Don,
My personal experience with Jeff DePolo (a member here on the list) has been
very good.
He built a duplexer/isolator system for me for a 900 repeater I put together
about a year or so ago - and it was a VERY nice system. Prices very
reasonable. So I would heartily recommend him. At least
Don
I have purchased several pass-notch and bandpass duplexers from Telewave,
along with several dual bandpass cavity filters, in both VHF and UHF-
including Ham band units. Telewave offers a 25% discount from the published
price for Amateur users. I double-check the tuning with my network
: RE: [Repeater-Builder] Duplexer Source.
Don
I have purchased several pass-notch and bandpass duplexers from Telewave,
along with several dual bandpass cavity filters, in both VHF and UHF-
including Ham band units. Telewave offers a 25% discount from the published
price for Amateur users. I
The length is fine for 6-meter cans. Diameter could be larger, I suppose,
but worth a try. Worst case you'll need to use 6 cans. But you might get
away with 4 (I'm talking in BP-BR configuration).
Chuck
- Original Message -
From: Glenn Little WB4UIV [EMAIL PROTECTED]
To:
At 08:50 7/27/2008, Glenn Little WB4UIV wrote:
I have some copper pipe that is 6 inches in diameter and about 60
inches long.
Would these work for a 6 meter repeater?
I agree they could be a bit longer (about 38% longer), but this stuff
is over $100 per foot. Better to get one and a half
Hi Michael.
Would Recommend Ron Wright N9EE in Tampa Who owns an 2 meter Repeater in
Tampa(very Knowligable.
Wesley AB8KD
- Original Message -
From: Michael Ryan
To: Repeater-Builder@yahoogroups.com
Sent: Friday, July 25, 2008 3:42 PM
Subject: [Repeater-Builder] Duplexer
: [Repeater-Builder] Duplexer Tuning HELP
Hi Michael.
Would Recommend Ron Wright N9EE in Tampa Who owns an 2 meter Repeater in
Tampa(very Knowligable.
Wesley AB8KD
- Original Message -
From: Michael Ryan
To: Repeater-Builder@yahoogroups.com
mailto:Repeater-Builder%40yahoogroups.com
(It's easier to see this than to describe it in e-mail. Maybe someone
will send some screen-shots of what it looks like someday... I've tried
taking photos of my IFR 1500 with my cheap digital camera (4MP
point-and-shoot Nikon) and it just doesn't look right.
Each message I read makes me
Group,
While looking for something yesterday I found a box that I have not
opened in a few years. Inside is a file marked Duplexers containing
many articles and booklets on the subject. There is also a binder from
TxRx with all sorts of technical information on their products,
including
I think we are making much ado about nothing here. Certainly, for UHF
and VHF duplexers, the lengths of the cables that came with it should be
fine for the ham band as well. At least I've never seen one that it
matters. Now, I suppose moving one that is for 160-175 down to 146,
yeah, you'd
Alexandre Souza wrote:
For RG214 which has a velocity factor of 0.66 at 147 the cables would be
about 13.25 inches. Now the type of connectors can influence this in that
the connector type might lengthen the cable. N-connectors protude beyond
the cable where PL259s do not.
Now
Shanon KA8SPW wrote:
Here is an idea.
How about those of us who have repeaters with duplexers take
measurements and post them.
1. I'm not disconnecting all my working system's cables to measure
things. Messing with cables and connectors is a sure-fire way to
introduce new problems.
, 2008 3:56 PM
Subject: Re: [Repeater-Builder] Duplexer cables
Alexandre Souza wrote:
For RG214 which has a velocity factor of 0.66 at 147 the cables would be
about 13.25 inches. Now the type of connectors can influence this in that
the connector type might lengthen the cable. N
Sent: Thursday, July 24, 2008 4:10 PM
Subject: Re: [Repeater-Builder] Duplexer cables - Data Base Idea
Shanon KA8SPW wrote:
Here is an idea.
How about those of us who have repeaters with duplexers take
measurements and post them.
1. I'm not disconnecting all my working
Mike Dietrich wrote:
What is the best way(hookup) to test cables like these to see if they
are resonant on a particular freq?
With or without the coupling loops attached etc. for duplexers say
The technique I've seen used and participated in is to test the entire
section of the duplexer as a
changes, but will try that
and see how much it changes.
Thanks,
Mike
- Original Message -
From: Nate Duehr
To: Repeater-Builder@yahoogroups.com
Sent: Thursday, July 24, 2008 7:07 PM
Subject: Re: [Repeater-Builder] Duplexer cables
Mike Dietrich wrote:
What is the best way
Mike Dietrich wrote:
I asked that question for most of the people on the list that have not
tuned a duplexer themselves or don't have the proper test equip to do it
right and have done it with 2 radios or signal gen and a receiver.
These work but it is so much easier with a tracking
Here is an idea.
How about those of us who have repeaters with duplexers take
measurements and post them. This would need to include ALL the
information or as much as possible. Even the frequency in use, length
and brand would help. The best information would be from duplexers that
were
David,
My understanding is the cables between cans is 1/4 wavelength electrically.
For RG214 which has a velocity factor of 0.66 at 147 the cables would be about
13.25 inches. Now the type of connectors can influence this in that the
connector type might lengthen the cable. N-connectors
For RG214 which has a velocity factor of 0.66 at 147 the cables would be
about 13.25 inches. Now the type of connectors can influence this in that
the connector type might lengthen the cable. N-connectors protude beyond
the cable where PL259s do not.
Now there is an intersting
Sent: Saturday, July 19, 2008 12:27 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Duplexer Tuning / Desense
Mike, that RG-8X is the first thing I would get rid of. It is typically
only %95 covered in shield braid, and that is a path for a lot of leakage.
The rule
Get rid of the rg-8x and get some double shielded cable. Even a couple of feet
of single shielded cable can cause much desense.
Depending on the sensitivity and power level, a 4 cavity duplexer is just
barley enough for a 600 KHz spacing on 2 meters.
--- On Fri, 7/18/08, Mike Besemer
Thanks to all who responded so far. I spent a couple hours at the site
today doing prep work and as soon as I got home I spent a few minutes
working on the repeater. I found that there was JUST enough room for a UHF
to N adapter and an N elbow in back of the transmitter, which allowed me to
a good job,
so I'm pretty confident these will be alright, once I learn what I'm doing!
Mike
WM4B
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Ralph Mowery
Sent: Saturday, July 19, 2008 10:05 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater
[EMAIL PROTECTED] wrote:
From: Ralph Mowery [EMAIL PROTECTED]
Subject: Re: [Repeater-Builder] Duplexer Tuning / Desense
To: Repeater-Builder@yahoogroups.com
Date: Saturday, July 19, 2008, 9:05 AM
Depending on the sensitivity and power level, a 4 cavity duplexer is just
barley enough for a 600 KHz
Mike, that RG-8X is the first thing I would get rid of. It is typically only
%95 covered in shield braid, and that is a path for a lot of leakage.
The rule of thumb in the whole repeater cabinet is double shielded RG-214 or
RG-142. That takes away a lot of paths for leakage to bypass your
Darrel,
I've not used a scope for tuning duplexers, but know it can work if use the
input level settings and sig gen level output adjustment. The scope is a
device that can measure amplitude.
Proper termination using things like dummy loads and other terminator would be
required due to the
Hi Darrell,
I never done it, and will like to try it. Can you send me a sketch of the
setup, with a brief explanation of your procedure for accomplishing this?
Will appreciate it very much Darrell.
v44kai.Joel.
- Original Message -
From: jistabout [EMAIL PROTECTED]
To:
: [Repeater-Builder] Duplexer tuning with an Oscilloscope
Hi Darrell,
I never done it, and will like to try it. Can you send me a sketch of the
setup, with a brief explanation of your procedure for accomplishing this?
Will appreciate it very much Darrell.
v44kai.Joel
If the load, antenna, were not 50 Ohm resistive and connecting it caused
the duplexer to become untuned then tuning it with the load would make
very much RF since. Tuning it with a dummy load is only done to insure
a good load, but is not tuning for the real situation.
However, in this
if you are using the same wires from the cans to the tees, about all I
can suggest is maybe retuning the duplexers while connected to the antenna.
Also check and recheck each section of cable between the cans, etc...
Not saying this will be the answer, but at this point you seem to have
At 5/9/2008 13:40, you wrote:
if you are using the same wires from the cans to the tees, about all I
can suggest is maybe retuning the duplexers while connected to the antenna.
If there is 0 dB of desense looking into a dummy load 30 dB into an
antenna, duplexer retuning is not the answer.
On May 9, 2008, at 2:54 PM, [EMAIL PROTECTED] wrote:
At 5/9/2008 13:40, you wrote:
if you are using the same wires from the cans to the tees, about
all I
can suggest is maybe retuning the duplexers while connected to the
antenna.
If there is 0 dB of desense looking into a dummy load
Search for a 600kHz switch mode power supply opperating in the
vicinity of your repeater. These are usually found in boats as battery
chargers. They are also starting to appear in wall warts on stuff like
answering machines and routers.
I had on which would mix with the TX and desence on both
blisswheeler wrote:
I've run into a problem that baffles me.
I have two sets of WACOM WP-641 4 can Duplexers. They have been tuned
to TX on 146.96 mHz and RX on 146.36. One set was tuned in a
Professional Lab, the other I tuned myself. They tune very well with
excellent rejection ~90db.
At 5/8/2008 11:26, you wrote:
Search for a 600kHz switch mode power supply opperating in the
vicinity of your repeater.
...or a video camera, TV or Dish Network/DirecTV dish. I've had mixes
occur in all three.
Bob NO6B
On Feb 20, 2008, at 10:10 AM, ldgelectronics wrote:
Hi,
I've got two more of the DB duplexer cabinets (no duplexers inside)
that need a good home. They are 20w x 19d x 34h. Normally, there is a
DB-4060 duplexer in there.
Total cost, including UPS shipping, is $50 for east coast, $75 for
At 12:32 PM 02/09/08, you wrote:
Hi all,
I have a couple of duplexer cabinets if anyone is looking for those. No
duplexer, just the cabinet they go in. Sinclair 202 and DB 4060 types
are avaialble. Contact me off list if interested.
Dwayne Kincaid
WD8OYG
Location?
Mike
Southern Maryland.
At 02:13 AM 2/10/2008, you wrote:
At 12:32 PM 02/09/08, you wrote:
Hi all,
I have a couple of duplexer cabinets if anyone is looking for those. No
duplexer, just the cabinet they go in. Sinclair 202 and DB 4060 types
are avaialble. Contact me off list if interested.
Jack,
Contact Sinclair Tech Support for guidance. Go here:
www.sinctech.com
Some Res-Lok duplexers are problematic when attempting to move them to a new
split, because the coupling between cavities is via a machined slot rather
than an external jumper. Dunno if yours is like that. When you
what kind are you looking for?
thanks John
- Original Message -
From: ldgelectronics
To: Repeater-Builder@yahoogroups.com
Sent: Thursday, December 06, 2007 9:07 PM
Subject: [Repeater-Builder] Duplexer
Darn, I didn't know that was you I was bidding against for that VHF
John,
If I'm reading this correctly, you're trying to do this all in a trailer -
yes? Since you are operating portable, does your coordinating body have
an Itinerant UHF pair you can use for the repeater? If so, this might
make your situation MUCH easier to engineer.
Mark - N9WYS
OK - let me throw a little more gas on this fire... Just for giggles, I
went to Mouser Electronics, and selected their page for Passive
Components.
http://www.mouser.com/search/Refine.aspx?Ne=254016+1447464N=1323038%2025427
1Ns=P_SFieldRefType=Header
Guess what?? Capacitors are listed
.
_
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of n9wys
Sent: Wednesday, October 24, 2007 11:03 AM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] duplexer isolation and reciever noise budget
John,
If I'm reading
.
Interesting approach.
73, ron, n9ee/r
From: n9wys [EMAIL PROTECTED]
Date: 2007/10/24 Wed AM 11:15:25 CDT
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] duplexer isolation and reciever noise budget
OK - let me throw a little more gas on this fire... Just
backyard pair (once I find out what it is !!)
_
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Joe Montierth
Sent: Friday, October 05, 2007 7:43 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] duplexer isolation and receiver noise
before hitting the cavities
for the 3 recievers
Bring on the other ideas :-)
_
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Eric Lemmon
Sent: Thursday, October 04, 2007 9:50 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder
:-)
_
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Eric Lemmon
Sent: Thursday, October 04, 2007 9:50 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] duplexer isolation and receiver noise
budget
John,
It might
You won't do it with band pass cavities unless you crank the insertion loss
way up. What would work for the two simplex radios with the 660 Khz spacing
is a pass/notch duplexer. It needs to work just like a regular repeater
duplexer with the same kind of isolation from one radio to the other. You
If this is going mobile on a 40 ft crank up I would sure consider
separate antennas is possible. You can get into some real challenges,
and even with separate antennas you will still have issues to consider.
Also you will have a much better idea when the repeater pair is
determined. Steve NU5D
John,
It might be instructive to let the big-name combiner companies make
proposals to solve your dilemma. Send a request for proposals to Telewave,
TX-RX, and RFS/Celwave to see what they would recommend. Don't try to
design it for them; just give them the frequencies, power outputs, receive
Dan,
My guess is that the duplexer tuning was disturbed when you took it apart.
Most likely, the notch for the RX frequency on the TX side is not exactly
tuned to notch out the TX carrier, leading to major desense of the RX.
Unless you have a network analyzer, or a good spectrum analyzer with
Well now---
I've got two 2 meter Phelps-Dodge duplexers that tune beautifully but are
unusable in duplex service do to receiver desense-internal microarcs
between failed silver plated movable and fixed parts of the center element in a
couple of the cavities of each.
Also, some time ago,
at what one wants...freq spacing and the amount of
notch/filtering and pass attenuation.
73, ron, n9ee/r
From: sms mms [EMAIL PROTECTED]
Date: 2007/08/26 Sun AM 09:00:13 CDT
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] duplexer design
I require the value of insertion loss
-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] duplexer design
I require the value of insertion loss on both frequencies. I have to design
band reject type duplexer,please suggest the design. I will be grateful.
vikash
Ron Wright [EMAIL PROTECTED] wrote: Sounds
I require the value of insertion loss on both frequencies.
I have to design band reject type duplexer,please suggest the design.
I will be grateful.
vikash
Ron Wright [EMAIL PROTECTED] wrote:
Sounds as if you are designing a duplexer with coils and caps. It is
often this approach
Sounds as if you are designing a duplexer with coils and caps. It is often
this approach will not have a high enough Q to have a notch at one freq and at
the same time pass freq with low enough insertion loss.
Normally duplexers use cavities which are made from coax made from heavy metal
On Jun 2, 2007, at 5:43 PM, Gary Schafer wrote:
Mostly correct but an isolator could be thought of as a device to
clean up
a transmitter too. An isolator provides a flat 50 ohm load to the
transmitter no matter what kind of load the antenna or duplexer may
present.
Sometimes
On May 31, 2007, at 7:13 PM, Bob M. wrote:
The duplexers on UHF are typically set for 5 MHz
spacing, although closer spacing is often available.
The purpose of the duplexer is to allow the receiver
and transmitter to share one antenna. They offer very
little filtering of other nearby
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
[EMAIL PROTECTED] On Behalf Of Nate Duehr
Sent: Saturday, June 02, 2007 3:03 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Duplexer tuning - sanity check
On May 31, 2007, at 7
2d question only.
If you have adjacent channel repeaters close to you, something is wrong
with your frequency coordinators. 2 mtrs has enough trouble with 600
khz spacing, to expect 16 khz is ludicrous. The only solution for
adjacent channel repeaters is distance.
--
73,
Larry, W1HJF
At 5/31/2007 18:16, you wrote:
2d question only.
If you have adjacent channel repeaters close to you, something is wrong
with your frequency coordinators.
Depends on what you call close. We've successfully coordinated/operated
2 repeaters 15 kHz only a few miles apart with no interference to
Some duplexers pass the desired frequency, lose
something on each side, but then pass stuff from DC to
over 1GHz as if it's not even in the circuit. My
Celwave 526 operates that way. The bandpass tuning is
rather broad and serves to match the impedance more
than effect the bandpass of the signal.
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