Re: [Repeater-Builder] GMRS Repeater ANT (UHF)

[Robert Boles]

Thanks to everybody I wll go with the duplexers

--- On Sat, 5/29/10, ZPO  wrote:


From: ZPO 
Subject: Re: [Repeater-Builder] GMRS Repeater ANT (UHF)
To: Repeater-Builder@yahoogroups.com
Date: Saturday, May 29, 2010, 10:22 PM


  



I trust Eric's experience and software more than my SWAG any day.

Given the prices for mobile notch duplexers, I don't see a reason not
to use one.

73-N5VFF/Brian

On Sat, May 29, 2010 at 10:05 PM, Eric Lemmon  wrote:
> Robert,
>
> I put 50 watts and 0.3 uV at GMRS frequencies into my Comm Shop for Windows
> program, and it suggests that 73 dB of isolation is needed to avoid desense.
> This amount of isolation can be achieved with about 39 feet of vertical
> antenna separation or about 1020 feet of horizontal separation.  Since you
> can use a typical mobile notch duplexer for this application, it hardly
> makes any sense to erect a tower so that you can run two antennas.  Even so,
> you should elevate your antenna as much as possible if you expect to get any
> decent range.
>
> 73, Eric Lemmon WB6FLY
>
>
> -Original Message-
> From: Repeater-Builder@yahoogroups.com
> [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Robert Boles
> Sent: Saturday, May 29, 2010 9:46 PM
> To: Repeater-Builder@yahoogroups.com
> Subject: Re: [Repeater-Builder] GMRS Repeater ANT (UHF)
>
>
>
> it is 50 watts out,   its at my home , and no other repeater with miles  of
> this location and i have the ant and hard line
>
> --- On Sat, 5/29/10, ZPO  wrote:
>
>
>
>        From: ZPO 
>        Subject: Re: [Repeater-Builder] GMRS Repeater ANT (UHF)
>        To: Repeater-Builder@yahoogroups.com
>        Date: Saturday, May 29, 2010, 9:18 PM
>
>
>
>        Depends on the power level. What type of site will the repeater be
>        located at? A duplexer is probably going to be cheaper than a 2nd
>        antenna and 2nd run of superflex.
>
>        73-N5VFF/Brian
>
>        On Sat, May 29, 2010 at 7:21 AM, Robert   > wrote:
>        > how much space is needed between the TX and RX ant and which type
> of cable to use ?
>        >
>        >
>        >
>        > 
>        >
>        >
>        >
>        > Yahoo! Groups Links
>        >
>        >
>        >
>        >
>
>
>
>
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>
>

[Repeater-Builder] Legal radios for a repeater

[terry dalpoas]

I was asked the other day by a friend if you could use an older mobile (Micor, 
Mitrek, Mastr II and Exec) that has been duplexed for a repeater in GMRS, 
public safety, etc.  I told them that I was pretty sure it was legal since the 
transmitters are FCC type accepted and as long as they transmit a clean signal. 
 Was I correct on this?

Re: [Repeater-Builder] GMRS Repeater ANT (UHF)

[ZPO]

I trust Eric's experience and software more than my SWAG any day.

Given the prices for mobile notch duplexers, I don't see a reason not
to use one.

73-N5VFF/Brian

On Sat, May 29, 2010 at 10:05 PM, Eric Lemmon  wrote:
> Robert,
>
> I put 50 watts and 0.3 uV at GMRS frequencies into my Comm Shop for Windows
> program, and it suggests that 73 dB of isolation is needed to avoid desense.
> This amount of isolation can be achieved with about 39 feet of vertical
> antenna separation or about 1020 feet of horizontal separation.  Since you
> can use a typical mobile notch duplexer for this application, it hardly
> makes any sense to erect a tower so that you can run two antennas.  Even so,
> you should elevate your antenna as much as possible if you expect to get any
> decent range.
>
> 73, Eric Lemmon WB6FLY
>
>
> -Original Message-
> From: Repeater-Builder@yahoogroups.com
> [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Robert Boles
> Sent: Saturday, May 29, 2010 9:46 PM
> To: Repeater-Builder@yahoogroups.com
> Subject: Re: [Repeater-Builder] GMRS Repeater ANT (UHF)
>
>
>
> it is 50 watts out,   its at my home , and no other repeater with miles  of
> this location and i have the ant and hard line
>
> --- On Sat, 5/29/10, ZPO  wrote:
>
>
>
>        From: ZPO 
>        Subject: Re: [Repeater-Builder] GMRS Repeater ANT (UHF)
>        To: Repeater-Builder@yahoogroups.com
>        Date: Saturday, May 29, 2010, 9:18 PM
>
>
>
>        Depends on the power level. What type of site will the repeater be
>        located at? A duplexer is probably going to be cheaper than a 2nd
>        antenna and 2nd run of superflex.
>
>        73-N5VFF/Brian
>
>        On Sat, May 29, 2010 at 7:21 AM, Robert   > wrote:
>        > how much space is needed between the TX and RX ant and which type
> of cable to use ?
>        >
>        >
>        >
>        > 
>        >
>        >
>        >
>        > Yahoo! Groups Links
>        >
>        >
>        >
>        >
>
>
>
>
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>
>

RE: [Repeater-Builder] GMRS Repeater ANT (UHF)

[Eric Lemmon]

Robert,

I put 50 watts and 0.3 uV at GMRS frequencies into my Comm Shop for Windows
program, and it suggests that 73 dB of isolation is needed to avoid desense.
This amount of isolation can be achieved with about 39 feet of vertical
antenna separation or about 1020 feet of horizontal separation.  Since you
can use a typical mobile notch duplexer for this application, it hardly
makes any sense to erect a tower so that you can run two antennas.  Even so,
you should elevate your antenna as much as possible if you expect to get any
decent range.

73, Eric Lemmon WB6FLY
 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Robert Boles
Sent: Saturday, May 29, 2010 9:46 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] GMRS Repeater ANT (UHF)

  

it is 50 watts out,   its at my home , and no other repeater with miles  of
this location and i have the ant and hard line 

--- On Sat, 5/29/10, ZPO  wrote:



From: ZPO 
Subject: Re: [Repeater-Builder] GMRS Repeater ANT (UHF)
To: Repeater-Builder@yahoogroups.com
Date: Saturday, May 29, 2010, 9:18 PM


  
Depends on the power level. What type of site will the repeater be
located at? A duplexer is probably going to be cheaper than a 2nd
antenna and 2nd run of superflex.

73-N5VFF/Brian

On Sat, May 29, 2010 at 7:21 AM, Robert http://us.mc802.mail.yahoo.com/mc/compose?to=bobeic2%40yahoo.com> > wrote:
> how much space is needed between the TX and RX ant and which type
of cable to use ?
>
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>
>

Re: [Repeater-Builder] GMRS Repeater ANT (UHF)

[ZPO]

Here is a link to a page on the RB web site -
http://www.repeater-builder.com/antenna/separation.html

Per the graphs - 25-30ft of vertical separation between antenna centers
should get you approximately 65dB of isolation.  800-900ft of horizontal
separation would be required to get the same isolation.

73-N5VFF/Brian

On Sat, May 29, 2010 at 9:45 PM, Robert Boles  wrote:

>
>
> it is 50 watts out,   its at my home , and no other repeater with miles  of
> this location and i have the ant and hard line
>
> --- On *Sat, 5/29/10, ZPO * wrote:
>
>
> From: ZPO 
> Subject: Re: [Repeater-Builder] GMRS Repeater ANT (UHF)
> To: Repeater-Builder@yahoogroups.com
> Date: Saturday, May 29, 2010, 9:18 PM
>
>
>
> Depends on the power level. What type of site will the repeater be
> located at? A duplexer is probably going to be cheaper than a 2nd
> antenna and 2nd run of superflex.
>
> 73-N5VFF/Brian
>
> On Sat, May 29, 2010 at 7:21 AM, Robert 
> http://us.mc802.mail.yahoo.com/mc/compose?to=bobeic2%40yahoo.com>>
> wrote:
> > how much space is needed between the TX and RX ant and which type of
> cable to use ?
> >
> >
> >
> > 
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
>
>
>
> 

Re: [Repeater-Builder] GMRS Repeater ANT (UHF)

[Robert Boles]

it is 50 watts out,   its at my home , and no other repeater with miles  of 
this location and i have the ant and hard line 

--- On Sat, 5/29/10, ZPO  wrote:


From: ZPO 
Subject: Re: [Repeater-Builder] GMRS Repeater ANT (UHF)
To: Repeater-Builder@yahoogroups.com
Date: Saturday, May 29, 2010, 9:18 PM


  



Depends on the power level. What type of site will the repeater be
located at? A duplexer is probably going to be cheaper than a 2nd
antenna and 2nd run of superflex.

73-N5VFF/Brian

On Sat, May 29, 2010 at 7:21 AM, Robert  wrote:
> how much space is needed between the TX and RX ant and which type of cable to 
> use ?
>
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>
>

Re: [Repeater-Builder] Retuning a UHF Motorola Micor without a deviation meter or signal generator ?

[Mike Morris]

At 08:31 PM 05/29/10, you wrote:

>I will apologize in advance, as I am an extreme newby in the world 
>of repeater building / operation.

No apology needed.  We've all had to start somewhere.

>We've been donated a UHF Motorola Micor system.  The system has 
>documentation that shows that it once ran at 78W out in commercial service.

Is that on the "Power Set" sticker, or do you actually
have a station logbook? (very rare).

>Being an amateur radio operator without a commercial or well-stocked 
>test bench, I do not have ready access to a deviation meter or 
>signal generator.

Nobody does when they get started.  But both can be "faked".

>Is it possible to retune these things down to the amateur radio 440 
>band without these two pieces of test equipment?

Yes, but it is more difficult without them.

Where is the station now (i.e. frequency) ?

Where are you going?   (i.e. frequency) ?
Do you have a coordination there?

A peak deviation meter can be faked with a
DC coupled oscilloscope and a discriminator
based receiver,   You offset the transmitter +
and - 5khz and adjust the gain so that the display
shifts + and - 5 lines on the scope face.  Then
you run enough audio into the transmitter to
saturate the audio stages (i.e. force it into limiting)
and set for 4.8 KHz.  Set this way nothing is going
to go beyond that point.  Then you adjust the level
from the repeater controller for a 1:1 repeat gain.
There's more to it than that but that will get you
started.

A signal generator can be faked with a
programmable scanner (you use the local
oscillator / multiplier as an uncalibrated
radiating source).  There was a comment
thread on that topic not long ago, you
might want to check the list archives.

>How likely is it that I will run into significant performance issues 
>without these pieces of equipment?

You might want to say where you are.  This mailing list
has almost 5,000 members worldwide, mostly in the USA,
and we might have someone local to you that would
be willing to "Elmer".

And retuning the station only has to be done once.  When
I was getting started I would take the receiver and transmitter
chassis over to a friends 2-way shop, we'd tune them up,
and I'd take them back home and do the rest of the work
there.

>Thanks!
>
>Brian, WW9A

Your license comes back to Columbus,  Indiana which
is south of Indianapolis.  Is that where you are located?

Mike WA6ILQ

Re: [Repeater-Builder] GMRS Repeater ANT (UHF)

[ZPO]

Depends on the power level.  What type of site will the repeater be
located at?  A duplexer is probably going to be cheaper than a 2nd
antenna and 2nd run of superflex.

73-N5VFF/Brian


On Sat, May 29, 2010 at 7:21 AM, Robert  wrote:
> how much space is needed between the TX and RX ant and which type of cable to 
> use ?
>
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>
>

Re: [Repeater-Builder] Re: Help Needed (Guidance and advice) tuning a DB Products Duplexer

[Tony KT9AC]

All is not lost Josh - I'm running Motorola T1507 which are 4-can 
pass-only cavities on my Micor. Actually pass-only are better for 
commercial sites since they will help keep out a lot of intermod on 
either side of how they are tuned.


Pass-notch on the other hand will pass the tuned frequency, but do a 
poor job of "everything else" rejection (other than the notch of course).




On 05/29/2010 08:27 PM, Josh wrote:


Certainly not what I was expecting... Yeah, I bought one from 'that 
guy'. It's more than an untrained eye - he straight lied to me... said 
'under these caps are where you'll tune the capacitors' - I should 
have popped one off and looked down the hole. Maybe he was clued in, 
maybe he wasnt - either way, that's what I bought. Dangit :P


So if all I have are pass cavities what 'are' they good for ?

Guess I've got to find another dupelxer.

j

--- In Repeater-Builder@yahoogroups.com 
, "Jeff DePolo"  
wrote:

>
> > Ok so here's what I've got (I think)
> >
> > http://www.n2ckh.com/FORSALE/REPEATERS/DUPLEXERS/DB4076/DSC02678.JPG
> >
> > Hamvention special, 4 cavities, appears to be a DB Products
> > 4076 family unit. My bench tools: HP 8924c w/ Spec Analyzer
> > and Tracking Generator.
>
> There was a guy at the Hamvention that had several sets of Decibel
> four-cavity window filters, selling for $50 each, which, to the 
untrained
> eye, would look like an older DB4076. As you said, there would be 
nothing
> in the hole where the capacitor would be in a regular DB4076. In 
essecence,

> what you have are just plain-jane pass cavities.
>
> As a second means of confirming that you do, in fact, have a window 
filter,

> is there an antenna "tee", or are the four cavities cabled together in
> cascade? If the latter, then you probably have a window filter.
>
> And as a third means of confirming, is there is a label on the front? If
> not, was there any signs of a label having once been there? If not, then
> that's yet one more indication that it isn't a DB4076.
>
> Decibel made two varieties of pass cavities used in window filters 
in that
> era. One had adjustable loops (less common), the other had fixed 
loops. If

> your loop connectors have a rectangular chrome plate around them with
> insertion loss calibration marks, you have the less-common 
adjustable ones.

> If you just see four philips-head screws and no chromed plate around the
> connectors, then yours is not adjustable.
>
> If you have the adjustable type, you could probably use them as a 
pass-only
> duplexer, but with mediocre isolation, even with the insertion loss 
cranked
> up higher than you'd like. If you have the non-adjustable ones, they 
have
> very tight coupling, so you're not going to get the isolation you'd 
need for

> a repeater.
>
> > Did I buy a piece of junkola? Teach me obie-wan.
>
> Not junk, but maybe not what you were expecting...
>
> --- Jeff WN3A
>

[Repeater-Builder] Re: Retuning a UHF Motorola Micor without a deviation meter or signal generator ?

[Josh]

Brian, 
 Here's what your project would look like.

First, you'll need crystals. Those can be ordered.

Second you'll need access to a 'test set' of sorts for the micor. There are 
several types, this'll set you back $20 to $100 (depending what test set you 
get). This is necessary to 'tune' the RX and TX on the unit to work with your 
new crystals.  

Third, You've got filters to tune. The easiest way to do this is with a 
spectrum analyzer and tracking generator.  I just bought one for $1100 - there 
are other, less accurate ways to do this, but I chose the 'buy the right tool 
for the job' route. You really want to see whats going on. This same tool 
will be required (or use other processes) to tune a duplexer so you can use a 
common antenna for TX and RX.

You'll be interfacing an external repeater controller (not difficult, although 
I'm fighting a COS issue right now on my micor project) to give you a time out 
timer, CW or voice ID'er, and the DTMF control you'll want (disabling the 
repeater if it goes berzerk).  I'm using the NHRC-2 , under $100 if you do it 
as a kit. 

Micors are REALLY easy to work on and a lot of fun - I'm getting close to the 
end of my project on one here, and I've learned a ton.
 
If you don't have access to the tools, and dont have friends that do, there are 
folks on the groups (this and others) that might be willing to 'tune stuff' for 
you, so you can do all but a few parts yourself. 

Good luck with your project!

Josh
--- In Repeater-Builder@yahoogroups.com, Brian Smith  wrote:
>
> I will apologize in advance, as I am an extreme newby in the world of 
> repeater building / operation.
> �
> We've been donated a UHF Motorola Micor system.� The system has 
> documentation that shows that it once ran at 78W out in commercial service.
> �
> Being an amateur radio operator without a commercial or well-stocked test 
> bench, I do not have ready access to a deviation meter or signal generator.
> Is it possible to retune these things down to the amateur radio 440 band 
> without these two pieces of test equipment?
> How likely is it that I will run into significant performance issues without 
> these pieces of equipment?
> �
> Thanks!
> Brian, WW9A
>

[Repeater-Builder] Retuning a UHF Motorola Micor without a deviation meter or signal generator ?

[Brian Smith]

I will apologize in advance, as I am an extreme newby in the world of repeater 
building / operation.
 
We've been donated a UHF Motorola Micor system.  The system has documentation 
that shows that it once ran at 78W out in commercial service.
 
Being an amateur radio operator without a commercial or well-stocked test 
bench, I do not have ready access to a deviation meter or signal generator.
Is it possible to retune these things down to the amateur radio 440 band 
without these two pieces of test equipment?
How likely is it that I will run into significant performance issues without 
these pieces of equipment?
 
Thanks!
Brian, WW9A


  

[Repeater-Builder] Motorola Micor COS Issues

[Josh]

I'm having COS issues with my motorola micor. I've got a normal audio/squelch 
board modded per these
instructions

http://www.repeater-builder.com/micor/station-a-s.html

I'm unable to recover COS from pin 13 of J2 (pin 8 of the audio sq board).

Any thoughts?

Side note, related or unrelated, I don't know - my volume and squelch knobs - on
any audio / squelch board (I've used several) seem to have no influence on
system behavior. Local station audio has never seemed to work properly. Im
wondering if there's something going on jumper-wise.

Any assistance would be greatly appreciated.

j

[Repeater-Builder] Re: Tuning DB Products Duplexer

[Kuby]

I also bought a set(x4) of these model DB SP4626.

Reading this string I decided to investigate my Dayton cans further. They have 
a goof plug covering the notch hole with no cap inside. They are all copper 
cans. 

I cracked one open (just a thin bead of solder on two sides holding the copper 
base plate. 

The N connectors have ~0.50" wide copper L strap attached ~1.65" by 0.50" to 
the side of the can. The copper cavity tube is 1.0" dia. by 4.40", with copper 
fingers to the tunable brass insert tube ~0.75" by 1.90" (as set for 
465.500MHz). 

Like to know more about the configuration of the frequency set capacitor/notch 
set - if this could be added to make these cans fully functional as duplexer's. 
This is a hobby

Anyone have some diagrams/dwg's of tunable cavities?  


--- In Repeater-Builder@yahoogroups.com, "Jeff DePolo"  wrote:
>
> > Ok so here's what I've got (I think)
> > 
> > http://www.n2ckh.com/FORSALE/REPEATERS/DUPLEXERS/DB4076/DSC02678.JPG
> > 
> > Hamvention special, 4 cavities, appears to be a DB Products 
> > 4076 family unit. My bench tools: HP 8924c w/ Spec Analyzer 
> > and Tracking Generator.
> 
> There was a guy at the Hamvention that had several sets of Decibel
> four-cavity window filters, selling for $50 each, which, to the untrained
> eye, would look like an older DB4076.  As you said, there would be nothing
> in the hole where the capacitor would be in a regular DB4076.  In essecence,
> what you have are just plain-jane pass cavities.  
> 
> As a second means of confirming that you do, in fact, have a window filter,
> is there an antenna "tee", or are the four cavities cabled together in
> cascade?  If the latter, then you probably have a window filter.
> 
> And as a third means of confirming, is there is a label on the front?  If
> not, was there any signs of a label having once been there?  If not, then
> that's yet one more indication that it isn't a DB4076.
> 
> Decibel made two varieties of pass cavities used in window filters in that
> era.  One had adjustable loops (less common), the other had fixed loops.  If
> your loop connectors have a rectangular chrome plate around them with
> insertion loss calibration marks, you have the less-common adjustable ones.
> If you just see four philips-head screws and no chromed plate around the
> connectors, then yours is not adjustable.
> 
> If you have the adjustable type, you could probably use them as a pass-only
> duplexer, but with mediocre isolation, even with the insertion loss cranked
> up higher than you'd like.  If you have the non-adjustable ones, they have
> very tight coupling, so you're not going to get the isolation you'd need for
> a repeater.
> 
> > Did I buy a piece of junkola? Teach me obie-wan.
> 
> Not junk, but maybe not what you were expecting...
> 
>   --- Jeff WN3A
>

[Repeater-Builder] GMRS Repeater ANT (UHF)

[Robert]

how much space is needed between the TX and RX ant and which type of cable to 
use ?

[Repeater-Builder] Re: Help Needed (Guidance and advice) tuning a DB Products Duplexer

[Josh]

Certainly not what I was expecting... Yeah, I bought one from 'that guy'.   
It's more than an untrained eye - he straight lied to me... said 'under these 
caps are where you'll tune the capacitors' - I should have popped one off and 
looked down the hole.  Maybe he was clued in, maybe he wasnt - either way, 
that's what I bought.  Dangit :P

So if all I have are pass cavities what 'are' they good for ?  

Guess I've got to find another dupelxer.

j

--- In Repeater-Builder@yahoogroups.com, "Jeff DePolo"  wrote:
>
> > Ok so here's what I've got (I think)
> > 
> > http://www.n2ckh.com/FORSALE/REPEATERS/DUPLEXERS/DB4076/DSC02678.JPG
> > 
> > Hamvention special, 4 cavities, appears to be a DB Products 
> > 4076 family unit. My bench tools: HP 8924c w/ Spec Analyzer 
> > and Tracking Generator.
> 
> There was a guy at the Hamvention that had several sets of Decibel
> four-cavity window filters, selling for $50 each, which, to the untrained
> eye, would look like an older DB4076.  As you said, there would be nothing
> in the hole where the capacitor would be in a regular DB4076.  In essecence,
> what you have are just plain-jane pass cavities.  
> 
> As a second means of confirming that you do, in fact, have a window filter,
> is there an antenna "tee", or are the four cavities cabled together in
> cascade?  If the latter, then you probably have a window filter.
> 
> And as a third means of confirming, is there is a label on the front?  If
> not, was there any signs of a label having once been there?  If not, then
> that's yet one more indication that it isn't a DB4076.
> 
> Decibel made two varieties of pass cavities used in window filters in that
> era.  One had adjustable loops (less common), the other had fixed loops.  If
> your loop connectors have a rectangular chrome plate around them with
> insertion loss calibration marks, you have the less-common adjustable ones.
> If you just see four philips-head screws and no chromed plate around the
> connectors, then yours is not adjustable.
> 
> If you have the adjustable type, you could probably use them as a pass-only
> duplexer, but with mediocre isolation, even with the insertion loss cranked
> up higher than you'd like.  If you have the non-adjustable ones, they have
> very tight coupling, so you're not going to get the isolation you'd need for
> a repeater.
> 
> > Did I buy a piece of junkola? Teach me obie-wan.
> 
> Not junk, but maybe not what you were expecting...
> 
>   --- Jeff WN3A
>

Re: [Repeater-Builder] Transformer cores

[x.tait.tech]

I am amased to say the least to fathom, how without brute force, less wear
and tare, ( Must have been many years constant retuning ) to wear out the
slug cavity, that allowed the ferrit slug to fall through the threads to the
bottom of the can

most tips and hints have already been covered, and these ideas only help
prevent the slug turning what you need is to stop it falling, but most have
not hit on the reason why it has happened

The reason we inserted the rubber strip was to prevent the tuning slug from
turning due to viabration, the threads are what stops the slug from falling
to the bottom

so lets take the ideas and use them

wax as one person stated help to make the slug adhere ( sticky ) to the
cavity wall threads
one stated thread seal tape,

my favourite is the threadseal tape but not wrapped around the slug, (
Fingers are to fat and podgy ) more cut to length and folded to make a
simulated  rubber band and insert into can, insert slug and tune
i used to use at home when all else failed a thinly sliced piece of pla

Marcus


On Sun, May 30, 2010 at 4:37 AM, Doug Hutchison
wrote:

>
>
> Hello,
>
> Got situation where the 'elastic' or whatever inside RX IF transformer
> has disintegrated through age allowing ferrite core to drop to bottom
> thus negating adjustment.
>
> What successful fixes have been found for such a problem which will
> continue to allow adjustment yet not jam the core?
>
> Doug - GM7SVK
>
>  
>

RE: [Repeater-Builder] Help Needed (Guidance and advice) tuning a DB Products Duplexer

[Jeff DePolo]

> Ok so here's what I've got (I think)
> 
> http://www.n2ckh.com/FORSALE/REPEATERS/DUPLEXERS/DB4076/DSC02678.JPG
> 
> Hamvention special, 4 cavities, appears to be a DB Products 
> 4076 family unit. My bench tools: HP 8924c w/ Spec Analyzer 
> and Tracking Generator.

There was a guy at the Hamvention that had several sets of Decibel
four-cavity window filters, selling for $50 each, which, to the untrained
eye, would look like an older DB4076.  As you said, there would be nothing
in the hole where the capacitor would be in a regular DB4076.  In essecence,
what you have are just plain-jane pass cavities.  

As a second means of confirming that you do, in fact, have a window filter,
is there an antenna "tee", or are the four cavities cabled together in
cascade?  If the latter, then you probably have a window filter.

And as a third means of confirming, is there is a label on the front?  If
not, was there any signs of a label having once been there?  If not, then
that's yet one more indication that it isn't a DB4076.

Decibel made two varieties of pass cavities used in window filters in that
era.  One had adjustable loops (less common), the other had fixed loops.  If
your loop connectors have a rectangular chrome plate around them with
insertion loss calibration marks, you have the less-common adjustable ones.
If you just see four philips-head screws and no chromed plate around the
connectors, then yours is not adjustable.

If you have the adjustable type, you could probably use them as a pass-only
duplexer, but with mediocre isolation, even with the insertion loss cranked
up higher than you'd like.  If you have the non-adjustable ones, they have
very tight coupling, so you're not going to get the isolation you'd need for
a repeater.

> Did I buy a piece of junkola? Teach me obie-wan.

Not junk, but maybe not what you were expecting...

--- Jeff WN3A

Re: [Repeater-Builder] Transformer cores

[Joel Liburd]

Very very good  Doug,
It always work for me, never had to even undo one.

v44kai.Joel.


- Original Message - 
From: "Doug Hutchison" 
To: 
Sent: Saturday, May 29, 2010 3:17 PM
Subject: Re: [Repeater-Builder] Transformer cores


> Yep, thought that might be a problem when it sets.PTFE is a good
> solution...been winding the cores in and out for over 15 minutes and no
> problems.
>
> Thank you,
> Doug
>
> On 29/05/2010 18:50:09, Bill Smith (brsc...@yahoo.com) wrote:
> > You need to be careful with Beeswax. it can hold the core tight enough
> > that you break it.
> >
> >
> >
> >
> -
> > From: Chuck Kelsey 
> > To: Repeater-Builder@yahoogroups.com
> > Sent: Sat, May 29, 2010 11:46:19 AM
> > Subject: Re: [Repeater-Builder] Transformer cores
> >
> > I've always heard about inserting a small diameter piece of rubber
> band in
> > between, but have never found anyone that actually had it work.
> >
> > If it were me, I'd
> > get some bees wax, melt it, and quickly dip the core in
> > it using a tuning tool so as not to coat the innards. This would put a
> > small
> > coating of bees wax on it, increasing the diameter and making it a bit
> > sticky.
> >
> > That said,
> > I've never done any procedure.
> >
> > Chuck
> > WB2EDV
> >
> >
> >
> > - Original Message -
> > From: "Doug Hutchison"  mailto:specialq@ntlworld.com]>
> > To:  mailto:repeater-buil...@yahoogroups.com]>
> > Sent: Saturday, May 29, 2010 12:37 PM
> > Subject: [Repeater-Builder] Transformer cores
> >
> >
> > > Hello,
> > >
> > > Got situation where the 'elastic' or whatever inside RX IF transformer
> > > has disinteg
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>

Re: [Repeater-Builder] Transformer cores

[Doug Hutchison]

Yep, thought that might be a problem when it sets.PTFE is a good 
solution...been winding the cores in and out for over 15 minutes and no 
problems.

Thank you,
Doug

On 29/05/2010 18:50:09, Bill Smith (brsc...@yahoo.com) wrote:
 > You need to be careful with Beeswax. it can hold the core tight enough
 > that you break it.
 >
 >
 >
 > 
-
 > From: Chuck Kelsey 
 > To: Repeater-Builder@yahoogroups.com
 > Sent: Sat, May 29, 2010 11:46:19 AM
 > Subject: Re: [Repeater-Builder] Transformer cores
 >
 > I've always heard about inserting a small diameter piece of rubber 
band in
 > between, but have never found anyone that actually had it work.
 >
 > If it were me, I'd
 > get some bees wax, melt it, and quickly dip the core in
 > it using a tuning tool so as not to coat the innards. This would put a
 > small
 > coating of bees wax on it, increasing the diameter and making it a bit
 > sticky.
 >
 > That said,
 > I've never done any procedure.
 >
 > Chuck
 > WB2EDV
 >
 >
 >
 > - Original Message -
 > From: "Doug Hutchison" mailto:specialq@ntlworld.com]>
 > To: mailto:repeater-buil...@yahoogroups.com]>
 > Sent: Saturday, May 29, 2010 12:37 PM
 > Subject: [Repeater-Builder] Transformer cores
 >
 >
 > > Hello,
 > >
 > > Got situation where the 'elastic' or whatever inside RX IF transformer
 > > has disinteg

Re: [Repeater-Builder] Transformer cores

[Bill Smith]

You need to be careful with Beeswax. it can hold the core tight enough that you 
break it.  





From: Chuck Kelsey 
To: Repeater-Builder@yahoogroups.com
Sent: Sat, May 29, 2010 11:46:19 AM
Subject: Re: [Repeater-Builder] Transformer cores

I've always heard about inserting a small diameter piece of rubber band in 
between, but have never found anyone that actually had it work.

If it were me, I'd get some bees wax, melt it, and quickly dip the core in 
it using a tuning tool so as not to coat the innards. This would put a small 
coating of bees wax on it, increasing the diameter and making it a bit 
sticky.

That said, I've never done any procedure.

Chuck
WB2EDV



- Original Message - 
From: "Doug Hutchison" 
To: 
Sent: Saturday, May 29, 2010 12:37 PM
Subject: [Repeater-Builder] Transformer cores


> Hello,
>
> Got situation where the 'elastic' or whatever inside RX IF transformer
> has disintegrated through age allowing ferrite core to drop to bottom
> thus negating adjustment.
>
> What successful fixes have been found for such a problem which will
> continue to allow adjustment yet not jam the core?
>
> Doug - GM7SVK
>
>







Yahoo! Groups Links



    http://docs.yahoo.com/info/terms/

Re: [Repeater-Builder] Transformer cores

[Joel Liburd]

You are welcome,

Just make sure you wind the tape the same way you would for the pipe thread 
(right hand for tightening) so that when screwing it in the thread will seal 
it, then taking it out wouldn't be a problem.

v44kai.Joel.


- Original Message - 
From: "Doug Hutchison" 
To: 
Sent: Saturday, May 29, 2010 2:15 PM
Subject: Re: [Repeater-Builder] Transformer cores


> Hello again and thank you all for the input.
>
> I shall try the thread/wax combination but remembered I had a plumbers
> wrench kit which has a roll of PTFE, wrapped some on one of the three
> cores which have dropped out and it works a treat.
> Good idea Joel.
>
> Best regards,
> Doug - GM7SVK
>
>
> On 29/05/2010 17:40:57, Joel Liburd (v44...@caribsurf.com) wrote:
> > Hi Doug,
> > I have had this on many occasion, my first experience was, what the heck
> > I'm
> > going to do now! I have tried thread, wax, rubber band and others, best
> > that works 100% of the times are the (right size fishing line) and my
> > favorite plumbers tape (wrap it on the threaded core) I keep a roll
> in my
> > tool bag.
> > I hope this helped.
> >
> > v44kai.Joel.
> >
> >
> > - Original Message -
> > From: "Doug Hutchison" 
> > To: 
> > Sent: Saturday, May 29, 2010 12:37 PM
> > Subject: [Repeater-Builder] Transformer cores
> >
> >
> > > Hello,
> > >
> > > Got situation where the 'elastic' or whatever inside RX IF transformer
> > > has disintegrated through age allowing ferrite core to drop to bottom
> > > thus negating adjustment.
> > >
> > > What successful fixes have been found for such a problem which will
> > > continue to allow adjustment yet not jam the core?
> > >
> > > Doug - GM7SVK
> > >
> > >
> > >
> > >
> > > 
> > >
> > >
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> >
> >
> >
> > 
> >
> >
> >
> > Yahoo! Groups Links
> %3
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>

Re: [Repeater-Builder] Transformer cores

[Doug Hutchison]

Hello again and thank you all for the input.

I shall try the thread/wax combination but remembered I had a plumbers 
wrench kit which has a roll of PTFE, wrapped some on one of the three 
cores which have dropped out and it works a treat.
Good idea Joel.

Best regards,
Doug - GM7SVK


On 29/05/2010 17:40:57, Joel Liburd (v44...@caribsurf.com) wrote:
 > Hi Doug,
 > I have had this on many occasion, my first experience was, what the heck
 > I'm
 > going to do now! I have tried thread, wax, rubber band and others, best
 > that works 100% of the times are the (right size fishing line) and my
 > favorite plumbers tape (wrap it on the threaded core) I keep a roll 
in my
 > tool bag.
 > I hope this helped.
 >
 > v44kai.Joel.
 >
 >
 > - Original Message -
 > From: "Doug Hutchison" 
 > To: 
 > Sent: Saturday, May 29, 2010 12:37 PM
 > Subject: [Repeater-Builder] Transformer cores
 >
 >
 > > Hello,
 > >
 > > Got situation where the 'elastic' or whatever inside RX IF transformer
 > > has disintegrated through age allowing ferrite core to drop to bottom
 > > thus negating adjustment.
 > >
 > > What successful fixes have been found for such a problem which will
 > > continue to allow adjustment yet not jam the core?
 > >
 > > Doug - GM7SVK
 > >
 > >
 > >
 > >
 > > 
 > >
 > >
 > >
 > > Yahoo! Groups Links
 > >
 > >
 > >
 >
 >
 >
 > 
 >
 >
 >
 > Yahoo! Groups Links
%3

Re: [Repeater-Builder] Transformer cores

[Joel Liburd]

Hi Doug,
I have had this on many occasion, my first experience was, what the heck I'm 
going to do now!  I have tried thread, wax, rubber band and others, best 
that works 100% of the times are the (right size fishing line) and my 
favorite plumbers tape (wrap it on the threaded core) I keep a roll in my 
tool bag.
I hope this helped.

v44kai.Joel.


- Original Message - 
From: "Doug Hutchison" 
To: 
Sent: Saturday, May 29, 2010 12:37 PM
Subject: [Repeater-Builder] Transformer cores


> Hello,
>
> Got situation where the 'elastic' or whatever inside RX IF transformer
> has disintegrated through age allowing ferrite core to drop to bottom
> thus negating adjustment.
>
> What successful fixes have been found for such a problem which will
> continue to allow adjustment yet not jam the core?
>
> Doug - GM7SVK
>
>
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>

Re: [Repeater-Builder] is a repeater needed

[MCH]

Simple answer: Do you have repeaters that cover the same area yours 
would cover?

Joe M.

Lane wrote:
> Hi all,
> 
> I've been interested in building a repeater for a while now, but before I do, 
> I guess the first step is in knowing whether or not a repeater is needed for 
> my area.
> 
> I live in Houston and have an excellent area for putting up a repeater *if* 
> one is needed, but how do I go about finding out if one would be useful to 
> others and on what frequencies. There are lots of repeaters here in Houston 
> and I'd hate to saturate or further complicate anything if that would be the 
> case. 
> 
> Any help, suggestions, advice much appreciated.
> 
> 
> 
> 
> 
> 
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 
> 
> 
> Internal Virus Database is out of date.
> Checked by AVG - www.avg.com 
> Version: 9.0.783 / Virus Database: 271.1.1/2746 - Release Date: 03/14/10 
> 03:33:00
> 

Re: [Repeater-Builder] Help Needed (Guidance and advice) tuning a DB Products Duplexer

[Glenn (Butch) Kanvick]

Hello Josh.

Look under the caps between the coax connectors.
That should be the notch adjustment.

They may not go that low,but all you can do is try.
Good luck.

Butch, KE7FEL/r

On Fri, May 28, 2010 at 6:53 PM, Josh  wrote:

>
>
> Ok so here's what I've got (I think)
>
> http://www.n2ckh.com/FORSALE/REPEATERS/DUPLEXERS/DB4076/DSC02678.JPG
>
> Hamvention special, 4 cavities, appears to be a DB Products 4076 family
> unit. My bench tools: HP 8924c w/ Spec Analyzer and Tracking Generator.
>
> My problem - existing set of cans is tuned for 460~mhz. I need to bring
> them down to 443/448. It was my understanding that they would have dual
> adjustments - one for setting the band pass frequency, one for setting the
> reject frequency. Sounds simple. Except under the 'covers' there is nothing
> else to adjust... So are they just single frequency pass or notch filters?
>
> So thats the first question - The second question is - ok , so if they're
> just single frequency filters, why can't I spin them 'into the right range'
> as easily as I thought I'd be able to do I've tuned a couple of motorola
> micor filters on the spec analyzer in the last couple of days, mostly made
> sense and was smooth as silk... However, after messing with the first can,
> I'm confused. Moving the adjustment certainly changes the properties of the
> notching - but it didnt really move the bandpass around... It mostly changed
> the shape and depth of the notching - not the frequency.
>
> What knowledge am I missing - I'm an amateur :)
>
> Yes I've seen the 'how to tune db products duplexor' doc - but it talks
> about dual controls, which apparently I don't have.
>
> Did I buy a piece of junkola? Teach me obie-wan.
>
> j
>
>  
>

RE: [Repeater-Builder] Transformer cores

[Mike Besemer (WM4B)]

I've used a small rubber band or some thread.  Most of the time, I've had to
trim the rubber band with a razor blade to get very narrow.  I've also
coated the thread in wax prior to dangling it into the tube.

 

73,

 

Mike

WM4B

 

 

 

From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey
Sent: Saturday, May 29, 2010 12:46 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Transformer cores

 

  

I've always heard about inserting a small diameter piece of rubber band in 
between, but have never found anyone that actually had it work.

If it were me, I'd get some bees wax, melt it, and quickly dip the core in 
it using a tuning tool so as not to coat the innards. This would put a small

coating of bees wax on it, increasing the diameter and making it a bit 
sticky.

That said, I've never done any procedure.

Chuck
WB2EDV

- Original Message - 
From: "Doug Hutchison" mailto:specialq.que%40ntlworld.com> >
To: mailto:repeater-builder%40yahoogroups.com> >
Sent: Saturday, May 29, 2010 12:37 PM
Subject: [Repeater-Builder] Transformer cores

> Hello,
>
> Got situation where the 'elastic' or whatever inside RX IF transformer
> has disintegrated through age allowing ferrite core to drop to bottom
> thus negating adjustment.
>
> What successful fixes have been found for such a problem which will
> continue to allow adjustment yet not jam the core?
>
> Doug - GM7SVK
>
>

Re: [Repeater-Builder] Transformer cores

[Chuck Kelsey]

I've always heard about inserting a small diameter piece of rubber band in 
between, but have never found anyone that actually had it work.

If it were me, I'd get some bees wax, melt it, and quickly dip the core in 
it using a tuning tool so as not to coat the innards. This would put a small 
coating of bees wax on it, increasing the diameter and making it a bit 
sticky.

That said, I've never done any procedure.

Chuck
WB2EDV



- Original Message - 
From: "Doug Hutchison" 
To: 
Sent: Saturday, May 29, 2010 12:37 PM
Subject: [Repeater-Builder] Transformer cores


> Hello,
>
> Got situation where the 'elastic' or whatever inside RX IF transformer
> has disintegrated through age allowing ferrite core to drop to bottom
> thus negating adjustment.
>
> What successful fixes have been found for such a problem which will
> continue to allow adjustment yet not jam the core?
>
> Doug - GM7SVK
>
>

[Repeater-Builder] Transformer cores

[Doug Hutchison]

Hello,

Got situation where the 'elastic' or whatever inside RX IF transformer 
has disintegrated through age allowing ferrite core to drop to bottom 
thus negating adjustment.

What successful fixes have been found for such a problem which will 
continue to allow adjustment yet not jam the core?

Doug - GM7SVK

[Repeater-Builder] Re: is a repeater needed

[George C]

The project can be fun, and educational...but are you talking amateur or GMRS? 

If amateur, look here:
http://www.txvhffm.org/repeater/

Set location to Houston and the hit "search". But look at surrounding towns as 
well. 

As far as coordination goes, there is a waiting list on 2 meters, not on other 
bands. 
http://www.txvhffm.com/index.php?option=com_content&task=view&id=113&Itemid=38

Look at "zone 2", which includes Houston. 

If you're talking GMRS, its tough. No coordinating body, but a good web site 
for info, and to see what's out there is http://www.mygmrs.com/

GeorgeC
W2DB/5
Cedar Park, TX



--- In Repeater-Builder@yahoogroups.com, "Lane"  wrote:
>
> Hi all,
> 
> I've been interested in building a repeater for a while now, but before I do, 
> I guess the first step is in knowing whether or not a repeater is needed for 
> my area.
> 
> I live in Houston and have an excellent area for putting up a repeater *if* 
> one is needed, but how do I go about finding out if one would be useful to 
> others and on what frequencies. There are lots of repeaters here in Houston 
> and I'd hate to saturate or further complicate anything if that would be the 
> case. 
> 
> Any help, suggestions, advice much appreciated.
>

RE: [Repeater-Builder] is a repeater needed

[Stanley Stanukinos]

Lane, what frequency are you trying to go on'? Houston has a waiting list
for VHF and UHF is pretty full. I think if you look around Houston proper is
covered fairly well.  Look at the www.txvhffm.org web site. You can do
search's there. If you would like to set up and play there are several UHF
back yard repeater pairs you can coordinate on.  Try making contacts on the
repeaters in your area to check their coverage and usage. You may find that
Houston has extremely good coverage. If you really want something up on the
air try 900 or 1.2

 

Stan 

 

From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Lane
Sent: Friday, May 28, 2010 3:02 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] is a repeater needed

 

  

Hi all,

I've been interested in building a repeater for a while now, but before I
do, I guess the first step is in knowing whether or not a repeater is needed
for my area.

I live in Houston and have an excellent area for putting up a repeater *if*
one is needed, but how do I go about finding out if one would be useful to
others and on what frequencies. There are lots of repeaters here in Houston
and I'd hate to saturate or further complicate anything if that would be the
case. 

Any help, suggestions, advice much appreciated.

[Repeater-Builder] Duplex Can set ???

[Kuby]

I have a rack mount set of four square duel N connector port cans made by 
Decibel, model SP4626 on freq 465.500MHz

What do I own?
Where can I get data spec sheet on these cans?
Can they be used as 440 duplexer cans? What needs to be done?

I did notice the coax jumpers are 7" t/t, and my 440 repeater duplex jumpers 
are 13" t/t. Do I need new jumpers? 
What is the relationship of jumper length to freq?  
 

Re: [Repeater-Builder] Using DAVIS BURY FLEX

[Chuck Kelsey]

Some Heliax Superflex may help.

Chuck
WB2EDV



  - Original Message - 
  From: Michael Ryan 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Saturday, May 29, 2010 9:06 AM
  Subject: RE: [Repeater-Builder] Using DAVIS BURY FLEX





  Thanks Chuck, After getting the cable in front of me ( which was AFTER I 
posted the question) and peeling back the jacket, I saw the foil and braid 
shielding, so you are correct.  Looks like another hybrid of LMR-400, etc.   
This will be used around some tight turns where heliax might be difficult to 
use and I won't use the LMR type cables, so I think I will use a length of 
RG-214 instead.  Total run of cable is about 100ft and the rest is 7/8" Andrew. 
 Thanks for the reply.  - Mike

   

  From: Repeater-Builder@yahoogroups.com 
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey
  Sent: Saturday, May 29, 2010 8:40 AM
  To: Repeater-Builder@yahoogroups.com
  Subject: Re: [Repeater-Builder] Using DAVIS BURY FLEX

   



  I believe Bury Flex has foil/braid combination construction. If this is the 
case, I'd suggest not using it in a repeater installation. I'm pretty sure it's 
in the 9913/9914 family. I'd suggest a piece of 1/2" Heliax.

   

  Now, if the antenna is only going to be 20' from the repeater, you may still 
have issues.

   

  Chuck

  WB2EDV

   

   

   

- Original Message - 

From: Michael Ryan 

To: Repeater-Builder@yahoogroups.com 

Sent: Saturday, May 29, 2010 12:12 AM

Subject: [Repeater-Builder] Using DAVIS BURY FLEX

 

 

Question:

  Any reason that BURY FLEX can't or shouldn't be used ( short run of 20ft) 
in repeater service as a short transmission line?  -Mike

 




  __ Information from ESET NOD32 Antivirus, version of virus signature 
database 5154 (20100528) __

  The message was checked by ESET NOD32 Antivirus.

  http://www.eset.com

   

  __ Information from ESET NOD32 Antivirus, version of virus signature 
database 5154 (20100528) __

   

  The message was checked by ESET NOD32 Antivirus.

   

  http://www.eset.com



  __ Information from ESET NOD32 Antivirus, version of virus signature 
database 5154 (20100528) __

  The message was checked by ESET NOD32 Antivirus.

  http://www.eset.com



  


--



  No virus found in this incoming message.
  Checked by AVG - www.avg.com 
  Version: 9.0.819 / Virus Database: 271.1.1/2903 - Release Date: 05/29/10 
02:25:00

RE: [Repeater-Builder] Using DAVIS BURY FLEX

[Michael Ryan]

Thanks Chuck, After getting the cable in front of me ( which was AFTER I
posted the question) and peeling back the jacket, I saw the foil and braid
shielding, so you are correct.  Looks like another hybrid of LMR-400, etc.
This will be used around some tight turns where heliax might be difficult to
use and I won't use the LMR type cables, so I think I will use a length of
RG-214 instead.  Total run of cable is about 100ft and the rest is 7/8"
Andrew.  Thanks for the reply.  - Mike

 

From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey
Sent: Saturday, May 29, 2010 8:40 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Using DAVIS BURY FLEX

 

  

I believe Bury Flex has foil/braid combination construction. If this is the
case, I'd suggest not using it in a repeater installation. I'm pretty sure
it's in the 9913/9914 family. I'd suggest a piece of 1/2" Heliax.

 

Now, if the antenna is only going to be 20' from the repeater, you may still
have issues.

 

Chuck

WB2EDV

 

 

 

- Original Message - 

From: Michael Ryan   

To: Repeater-Builder@yahoogroups.com 

Sent: Saturday, May 29, 2010 12:12 AM

Subject: [Repeater-Builder] Using DAVIS BURY FLEX

 

 

Question:

  Any reason that BURY FLEX can't or shouldn't be used ( short run of 20ft)
in repeater service as a short transmission line?  -Mike

 





__ Information from ESET NOD32 Antivirus, version of virus signature
database 5154 (20100528) __

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com

 

__ Information from ESET NOD32 Antivirus, version of virus signature
database 5154 (20100528) __

 

The message was checked by ESET NOD32 Antivirus.

 

http://www.eset.com

Re: [Repeater-Builder] Using DAVIS BURY FLEX

[Chuck Kelsey]

I believe Bury Flex has foil/braid combination construction. If this is the 
case, I'd suggest not using it in a repeater installation. I'm pretty sure it's 
in the 9913/9914 family. I'd suggest a piece of 1/2" Heliax.

Now, if the antenna is only going to be 20' from the repeater, you may still 
have issues.

Chuck
WB2EDV


 
  - Original Message - 
  From: Michael Ryan 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Saturday, May 29, 2010 12:12 AM
  Subject: [Repeater-Builder] Using DAVIS BURY FLEX





   

  Question:

Any reason that BURY FLEX can't or shouldn't be used ( short run of 20ft) 
in repeater service as a short transmission line?  -Mike

   

Re: [Repeater-Builder] Help Needed (Guidance and advice) tuning a DB Products Duplexer

[Milt]

Josh,

Ed's description for tuning is right on the money.
I would try moving the unit just a slight bit to get used to how it tunes 
before trying to move it over such a wide frequency range.  Once you are 
comfortable with your equipment and how the duplexer tunes, then move it to 
the new amateur frequency.

Milt
N3LTQ


- Original Message -
From: "Ed Yoho" 
To: 
Sent: Saturday, May 29, 2010 12:09 AM
Subject: Re: [Repeater-Builder] Help Needed (Guidance and advice) tuning a 
DB Products Duplexer


> Josh wrote:
>> Ok so here's what I've got (I think)
>>
>> http://www.n2ckh.com/FORSALE/REPEATERS/DUPLEXERS/DB4076/DSC02678.JPG
>>
>> Hamvention special, 4 cavities, appears to be a DB Products 4076 family 
>> unit.   My bench tools: HP 8924c w/ Spec Analyzer and Tracking Generator.
>>
>> My problem - existing set of cans is tuned for 460~mhz.  I need to bring 
>> them down to 443/448.It was my understanding that they would have 
>> dual adjustments - one for setting the band pass frequency, one for 
>> setting the reject frequency.   Sounds simple.  Except under the 'covers' 
>> there is nothing else to adjust... So are they just single frequency pass 
>> or notch filters?
>>
>> So thats the first question - The second question is - ok , so if they're 
>> just single frequency filters, why can't I spin them 'into the right 
>> range' as easily as I thought I'd be able to do I've tuned a couple 
>> of motorola micor filters on the spec analyzer in the last couple of 
>> days, mostly made sense and was smooth as silk... However, after messing 
>> with the first can, I'm confused.  Moving the adjustment certainly 
>> changes the properties of the notching - but it didnt really move the 
>> bandpass around... It mostly changed the shape and depth of the 
>> notching - not the frequency.
>>
>> What knowledge am I missing - I'm an amateur :)
>>
>> Yes I've seen the 'how to tune db products duplexor' doc - but it talks 
>> about dual controls, which apparently I don't have.
>>
>> Did I buy a piece of junkola?  Teach me obie-wan.
>>
>> j
>>
>>
>
> Josh,
>
> The large nut tipped rods in the center of each cavity are the pass
> adjustments. Loosen the locking nut at the bottom of each tuning rod and
> turn the shafts clockwise to set the pass responses where you want. Be
> sure to keep them set high and low as they are labeled. Once the pass is
> where you want it, tighten the clamp nuts back down. Then remove the
> small round covers between the N connectors on each cavity and use a
> small screwdriver or metal tipped tuning tool to _carefully_ put the
> notches where they belong. Put the covers back on and enjoy.
>
> Be sure to put a termination on the side you are not tuning.
>
> Ed Yoho
> W6YJ
>
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>

Re: [Repeater-Builder] 220 duplexers

[Jim Lange]

Stan,

I sent something to your personal email the other day. Have you seen it? It may 
be what you need.


Jim
WA2RJP
  - Original Message - 
  From: Stan 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Saturday, May 29, 2010 07:29
  Subject: Re: [Repeater-Builder] 220 duplexers





  Well I don't know how you guys got the idea I am going to leave a bunch of 
junk on our tower, but that is not the case. Sorry. IF we stay on this tower we 
will replace the antenna, IF we move, the old tower will be removed. There will 
not be a "next guy". 

  I am simply looking for 220 duplexers for our single 220 antenna that is left 
there for now...

  And if all goes as planned, we are very lucky...

  Stan



  From: Mike Morris 
  Sent: Saturday, May 29, 2010 12:36 AM
  To: Repeater-Builder@yahoogroups.com 
  Subject: Re: [Repeater-Builder] 220 duplexers



  Chucks right on the money.  
  Do the next guy a favor and remove the useless junk from the tower.
  See this article:
  < http://www.repeater-builder.com/antenna/cracking.html>

  Mike WA6ILQ


  At 05:42 AM 05/28/10, you wrote:



I understand the move and money issue. Be aware that any loose hardware 
and/or damaged antenna can, and often does, generate noise all on it's own when 
hit with an RF source - your repeater or some other nearby transmitter.
 
Good luck with the move. And you got very lucky if you land a cell tower 
location for a good price.
 
Chuck
WB2EDV
 
 
 

  - Original Message - 

  From: Stan 

  To: Repeater-Builder@yahoogroups.com 

  Sent: Friday, May 28, 2010 8:36 AM

  Subject: Re: [Repeater-Builder] 220 duplexers


  Hi Chuck,

  The tower is 150' up and I keep forgetting my binoculars. But I think the 
elements are simply blown away. The cable appears to be still intact. AND we 
are expecting to move over to a new Cell Tower location soon and don't want to 
put a lot of work and money into the current tower. And I shut the 220 repeater 
down so it will not create any noise.



  Thanks

  Stan




  From: Chuck Kelsey 

  Sent: Friday, May 28, 2010 8:14 AM

  To: Repeater-Builder@yahoogroups.com 

  Subject: Re: [Repeater-Builder] 220 duplexers





  I never like the idea of leaving a known bad antenna on a tower. It will 
eventually become a noise generator. Yes, sometimes you can "get away" with it, 
but it's a real gamble. And if there are other services nearby, you could be 
bothering them and not know it.



  Chuck

  WB2EDV





- Original Message - 

From: Stan 

To: Repeater-Builder@yahoogroups.com 

Sent: Friday, May 28, 2010 8:04 AM

Subject: Re: [Repeater-Builder] 220 duplexers


The bad antenna is the Rx antenna. It won't hear beyond about a mile 
after a heavy wind storm. So swapping is not an option.


  
Stan




 

--


  No virus found in this incoming message.

  Checked by AVG - www.avg.com 

  Version: 9.0.819 / Virus Database: 271.1.1/2901 - Release Date: 05/28/10 
02:25:00









  <>

Re: [Repeater-Builder] 220 duplexers

[Chuck Kelsey]

My point was that if you get a duplexer, you should still consider removing the 
bad antenna as it could cause you grief. If the re-locate looks like it is 
going to be in a few months, I'd probably ride it out and leave the antenna 
until the entire tower comes down. It sounds like you are the only system in 
the immediate vicinity, so it's not likely that you'll cause a problem for 
another nearby service.

Chuck
WB2EDV



  - Original Message - 
  From: Stan 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Saturday, May 29, 2010 7:29 AM
  Subject: Re: [Repeater-Builder] 220 duplexers





  Well I don't know how you guys got the idea I am going to leave a bunch of 
junk on our tower, but that is not the case. Sorry. IF we stay on this tower we 
will replace the antenna, IF we move, the old tower will be removed. There will 
not be a "next guy". 

  I am simply looking for 220 duplexers for our single 220 antenna that is left 
there for now...

  And if all goes as planned, we are very lucky...

  Stan

<>

[Repeater-Builder] Combiner Search

[Com/Rad Inc]

Hello Group

We may require a VHF Combiner 2 to 4 channels ( <125 w input / chan ) and an 
associated receiver multicoupler.

Looking for what is out there in inventory - we will probably need to make a 
purchase within the next 10 days.

Regards to all 
Ed Folta  K9QPJ

[Repeater-Builder] Need soome power dividers

[Com/Rad Inc]

Looking for the following

Quantity 2 - UHF power divider ( 500 w ) single input, dual output ( 2 x 
splitter ) 455 - 465 range

2 - VHF power splitter ( 500 watt ) configured as above  151 - 159 
range

Ed K9QPJ

Re: [Repeater-Builder] 220 duplexers

[Stan]

Well I don't know how you guys got the idea I am going to leave a bunch of junk 
on our tower, but that is not the case. Sorry. IF we stay on this tower we will 
replace the antenna, IF we move, the old tower will be removed. There will not 
be a "next guy". 

I am simply looking for 220 duplexers for our single 220 antenna that is left 
there for now...

And if all goes as planned, we are very lucky...

Stan



From: Mike Morris 
Sent: Saturday, May 29, 2010 12:36 AM
To: Repeater-Builder@yahoogroups.com 
Subject: Re: [Repeater-Builder] 220 duplexers


  
Chucks right on the money.  
Do the next guy a favor and remove the useless junk from the tower.
See this article:
< http://www.repeater-builder.com/antenna/cracking.html>

Mike WA6ILQ


At 05:42 AM 05/28/10, you wrote:



  I understand the move and money issue. Be aware that any loose hardware 
and/or damaged antenna can, and often does, generate noise all on it's own when 
hit with an RF source - your repeater or some other nearby transmitter.
   
  Good luck with the move. And you got very lucky if you land a cell tower 
location for a good price.
   
  Chuck
  WB2EDV
   
   
   

- Original Message - 

From: Stan 

To: Repeater-Builder@yahoogroups.com 

Sent: Friday, May 28, 2010 8:36 AM

Subject: Re: [Repeater-Builder] 220 duplexers


Hi Chuck,

The tower is 150' up and I keep forgetting my binoculars. But I think the 
elements are simply blown away. The cable appears to be still intact. AND we 
are expecting to move over to a new Cell Tower location soon and don't want to 
put a lot of work and money into the current tower. And I shut the 220 repeater 
down so it will not create any noise.



Thanks

Stan




From: Chuck Kelsey 

Sent: Friday, May 28, 2010 8:14 AM

To: Repeater-Builder@yahoogroups.com 

Subject: Re: [Repeater-Builder] 220 duplexers


 


I never like the idea of leaving a known bad antenna on a tower. It will 
eventually become a noise generator. Yes, sometimes you can "get away" with it, 
but it's a real gamble. And if there are other services nearby, you could be 
bothering them and not know it.



Chuck

WB2EDV





  - Original Message - 

  From: Stan 

  To: Repeater-Builder@yahoogroups.com 

  Sent: Friday, May 28, 2010 8:04 AM

  Subject: Re: [Repeater-Builder] 220 duplexers


  The bad antenna is the Rx antenna. It won't hear beyond about a mile 
after a heavy wind storm. So swapping is not an option.



  Stan









No virus found in this incoming message.

Checked by AVG - www.avg.com 

Version: 9.0.819 / Virus Database: 271.1.1/2901 - Release Date: 05/28/10 
02:25:00






<>

Re: [Repeater-Builder] Re: Radio or Duplex watts

[x.tait.tech]

NoNo..No.and
again.NO.not at all.not ever




On Sat, May 29, 2010 at 7:46 PM, burkleoj  wrote:

>
>
> I was thinking it should be 39 Watts. The 4 Watt HT added to the 35 Watt
> rating of the Duplexer.
>
> --- In Repeater-Builder@yahoogroups.com,
> "Joel Liburd"  wrote:
> >
> > No, and no.
> > Your repeater would be putting out about 65 - 85 % of your 4 watts, based
> on the type of duplexer setup.
> >
> > v44kai.Joel.
> > - Original Message -
> > From: x.tait.tech
> > To: Repeater-Builder@yahoogroups.com
> > Sent: Friday, May 28, 2010 4:47 AM
> > Subject: Re: [Repeater-Builder] Radio or Duplex watts
> >
> >
> >
> >
> > yeah no, i have no problem with any of that, what i did have a concern
> over, was my misunderstanding of the way the question was asked
> >
> >
> >
> > " If I would to use 2 HT radios that are 4 watts each and a duplexer that
> is 35 watts to build a portable repeater, would my repeater be 4 watts or 35
> watts? "
> > Marcus
> >
> >
> >
> >
> >
> > On Fri, May 28, 2010 at 3:24 AM, Mike Morris  wrote:
> >
> >
> > Actually a duplexer does have a wattage - it has a
> > power LIMIT.
> >
> > The small chinese duplexers use a tiny, low voltage
> > capacitor inside each stage and the have a limit of
> > 35-40 watts.
> > I have a small duplexer here that has a limit of 50 watts and
> > a large rack mount unit that has a limit of several hundred watts.
> >
> > Things aren't pretty when a duplexer arcs over internally.
> > You have half a chance of repairing the ones that are
> > bolted together. The ones that are welded together
> > make halfway decent doorstops.
> >
> > Mike
> >
> >
> >
> > At 11:24 PM 05/26/10, you wrote:
> >
> >
> > A Duplexer has no wattage as it is neither a Transmiter nor Reciever
> > i am trying to understand your 35 watts point
> >
> > Marcus
> >
> >
> >
> > On Wed, May 26, 2010 at 6:00 PM, kf7eec  wrote:
> >
> >
> >
> >
> > If I would to use 2 HT radios that are 4 watts each and a duplexer that
> is 35 watts to build a portable repeater, would my repeater be 4 watts or 35
> watts?
> >
> >
> > Thanks!
> >
> >
> > Michael
> >
> > KF7EEC
> >
>
>  
>

[Repeater-Builder] Re: Radio or Duplex watts

[burkleoj]

I was thinking it should be 39 Watts. The 4 Watt HT added to the 35 Watt rating 
of the Duplexer.

--- In Repeater-Builder@yahoogroups.com, "Joel Liburd"  wrote:
>
> No, and no.
> Your repeater would be putting out about 65 - 85 % of your 4 watts, based on 
> the type of duplexer setup.
>  
> v44kai.Joel. 
>   - Original Message - 
>   From: x.tait.tech 
>   To: Repeater-Builder@yahoogroups.com 
>   Sent: Friday, May 28, 2010 4:47 AM
>   Subject: Re: [Repeater-Builder] Radio or Duplex watts
> 
> 
> 
> 
>   yeah no, i have no problem with any of that, what i did have a concern 
> over, was my misunderstanding of the way the question was asked
> 
> 
> 
> " If I would to use 2 HT radios that are 4 watts each and a duplexer that 
> is 35 watts to build a portable repeater, would my repeater be 4 watts or 35 
> watts? "
>   Marcus
> 
> 
> 
> 
> 
>   On Fri, May 28, 2010 at 3:24 AM, Mike Morris  wrote:
> 
>   
> Actually a duplexer does have a wattage - it has a 
> power LIMIT.
> 
> The small chinese duplexers use a tiny, low voltage 
> capacitor inside each stage and the have a limit of 
> 35-40 watts.
> I have a small duplexer here that has a limit of 50 watts and 
> a large rack mount unit that has a limit of several hundred watts.
> 
> Things aren't pretty when a duplexer arcs over internally.  
> You have half a chance of repairing the ones that are 
> bolted together.  The ones that are welded together 
> make halfway decent doorstops.
> 
> Mike
> 
> 
> 
> At 11:24 PM 05/26/10, you wrote:
> 
> 
>   A Duplexer has no wattage as it is neither a Transmiter nor Reciever
>   i am trying to understand your 35 watts point
> 
>   Marcus
> 
> 
> 
>   On Wed, May 26, 2010 at 6:00 PM, kf7eec  wrote:
> 
>  
> 
> 
> If I would to use 2 HT radios that are 4 watts each and a duplexer 
> that is 35 watts to build a portable repeater, would my repeater be 4 watts 
> or 35 watts?
> 
> 
> Thanks!
> 
> 
> Michael
> 
> KF7EEC
>

Re: [Repeater-Builder] Radio or Duplex watts

[Joel Liburd]

No, and no.
Your repeater would be putting out about 65 - 85 % of your 4 watts, based on 
the type of duplexer setup.
 
v44kai.Joel. 
  - Original Message - 
  From: x.tait.tech 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Friday, May 28, 2010 4:47 AM
  Subject: Re: [Repeater-Builder] Radio or Duplex watts




  yeah no, i have no problem with any of that, what i did have a concern over, 
was my misunderstanding of the way the question was asked



" If I would to use 2 HT radios that are 4 watts each and a duplexer that 
is 35 watts to build a portable repeater, would my repeater be 4 watts or 35 
watts? "
  Marcus





  On Fri, May 28, 2010 at 3:24 AM, Mike Morris  wrote:

  
Actually a duplexer does have a wattage - it has a 
power LIMIT.

The small chinese duplexers use a tiny, low voltage 
capacitor inside each stage and the have a limit of 
35-40 watts.
I have a small duplexer here that has a limit of 50 watts and 
a large rack mount unit that has a limit of several hundred watts.

Things aren't pretty when a duplexer arcs over internally.  
You have half a chance of repairing the ones that are 
bolted together.  The ones that are welded together 
make halfway decent doorstops.

Mike



At 11:24 PM 05/26/10, you wrote:


  A Duplexer has no wattage as it is neither a Transmiter nor Reciever
  i am trying to understand your 35 watts point

  Marcus



  On Wed, May 26, 2010 at 6:00 PM, kf7eec  wrote:

 


If I would to use 2 HT radios that are 4 watts each and a duplexer that 
is 35 watts to build a portable repeater, would my repeater be 4 watts or 35 
watts?


Thanks!


Michael

KF7EEC