Re: [Repeater-Builder] Astron switching supply for Battery Charger??

[kh6jkg]

Eric, thanks for your email.
What are your comments on a cut-off circuit to open the battery charger, when 
the battery is 
fully charged? I would not like to 'cook' the battery.
What about a a low voltage circuit that opens the load, for long periods of no 
AC?
I acquired the diodes from Astron, where is the best place to mount the 
diode/heat sinks?
On the power supply or on a rack panel, with good wires from the terminals to 
the diode terminals.
Thank you for your comments.
73's,   Jim   Kh6jkg.


-Original Message-
From: Eric Lemmon 
To: Repeater-Builder@yahoogroups.com
Sent: Mon, May 31, 2010 5:00 am
Subject: RE: [Repeater-Builder] Astron switching supply for Battery Charger??


 

John,

There's nothing about a switching power supply that might disqualify it for
battery float service. However, you should isolate the output of any power
supply from the battery with a Schottky diode, so that a failure within the
power supply- or the firing of the crowbar SCR- will not impose a dead short
on the battery. After determining the correct float voltage for your
battery plant, say, 14.2 VDC, set the output voltage of the power supply
slightly higher to account for the small forward voltage drop of the
Schottky diode. The load should be connected directly to the battery, not
to the power supply.

I have several Astron switching power supplies in service, along with
several similar units made by Duracomm and Samlex. They have all been
extremely reliable, and the high switching frequency results in no
perceptible buzz or ripple in the output. A decade ago, some switchers were
poorly designed and radiated spurious signals into the HF bands, but none of
the name-brand switchers produced today have that problem. In fact,
Motorola uses Duracomm and Astec switching power supplies in most of its
commercial repeater equipment.

One thing to be aware of is that some Astron power supplies, both linear and
switching, have an internal jumper that ties the negative output to chassis
ground. This jumper must be removed to avoid some problems with ground
loops and erratic controller functions. The presence of this jumper can be
tested by measuring the DC resistance between the grounding prong of the AC
power plug and the negative output terminal. If the resistance is above
10,000 ohms, you're good to go. Otherwise, you've got to get under the
hood...

73, Eric Lemmon WB6FLY


-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of ab6li
Sent: Monday, May 31, 2010 7:31 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Astron switching supply for Battery Charger??

Hello to the group.

Has anyone used an Astron SS series switching supply for a battery float
charger? I have seen the info on using the standard Astrons but I like the
efficiency of the switcher.

Any comments? 

Thanks in advance. John ab6li

[Repeater-Builder] Re: Heavy Duty Antenna question....

[burkleoj]

Doug,
Not to take anything from the SCALA antennas, because they can make some pretty 
impressive antennas, but as indicated, the ultra heavy duty antennas are very 
spendy. They also make normal antennas that are not designed for extreme 
conditions.

Having said that for 440 MHz I really like these Telewave antennas. Telewave 
does give a very nice HAM Discount also and these are UPS shippable. These are 
rugged antennas and will survive some pretty extreme conditions. We do make a 
simple ice bridge above the loops to help break up a major piece of falling ice 
to avoid a direct hit on the loops.

http://www.telewave.com/pdf/TWDS-7033.pdf

Best bang for the buck is the two loop ANT 450D3. I have one of these on our 
420 linking hub repeater on a site that is typically snowed in about 6 months 
each year and it actually will out talk the 444 repeater on a DB Products 8 
loop antenna. Another Nice thing is that these are very broad band 406-512 MHZ 
and you can adjust the loops to provide the best coverage pattern for your site.

Joe - WA7JAW 

--- In Repeater-Builder@yahoogroups.com, "batwing411"  wrote:
>
> Thanks for all the recommendations.
> 
> Fired an email off to Scala, curious to see what they come back with.
> 
> I read thru a few Scala datasheets... curious that they do not give wind 
> loading with radial ice... and... just my .02 here... from the pictures in 
> their catalog... those antennas sure don't look very durable to me...
> 
> 
> keep the recommendations coming - specific models would be quite helpful 
> (especially at 440MHz)
> 
> 
> doug
>

[Repeater-Builder] Re: Heavy Duty Antenna question....

[batwing411]

Thanks for all the recommendations.

Fired an email off to Scala, curious to see what they come back with.

I read thru a few Scala datasheets... curious that they do not give wind 
loading with radial ice... and... just my .02 here... from the pictures in 
their catalog... those antennas sure don't look very durable to me...


keep the recommendations coming - specific models would be quite helpful 
(especially at 440MHz)


doug

Re: [Repeater-Builder] Heavy Duty Antenna question....

[Mike Morris]

At 10:07 AM 05/31/10, you wrote:

>well, i tried to search, but.. alas, sorting thru 1400+ posts just 
>isn't going to work.
>
>i need actual use facts on high altitude (>11k feet), severe duty 
>antenna selection... i've always been a stationmaster (fiberglass) 
>antenna guy - and never had a problem... but...i've never put an 
>antenna up at this height.
>
>i am going to need something good for 150+ MPH winds, ICE, etc.
>
>Open to ideas.


One word: Scala.They are in Medford, Oregon.

Phone 541-779-6500
Email is   communications at kathrein dot com

Kathrein-Werke KG of Germany bought them but
everyone I know of still calls them Scala.

The Cal Tech Seismo Lab has a bunch of radio linked
seismographs and one is on Mt Whitney at 14,500 feet.

Another is on Mount San Antonio (also known as Mt Baldy)
at over 10,000 feet.

Those plus a lot more seismographs at lower altitudes all
use Scala beams.

Now those are beams but I've seen Scala Omni antennas as
well.   They are TOUGH.

In short, Scala make antennas that survive, but they are not
cheap.
  main web site

 VHF High Band

 UHF
Despite the words "uhf mobile" they make UHF station antennas as well.

I'd get their catalog, as well as the ones from Sinclair and
Telewave and maybe even Bogner.   Just be sitting down when
you get to pricing out your new toy.

Years ago a friend could not afford the Scala he wanted, so
he took lots of photos of one that was already in place at a
different site.  Those photos were blown up to 8x10s (I had
access to an enlarger and a darkroom then) and he took
them over to his brother-in-law the welder.

A couple of weeks later he had a homebrew copy of a Scala
VHF Omni with a reflector (think 8 foot tall corner reflector)
A trip to the galvanizers and then to the mountaintop resulted
in a very LOUD system

Mike WA6ILQ

[Repeater-Builder] Re: Heavy Duty Antenna question....

[burkleoj]

I would look at these Telelwave antennas. We have had very good luck with them 
on some pretty nasty sites here in Oregon.

http://www.telewave.com/pdf/TWDS-7045.pdf

175 MPH wind rating and 150 MPH wind rating with a 1/2" of ice loading.

As Fred mentioned Kathrein Scala makes a pretty stout antenna also.

I would think either one of these companies could come up with a solution for 
you that would outlast a fiberglass antenna in your extreme conditions.

Good Luck,
Joe - WA7JAW


> 
>  
> 
>  
> 
>   _  
> 
> From: Repeater-Builder@yahoogroups.com
> [mailto:repeater-buil...@yahoogroups.com] On Behalf Of batwing411
> Sent: Monday, May 31, 2010 12:07 PM
> To: Repeater-Builder@yahoogroups.com
> Subject: [Repeater-Builder] Heavy Duty Antenna question
> 
>  
> 
>   
> 
> 
> well, i tried to search, but.. alas, sorting thru 1400+ posts just isn't
> going to work.
> 
> i need actual use facts on high altitude (>11k feet), severe duty antenna
> selection... i've always been a stationmaster (fiberglass) antenna guy - and
> never had a problem... but...i've never put an antenna up at this height.
> 
> i am going to need something good for 150+ MPH winds, ICE, etc.
> 
> Open to ideas.
>

Re: [Repeater-Builder] Heavy Duty Antenna question....

[NORM KNAPP]

What about bogner? I have seen some pretty HD 700 and 800 mhz antennas from 
them. I don't know about other bands.

- Original Message -
From: Repeater-Builder@yahoogroups.com 
To: Repeater-Builder@yahoogroups.com 
Sent: Mon May 31 20:25:31 2010
Subject: RE: [Repeater-Builder] Heavy Duty Antenna question

  

Talk to Scala in Medford, OR. I'm sure you've heard of them. They'll make a 
super heavy duty gain omni if you're willing to pay. They're website is 
 >. I got one 
NOS some time back second hand and I’m pretty sure meteors, ICBM’s, and the 
like will bounce right off of it.
Gary

 

-Original Message-
From: Repeater-Builder@yahoogroups.com 
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of batwing411
Sent: Monday, May 31, 2010 10:07 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Heavy Duty Antenna question

 

 

well, i tried to search, but.. alas, sorting thru 1400+ posts just isn't going 
to work.

 

i need actual use facts on high altitude (>11k feet), severe duty antenna 
selection... i've always been a stationmaster (fiberglass) antenna guy - and 
never had a problem... but...i've never put an antenna up at this height.

 

i am going to need something good for 150+ MPH winds, ICE, etc.

 

Open to ideas.

 

 

 

 

 



 

 

 

Yahoo! Groups Links

 

http://groups.yahoo.com/group/Repeater-Builder/

 

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RE: [Repeater-Builder] Heavy Duty Antenna question....

[Gary]

Talk to Scala in Medford, OR. I'm sure you've heard of them. They'll make a
super heavy duty gain omni if you're willing to pay. They're website is
 >. I got one
NOS some time back second hand and I'm pretty sure meteors, ICBM's, and the
like will bounce right off of it.
Gary

 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of batwing411
Sent: Monday, May 31, 2010 10:07 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Heavy Duty Antenna question

 

 

well, i tried to search, but.. alas, sorting thru 1400+ posts just isn't
going to work.

 

i need actual use facts on high altitude (>11k feet), severe duty antenna
selection... i've always been a stationmaster (fiberglass) antenna guy - and
never had a problem... but...i've never put an antenna up at this height.

 

i am going to need something good for 150+ MPH winds, ICE, etc.

 

Open to ideas.

 

 

 

 

 



 

 

 

Yahoo! Groups Links

 

http://groups.yahoo.com/group/Repeater-Builder/

 

Individual Email | Traditional

 

http://groups.yahoo.com/group/Repeater-Builder/join

(Yahoo! ID required)

 

repeater-builder-dig...@yahoogroups.com 

repeater-builder-fullfeatu...@yahoogroups.com

 

repeater-builder-unsubscr...@yahoogroups.com

 

http://docs.yahoo.com/info/terms/

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

[allan crites]

I didn't want to overwhelm the gentleman.

wa9zzu

--- On Mon, 5/31/10, Richard W. Solomon  wrote:

> From: Richard W. Solomon 
> Subject: Re: [Repeater-Builder] Re: Help Needed (Guidance and advice) tuning 
> a DB Products Duplexer
> To: Repeater-Builder@yahoogroups.com
> Date: Monday, May 31, 2010, 8:09 PM
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
>  
>  
> 
> 
> 
>   
> 
> 
> 
>   
>   
>   You forgot the most important text:
> 
> 
> 
> Microwave Spectroscopy by Townes & Shalow.
> 
> 
> 
> 73, Dick, W1KSZ
> 
> 
> 
> -Original Message-
> 
> >From: allan crites 
> 
> >Sent: May 31, 2010 8:38 PM
> 
> >To: Repeater-Builder@yahoogroups.com
> 
> >Subject: Re: [Repeater-Builder] Re: Help Needed
> (Guidance and advice) tuning a DB Products Duplexer
> 
> >
> 
> >Kuby,
> 
> >
> 
> > You might start with "Electronic and Radio
> Engineering" by Frederick Emmons Terman, 4th Ed. 1955
> in the Circuit Elements and Circuit Theory section.
> 
> >
> 
> >And try "Radio Engineering Handbook" by Keith
> Henny, 5th Ed. 1959 in  Chapter 6, Wave Guides and
> Resonators by Harald Schutz.
> 
> >
> 
> >Also "Principals of Radar" 3rd Ed. 1952 by J.
> Francis Reintjes and Godfrey T. Coate in ch.9, Resonant
> Lines and Cavities.
> 
> >
> 
> >And "Microwave Transmission Design Data" by
> Theodore Moreno, 1948, ch. 13
> 
> >Cavity Resonators.
> 
> >
> 
> >Then when you finish with these publications you will
> have all the answers to all your questions and then some.
> 
> >
> 
> >WA9ZZU
> 
> >
> 
> >
> 
> >
> 
> >--- On Mon, 5/31/10, Kuby 
> wrote:
> 
> >
> 
> >> From: Kuby 
> 
> >> Subject: [Repeater-Builder] Re: Help Needed
> (Guidance and advice) tuning a DB Products Duplexer
> 
> >> To: Repeater-Builder@yahoogroups.com
> 
> >> Date: Monday, May 31, 2010, 1:22 PM
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >>  
> 
> >>  
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >>   
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >>   
> 
> >>   
> 
> >>   Anyone have white papers or info on how to
> 
> >> modify/design cavities? 
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >> What would it take to move a window 465 can to
> 445/435
> 
> >> tunable? 
> 
> >> 
> 
> >> What is the design parameters for the N connector
> straps? 
> 
> >> 
> 
> >> What is the design of existing tunable cans (L/C
> 
> >> components)? 
> 
> >> 
> 
> >> 
> 
> >> 
> 
> >> --- In Repeater-Builder@yahoogroups.com,
> 
> >> "Eric Lemmon"  wrote:
> 
> >> 
> 
> >> >
> 
> >> 
> 
> >> > Not really.  I had not seen this in any of my
> older
> 
> >> catalogs, and I wondered
> 
> >> 
> 
> >> > if in fact the unit was made by Decibel
> Products. 
> 
> >> Like many RF products,
> 
> >> 
> 
> >> > ferrite isolators in particular, the
> frequency range
> 
> >> stated in a
> 
> >> 
> 
> >> > manufacturer's catalog refers to the
> capability to
> 
> >> construct- which is not
> 
> >> 
> 
> >> > the same as the field-tunable range of a
> specific
> 
> >> product.  I was curious if
> 
> >> 
> 
> >> > the window filter (AKA preselector) could be
> useful in
> 
> >> the 70 cm Amateur
> 
> >> 
> 
> >> > band without modifying the coupling loops or
> jumper
> 
> >> cables.
> 
> >> 
> 
> >> > 
> 
> >> 
> 
> >> > 73, Eric Lemmon WB6FLY
> 
> >> 
> 
> >> >  
> 
> >> 
> 
> >> > 
> 
> >> 
> 
> >> > -Original Message-
> 
> >> 
> 
> >> > From: Repeater-Builder@yahoogroups.com
> 
> >> 
> 
> >> > [mailto:repeater-buil...@yahoogroups.com]
> 
> >> On Behalf Of Jeff DePolo
> 
> >> 
> 
> >> > Sent: Monday, May 31, 2010 6:09 AM
> 
> >> 
> 
> >> > To: Repeater-Builder@yahoogroups.com
> 
> >> 
> 
> >> > Subject: RE: [Repeater-Builder] Re: Help
> Needed
> 
> >> (Guidance and advice) tuning
> 
> >> 
> 
> >> > a DB Products Duplexer
> 
> >> 
> 
> >> > 
> 
> >> 
> 
> >> >   
> 
> >> 
> 
> >> > 
> 
> >> 
> 
> >> > 
> 
> >> 
> 
> >> > Mine don't have labels on them. Usually
> they were
> 
> >> sold as part of an SP
> 
> >> 
> 
> >> > package that included the window filters,
> 
> >> multicoupler, etc.
> 
> >> 
> 
> >> > 
> 
> >> 
> 
> >> > I haven't tuned or swept this particular
> set, but
> 
> >> from experience, the
> 
> >> 
> 
> >> > cavity resonance will tune over a wide swath,
> probably
> 
> >> the full 406-512 MHz,
> 
> >> 
> 
> >> > but the loop lengths may not be optimal over
> such a
> 
> >> wide span (depending on
> 
> >> 
> 
> >> > how the cavities are being used), and
> likewise, the
> 
> >> cable lengths will vary.
> 
> >> 
> 
> >> > 
> 
> >> 
> 
> >> > You have something in particular in mind you
> want me
> 
> >> to test?
> 
> >> 
> 
> >> > 
> 
> >> 
> 
> >> > --- Jeff WN3A
> 
> >> 
> 
> >> > 
> 
> >> 
> 
> >> > > -Original Message-
> 
> >> 
> 
> >> > > From: Repeater-Builder@yahoogroups.com
> 
> >> 
> 
> >> >
>   
> 
> >> 
> 
> >> > > [mailto:Repeater-Builder@yahoogroups.com
> 
> >> 
> 
> >> >
>  ] On
> 
> >> B

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

[Richard W. Solomon]

You forgot the most important text:

Microwave Spectroscopy by Townes & Shalow.

73, Dick, W1KSZ


-Original Message-
>From: allan crites 
>Sent: May 31, 2010 8:38 PM
>To: Repeater-Builder@yahoogroups.com
>Subject: Re: [Repeater-Builder] Re: Help Needed (Guidance and advice) tuning a 
>DB Products Duplexer
>
>Kuby,
>
> You might start with "Electronic and Radio Engineering" by Frederick Emmons 
> Terman, 4th Ed. 1955 in the Circuit Elements and Circuit Theory section.
>
>And try "Radio Engineering Handbook" by Keith Henny, 5th Ed. 1959 in  Chapter 
>6, Wave Guides and Resonators by Harald Schutz.
>
>Also "Principals of Radar" 3rd Ed. 1952 by J. Francis Reintjes and Godfrey T. 
>Coate in ch.9, Resonant Lines and Cavities.
>
>And "Microwave Transmission Design Data" by Theodore Moreno, 1948, ch. 13
>Cavity Resonators.
>
>Then when you finish with these publications you will have all the answers to 
>all your questions and then some.
>
>WA9ZZU
>
>
>
>--- On Mon, 5/31/10, Kuby  wrote:
>
>> From: Kuby 
>> Subject: [Repeater-Builder] Re: Help Needed (Guidance and advice) tuning a 
>> DB Products Duplexer
>> To: Repeater-Builder@yahoogroups.com
>> Date: Monday, May 31, 2010, 1:22 PM
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>>  
>>  
>> 
>> 
>> 
>>   
>> 
>> 
>> 
>>   
>>   
>>   Anyone have white papers or info on how to
>> modify/design cavities? 
>> 
>> 
>> 
>> What would it take to move a window 465 can to 445/435
>> tunable? 
>> 
>> What is the design parameters for the N connector straps? 
>> 
>> What is the design of existing tunable cans (L/C
>> components)? 
>> 
>> 
>> 
>> --- In Repeater-Builder@yahoogroups.com,
>> "Eric Lemmon"  wrote:
>> 
>> >
>> 
>> > Not really.  I had not seen this in any of my older
>> catalogs, and I wondered
>> 
>> > if in fact the unit was made by Decibel Products. 
>> Like many RF products,
>> 
>> > ferrite isolators in particular, the frequency range
>> stated in a
>> 
>> > manufacturer's catalog refers to the capability to
>> construct- which is not
>> 
>> > the same as the field-tunable range of a specific
>> product.  I was curious if
>> 
>> > the window filter (AKA preselector) could be useful in
>> the 70 cm Amateur
>> 
>> > band without modifying the coupling loops or jumper
>> cables.
>> 
>> > 
>> 
>> > 73, Eric Lemmon WB6FLY
>> 
>> >  
>> 
>> > 
>> 
>> > -Original Message-
>> 
>> > From: Repeater-Builder@yahoogroups.com
>> 
>> > [mailto:repeater-buil...@yahoogroups.com]
>> On Behalf Of Jeff DePolo
>> 
>> > Sent: Monday, May 31, 2010 6:09 AM
>> 
>> > To: Repeater-Builder@yahoogroups.com
>> 
>> > Subject: RE: [Repeater-Builder] Re: Help Needed
>> (Guidance and advice) tuning
>> 
>> > a DB Products Duplexer
>> 
>> > 
>> 
>> >   
>> 
>> > 
>> 
>> > 
>> 
>> > Mine don't have labels on them. Usually they were
>> sold as part of an SP
>> 
>> > package that included the window filters,
>> multicoupler, etc.
>> 
>> > 
>> 
>> > I haven't tuned or swept this particular set, but
>> from experience, the
>> 
>> > cavity resonance will tune over a wide swath, probably
>> the full 406-512 MHz,
>> 
>> > but the loop lengths may not be optimal over such a
>> wide span (depending on
>> 
>> > how the cavities are being used), and likewise, the
>> cable lengths will vary.
>> 
>> > 
>> 
>> > You have something in particular in mind you want me
>> to test?
>> 
>> > 
>> 
>> > --- Jeff WN3A
>> 
>> > 
>> 
>> > > -Original Message-
>> 
>> > > From: Repeater-Builder@yahoogroups.com
>> 
>> >   
>> 
>> > > [mailto:Repeater-Builder@yahoogroups.com
>> 
>> >  ] On
>> Behalf Of Eric Lemmon
>> 
>> > > Sent: Sunday, May 30, 2010 12:29 PM
>> 
>> > > To: Repeater-Builder@yahoogroups.com
>> 
>> >  
>> 
>> > > Subject: RE: [Repeater-Builder] Re: Help Needed
>> (Guidance and 
>> 
>> > > advice) tuning a DB Products Duplexer
>> 
>> > > 
>> 
>> > > 
>> 
>> > > 
>> 
>> > > Jeff,
>> 
>> > > 
>> 
>> > > Can you positively identify the window filters by
>> part 
>> 
>> > > number? Also, what
>> 
>> > > is the useful frequency range of the units you
>> purchased?
>> 
>> > > 
>> 
>> > > 73, Eric Lemmon WB6FLY
>> 
>> > > 
>> 
>> > > -Original Message-
>> 
>> > > From: Repeater-Builder@yahoogroups.com
>> 
>> >   
>> 
>> > > 
>> 
>> 
>> > > [mailto:Repeater-Builder@yahoogroups.com
>> 
>> >   
>> 
>> > > 
>> ] On Behalf Of Jeff DePolo
>> 
>> > > Sent: Sunday, May 30, 2010 8:39 AM
>> 
>> > > To: Repeater-Builder@yahoogroups.com
>> 
>> >   
>> 
>> > > 
>> 
>> 
>> > > Subject: RE: [Repeater-Builder] Re: Help Needed
>> (Guidance and 
>> 
>> > > advice) tuning
>> 
>> > > a DB Products

RE: [Repeater-Builder] Heavy Duty Antenna question....

[Fred Seamans]

I have tried DB, Comm. Products, and Antenna Specialist for some Mountain
top sites in Montana. None of them held up through the Winter. I finally
went to Scala, now Kathrein Scala Division, had them build a tank of an
antenna in 1989. To the best of my knowledge they are still in service.
Kathrein Scala has a web site and a catalog to view. Good Luck

Fred  W5VAY

 

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of batwing411
Sent: Monday, May 31, 2010 12:07 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Heavy Duty Antenna question

 

  


well, i tried to search, but.. alas, sorting thru 1400+ posts just isn't
going to work.

i need actual use facts on high altitude (>11k feet), severe duty antenna
selection... i've always been a stationmaster (fiberglass) antenna guy - and
never had a problem... but...i've never put an antenna up at this height.

i am going to need something good for 150+ MPH winds, ICE, etc.

Open to ideas.

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

[allan crites]

Kuby,

 You might start with "Electronic and Radio Engineering" by Frederick Emmons 
Terman, 4th Ed. 1955 in the Circuit Elements and Circuit Theory section.

And try "Radio Engineering Handbook" by Keith Henny, 5th Ed. 1959 in  Chapter 
6, Wave Guides and Resonators by Harald Schutz.

Also "Principals of Radar" 3rd Ed. 1952 by J. Francis Reintjes and Godfrey T. 
Coate in ch.9, Resonant Lines and Cavities.

And "Microwave Transmission Design Data" by Theodore Moreno, 1948, ch. 13
Cavity Resonators.

Then when you finish with these publications you will have all the answers to 
all your questions and then some.

WA9ZZU



--- On Mon, 5/31/10, Kuby  wrote:

> From: Kuby 
> Subject: [Repeater-Builder] Re: Help Needed (Guidance and advice) tuning a DB 
> Products Duplexer
> To: Repeater-Builder@yahoogroups.com
> Date: Monday, May 31, 2010, 1:22 PM
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
>  
>  
> 
> 
> 
>   
> 
> 
> 
>   
>   
>   Anyone have white papers or info on how to
> modify/design cavities? 
> 
> 
> 
> What would it take to move a window 465 can to 445/435
> tunable? 
> 
> What is the design parameters for the N connector straps? 
> 
> What is the design of existing tunable cans (L/C
> components)? 
> 
> 
> 
> --- In Repeater-Builder@yahoogroups.com,
> "Eric Lemmon"  wrote:
> 
> >
> 
> > Not really.  I had not seen this in any of my older
> catalogs, and I wondered
> 
> > if in fact the unit was made by Decibel Products. 
> Like many RF products,
> 
> > ferrite isolators in particular, the frequency range
> stated in a
> 
> > manufacturer's catalog refers to the capability to
> construct- which is not
> 
> > the same as the field-tunable range of a specific
> product.  I was curious if
> 
> > the window filter (AKA preselector) could be useful in
> the 70 cm Amateur
> 
> > band without modifying the coupling loops or jumper
> cables.
> 
> > 
> 
> > 73, Eric Lemmon WB6FLY
> 
> >  
> 
> > 
> 
> > -Original Message-
> 
> > From: Repeater-Builder@yahoogroups.com
> 
> > [mailto:repeater-buil...@yahoogroups.com]
> On Behalf Of Jeff DePolo
> 
> > Sent: Monday, May 31, 2010 6:09 AM
> 
> > To: Repeater-Builder@yahoogroups.com
> 
> > Subject: RE: [Repeater-Builder] Re: Help Needed
> (Guidance and advice) tuning
> 
> > a DB Products Duplexer
> 
> > 
> 
> >   
> 
> > 
> 
> > 
> 
> > Mine don't have labels on them. Usually they were
> sold as part of an SP
> 
> > package that included the window filters,
> multicoupler, etc.
> 
> > 
> 
> > I haven't tuned or swept this particular set, but
> from experience, the
> 
> > cavity resonance will tune over a wide swath, probably
> the full 406-512 MHz,
> 
> > but the loop lengths may not be optimal over such a
> wide span (depending on
> 
> > how the cavities are being used), and likewise, the
> cable lengths will vary.
> 
> > 
> 
> > You have something in particular in mind you want me
> to test?
> 
> > 
> 
> > --- Jeff WN3A
> 
> > 
> 
> > > -Original Message-
> 
> > > From: Repeater-Builder@yahoogroups.com
> 
> >   
> 
> > > [mailto:Repeater-Builder@yahoogroups.com
> 
> >  ] On
> Behalf Of Eric Lemmon
> 
> > > Sent: Sunday, May 30, 2010 12:29 PM
> 
> > > To: Repeater-Builder@yahoogroups.com
> 
> >  
> 
> > > Subject: RE: [Repeater-Builder] Re: Help Needed
> (Guidance and 
> 
> > > advice) tuning a DB Products Duplexer
> 
> > > 
> 
> > > 
> 
> > > 
> 
> > > Jeff,
> 
> > > 
> 
> > > Can you positively identify the window filters by
> part 
> 
> > > number? Also, what
> 
> > > is the useful frequency range of the units you
> purchased?
> 
> > > 
> 
> > > 73, Eric Lemmon WB6FLY
> 
> > > 
> 
> > > -Original Message-
> 
> > > From: Repeater-Builder@yahoogroups.com
> 
> >   
> 
> > > 
> 
> 
> > > [mailto:Repeater-Builder@yahoogroups.com
> 
> >   
> 
> > > 
> ] On Behalf Of Jeff DePolo
> 
> > > Sent: Sunday, May 30, 2010 8:39 AM
> 
> > > To: Repeater-Builder@yahoogroups.com
> 
> >   
> 
> > > 
> 
> 
> > > Subject: RE: [Repeater-Builder] Re: Help Needed
> (Guidance and 
> 
> > > advice) tuning
> 
> > > a DB Products Duplexer
> 
> > > 
> 
> > > 
> 
> > > 
> 
> > > I bought two sets of those window filters from
> the same guy, 
> 
> > > but I knew what
> 
> > > they were, caveat emptor is the golden rule at
> Dayton or any 
> 
> > > other hamfest.
> 
> > > Actually I think I gave him $75 for the pair, and
> I took the two
> 
> > > cleanest/newest ones he had (the newer dark-tan
> ones).
> 
> > > 
> 
> > > --- Jeff WN3A
> 
> > > 
> 
> > > 
> 
> > > 
> 
> > > 
> 
> > > 
> 
> > > 
> 
> > >
> 
> >
> 
> 
> 
> 
> 
> 
>  
> 
> 
> 
> 
> 
>  
> 
> 
> 
>

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

[Jeff DePolo]

Yes, they did sell window filter as a separate catalog item, but if they
were sold as such they would have had a factory sticker on it.  The ones I
have don't have a sticker, which is why I said they were probably part of a
package that would likely have had an SP part number rather than a DB.

These cavities are very tightly coupled, typically about 0.3 dB or so
insertion loss per cavity.  Strung together, the total insertion loss is
about 1.5 dB.  Because of the coupling, each cavity individually doesn't
have a very high Q, so if you were to take one of these units and "split" it
to try to make a duplexer out of it, you'd probably only get about 40 dB or
so of isolation at 5 MHz offset.  Even if you did want to try it, you'd have
to change cable lengths to get the pass response of each cavity to add
on-frequency rather than creating a wide window filter passband as they were
originally cabled.

They do tune fine down to 440 as-is (i.e. as a window filter).

--- Jeff


> -Original Message-
> From: Repeater-Builder@yahoogroups.com 
> [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Eric Lemmon
> Sent: Monday, May 31, 2010 12:52 PM
> To: Repeater-Builder@yahoogroups.com
> Subject: RE: [Repeater-Builder] Re: Help Needed (Guidance and 
> advice) tuning a DB Products Duplexer
> 
>   
> 
> Not really. I had not seen this in any of my older catalogs, 
> and I wondered
> if in fact the unit was made by Decibel Products. Like many 
> RF products,
> ferrite isolators in particular, the frequency range stated in a
> manufacturer's catalog refers to the capability to construct- 
> which is not
> the same as the field-tunable range of a specific product. I 
> was curious if
> the window filter (AKA preselector) could be useful in the 70 
> cm Amateur
> band without modifying the coupling loops or jumper cables.
> 
> 73, Eric Lemmon WB6FLY
> 
> 
> -Original Message-
> From: Repeater-Builder@yahoogroups.com 
>  
> [mailto:Repeater-Builder@yahoogroups.com 
>  ] On Behalf Of Jeff DePolo
> Sent: Monday, May 31, 2010 6:09 AM
> To: Repeater-Builder@yahoogroups.com 
>  
> Subject: RE: [Repeater-Builder] Re: Help Needed (Guidance and 
> advice) tuning
> a DB Products Duplexer
> 
> Mine don't have labels on them. Usually they were sold as 
> part of an SP
> package that included the window filters, multicoupler, etc.
> 
> I haven't tuned or swept this particular set, but from experience, the
> cavity resonance will tune over a wide swath, probably the 
> full 406-512 MHz,
> but the loop lengths may not be optimal over such a wide span 
> (depending on
> how the cavities are being used), and likewise, the cable 
> lengths will vary.
> 
> You have something in particular in mind you want me to test?
> 
> --- Jeff WN3A
> 
> > -Original Message-
> > From: Repeater-Builder@yahoogroups.com 
>  
>  
> > [mailto:Repeater-Builder@yahoogroups.com 
>  
>  ] On Behalf Of Eric Lemmon
> > Sent: Sunday, May 30, 2010 12:29 PM
> > To: Repeater-Builder@yahoogroups.com 
>  
>  
> > Subject: RE: [Repeater-Builder] Re: Help Needed (Guidance and 
> > advice) tuning a DB Products Duplexer
> > 
> > 
> > 
> > Jeff,
> > 
> > Can you positively identify the window filters by part 
> > number? Also, what
> > is the useful frequency range of the units you purchased?
> > 
> > 73, Eric Lemmon WB6FLY
> > 
> > -Original Message-
> > From: Repeater-Builder@yahoogroups.com 
>  
>  
> >  
> > [mailto:Repeater-Builder@yahoogroups.com 
>  
>  
> >  ] On Behalf Of 
> Jeff DePolo
> > Sent: Sunday, May 30, 2010 8:39 AM
> > To: Repeater-Builder@yahoogroups.com 
>  
>  
> >  
> > Subject: RE: [Repeater-Builder] Re: Help Needed (Guidance and 
> > advice) tuning
> > a DB Products Duplexer
> > 
> > 
> > 
> > I bought two sets of those window filters from the same guy, 
> > but I knew what
> > they were, caveat emptor is the golden rule at Dayton or any 
> > other hamfest.
> > Actually I think I gave him $75 for the pair, and I took the two
> > cleanest/newest ones he had (the newer dark-tan ones).
> > 
> > --- Jeff WN3A
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> 
> 
> 
> 
> 

[Repeater-Builder] Re: Hamtronics versus Commercial (Kenwood) Repeater Selection

[Greg Beat]

Easy answer.
We have a Motorola of that vintage in as a temporary repeater  --
our earlier Yaesu/Vertex and TPL amp failed last month after over 12 years of 
full-time service.

We are assembling a new repeater system -- 
and plan to have the Kenwood TKR-850 as the main component of the new system !

g. beat

Re: [Repeater-Builder] Heavy Duty Antenna question....

[Chuck Kelsey]

I know that Comprod makes a special order, extra heavy-duty line. Might want 
to contact them.

Chuck
WB2EDV



- Original Message - 
From: "batwing411" 
To: 
Sent: Monday, May 31, 2010 1:07 PM
Subject: [Repeater-Builder] Heavy Duty Antenna question


>
> well, i tried to search, but.. alas, sorting thru 1400+ posts just isn't 
> going to work.
>
> i need actual use facts on high altitude (>11k feet), severe duty antenna 
> selection... i've always been a stationmaster (fiberglass) antenna guy - 
> and never had a problem... but...i've never put an antenna up at this 
> height.
>
> i am going to need something good for 150+ MPH winds, ICE, etc.
>
> Open to ideas.
>
>
>
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>






No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 9.0.819 / Virus Database: 271.1.1/2908 - Release Date: 05/31/10 
02:25:00

[Repeater-Builder] Heavy Duty Antenna question....

[batwing411]

well, i tried to search, but.. alas, sorting thru 1400+ posts just isn't going 
to work.

i need actual use facts on high altitude (>11k feet), severe duty antenna 
selection... i've always been a stationmaster (fiberglass) antenna guy - and 
never had a problem... but...i've never put an antenna up at this height.

i am going to need something good for 150+ MPH winds, ICE, etc.

Open to ideas.

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

[Kuby]

Anyone have white papers or info on how to modify/design cavities? 

What would it take to move a window 465 can to 445/435 tunable? 
What is the design parameters for the N connector straps? 
What is the design of existing tunable cans (L/C components)? 

--- In Repeater-Builder@yahoogroups.com, "Eric Lemmon"  wrote:
>
> Not really.  I had not seen this in any of my older catalogs, and I wondered
> if in fact the unit was made by Decibel Products.  Like many RF products,
> ferrite isolators in particular, the frequency range stated in a
> manufacturer's catalog refers to the capability to construct- which is not
> the same as the field-tunable range of a specific product.  I was curious if
> the window filter (AKA preselector) could be useful in the 70 cm Amateur
> band without modifying the coupling loops or jumper cables.
> 
> 73, Eric Lemmon WB6FLY
>  
> 
> -Original Message-
> From: Repeater-Builder@yahoogroups.com
> [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jeff DePolo
> Sent: Monday, May 31, 2010 6:09 AM
> To: Repeater-Builder@yahoogroups.com
> Subject: RE: [Repeater-Builder] Re: Help Needed (Guidance and advice) tuning
> a DB Products Duplexer
> 
>   
> 
> 
> Mine don't have labels on them. Usually they were sold as part of an SP
> package that included the window filters, multicoupler, etc.
> 
> I haven't tuned or swept this particular set, but from experience, the
> cavity resonance will tune over a wide swath, probably the full 406-512 MHz,
> but the loop lengths may not be optimal over such a wide span (depending on
> how the cavities are being used), and likewise, the cable lengths will vary.
> 
> You have something in particular in mind you want me to test?
> 
> --- Jeff WN3A
> 
> > -Original Message-
> > From: Repeater-Builder@yahoogroups.com
>   
> > [mailto:Repeater-Builder@yahoogroups.com
>  ] On Behalf Of Eric Lemmon
> > Sent: Sunday, May 30, 2010 12:29 PM
> > To: Repeater-Builder@yahoogroups.com
>  
> > Subject: RE: [Repeater-Builder] Re: Help Needed (Guidance and 
> > advice) tuning a DB Products Duplexer
> > 
> > 
> > 
> > Jeff,
> > 
> > Can you positively identify the window filters by part 
> > number? Also, what
> > is the useful frequency range of the units you purchased?
> > 
> > 73, Eric Lemmon WB6FLY
> > 
> > -Original Message-
> > From: Repeater-Builder@yahoogroups.com
>   
> >  
> > [mailto:Repeater-Builder@yahoogroups.com
>   
> >  ] On Behalf Of Jeff DePolo
> > Sent: Sunday, May 30, 2010 8:39 AM
> > To: Repeater-Builder@yahoogroups.com
>   
> >  
> > Subject: RE: [Repeater-Builder] Re: Help Needed (Guidance and 
> > advice) tuning
> > a DB Products Duplexer
> > 
> > 
> > 
> > I bought two sets of those window filters from the same guy, 
> > but I knew what
> > they were, caveat emptor is the golden rule at Dayton or any 
> > other hamfest.
> > Actually I think I gave him $75 for the pair, and I took the two
> > cleanest/newest ones he had (the newer dark-tan ones).
> > 
> > --- Jeff WN3A
> > 
> > 
> > 
> > 
> > 
> > 
> >
>

[Repeater-Builder] MSR2000 UHF PA parts or whole PA needed.

[kc7stw]

Hello to all in the group.

I have a early A version PA that is going to die soon.  It was repaired by a 
local shop a long time ago. (looks like a CBer did the work)  

I would like to know.  If any one knows if A. Motorola still makes the 
transistor cards/kit/parts.  I phone number that will get me to the correct 
people if they still have the parts.  All the numbers I have found online don't 
seem to contact the correct person.

Or, if someone has a PA that they would like to sell or trade.  The PA I have 
now is the intermittent duty PA.

I have VHF msr2000 stations, full duty PA's etc.  Will trade a full VHF MSR2000 
with 100 watt full duty PA, for a UHF PA.

Thanks

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

[Eric Lemmon]

Not really.  I had not seen this in any of my older catalogs, and I wondered
if in fact the unit was made by Decibel Products.  Like many RF products,
ferrite isolators in particular, the frequency range stated in a
manufacturer's catalog refers to the capability to construct- which is not
the same as the field-tunable range of a specific product.  I was curious if
the window filter (AKA preselector) could be useful in the 70 cm Amateur
band without modifying the coupling loops or jumper cables.

73, Eric Lemmon WB6FLY
 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jeff DePolo
Sent: Monday, May 31, 2010 6:09 AM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Re: Help Needed (Guidance and advice) tuning
a DB Products Duplexer

  


Mine don't have labels on them. Usually they were sold as part of an SP
package that included the window filters, multicoupler, etc.

I haven't tuned or swept this particular set, but from experience, the
cavity resonance will tune over a wide swath, probably the full 406-512 MHz,
but the loop lengths may not be optimal over such a wide span (depending on
how the cavities are being used), and likewise, the cable lengths will vary.

You have something in particular in mind you want me to test?

--- Jeff WN3A

> -Original Message-
> From: Repeater-Builder@yahoogroups.com
  
> [mailto:Repeater-Builder@yahoogroups.com
 ] On Behalf Of Eric Lemmon
> Sent: Sunday, May 30, 2010 12:29 PM
> To: Repeater-Builder@yahoogroups.com
 
> Subject: RE: [Repeater-Builder] Re: Help Needed (Guidance and 
> advice) tuning a DB Products Duplexer
> 
> 
> 
> Jeff,
> 
> Can you positively identify the window filters by part 
> number? Also, what
> is the useful frequency range of the units you purchased?
> 
> 73, Eric Lemmon WB6FLY
> 
> -Original Message-
> From: Repeater-Builder@yahoogroups.com
  
>  
> [mailto:Repeater-Builder@yahoogroups.com
  
>  ] On Behalf Of Jeff DePolo
> Sent: Sunday, May 30, 2010 8:39 AM
> To: Repeater-Builder@yahoogroups.com
  
>  
> Subject: RE: [Repeater-Builder] Re: Help Needed (Guidance and 
> advice) tuning
> a DB Products Duplexer
> 
> 
> 
> I bought two sets of those window filters from the same guy, 
> but I knew what
> they were, caveat emptor is the golden rule at Dayton or any 
> other hamfest.
> Actually I think I gave him $75 for the pair, and I took the two
> cleanest/newest ones he had (the newer dark-tan ones).
> 
> --- Jeff WN3A
> 
> 
> 
> 
> 
> 
> 

Re: [Repeater-Builder] Legal radios for a repeater

[Kris Kirby]

On Mon, 31 May 2010, WD7F - John in Tucson wrote:
> Ah ha!  Now I have it...your job title explains the comment about Part 
> 90. de WD7F John in Tucson
> > For Part 90 use, something narrowband complaint because the deadline is 
> > a loomin'.

Well, spending $2000 now is usually cheaper than spending $500 now and 
$2000 later. Even if it takes three years to implement; swapping out a 
fleet of 100 - 2500 radios takes time. 

--
Kris Kirby, KE4AHR
Disinformation Analyst

[Repeater-Builder] R2001D Parts/boards

[Joel]

Hi to all here on the group,

Is anyone in the group know where I can get parts and boards for the 
Motorola R2001D service monitor?  I'm particularly interested in the A2 and 
A7 boards.

v44kai.Joel.


--
I am using the free version of SPAMfighter.
We are a community of 7 million users fighting spam.
SPAMfighter has removed 836 of my spam emails to date.
Get the free SPAMfighter here: http://www.spamfighter.com/len

The Professional version does not have this message

Re: [Repeater-Builder] Astron switching supply for Battery Charger??

[Thomas Oliver]

I have been using a Samlex 20 amp switcher to float charge 4 six volt 
golf car batteries wired in series parallel for the last 5 years,

The repeater and packet device are both Syntor X radios and have not 
been off the air in over 4 years.

I keep the voltage set at 13.2 with the power supply wired direct to the 
batteries (through a fuse of course) but find no reason to place a diode 
in series as the supply must be already protected from back current flow.

I picked 13.2 volts because  electrolite loss is minimal at that 
voltage, it may not be the optimum setup but it works for me.

I still need to figure out how to equilizie the batteries easily with 
this set up.

tom

On 5/31/2010 10:31 AM, ab6li wrote:
> Hello to the group.
>
> Has anyone used an Astron SS series switching supply for a battery float 
> charger? I have seen the info on using the standard Astrons but I like the 
> efficiency of the switcher.
>
> Any comments?
>
> Thanks in advance. John   ab6li
>
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>
>
>

Re: [Repeater-Builder] Legal radios for a repeater

[WD7F - John in Tucson]

Ah ha!  Now I have it...your job title explains the comment about Part 90.
de WD7F
John in Tucson

- Original Message - 
From: "Kris Kirby" 
To: "terry dalpoas" 
Cc: 
Sent: Sunday, May 30, 2010 12:57 PM
Subject: Re: [Repeater-Builder] Legal radios for a repeater


> On Sat, 29 May 2010, terry dalpoas wrote:
>> 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?
> 
> For ham use, literally anything as long as it doesn't cause harmful 
> interference to other services.
> 
> For Part 90 use, something narrowband complaint because the deadline is 
> a loomin'.
> 
> --
> Kris Kirby, KE4AHR
> Disinformation Analyst

RE: [Repeater-Builder] Astron switching supply for Battery Charger??

[Eric Lemmon]

John,

There's nothing about a switching power supply that might disqualify it for
battery float service.  However, you should isolate the output of any power
supply from the battery with a Schottky diode, so that a failure within the
power supply- or the firing of the crowbar SCR- will not impose a dead short
on the battery.  After determining the correct float voltage for your
battery plant, say, 14.2 VDC, set the output voltage of the power supply
slightly higher to account for the small forward voltage drop of the
Schottky diode.  The load should be connected directly to the battery, not
to the power supply.

I have several Astron switching power supplies in service, along with
several similar units made by Duracomm and Samlex.  They have all been
extremely reliable, and the high switching frequency results in no
perceptible buzz or ripple in the output.  A decade ago, some switchers were
poorly designed and radiated spurious signals into the HF bands, but none of
the name-brand switchers produced today have that problem.  In fact,
Motorola uses Duracomm and Astec switching power supplies in most of its
commercial repeater equipment.

One thing to be aware of is that some Astron power supplies, both linear and
switching, have an internal jumper that ties the negative output to chassis
ground.  This jumper must be removed to avoid some problems with ground
loops and erratic controller functions.  The presence of this jumper can be
tested by measuring the DC resistance between the grounding prong of the AC
power plug and the negative output terminal.  If the resistance is above
10,000 ohms, you're good to go.  Otherwise, you've got to get under the
hood...

73, Eric Lemmon WB6FLY
 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of ab6li
Sent: Monday, May 31, 2010 7:31 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Astron switching supply for Battery Charger??

  

Hello to the group.

Has anyone used an Astron SS series switching supply for a battery float
charger? I have seen the info on using the standard Astrons but I like the
efficiency of the switcher.

Any comments? 

Thanks in advance. John ab6li

[Repeater-Builder] Astron switching supply for Battery Charger??

[ab6li]

Hello to the group.

Has anyone used an Astron SS series switching supply for a battery float 
charger? I have seen the info on using the standard Astrons but I like the 
efficiency of the switcher.

Any comments?  

Thanks in advance. John   ab6li

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

[Jeff DePolo]

Mine don't have labels on them.  Usually they were sold as part of an SP
package that included the window filters, multicoupler, etc.

I haven't tuned or swept this particular set, but from experience, the
cavity resonance will tune over a wide swath, probably the full 406-512 MHz,
but the loop lengths may not be optimal over such a wide span (depending on
how the cavities are being used), and likewise, the cable lengths will vary.

You have something in particular in mind you want me to test?

--- Jeff WN3A

> -Original Message-
> From: Repeater-Builder@yahoogroups.com 
> [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Eric Lemmon
> Sent: Sunday, May 30, 2010 12:29 PM
> To: Repeater-Builder@yahoogroups.com
> Subject: RE: [Repeater-Builder] Re: Help Needed (Guidance and 
> advice) tuning a DB Products Duplexer
> 
>   
> 
> Jeff,
> 
> Can you positively identify the window filters by part 
> number? Also, what
> is the useful frequency range of the units you purchased?
> 
> 73, Eric Lemmon WB6FLY
> 
> -Original Message-
> From: Repeater-Builder@yahoogroups.com 
>  
> [mailto:Repeater-Builder@yahoogroups.com 
>  ] On Behalf Of Jeff DePolo
> Sent: Sunday, May 30, 2010 8:39 AM
> To: Repeater-Builder@yahoogroups.com 
>  
> Subject: RE: [Repeater-Builder] Re: Help Needed (Guidance and 
> advice) tuning
> a DB Products Duplexer
> 
> 
> 
> I bought two sets of those window filters from the same guy, 
> but I knew what
> they were, caveat emptor is the golden rule at Dayton or any 
> other hamfest.
> Actually I think I gave him $75 for the pair, and I took the two
> cleanest/newest ones he had (the newer dark-tan ones).
> 
> --- Jeff WN3A
> 
> 
> 
> 
> 
> 
>