Re: [Repeater-Builder] Vertex vs. Kenwood

[John Barrett]

What sort of problems are you having with the system at the current 
site, and generally how much quieter is the new site. Was there any 
additional filtering or other adjustments made to get the gear 
functional at the old site that might be eliminated at the new site 
without sacrificing so much isolation/protection that you create new 
problems ?? And a dozen more questions I could ask :) What I'm looking 
for here is anything that would indicate that the current system could 
be made to perform better at the new site.

Given that any issues at the old site are primarily related to the 
problems of operating in a high-RF environment, and there is nothing 
particularly wrong with the current repeater electronics excepting mods 
made to deal with the high-RF, I personally would look at moving the 
gear as is and see how it performs at the new site, THEN decide if the 
gear needs to be replaced.

But you have a possible advantage in having a buyer for the old gear and 
the desire for new gear -- you can latch on to the new gear first, get 
it installed and tested at the new location, THEN take down the old 
site... minimal down time and no pressure to move the old gear to the 
new site fast and get it back on the air. The only question in my 
mind would be if the buyer wants the entire old system so you can do a 
total replacement without reusing parts from the old site.. if so, I'd 
be giving this option serious consideration.

So there is the trade-off -- downtime plus possible double work 
rebuilding the old repeater plus installing a new repeater if the old 
one does not perform well at the new site versus the up front expense of 
buying and installing a complete new system before taking the old one down.


[EMAIL PROTECTED] wrote:
>
> Hi Joe,
>
> >I'm still trying to comprehend why you would need replacements just
> because a site is more quiet. If they work at the crowded site, they
> should work fine at the quiet one.
>
>
> That's just it -- they don't work all that well at this mountaintop 
> site with literally hundreds of RF sources. Since we have an 
> opportunity to sell them, it seems like a good time for an upgrade. 
> But if K is no better in this situation than V, you're right, we're 
> going down the wrong path.
>
> This is a club that went from Micor vintage equipment that was showing 
> its age to Vertex and now has an opportunity to change once again. The 
> bias is toward new, low-maintenance gear rather than refurbished old 
> commercial gear.
>
> 73,
> Bob
>
> -Original Message-
> From: MCH <[EMAIL PROTECTED]>
> To: Repeater-Builder@yahoogroups.com
> Sent: Thu, 2 Oct 2008 9:50 pm
> Subject: Re: [Repeater-Builder] Vertex vs. Kenwood
>
> I'm still trying to comprehend why you would need replacements just
> because a site is more quiet. If they work at the crowded site, they
> should work fine at the quiet one.
>
> Joe M.
>
> [EMAIL PROTECTED] wrote:
> > Hi All,
> >
> > My club has some 3-year-old VHF and UHF Vertex repeaters at a high-RF
> > site. A possible deal would move them to a much quieter site, and if
> > that happens we'll need replacements.
> >
> > Members of this list have consistently shown a preference for Kenwoods,
> > and it appears both brands are priced about the same. However, I'm
> > concerned that much of what has been posted falls into the true 
> believer
> > category, and this decision must be based on technical data. How about
> > it, RF gurus? If you have facts, please spill 'em.
> >
> > Thanks!
> >
> > 73,
> > Bob, WA9FBO
> >
> >
> >
> > --
> > Looking for simple solutions to your real-life financial challenges?
> > Check out WalletPop for the latest news and information, tips and
> > calculators
> > 
> .
> >
> >
> >
> > --
> >
> > No virus found in this incoming message.
> > Checked by AVG.
> > Version: 7.5.526 / Virus Database: 270.7.5/1703 - Release Date: 
> 10/2/2008 7:46 AM
> 
> Find phone numbers fast with the New AOL Yellow Pages 
> !
>  

Re: [Repeater-Builder] Vertex vs. Kenwood

[John Barrett]

my question exactly -- if the new site is quieter and you had the 
duplexer cranked back (insertion loss increased) to get better 
isolation, you may may even be able to open it up a little and get some 
additional receive sensitivity... other than that, why change what works 
unless there are significant issues with the old gear.

I'd be looking at it as a chance to go over the entire system and fix 
any minor problems like old/stressed coax, oxidized connections, etc.. 
make sure its going to work trouble free for another 3 years.

MCH wrote:
>
> I'm still trying to comprehend why you would need replacements just
> because a site is more quiet. If they work at the crowded site, they
> should work fine at the quiet one.
>
> Joe M.
>
> [EMAIL PROTECTED]  wrote:
> > Hi All,
> >
> > My club has some 3-year-old VHF and UHF Vertex repeaters at a high-RF
> > site. A possible deal would move them to a much quieter site, and if
> > that happens we'll need replacements.
> >
> > Members of this list have consistently shown a preference for Kenwoods,
> > and it appears both brands are priced about the same. However, I'm
> > concerned that much of what has been posted falls into the true 
> believer
> > category, and this decision must be based on technical data. How about
> > it, RF gurus? If you have facts, please spill 'em.
> >
> > Thanks!
> >
> > 73,
> > Bob, WA9FBO
> >
> >
> >
> > --
> > Looking for simple solutions to your real-life financial challenges?
> > Check out WalletPop for the latest news and information, tips and
> > calculators
> > 
>   
> >.
> >
> >
> >
> > --
> >
> > No virus found in this incoming message.
> > Checked by AVG.
> > Version: 7.5.526 / Virus Database: 270.7.5/1703 - Release Date: 
> 10/2/2008 7:46 AM
>
>  

Re: [Repeater-Builder] Portable Temporary Repeater

[John Barrett]

technically you can do anything -- look at Amsat -- 2m input, 10m 
output, 70cm input, 2m output..

in general -- the larger the split, the easier it is to prevent receiver 
desense. -- 600kc split on 2m is a royal pain to deal with :)


Dave Gomberg wrote:
>
> At 11:39 9/30/2008, John Barrett wrote:
> > there are
> >too many situations where the repeater would be useful that do not in
> >any sense meet the emergency use regs. (special events spring to mind)
>
> This is definitely so. We would need special (limited) drill and
> practice operation permission from the FCC. My question
> was: What (if anything) is TECHNICALLY wrong with the idea of using
> an out-of-band repeater output freq?
>
> -- 
> Dave Gomberg, San Francisco NE5EE gomberg1 at wcf dot com
> All addresses, phones, etc. at http://www.wcf.com/ham/info.html 
> <http://www.wcf.com/ham/info.html>
> --
>
>  

Re: [Repeater-Builder] Portable Temporary Repeater

[John Barrett]

here goes the regs debate -- my interpretation is you can go anywhere 
you need to to make the initial report and get first responders moving 
-- once first responders are on the scene -- keep it in band unless 
specifically requested by the served agency and on frequencies normally 
used by that agency !! I've got a portable UHF repeater for emergency 
use.. never even considered setting it up out of band because there are 
too many situations where the repeater would be useful that do not in 
any sense meet the emergency use regs. (special events spring to mind)

Dave Gomberg wrote:
>
> At 10:16 9/30/2008, Robert Pease wrote:
>
>> Not to start a reg debate but I believe the fcc only allows any and 
>> all means of communication when there is an imminent threat to life 
>> or property 
>
> Such as a forest fire, earthquake recovery, flood coming or just been 
> here, etc.
>
>> AND there is no other means of communications available.
>
> Hey, if the cell phones work we are not needed, right?   And how many 
> forest fire scenes have cell phone coverage   If you don't have 
> the great duplexer needed for 600KHz separation, that mode is NOT 
> AVAILABLE.
>
>
>> For the event mentioned this would not be the case 
>
> Huh???   What event?
>
>
> -- 
> Dave Gomberg, San Francisco   NE5EE gomberg1 at wcf dot com
> All addresses, phones, etc. at http://www.wcf.com/ham/info.html
>  
> -
>
>  

Re: [Repeater-Builder] Triplexer noise

[John Barrett]

add a filter between the triplexer and the desensed radio -- knock down 
that interfering signal a little more -- one can should do the trick and 
only cost you a DB or so :)

Dr. Ron Johnson wrote:
>
> We are using a comet 324 triplexer here for 2m, 220, and 440.  Working 
> with a triband antenna.  Only problem is desense on 2m through the 
> triplexerany ideas other than throwing the thing awayThe 
> desense is present at very low levels of signal...at about .2mv but 
> will cycle the repeater.  Makes it hard for portables getting in.  The 
> triplexer is grounded, all connections are fine.  Have been chasing 
> this for some time now...I opened it up and even touched up the solder 
> jointsnothingstill desense...  Maybe somebody out there has 
> had the same problem and has beaten it
>  
> thanks, ron
>  

Re: [Repeater-Builder] Volt-Amp (Re: APC UPS Charging Power)

[John Barrett]

This doesn't mesh up with what I've learned about power factor -- the 
impression that I got was a perfect power factor was 1 (one) (current in 
phase with voltage, equipment using everything the the power company 
charges you for to do useful work). Anything other than PF=1 meant that 
the equipment was using the power less efficiently, and therefore you 
were paying more in KWH than the work actually performed. That 
description excludes the possibly that the equipment could use more 
power than the power company records as being delivered (heck, 
conservation of energy says that in any case). any load reactance 
(inductive or capacitive) and the very low PF numbers stated sound more 
like what I get off my linear power supplies with big capacitance and no 
power factor correction. In any case, anything other than PF=1 should 
mean that you are paying for more power than you are actually using.

Tell me where I goofed this up ??



Bob M. wrote:
>
> Thank you Eric. This was the explanation I was looking for. The UPS is 
> saving me money when drawing 181 Volt-Amps, yet the electric meter is 
> only recording and charging me for 31 Watts. I wonder if APC did this 
> on purpose. I don't know how much current is actually being fed to the 
> batteries; they've been in there for a couple of months and should be 
> fully charged by now, so it should just be trickling them (eight 12V 
> 7A SLA cells in series/parallel for 48V).
>
> Bob M.
> ==
> --- On Tue, 9/16/08, Eric Lemmon <[EMAIL PROTECTED] 
> > wrote:
>
> > From: Eric Lemmon <[EMAIL PROTECTED] >
> > Subject: RE: [Repeater-Builder] Volt-Amp (Re: APC UPS Charging Power)
> > To: Repeater-Builder@yahoogroups.com 
> 
> > Date: Tuesday, September 16, 2008, 9:21 PM
> > Albert,
> >
> > You are forgiven, because you pose an important question!
> >
> > The spinning aluminum disk in the kilowatthour meter found
> > on most
> > residential service-entrance panels measures true power in
> > kilowatts versus
> > time, which equals energy. Thus, your electric utility
> > charges you for the
> > true power you use, not for volts times amperes- known as
> > reactive power.
> > Although the utility must provide the capability to supply
> > all of the
> > amperes you need, some of those amperes are "given
> > back" to the utility due
> > to a lower than unity power factor. That is why many
> > utility companies
> > charge a "kVAR Penalty" to certain industrial
> > power users whose volt-ampere
> > demands far exceed their watt demands, meaning that the
> > power factor is low.
> > Industrial power users strive to keep their power factors
> > at 0.95 or above,
> > to avoid some really painful penalties! The power factor,
> > or PF, is simply
> > watts divided by volts time amperes.
> >
> > The issue of power factor is why large Diesel generator
> > sets have ratings
> > such as 1000 kW/1250 kVAR. In simple terms, any AC
> > generator requires
> > torque (engine horsepower) to meet true power demands, and
> > excitation (field
> > flux intensity) to meet reactive power demands. When the
> > generator load is
> > reactive, that is, it has a power factor less than unity,
> > the generator must
> > not only have the horsepower to supply the energy in watts,
> > but it must have
> > excess capacity to handle the additional current required
> > by motors and
> > other low-power-factor loads. In a nutshell, that is why a
> > 1000 watt
> > generator may be unable to keep running a refrigerator that
> > uses only 900
> > watts; the fridge may require 1200 VA to operate because it
> > has a low power
> > factor, and the small generator has no ability to handle
> > such loads.
> > Because of its relatively small amount of spinning mass,
> > such a small
> > generator probably could not even handle the
> > refrigerator's starting
> > current- which is about 5 to 6 times its running current.
> >
> > 73, Eric Lemmon WB6FLY
> >
> >
> >
> > -Original Message-
> > From: Repeater-Builder@yahoogroups.com 
> 
> > [mailto:Repeater-Builder@yahoogroups.com 
> ] On Behalf Of
> > Albert
> > Sent: Tuesday, September 16, 2008 2:13 PM
> > To: Repeater-Builder@yahoogroups.com 
> 
> > Subject: [Repeater-Builder] Volt-Amp (Re: APC UPS Charging
> > Power)
> >
> > Hopefully, you will forgive me for hijacking the post, but
> > this brings up a
> > question I have had for a long time. What on earth is a
> > "volt-amp"?
> > My logic would state that is is the same as a watt, which
> > is volts x amps,
> > as you probably well know. So what on earth is it?
> >
> > Confused.
> >
> > Albert
>
>  

Re: [Repeater-Builder] APC UPS Charging Power

[John Barrett]

low power factors are bad -- you pay for the higher VA, but are only 
using the lower watts to do actual work !!

I'm really surprised that USP doesn't have a PFC front end to bring 
everything back into line.

Bob M. wrote:
>
> I have an APC SU2200 (SmartUPS, 2200VA) 3U tall, that I put new 
> batteries in a few months ago. So far it's just sitting, plugged in, 
> turned off, with no load. I got curious as to how much power it was 
> sucking out of the wall outlet, so I plugged the UPS into my 
> Kill-A-Watt device and plugged that into the wall. Here are the 
> numbers I observed:
>
> 122.2 Volts
> 1.48 Amps
> 31 Watts
> 181 Volt-Amps
> 0.17 Power Factor
>
> The values were identical with the unit turned on, also with no load. 
> The only thing running inside the UPS is the battery charger; the 
> inverter is completely bypassed and is not running.
>
> I then ran the UPS into a test cycle, again with no load, but this 
> time the inverter turned on and powered the load, thus disconnecting 
> itself from the commercial AC power. Surprisingly, there was still a 
> little bit of power being used, probably by the transformer and line 
> sampling circuit. Here are the readings I got during the self-test:
>
> 122.4 Volts
> 0.09 Amps
> 0 Watts
> 11 Volt-Amps
> 0.06 Power Factor
>
> As far as I know, the utility's kilowatt-hour meter on the side of my 
> house, which is a rotating aluminum-disc style, measures WATTS, not 
> Volt-Amps. Somehow APC has managed to get their charging circuit to 
> draw a lot of current while keeping the power factor and Wattage power 
> extremely low. I suspect it's highly capacitive.
>
> So here's where you all get to jump in. Is this UPS costing me a lot 
> just to keep the batteries charged (180 VA) or am I only being charged 
> for the wattage it draws?
>
> Bob M.
>
>  

Re: [Repeater-Builder] Re: Scanner as repeater receiver?

[John Barrett]

Much appreciated !! I'll pass the info on (though I think the guy is monitoring 
the list now hi hi !!)

  - Original Message - 
  From: Nate Duehr 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Wednesday, August 20, 2008 6:10 PM
  Subject: Re: [Repeater-Builder] Re: Scanner as repeater receiver?


  Sorry, replying to myself...

  Another website about the USB dongles...

  http://app-rpt.qrvc.com/usbsoundfob.html

  Nate WY0X


   

Re: [Repeater-Builder] Re: Scanner as repeater receiver?

[John Barrett]

I'm just middle-manning this one -- astrisk was rejected by the guy setting up 
the repeater due to complexity and hardware required -- echolink due to 
requiring a true connection to the internet -- this has got to work completely 
within the private network already in existance between the sites, and it must 
be able to start up on boot and re-establish the connection in case of power 
failure, preferably as a windows service, though linux has not been rejected.

Someone tell me that echolink can be configured for LAN only, or that astersk 
can be setup for start on boot without using a special radio interface board, 
and we'll move forward along those lines :)

Re: [Repeater-Builder] Re: Scanner as repeater receiver?

[John Barrett]

I'm consulting with another ham on setting up a one way VoIP link for a split 
site VHF repeater, RX and TX to be located about 2 miles apart.

I've got a tenative solution using and off the shelf streaming audio server and 
client, with a custom app to poll the PC parallel port for any digial signaling 
that need to be pulled off the reciever and transfered to the 
controller/transmitter via another custom app that will output to the parallel 
port.

Is there anything out there a little more integrated that can handle the job, 
or other suggestions as to a solution ?? Prefered environment is Windows, with 
some hope that a "service app" that will run at boot can be found.  2 way 
solutions like Echolink and Asterisk have already been rejected, as have any 
solutions that require hardware beyond a PC with a sound card and parallel port.



  - Original Message - 
  From: Nate Duehr 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Monday, August 18, 2008 12:52 PM
  Subject: Re: [Repeater-Builder] Re: Scanner as repeater receiver?


  JOHN MACKEY wrote:
  > Skipp-
  > Everything you say below is correct. But I would still argue that it simply
  > isn't worth it to do all the modifications you suggest to a scanner when you
  > can pick up a good receiver from a Motrac/Micor/MastrII/MastrPro for $25 at 
a
  > hamfest or ebay and have a receiver that is still better than the modified
  > scanner.

  Heck, at the hamfest I was at yesterday, there were two Micors already 
  duplexed, a Mastr II already duplexed, and a Mastr Pro sitting in a pile 
  on a table with a sign that said "$25 takes all", if I read it correctly.

  I looked at the MASTR II -- it was a 66-split (VHF). I assume the 
  others were also, don't know. Didn't check. I didn't need any more VHF 
  stuff...

  Seller was "Dutch", K0AWS ... if someone wants to try to hunt him down 
  to buy any of it.

  His club is: http://www.ab0pc.org/

  There ya go... a real "guess what I saw at a hamfest" story, but with 
  real follow-up information on who was selling the stuff.

  Happy gear hunting...

  Nate WY0X


   

RE: [Repeater-Builder] 24 vdc to 12vdc

[John Barrett]

The Xantrex converters I mentioned will take any input from 14v to 80v and
deliver 40 amps out.. the output is actually a full blown 3 stage battery
charger... so you really need to have a gel cell on the output, which will
double as filtering.. and should work just fine under any load conditions,
as one of the unit configurations is as a load diverter.. to direct current
to an alternative load when the battery bank is fully charged (for instance,
go a bank of grid-tie inverters)

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Paul Finch
Sent: Tuesday, March 25, 2008 10:05 AM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] 24 vdc to 12vdc

Hello Group,

I will say right now, a resistor is a bad idea but it can work of done
correctly and the load is a constant.  Back before I knew better I did just
that.  I needed 12 VDC for the filament of a GE Mastr Pro UHF transmitter, I
can't remember the current right now, it's been 20 years.  I built a DC
supply and built a regulator with a 2N3055 NPN pass transistor, it worked OK
but the transistor was dropping way to much voltage creating a lot of heat.
I installed a high wattage series resistor that was heat sinked to a big
aluminum plate before the 2N3055 and with a big Moose of a capacitor on the
input of the 3055 to keep down noise.  The resistor dropped the input
voltage about 10 volts and the transistor ran cool.  All of this was before
any DC to DC converters were popular or available to the average Joe Ham.  

The system ran like that with no problem for years, I shut the repeater down
and left it on the building, it was not worth the effort to bring it down
from the penthouse.  As far as I know it's still up there could possibly be
fired back up on 444.850 if needed.  My friend that got me that site retired
so I faded away.

The Converters are by far the best but if the load is fairly constant and if
all you have to work with is a series resistor and a regulator it can work. 

Also, you don't have to buy these from Astron, you can buy small "bricks"
that do this same thing and all you have to do is add some capacitance to
the output unless they have variable outputs.  Don't know what Astron gets
on their units but I have several 48 to 5, 12 and 24 volts units in service
now like the ones below.

Here are a few, I have used the Powerstream and Murata products in the past.

http://www.vicr.com/  
http://www.v-infinity.com/
http://www.powerstream.com/dcdc.htm
http://www.murata-ps.com/mps-home.html

Again, don't get me wrong, THE DC to DC CONVERTER IS BEST!  Just trying to
avoid flames.

Paul


-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright
Sent: Tuesday, March 25, 2008 7:34 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] 24 vdc to 12vdc

Rick,

Definitely do not use a resistor.  Its drop depends on current draw and if
the rig is a transceiver it will draw much more current on TX than RX
changing the drop.

You can use the lower battery, the one connected to ground.  However, as
some others suggested might be better to have a 24-to-12 V converter.

73, ron, n9ee/r



>From: Rick & Charlotte <[EMAIL PROTECTED]>
>Date: 2008/03/24 Mon PM 02:21:31 CDT
>To: Repeater-Builder@yahoogroups.com
>Subject: [Repeater-Builder] 24 vdc to 12vdc

>
>I hope some one on the group can help me out here 
>
>I want to put a  radio in a jeep 
>
>the problem is the jeep runs 24 v and as you know radios run 12v
>
>Is there a device that will drop 24v down to 12 vdv ? I know I could use a 
>droping resistor but I can see it making a lot of heat 
>
>if I remember right the jeep uses 2 12 v batts can I just tape off one set
for 
>the radio ?
>
>I know this is not about repeaters , but just thought some one might  have 
>an idea .. 
>
>Thanks
>
>Rick
>
>Of all the intelligent animals, Human is the species that is least likely
to learn 
>from its experience.
>That explains why so manny of us have more then one Border Collie !
>
>==  www.karolinabc.ca  == 
>
>Rick,Charlote & Kids
>Our Border Collies
>Miss Daisy Duke
>Sir Red-A-Lot
>Miss Elly May
>Mr Boots
>Mr. Balue
>Our Border Collie Message Group
>[EMAIL PROTECTED]
>
>



Ron Wright, N9EE
727-376-6575
MICRO COMPUTER CONCEPTS
Owner 146.64 repeater Tampa Bay, FL
No tone, all are welcome.







Yahoo! Groups Links





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3:03 PM

RE: [Repeater-Builder] Re: 24 vdc to 12 vdc

[John Barrett]

The practical effect is that the charge on the two batteries will be
imbalanced, and should the charger ever get the more charge battery fully
charged, the under charged battery will fool the charger into thinking the
pair is not fully charged, resulting the in the fully charged battery being
overcharged, and if not quickly damaged, then at least dramatically reduced
in lifetime.

 

Some sort of converter is required to keep the load balanced across both
batteries, and therefore the charge on the batteries balanced.. whether it
be Xantrex or Astron. either will do the job and protect your batteries.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright
Sent: Tuesday, March 25, 2008 6:04 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Re: 24 vdc to 12 vdc

 

Depending on the load connecting across one battery, the one connected to
ground or the lower of the 2 12 batteries, will work. I would not do is load
is heavy because I am sure the charging system is for both batteries and
draining one much more than the other could upset things.

Kirchhoff's current law says the sum of the currents will be zero.
Kirchhoff's voltage law says sum of voltages will be zero. Not sure why
revelant here, but I am sure Kirchhoff had something else to do with voltage
and current sources. Would like to know.

73, ron, n9ee/r

>From: Al Wolfe <[EMAIL PROTECTED]  >
>Date: 2008/03/24 Mon PM 04:36:54 CDT
>To: Repeater-Builder@ 
yahoogroups.com
>Subject: [Repeater-Builder] Re: 24 vdc to 12 vdc

> 
>>This is a very common issue in aircraft. The most obvious question is
>>does your jeep use 2 each 12 volt batteries? If so, simply connect
>>your radio across one of 'em.
>
>This is done all the time but is a very, very bad idea. Ever hear of 
>Kirchhoff's law? Check it out. It's a very quick way to ruin two batteries.
>
>Get a real converter. The switching kind are much more efficient than the 
>linear voltage dropping kind.
>
>Al, K9SI
> 
>
> 

Ron Wright, N9EE
727-376-6575
MICRO COMPUTER CONCEPTS
Owner 146.64 repeater Tampa Bay, FL
No tone, all are welcome.

 

RE: [Repeater-Builder] 24 vdc to 12vdc

[John Barrett]

Or look at Xantrex solar charge controllers.. they will take anything up to
around 80v in and give you 12,24, or 48 out.. your choice.. stick a small
12v gel cell on the output, or some filter caps, and get up to 40 amps for a
little over $100, though I have found they have clean enough output without
anything extra for most situations

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Steve Kometz
Sent: Monday, March 24, 2008 1:44 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] 24 vdc to 12vdc

 

You can "cheat" and run off one of the 12 v batteries.

But the better way is to use something like the Astron 2412 DC to DC
converters.

I used several of them in the past running 12 v radios in 24 v helicopters.

Like a lot of Astron stuff, they worked very well.

I think the 9 amp version starts arround 60 bucks.

 

 

RE: [Repeater-Builder] SO239 Barrel Nut Size

[John Barrett]

At least 2 listed on eBay.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Saturday, February 09, 2008 3:22 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] SO239 Barrel Nut Size

 

Is there a 24 pitch tap or die readily available in 5/8"? SAE coarse is 11
TPI and SAE fine

is 18 TPI. Outside of the connector industry, where is it used? The
threading on UHF and

type N connectors looks identical. 

 

 

In a message dated 2/9/2008 12:39:43 P.M. Pacific Standard Time,
[EMAIL PROTECTED] writes:

Jim,

Both the UHF and the N connector have 5/8-24 threads.

73, Eric Lemmon WB6FLY

 





  _  

Who's never won? Biggest
  Grammy Award surprises of all time on AOL Music.

 

RE: [Repeater-Builder] 10 Meter Repeater

[John Barrett]

I was looking at the same general idea for combining a 2m repeater with 2
simplex radios (APRS and WinLink) on the same antenna - it MIGHT have worked
- but I got the repeater on 440 which eliminated a lot of problems trying to
work 4 frequencies within a 1mhz span.

 

In general though - a hybrid ring isn't going to get you much more than
25-30db of isolation, so you will still need band pass filters between the
RX/TX and the ring.. as much as needed to achieve the isolation needed based
on your TX power . hehehe what do you make a cavity filter for 10 meters out
of ?? two stacked beer kegs ??? hi hi :-)

 

Note also that using a ring duplexer like this will pump any reflected power
from the feed/antenna right back into the RX path. so everything needs to be
extremely well matched. Feeding 100w into a 1.2:1 VSWR will pump nearly 0.1w
back into the RX path, where the only thing slowing it down is your RX
filters

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of DCFluX
Sent: Tuesday, January 29, 2008 1:04 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] 10 Meter Repeater

 

What about a Hybrid-Ring style duplexer? With 1 5/8 hardline and
copper water pipe variable sections for tuning?

 

RE: [Repeater-Builder] 10 Meter Repeater

[John Barrett]

Rather than 2 full controllers - put the full controller at the RX end and a
bare bones microcontroller based DTMF (or other command format) decoder on
the TX to enable a TX cutoff. Doing up an AVR to handle the function would
take little work as the software  DTMF decoder is readily available . 1 18
pin CPU chip, regulator, caps, and a 5v relay would do the trick.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Scott Zimmerman
Sent: Monday, January 28, 2008 12:30 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] 10 Meter Repeater

 

It could be and *should* be to be legal, I guess. In my opinion, it would be

more in the spirit of good amateur practice to be able to shut off the Tx in

case of interference on the link, rather than to ID the link frequency. If 
the user's audio is being passed completely, their callsign is being 
transferred on the link frequency as well. While I agree, if someone wanted 
to press the issue, that the user's callsign cannot ID the link; but it *is*

being ID'd by an amateur operator. The best way to handle the situation 
would be to use two controllers, one on each end. Doing this would allow 
shutdown of the system in many ways from either end. But to me it's a waste 
of money to spend the extra $$ for two controllers.

Not to get into a rules discussion, but I think that the issue of ID'ing 
linkback frequencies for split site machines and remote receivers should be 
FCC ruled separately than Remote Base linking between two sites. It would 
definitely make it easier as far as linking equipment is concerned. I don't 
know how to accurately define one purpose from the other to propose a 
rewrite to the rules. Other than FCC rule, I personally see no reason why a 
remote receiver link or split site link would need to be ID'd locally. In my

opinion, the user's ID should suffice to ID any audio path his audio would 
take. In other words, the amateur is ID'ing the transmission, not the 
equipment he is using.

Scott

Scott Zimmerman
Amateur Radio Call N3XCC
612 Barnett Rd
Boswell, PA 15531

- Original Message - 
From: "MCH" <[EMAIL PROTECTED]  >
To: mailto:Repeater-Builder%40yahoogroups.com>
yahoogroups.com>
Sent: Monday, January 28, 2008 12:02 PM
Subject: Re: [Repeater-Builder] 10 Meter Repeater

> Shouldn't the controller be at the 10M RX site so the link is ID'ed too?
> It's the 10X TX site that can be 'dumb'. That's the way mine is.
>
>
> Joe M.
>
> Scott Zimmerman wrote:
>>
>> Tom,
>>
>> The method I have built for customers is using split sites. (transmitter 
>> at
>> one site and receiver at another) These sites should be separated by 
>> about
>> 1/2 to 1 mile. A UHF or 220 link is used to go between the two sites. We 
>> use
>> GE MII equipment for all the Tx's and Rx's. Basically it requires two
>> radios: a 10M MII and a UHF MII. We swap the 10M Rx into the UHF radio 
>> and
>> the UHF Rx into the 10M radio. The result is a 10M -> UHF and a UHF ->10M
>> cross band repeater. The 10M Rx end is usually made to be dumb. Whatever
>> comes in on the 10M Rx goes out on the UHF link channel. (CTCSS, Voice,
>> etc.) This end of the system is simply controlled by COS logic on the 10M
>> Rx.
>>
>> The system controller is located at the 10M Tx site. Since everything is
>> coming back on the UHF link, you can run CTCSS on the system (helpful to
>> eliminate co-channel users) The CTCSS decoder nicely interfaces with the
>> on-site repeater controller. The other advantage is that you have a UHF
>> frequency that you can run a control signal into to shut the system down 
>> if
>> needed.
>>
>> This is a basic overview, but it will give you some ideas.
>> Scott
>>
>> Scott Zimmerman
>> Amateur Radio Call N3XCC
>> 612 Barnett Rd
>> Boswell, PA 15531
>>
>> - Original Message -
>> From: "tom_kd8deg" <[EMAIL PROTECTED] 
net>
>> To: mailto:Repeater-Builder%40yahoogroups.com>
yahoogroups.com>
>> Sent: Saturday, January 26, 2008 8:23 PM
>> Subject: [Repeater-Builder] 10 Meter Repeater
>>
>> > Hi All,
>> >
>> > HELP
>> >
>> > Is there anyone out there with any knowlage with building a 10 meter
>> > repeater. My self and another ham want to put up a 10 meter repeater
>> > and finding nothing in the great World Wide Web on how to go about it.
>> >
>> > 73
>> >
>> > de Tom KD8DEG
>> >
>> >
>> >
>> >
>> >
>> >
>> > Yahoo! Groups Links
>> >
>> >
>> >
>> >
>> >
>> > --
>> > No virus found in this incoming message.
>> > Checked by AVG Free Edition.
>> > Version: 7.5.516 / Virus Database: 269.19.13/1246 - Release Date:
>> > 1/27/2008 6:39 PM
>> >
>> >
>>
>>
>> Yahoo! Groups Links
>>
>>
>>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
> -- 
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.516 / Virus Database: 269.19.14/1247 - Release Date: 
> 1/28/2008 10:59 AM
>
> 

 

RE: [Repeater-Builder] Re: "Cheap" P25 repeater ...

[John Barrett]

*flame on*

 

So what ?? so what about folks like me that don't want to lay out $1000 for
a 1.2ghz DSTAR data radio, or who would like to operate DSTAR using SDR
gear. What about PACTOR3 - plenty of decoders, but if you write an encoder,
the folks that came up with it land on you like a ton of bricks

 

Kind of defeats the spirit of experimentation and innovation that has been
part of the hobby for so long.

 

But I guess not too many people care any more - they want plug and play
instant gratification - and picking up a soldering iron or reading a
schematic just doesn't cut it. "put the green cable in the green socket" is
about as technical as they can get.

 

*flame off* 

 

I'm going back to wiring up my 80 amp power system and 2000ah battery backup
array for the shack.. gotta love rural power.. we lose it at least twice a
week :-)

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of nj902
Sent: Sunday, December 30, 2007 10:53 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: "Cheap" P25 repeater ...

 

I don't see why not. 

Hams all over the country are experimenting with a variety of 
digital voice formats including D-Star, P25, AOR, FDMDV, and 
Mototrbo TDMA. If some of these are only available from one 
manufacturer - so what? 

See: http://www.hamradio  -dv.org/

Since this list is not for rules debate - let's just build some 
digital repeaters and have some fun.

--
--- In Repeater-Builder@ 
yahoogroups.com, Dan Blasberg <[EMAIL PROTECTED]> 
wrote:

"Thanks for the clarification.

"As for using VSLEP, if it is all that was available at the time the 
radios where received, why not use it? ..."

 

RE: [Repeater-Builder] RPT Antenna trimming -Length to RX or TX freq?

[John Barrett]

TX - you want minimum reflected power - minimum feeding back into the RX
side :-)

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Peter P J
Sent: Saturday, December 22, 2007 11:51 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] RPT Antenna trimming -Length to RX or TX freq?

 



Our new Diamond F22 antenna elements to be trimmed as per the enclosed
cutting chart for the 145.650 with -600 shift.

What length is best from the cutting chart is in doubt.

Whether it should be the length for the Tx freq-145.650 or for
145.050-the Rx?

Peter VU2PJP

 

RE: [Repeater-Builder] Re: power supply / battery system for repeater site

[John Barrett]

That's the Xantrex C40 series configured as a load controller.. gives you an
adjustable cutoff to protect your batteries from overdischarge

 

They are up on EBay all the time --- easy to find

 

Use another C40 as the charge controller - run your power supply a little
hot (equalize switch ON at all times) and let the C40 step that down and do
3 stage charging on your batteries.

 

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Friday, December 14, 2007 3:34 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: power supply / battery system for repeater
site

 

I want to thank all that helped guide me to Motorola TPN1105/TPN1106
schematics, back in July 2007.

Although, these above schematics are not the Motorola Micor power supply,
that I have. They are similar.

I have a Motorola Micor power supply, with the float/equilize slide switch
for an battery option.

I understand from reading a MSR-2000 manual, the power supply can be set for
Nicad or Lead-acid batteries.

I was mostly interested in a battery cut-off circuit, so the power supply
doesn't over charge the battery.

Although, from reading the emails, a over discharge circuit should also be
used.

Does Xantrex or http://www.newmarpower.com/ have a cut-off & a over
discharge circuit?

My batteries are awaiting for the properly controlled charger, with as much
details.

Thanks & 73's,
Jim   Kh6jkg.

  _  

More new features than ever. Check out the new AIM(R) Mail
 !

 

RE: [Repeater-Builder] Re: power supply / battery system for repeater site (long)

[John Barrett]

My suggestion would be to look at the Xantrex C12/C30/C40/C60 Charge/Load
controllers (they can be used as either, but not both at the same time).

 

As a load controller, it provides a low battery voltage cut-off so you don't
destroy the battery by over discharging

 

As a solar charge controller, it gives you full 3 stage charging for SLA/AGM
batteries. and they co-exist nicely with the Xantrex battery chargers for
the times when you have "shore" power available to recharge the batteries.

 

If you are looking for a 120vac solution.. look at the Xantrex Freedom
inverter/charger combo - that's what I use on my emergency services trailer.
140 amp charger, 3000w inverter, and 2000ah of SLA battery bank :-) Most of
the gear runs on 12v, but I've got 120 for the gear that needs it. and a C40
charge controller in load control mode between the batteries and the gear to
protect the batteries.

 

If your gear is picky about the voltage it is happy at. look into a 13.8v
stabilizer - normally used in huge car stereo installations. it is
essentially a 13.8v supply that will work from any input voltage 9v or
greater. you don't ever want to discharge SLAs below 10v (the load
controller handles that) but most radios are unhappy below 12v (and the
stabilizer handles that, bringing up whatever is there to 13.8v). I found a
40 amp stabilizer for right around $100

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of ldgelectronics
Sent: Thursday, December 13, 2007 4:55 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: power supply / battery system for repeater
site (long)

 

Mark, 

There have been some good suggestions. However, there are two issues 
that you need to watch carefully for remote battery backup operation. 
The first, as some have mentioned, is the charge current if the 
battery is run down and AC power comes back. 

For example, if you just tie a battery across your power supply (with 
a diode or whatever), it will be a great back up. But after it has 
run on the battery for many hours and the AC power comes back up, the 
power supply will send a bunch of current to try to charge the nearly 
dead battery. This will almost certainly blow the fuse between the 
power supply and battery as it could be 100 or more amps.

A simple solution is to run the repeater off the battery and just use 
a charger to keep the battery happy (charged or uncharged).

While this sounds good, it exposes a huge problem that is often 
overlooked. And that is what happens when the battery runs down.

Running the battery completely down does two things, first it 
drastically reduces the number of times it can be charged and second 
it usually ends up in transmitter cycling mode for many hours or days.

[Transmitter cycling mode is when the battery runs down far enough 
that it can't power the transmitter, but can barely power the 
controller. This ends up with the controller coming on, which keys 
the transmitter to ID, then the battery voltage drops (because of the 
transmitter) and the controller turns off because the voltage is too 
low. The transmitter goes off when the controller goes off and the 
battery voltage slowly increases back to the point to where the 
controller will come on. Repeat this for days and days or until the 
battery is completely dead and probably could never be charged again]

To combat these two issues, there are two options. One is to power 
the system off the battery and use a small power supply to charge it, 
but then insert a battery controller system to handle the charging 
and Low Voltage Disconnect (LVD).

The are plenty of 20 amp solar panel controllers for around $50 that 
will handle nearly everything for you. Larger ones are also available.

The second method is to modify a simple Uninterruptible Power Supply 
(UPS). Just take the battery out and connect your larger external 
battery in its place. It will take care of the charging, LVD and give 
you 110 volts. Just be sure to pick one that is rated twice of your 
max watts. If your repeater draws 20 amps at 12 volts, that's 240 
watts. So be sure to get a 600 watt UPS (or higher). 

Used 1200 watt UPSs are under $50 on ebay. Many of them that cheap 
may have a bad battery. Since you're going to use your own external 
120 AH (or whatever) battery, it would not matter if the used one is 
bad. You get the better deal since no one else wants to buy a UPS 
with a dead battery.

I have both types and while the solar controller method is more 
efficient, the UPS method is somewhat easier. Take your pick.

Dwayne Kincaid
WD8OYG

> Willis, I have used a simple diode circuit in several
> repeaters I have converted to battery backup. I like
> the solid state solution more than a mechanical relay
> for reliability.
> 
> The circuit is as follows:
> 
> Place a diode in series with the output of your power
> supply. (it can be the internal supply)
> 
> Place a diode in series with the battery ou

RE: [Repeater-Builder] TKR-820 Reciever Issues

[John Barrett]

I've got the chip pulled, and a socket installed, but I'd prefer to wait on
sending a chip out until my replacement programmer gets here and I can
validate the chip myself.. if I'm lucky it will be here tomorrow.

 

The unit was previously programmed for 451.125/456.125.. I'm moving it down
10mhz to 441.350/446.350. the data in the chip is CC 84 3C 83 if you want to
compare that to what your programmer would put in.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Steve S. Bosshard
(NU5D)
Sent: Wednesday, November 21, 2007 6:33 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] TKR-820 Reciever Issues

 

If you are up to removing the eeprom from the front panel (soldered in) 
and mail it to me I will put it in my kpt20 and verify operation - I
have never run into trouble with a UHF repeater. Some of the TKR720's
were borderline, but the TKR820's were OK. You don't have a T band unit
or something out of the ordinary do you?

Steve NU5D

John Barrett wrote:
>
> Byte swapped version of the chip was unable to get the test point
> voltages above 150mV on either TX or RX, so I presume I have the byte
> order correct J
>
> 
>
> Data for the chip was generated with KPG21D (the programming software
> for this repeater) and validated with the formula from a 3^rd party
> document detailing the frequency to hex code calculation. The binary
> data saved by KPG21D was edited with a hex editor to extract the 128
> bytes needed for the frequency eeprom.
>

 

RE: [Repeater-Builder] TKR-820 Reciever Issues

[John Barrett]

Seller claimed the repeater was removed from operation, and it was labeled
451/456 - so it should be the right one to tune down

 

The 1st 4 bytes are CC 84 3C 83 if you can compare that to the data your
programmer would write..  The target frequencies are 441.350 TX and 456.350
RX

 

I've already removed the chip and installed a socket . I'll consider sending
the chip if no other viable solution comes up.

 

I don't know what T band is, unless that's the 470-500 version of the
repeater. How would I tell ?? I don't see any particular markings on the
chassis or boards that would tell me what exactly I have.. The only thing
that might be relevant is a sticker on the RX VCO marked "COM15"

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Steve S. Bosshard
(NU5D)
Sent: Wednesday, November 21, 2007 6:33 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] TKR-820 Reciever Issues

 

If you are up to removing the eeprom from the front panel (soldered in) 
and mail it to me I will put it in my kpt20 and verify operation - I
have never run into trouble with a UHF repeater. Some of the TKR720's
were borderline, but the TKR820's were OK. You don't have a T band unit
or something out of the ordinary do you?

Steve NU5D

John Barrett wrote:
>
> Byte swapped version of the chip was unable to get the test point
> voltages above 150mV on either TX or RX, so I presume I have the byte
> order correct J
>
> 
>
> Data for the chip was generated with KPG21D (the programming software
> for this repeater) and validated with the formula from a 3^rd party
> document detailing the frequency to hex code calculation. The binary
> data saved by KPG21D was edited with a hex editor to extract the 128
> bytes needed for the frequency eeprom.
>

 

RE: [Repeater-Builder] TKR-820 Reciever Issues

[John Barrett]

Byte swapped version of the chip was unable to get the test point voltages
above 150mV on either TX or RX, so I presume I have the byte order correct
:-)

 

Data for the chip was generated with KPG21D (the programming software for
this repeater) and validated with the formula from a 3rd party document
detailing the frequency to hex code calculation. The binary data saved by
KPG21D was edited with a hex editor to extract the 128 bytes needed for the
frequency eeprom.

 

 

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of DCFluX
Sent: Wednesday, November 21, 2007 5:29 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] TKR-820 Reciever Issues

 

Did you calculate the correct LO frequency? Also you may try reversing the
high byte and low byte figures of the receive frequency.

On 11/21/07, John Barrett <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> net
> wrote:

This one is for folks that know the Kenwood TKR-820 repeater :-) Or how to
modify a VCO frequency range :-) 

 

I have a known working on 451.125/456.125 TKR-820 UHF repeater that I'm
attempting to move down to 441.350/446.350. I've got the chip reprogrammed
and the transmit VCO had no problems retuning to the target frequency
(441.350). The receive VCO is another story. The manual says that PLL/VCO
lock happens when the voltage from the PLL's integrator is between 4 and 5
volts, with a target of 4.5 volts. After adjusting the VCO's variable
capacitor (the only adjustment available), the best I can get is 2.5 volts,
and I'm getting a slow sawtooth on the integrator output from the PLL. This
is surprising to me since it seems the RX and TX use identical PLL and VCO
modules, and the RX VCO only has to tune down to 446.350. 5mhz higher than
the TX. In any case.. the 2.5v control voltage is obviously incorrect since
I cannot key the repeater with my HT at that adjustment.

 

I have pulled the CTCSS configuration chip as recommended in one set of
retuning instructions so I should be able to key the repeater without a PL
(the repeater controller will be handling that in any case, so that chip
will likely never be reinstalled).

 

Any ideas what I might be doing wrong, or any tricks on how to get
everything tuned up ??

 

 

[Repeater-Builder] TKR-820 Reciever Issues

[John Barrett]

This one is for folks that know the Kenwood TKR-820 repeater :-) Or how to
modify a VCO frequency range :-)

 

I have a known working on 451.125/456.125 TKR-820 UHF repeater that I'm
attempting to move down to 441.350/446.350. I've got the chip reprogrammed
and the transmit VCO had no problems retuning to the target frequency
(441.350). The receive VCO is another story. The manual says that PLL/VCO
lock happens when the voltage from the PLL's integrator is between 4 and 5
volts, with a target of 4.5 volts. After adjusting the VCO's variable
capacitor (the only adjustment available), the best I can get is 2.5 volts,
and I'm getting a slow sawtooth on the integrator output from the PLL. This
is surprising to me since it seems the RX and TX use identical PLL and VCO
modules, and the RX VCO only has to tune down to 446.350. 5mhz higher than
the TX. In any case.. the 2.5v control voltage is obviously incorrect since
I cannot key the repeater with my HT at that adjustment.

 

I have pulled the CTCSS configuration chip as recommended in one set of
retuning instructions so I should be able to key the repeater without a PL
(the repeater controller will be handling that in any case, so that chip
will likely never be reinstalled).

 

Any ideas what I might be doing wrong, or any tricks on how to get
everything tuned up ??

RE: [Repeater-Builder] Usage of Linked Repeater Systems vs. Stand Alone Repeaters

[John Barrett]

I think the main problem is TOO MANY REPEATERS :-) I've got a good antenna
where I'm at and can hit every repeater in a 75-100 mile radius. as part of
my hunting for a pair, I checked EVERY VHF repeater that I found in the K1IW
database in a 100 mile radius.. About 30% were dead (not responding to key
up with a courtesy tone.. but they may not have had courtesy tones turned
on), and maybe 2-3 dozen of the rest actually with traffic on them.. Call it
about 1 repeater per city/club in the area that was actually getting used.
The sample was taken between 4pm and 7pm (drive time) over a couple of
weeks, though I didn't spend more than 30 minutes (less if I heard traffic)
on any given repeater so I could have missed something. 

 

I've got 4 repeaters listed In my county. only one gets any serious use, the
other is dead except as a C3 channel for ARES and Weather Nets, and one
other has a small group that uses it pretty exclusively.. the 4th is on the
air, but inactive.

 

People just don't have much to talk about with people too far away from
them, pointing up the fact that repeaters are mostly social gathering
places, and its not interesting to socialize with people you don't really
know :-)

 

I guess I'm as bad as anyone though. I stick to one repeater, monitor one
other but rarely talk on it (just a couple of people there that I talk to,
and they aren't on much), and ignore the rest of the repeaters around :-)

 

 

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Tony L.
Sent: Wednesday, November 21, 2007 9:59 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Usage of Linked Repeater Systems vs. Stand Alone
Repeaters

 

Our club operates a RF full-time linked repeater system in metro New 
York City, currently comprised of four (4) repeaters. We've observed 
that the addition of a new repeater into the system doesn't always 
equate to added usage. In fact, we've noticed that many of the linked 
systems in metro NYC typically aren't as busy as local area stand alone 
systems.

We're puzzled as to why people seem to shy away from most, but not all, 
of the very wide coverage area systems. The busiest repeaters in our 
area seem to be the "no frills" stand alones. Are voice IDs, courtesy 
tones, and coverage footprints beyond a 25-mile radius just more than 
people can handle nowadays?

Comments anyone?

 

RE: [Repeater-Builder] Repeater Controller on a plug in (ISA) Card

[John Barrett]

37-21-42-5-19 :-)

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of skipp025
Sent: Tuesday, November 20, 2007 7:13 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Repeater Controller on a plug in (ISA) Card

 

Re: Repeater Controller on a plug in (ISA) Card

I found a repeater controller on an ISA Bus Computer Card, 
which appears to be made by PCR or PRC. 

Anyone ever had one of these...? running one now..? Know 
where the software and/or manual can be found? Have the 
next six Calif Lotto Numbers? :-) 

Any history or trivia you can provide would be appreciated. 

cheers, 
s. 

 

RE: [Repeater-Builder] Wide Area Coverage

[John Barrett]

Propagation :-( something I'm learned a lot about this last couple of weeks
- neat app called Radio Mobile I've been using to map out theoretical
coverage at various locations where I may be asked to drop my portable
repeater.. Makes me wish I had held out for a 60-75ft 3 section crank up to
put on my trailer, or a really tall hill to park on :-) Unfortunately - not
a lotta hills around this part of Texas :-(

 

Radio Mobile uses USGS topographical data and can do map overlays from
several free sources - check it out if you want to get some ideas where your
setup will have problems !!

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of n9wys
Sent: Sunday, November 18, 2007 8:55 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Wide Area Coverage

 

No, the complaints start when they can't hear/access the machine everywhere
with a full quieting signal.  It's amazing that some amateur licensees still
don't understand signal propagation. 

 

But now I'm starting to get WAY off-topic.

 

73 de Mark - N9WYS

 

  _  

From: Repeater-Builder@yahoogroups.com On Behalf Of Bill

I kinda agree.  Get used to the infrastructure systems and you can't make a
contact when it goes down, that's when the complaining starts.  i.e.
cellphones and isp problems.  Heck that's when real amateur radio can shine!
Heck, the complaints start even when "the repeater" craps out.

 

William A. Collister

N7MOG 

 

RE: [Repeater-Builder] Wide Area Coverage

[John Barrett]

Ohhh geez - just get your general and work some HF !! Internet linking just
to make contacts is NOT ham radio. setting up regional repeaters and such..
there is a good use for internet linking.

 

The ARRL Phone Sweeps are running this weekend . made any contacts ??

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Steve S. Bosshard
(NU5D)
Sent: Sunday, November 18, 2007 8:51 AM
To: [EMAIL PROTECTED]; [EMAIL PROTECTED];
Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Wide Area Coverage

 

Imagine your 2M or 70CM base station were on a tall, tall, tower and you 
can key and operate any one of 140 different repeaters world wide, no 
noise, static, etc.

Thats DSTAR today. From Hawaii to Alaska, to Vancouver to Ottawa, to 
Los Angeles, to London, to Berlin to Venice, to Darwin, AU. Today and NOW.

I know this is probably a bit off topic, and I appreciate your indulgence.

visit www.dstarusers.org and see who's talking.

Steve NU5D, /K5CTX B Temple, Texas US

-- 
/Subscribe to dstar_digital/

Powered by groups.yahoo.com 
yahoo.com/group/dstar_digital/>

 

RE: [Repeater-Builder] MTR 2000

[John Barrett]

OK. Steps To Configuring A Repeater:

 

Tools Needed: 

Communications Service Monitor with tracking generator and spectrum analyzer
or a Plain Service Monitor and a network analayzer

 

reprogram the frequencies (Which you say you have already done)

 

re-align/tune the transmitter and receiver to the new frequencies. Most
repeaters require some adjustment for most efficient operation when changing
the pair. This is the part where the service monitor will come in handy.

 

tune the duplexer using the spectrum analyzer/tracking generator or the
network analyzer.

 

Configure the repeater controller. (you will probably need the controller
minimally functional to complete the previous steps)

 

If you don't have the test equipment (and believe me, this stuff aint cheap
!! I've been trying to get both items for months and haven't found any I can
afford yet), check around with some of the other people that have repeaters
in your area.. one of them will have the gear you need, or will know someone
who does. They can help you with the fine details on how to perform the
needed procedures.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of exodus
Sent: Monday, November 12, 2007 7:04 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] MTR 2000

 

Ladies and gentlemen,

Does any body can give me advise on making my repeater MTR 2000 work 
better or any guidance that you may have...please dont use any code 
words or any number referance ie..."you should use NFSL32564"... coz I 
will not understand what you saying... I am dumb when it come to this 
kind of communication or should i just say that I am completely 
clueless on what I'm doing... so please break it down barney style...

Anyway... here is what I got so for... I put up a 50ft tower with this 
13 ft antenna that comes with that repeater MTR 2000. I programmed the 
device with two different freq and hoping that it will work once I plug 
this in... please advise... thank you very much...

oh if you guys are wondering why I'm messing with this type of comm...I 
found it sitting in the corner and being used as a dust collector... so 
I decided to mess with it and make it work... 

 

RE: [Repeater-Builder] Re: Possible interference on 146.160

[John Barrett]

Not that bizarre - There used to be a piece of software for DOS back in the
286/386 days that would play sounds on your AM radio by running loops of
instructions specifically designed to cause interference :-)

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of lpcoates
Sent: Sunday, November 11, 2007 9:22 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Possible interference on 146.160

 

Thanks to everyone who replied. On a related note, I found something 
at home that probably answered my question. Lately I noticed that 
there was a weak carrier centered on 144.390. This was causing my APRS 
IGate to not transmit because it sensed that the channel was busy. It 
took a long time to find the source which turned out to be my APRS 
IGate computer. Further investigation showed that it only happened 
when certain combinations of programs were running. Any other 
combination of running programs created no interferenc anywhere in the 
2m band. Further investigation with a spectrum analyzer confirmed 
this. I then tried using my frequency counter to get an exact 
frequency only to find that it generated another half dozen spikes 
throughout the 2m band.

So I think the answer is that just about anything electronic is a 
potential source of my interference and sometimes the source is so 
bizarre that you would never suspect it.

73, Bruce

 

RE: Re: [Repeater-Builder] Part 97 question reference to Repeater control

[John Barrett]

Just FYI since I started this aspect of the thread :-) - the trailer will be
equipped with both local area Omni antennas on one router, and a point to
point on a separate router.. however, the point to point is only active on
an as needed basis for HSMM activities.. and while the control system will
work through it, the local area WiFi with Omni antennas is the primary
control path for 2.4ghz control. the 2m packet inputs are last ditch backups
in case I cannot reach the 2.4 access point or the repeater input. To make
it more clear.. it is actually the onboard computer that has true control.
and I have multiple means to issue commands to that computer.

 

Note that this is not a control link in the conventional sense. I'm not
running 1200 baud packet on a 2.4g frequency.. I'm running full a full WiFi
access point, and anyone that can connect and has the passwords and the
custom remote control software can gain full access to the trailer control
system.

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright
Sent: Friday, November 09, 2007 9:02 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: Re: [Repeater-Builder] Part 97 question reference to Repeater
control

 

Laryn,

My only reason for thinking 2.4 G would not be legal for control it did not
fall within the Auxiliary frequencies allowed for control or Telecommand.

However, there is the issue of 97.213(a) "fiber optic cable OR other
telecommunications service is considered wire-line". So if 2.4 G is
considered wire-line, and most use this service for such, it might be legal.

However, if one is putting up ones on point-to-point 2.4 G rx/tx for control
might be questionable.

73, ron, n9ee/r

>From: Laryn Lohman <[EMAIL PROTECTED]  com>
>Date: 2007/11/08 Thu PM 10:25:46 CST
>To: Repeater-Builder@ 
yahoogroups.com
>Subject: Re: [Repeater-Builder] Part 97 question reference to Repeater
control

> 
>Ron, please clarify why you think that Part 97 would not allow using
>2.4 gc. WiFi for a control link...
>
>Laryn K8TVZ
>

Ron Wright, N9EE
727-376-6575
MICRO COMPUTER CONCEPTS
Owner 146.64 repeater Tampa Bay, FL
No tone, all are welcome.

 

RE: [Repeater-Builder] Part 97 question reference to Repeater control

[John Barrett]

A repeater is NOT full duplex.. it is not simultaneously processing
completely separate audio streams in and out.. it is processing the SAME
audio in and out. There is only ONE audio path - full duplex requires TWO.
Telephones accomplish this by modulating both audio signals on a common
"carrier" (the DC power provided by the telco), modems do it by using
different tone frequencies for send and receive.. essentially half duplex,
but coerced into being full duplex by the behavior of the telephone line.
The modems accomplish this by negotiating which modem will use which
frequencies (hence all the V## protocols.. they define how the modems
negotiate)

 

A repeater is NOT bidirectional - audio streams flow in only one direction,
from sender to reciever

 

>From this point of view the repeater is a filter in a half duplex link. The
only reason a repeater uses 2 frequencies is because you cannot transmit on
the same frequency as you receive..

 

Full duplex direct (non-repeater) RF links require 2 frequencies.. one
transmit for user A, and one transmit for user B.. this is a true example of
full duplex.. both streams are completely independent, and have no influence
on the other except through "processing" at the end points, human, computer,
or otherwise.

 

You could accomplish an apparent full duplex repeater link in RF using 3
frequencies. 2 for input, one for output, and mix the inputs. The only
problem is the 2 users have to agree which input they will use ( shades
of modem negotiation here !!). a Party Line, or Conference Call would
require one input per user.. In each of these cases, all users listen to the
same output.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of MCH
Sent: Thursday, November 08, 2007 10:28 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Part 97 question reference to Repeater
control

 

Simplex: One frequency - you can either TX or RX, but not both.

Half Duplex - Two frequencies - you can either TX or RX, but not both.
Your TX frequency is different than your RX frequency.

Full Duplex - Two frequencies - you can RX and TX at the same time.

A repeater is Full Duplex operation. It can RX and TX at the same time.

Bi Directional means you can come in on one frequency and go out the
second, or come IN the second and go OUT the first.

Joe M.

Nate Duehr wrote:
> 
> On Nov 8, 2007, at 2:34 PM, Paul Plack wrote:
> 
> > Manufacturers sometimes market features on new radios without regard
> > to Part 97. I have an Alinco DR570T, one of the first, if not THE
> > first, dual-band mobile to feature full duplex crossband repeat. As
> > designed, it's crossband repeat function was clearly not legal.
> 
> From your description (and knowing the radio) you mean "bi-
> directional" (but not at the same time), not "full-duplex" (which
> means you can go both directions through it at the same time).
> 
> I'm seeing the term "full-duplex" misused more and more in regards to
> dual-banders in cross-band repeat mode... did someone publish an
> article with this less-than-accurate terminology again somewhere? :-)
> 
> --
> Nate Duehr, WY0X
> [EMAIL PROTECTED]  com
> 
> 
> Yahoo! Groups Links
> 
> 
> 

 

RE: [Repeater-Builder] "Full Duplex"

[John Barrett]

Ohh there should be SOME crosstalk - listen closely to your landline phone -
you can hear yourself in the earpiece - this is called "side tone" and is
pretty hard to get rid of without echo cancelling hardware. side tone
happens because of the way that the coupling transformer extracts receive
audio and impresses transmit audio on the DC "carrier" provided by the
telephone company central office. besides the fact that a person using a
repeater is still bound to the 10 minute ID rule, so some of the input must
be mixed to the output or the user would never be heard to ID on the output
while the patch was in operation.

 

Even an in band repeater with patch normally allows the radio user to
interrupt. by giving the repeater input priority over the telco input.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Paul Plack
Sent: Thursday, November 08, 2007 8:02 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] "Full Duplex"

 

Nate,

 

The telephone industry standard definition for the term "duplex" means able
to listen and talk simultaneously; the ability to have a channel in both
directions at the same time, without the need for push-to-talk.

 

In essence, if you can interrupt the other party without waiting for him to
finish, you're in "full duplex." Any dual-bander which can receive on one
band while it transmits on the other is capable of full duplex.

 

At one time, this was the difference between a "duplexer" and a "diplexer."
A duplexer was intended to allow simultaneous transmit and receive, as with
an in-band repeater; the diplexer allowed two transceivers on different
bands to function simultaneously into a common feedline and/or antenna.

 

Both these terms have been mangled pretty badly over the years.

 

The Scom controllers offer a duplex mode in their autopatches, but it would
only be useful on a crossband repeater. Mobiles could listen on 2M to the
caller while simultaneously transmitting on UHF, and the mobile station and
landline party could interrupt each other at any time, just like a normal
phone call.

 

In practice, this would drive licensees and control ops nuts, because the
mobile station's audio would not appear on the repeater output, and anyone
monitoring the repeater would only hear the landline party, without the
mobile station's side of the call.

 

73, Paul AE4KR

 

- Original Message - 

From: Nate Duehr   

To: Repeater-Builder@ 
yahoogroups.com 

Sent: Thursday, November 08, 2007 5:37 PM

Subject: Re: [Repeater-Builder] Part 97 question reference to Repeater
control

 


On Nov 8, 2007, at 2:34 PM, Paul Plack wrote:

> Manufacturers sometimes market features on new radios without regard 
> to Part 97. I have an Alinco DR570T, one of the first, if not THE 
> first, dual-band mobile to feature full duplex crossband repeat. As 
> designed, it's crossband repeat function was clearly not legal.

>From your description (and knowing the radio) you mean "bi- 
directional" (but not at the same time), not "full-duplex" (which 
means you can go both directions through it at the same time).

I'm seeing the term "full-duplex" misused more and more in regards to 
dual-banders in cross-band repeat mode... did someone publish an 
article with this less-than-accurate terminology again somewhere? :-)

--
Nate Duehr, WY0X
[EMAIL PROTECTED]  com

 

RE: Re: [Repeater-Builder] Part 97 question reference to Repeater control

[John Barrett]

Do you guys see a problem running the control link on 144.390 (APRS) or one
of the 145.* packet freqs ?? As a packet mode link ?? I'm sure the 2.4g WiFi
control link is fine, just want an opinion about running control capability
piggy-back with the APRS and Winlink radios I'm going to have on board. All
the packet, wifi, and repeater controllers are going to be hooked to a
single computer. thought it would make a nice centralized way to manage the
trailer remotely in all its features.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright
Sent: Wednesday, November 07, 2007 8:38 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: Re: [Repeater-Builder] Part 97 question reference to Repeater
control

 

Joe,

You might have a point. I cannot find either. Use to be for RF was on
Auxiliary frequencies only, most of 222, most of 420-450 and above. Cannot
find it is now required. Might be able to control on 14.313, hi.

73, ron, n9ee/r

>From: MCH <[EMAIL PROTECTED]  >
>Date: 2007/11/07 Wed PM 01:19:27 CST
>To: Repeater-Builder@ 
yahoogroups.com
>Subject: Re: [Repeater-Builder] Part 97 question reference to Repeater
control

> 
>This is the part I'm looking for in the rules. I can no longer find it.
>
>Joe M.
>
>Ron Wright wrote:
>> 
>> It can be in person, setting at the tx, or by wire (a phone line, etc) or
on 222 MHz and above.
> 

Ron Wright, N9EE
727-376-6575
MICRO COMPUTER CONCEPTS
Owner 146.64 repeater Tampa Bay, FL
No tone, all are welcome.

 

RE: [Repeater-Builder] Part 97 question reference to Repeater control

[John Barrett]

a Time Of Day macro to me is an automated function.. how can something that
is automatic not be considered automatic control

 

OK - lets define terms here... 

 

An automated function is anything the controller does without human input
beyond keying up and talking.

 

an ancillary function would be one that is commanded via DTMF. and in most
cases that I have seen commonly used, those commands are used for
information requests or temporary modifications to the repeater
functionality (changing the courtesy tone for a net, enabling or disabling
specific voice announcements, phone patch, etc)

 

I would define a Primary function to be one that made a major change to the
repeater functionality, for instance, enable/disable repeat or remote
shutdown.

 

Primary functions may be made available via the same mechanism (DTMF) used
for ancillary commands, or via a separate control link. In most cases where
Primary functions are available at all, they are on a control link since it
is risky to have them on the repeater input.

 

End Of Definitions

 

I don't consider that an information request or other ancillary function
takes the repeater out of automatic control, since functions of that type
generate an automated response (Phone patch breaks that rule, but its been
around so long that it's a special case, unless you want to define repeater
phone patch as remote control with the caller as the control operator)

 

Or are you saying the person pressing the DTMF keys is the temporary control
operator for all ancillary functions?? A point of view not supported by the
wording in Part 97, as ancillary functions are not considered remote
operation. The controller and the operator that designed/programmed it is
still the control operator the way Part 97 is worded. In my understanding of
the rules - the control operator is the person who has final control of the
repeater, and must answer to the FCC for the actions of the automatic
control, not for the actions of the repeater users. Part 97 is clear on
that. The repeater owner is not responsible for misuse by other operators.
(Part 97.205g)

 

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jim
Sent: Wednesday, November 07, 2007 4:47 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Part 97 question reference to Repeater
control

 

John Barrett wrote:

> No where can I see it stated that there MUST be a control link for a
> repeater !!

When it is in automatic operation, you are correct. It's when it is 
doing something other then repeating or identifying that it needs a 
control link. Someone punching in a code that commands the controller to 
speak the time of day, or the temperature at the site, or whatever, 
takes the station out of repeater use, and therefore out of automatic 
control and requires a control op. Even a macro that comes up and speaks 
the time of day automatically takes it out of automatic control. But of 
course, it still has to identify within 10 minutes of that!

-- 
Jim Barbour
WD8CHL

 

RE: [Repeater-Builder] Part 97 question reference to Repeater control

[John Barrett]

It doesn’t say anywhere in the rules that you cannot have both primary and
ancillary controls via DTMF on the input. Only that the ancillary controls
are not considered to be remote control of the repeater, which opens up a
point of ambiguity, since, as I’ve read, there is no requirement for a
primary/remote control of a repeater, at least not clearly stated. Which
leaves us with a “accepted practices” question.

 

You could always do what I’m doing :-) I’m going to have VHF APRS and
Winlink stations on board the trailer, and both will be set up to respond to
a set of commands that will let me monitor and control many functions on the
trailer through the on board computer… the computer will also be accessible
via WiFi and will have access to the same controls via a secure web server
or VNC remote console access. I still have a single point of failure if the
computer crashes – but it is on a watchdog timer and will reboot to a known
state if it crashes unexpectedly, so the only thing I worry about is an
outright hardware failure, and it would take a highly unlikely concatenation
of events for everything to fail in such a way that any of the radios were
stuck in TX and every path of remote control that I’ve designed in is
completely blocked.

 

The WiFi link seems particularly interesting to me given the availability of
DD-WRT… if you don’t mind hacking in some extra hardware features to allow
your router to control the repeater power. Techniques similar to those used
to add SD/MMC memory card ports to various routers could be used to give the
router some external I/O capability. Run an extra coax line up the tower and
a remote WiFi amp.. then all you need is a laptop and a high gain antenna to
remote control the site…. If you need more than 2-3 pins of I/O control… you
could implement I2C on the I/O pins and connect up any I2C memory or I/O
expansion device as needed :-) Would make for a nice HSMM “repeater” at the
same time.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Wednesday, November 07, 2007 3:01 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Part 97 question reference to Repeater
control

 

And that can be done though DTMF with my controller from 
the receive frequency on the repeater.

On Wed, 07 Nov 2007 14:57:14 -0600
"John Barrett" <[EMAIL PROTECTED] <mailto:ke5crp1%40verizon.net> net> wrote:
> According to Part 97.205e, ancillary functions (phone 
>patch, etc) are not
> considered remote control… which seems to limit the 
>meaning of remote
> control to enabling or disabling the repeater as a unit.
> 
> 
> 
> _ 
> 
>From: Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com>
yahoogroups.com
> [mailto:Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com>
yahoogroups.com] On Behalf Of 
>[EMAIL PROTECTED] <mailto:mung%40highwayusa.com> com
> Sent: Wednesday, November 07, 2007 2:41 PM
> To: Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com>
yahoogroups.com
> Subject: Re: [Repeater-Builder] Part 97 question 
>reference to Repeater
> control
> 
> 
> 
> Isn't any operator on the repeater in RF control of the 
> repeater when they are using it? Also isn't the DTMF 
>tone 
> control through the normal repeater pair remote control?
> 
> Vern
> 
> On Wed, 7 Nov 2007 13:54:32 -0600 (GMT-06:00)
> George Henry <[EMAIL PROTECTED] 
><mailto:ka3hsw%40earthlink.net> net> wrote:
>> -Original Message-
>>>From: MCH <[EMAIL PROTECTED] <mailto:mch%40nb.net>  <mailto:mch%40nb.net> >
>>>Sent: Nov 7, 2007 1:28 PM
>>>To: Repeater-Builder@ 
>>><mailto:Repeater-Builder%40yahoogroups.com>
> yahoogroups.com
>>>Subject: Re: [Repeater-Builder] Part 97 question 
>>>reference to Repeater control
>>>
>>>But where does it require a control link (AUX station) to 
>>>control the
>>>repeater? (or landline ot local)
>>>
>>>Joe M.
>>>
>> 
>> 
>> 97.7 states that EVERY amateur station (remember, a 
>>repeater is an amateur station: see 97.3(a)(39)) must 
>>have a control operator:
>> 
>> §97.7 Control operator required.
>> 
>> When transmitting, each amateur station must have a 
>>control operator. The 
>> control operator must be a person: 
>> 
>> (a) For whom an amateur operator/primary station license 
>>grant appears on the 
>> ULS consolidated licensee database, or 
>> 
>> (b) Who is authorized for alien reciprocal operation by 
>>§97.107 of this part 
>> 
>> 
>> 
>> And Station control is defined in 97.109:
>> 
>> §97.109 Station control. 
>&

RE: [Repeater-Builder] Part 97 question reference to Repeater control

[John Barrett]

According to Part 97.205e, ancillary functions (phone patch, etc) are not
considered remote control… which seems to limit the meaning of remote
control to enabling or disabling the repeater as a unit.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Wednesday, November 07, 2007 2:41 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Part 97 question reference to Repeater
control

 

Isn't any operator on the repeater in RF control of the 
repeater when they are using it? Also isn't the DTMF tone 
control through the normal repeater pair remote control?

Vern

On Wed, 7 Nov 2007 13:54:32 -0600 (GMT-06:00)
George Henry <[EMAIL PROTECTED]  net> wrote:
> -Original Message-
>>From: MCH <[EMAIL PROTECTED]  >
>>Sent: Nov 7, 2007 1:28 PM
>>To: Repeater-Builder@ 
yahoogroups.com
>>Subject: Re: [Repeater-Builder] Part 97 question 
>>reference to Repeater control
>>
>>But where does it require a control link (AUX station) to 
>>control the
>>repeater? (or landline ot local)
>>
>>Joe M.
>>
> 
> 
> 97.7 states that EVERY amateur station (remember, a 
>repeater is an amateur station: see 97.3(a)(39)) must 
>have a control operator:
> 
> §97.7 Control operator required.
> 
> When transmitting, each amateur station must have a 
>control operator. The 
> control operator must be a person: 
> 
> (a) For whom an amateur operator/primary station license 
>grant appears on the 
> ULS consolidated licensee database, or 
> 
> (b) Who is authorized for alien reciprocal operation by 
>§97.107 of this part 
> 
> 
> 
> And Station control is defined in 97.109:
> 
> §97.109 Station control. 
> 
> (a) Each amateur station must have at least one control 
>point. 
> (b) When a station is being locally controlled, the 
>control operator must be at 
> the control point. Any station may be locally 
>controlled. 
> (c) When a station is being remotely controlled, the 
>control operator must be at 
> the control point. Any station may be remotely 
>controlled. 
> (d) When a station is being automatically controlled, 
>the control operator need 
> not be at the control point. Only stations specifically 
>designated elsewhere in 
> this Part may be automatically controlled. Automatic 
>control must cease upon 
> notification by a District Director that the station is 
>transmitting improperly 
> or causing harmful interference to other stations. 
>Automatic control must not be 
> resumed without prior approval of the District Director. 
> (e) No station may be automatically controlled while 
>transmitting third party 
> communications, except a station transmitting a RTTY or 
>data emission. All 
> messages that are retransmitted must originate at a 
>station that is being 
> locally or remotely controlled.
> 
> And 97.205(d) states that a repeater may be 
>automatically controlled.
> 
> So, taking them all together, a repeater MUST have a 
>control operator, MAY be under automatic control, and at 
>all times when NOT operating under automatic control, 
>MUST be either locally (someone physically at the control 
>point) or remotely (RF or wireline) controlled. If 
>remotely controlled over RF, the control link is in 
>auxiliary operation, and may only be carried out in the 
>frequency segments specifically authorized in 97.201, 
>which, as someone else already pointed out, were recently 
>expanded to include certain sub-bands on 2 meters.
> 
> 
> George, KA3HSW

 

RE: [Repeater-Builder] Part 97 question reference to Repeater control

[John Barrett]

I though that's what bozo timers were supposed to cover :-) I.E. a function
of the automatic controls

 

I have just very carefully read the Part 97 section on repeaters and
automatic control, and my understanding is that a repeater does not require
any sort of control link.. Nothing in the sections 97.109d or 97.205 state
that an automatically controlled repeater station must have a control link.
the 3 minute restriction that was mentioned is a restriction on telecommand
stations (97.213) and I do not believe that a repeater is considered a
telecommand station, else it would state that in the repeater section or the
telecommand section, or those sections would be combined.

 

No where can I see it stated that there MUST be a control link for a
repeater !!

 

The question that needs to be asked is "what are the currently accepted best
practices for the type of installation" . and I know of several repeaters in
my area that are remotely located (if you want to consider a cabinet next to
a water tower as "remote") that have no Telco or RF controls. everything is
done via the repeater input or on site.. I personally would want something
more for a repeater less accessible than that. i.e. If someone can't get to
the machine in 15 minutes to shut it down, then I'd want something more. 

 

Just as a case in point.. there have been times where we have had jammers
and controller issues cause problems with our primary local VHF repeater,
and those problems went on for hours until someone was free to travel to the
site. The site has a phone patch, but to the best of my knowledge, there is
no capability to dial in and command a shutdown of the repeater.

 

The portable repeater I'm working on will have both packet and wifi control
links with the ability to completely cut power to the repeater . so I'm
covered there :-) 

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of George Henry
Sent: Wednesday, November 07, 2007 1:57 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Part 97 question reference to Repeater
control

 



-Original Message-
>From: Adam Vazquez Kb2Jpd <[EMAIL PROTECTED]
 net>
>Sent: Nov 7, 2007 1:50 PM
>To: Repeater-Builder@ 
yahoogroups.com
>Subject: Re: [Repeater-Builder] Part 97 question reference to Repeater
control
>
>Most 2M Repeater operators use their input free so I think you know
>what that means.
>

Primary control CANNOT be on the repeater input frequency. What if the
repeater is being jammed?

George, KA3HSW

 

RE: [Repeater-Builder] Kenwood tkr-820 and tkr-720

[John Barrett]

I'm going to run it in squelch mode anyway -- my controller has PL
capability so I'm gonna let it do all the work. And since I have separate RX
and TX available (no internal duplexer), I can hook and antenna up to rx,
dummy load on TX and light it up with an HT :)

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jim
Sent: Monday, November 05, 2007 2:23 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Kenwood tkr-820 and tkr-720

DCFluX wrote:
> On 11/5/07, John Barrett <[EMAIL PROTECTED]> wrote:
>> If I can validate the "remove and reprogram" procedure that I found
>> online, I'll submit it for the RB website

One problem with that write-up: the front panel squelch control has no 
effect on repeat, only the local speaker and rear panel/remote audio.

To open the repeat squelch, you have to open the unit and get into the 
controller board on top. I don't remember which pot to turn, but one of 
the pots on the controller is repeat squelch. But like you say, if it's 
programmed for CTCSS/DCS, you have to remove the EEPROM to put it in CSQ.
-- 
Jim Barbour
WD8CHL





 
Yahoo! Groups Links

RE: [Repeater-Builder] Kenwood tkr-820 and tkr-720

[John Barrett]

(after viewing attached instructions to hack the 820)

 

WOO HOO - thanks MUCHLY !! don't even need the kenwood software like the
other method did !!

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of DCFluX
Sent: Monday, November 05, 2007 12:49 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Kenwood tkr-820 and tkr-720

 

 

On 11/5/07, John Barrett <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> net>
wrote:

Dallas Texas area : :-(

 

If I can validate the "remove and reprogram" procedure that I found online,
I'll submit it for the RB website

 

If I can't reprogram it that way, or find someone local to do it - I'll be
buying the KPT-50 :-) 

 

At least the chips are still available if I fry one :-) 

 

  _  

From: Repeater-Builder@ <mailto:Repeater-Builder@yahoogroups.com>
yahoogroups.com [mailto:Repeater-Builder@
<mailto:Repeater-Builder@yahoogroups.com> yahoogroups.com] On Behalf Of
skipp025
Sent: Monday, November 05, 2007 11:25 AM
To: Repeater-Builder@ <mailto:Repeater-Builder@yahoogroups.com>
yahoogroups.com
Subject: [Repeater-Builder] Kenwood tkr-820 and tkr-720

 

Kenwood tkr-820 and tkr-720 

> You are going to have a fun time getting the repeater to receive 
> down that far. Those repeaters don't quite have the front end 
> as the newer TKR repeaters have.

The TKR-720 and TKR-820 Repeaters have a pretty good front end for 
what they are. I seem to remember a 3-Section front end that holds 
its own in actual operation. I've got them working down at 143 MHz 
no problama...

There are three known methods to program the tkr-820/720 radios 
and repeaters. The first and the best is using the KPT-50 programmer 
unit (which I as a Kenwood Dealer normally stock) with the matching 
kpg-20 dos software (on a laptop). 

I'm pretty sure one can also use the older Kenwood KPT-20 programmer 
unit... not so easy to find and not so fun to operate. I have a 
KPT-20 and a KPT-10 but why use them when the KPT-50 with the software 
is so... much nicer. 

The third method some people are trying to work out is to remove 
the two eproms from inside the repeater and program them "by hand" 
if you have the proper reprogram unit, the knowledge, a large note-
book and a lot of free time to spare.

If you're in the Northern California Area I'll reprogram your tkr 
repeaters for free. Helps the Amateur Radio people avoid the cost 
of the KPT-50 for a one time job. 

cheers, 
skipp 

skipp025 at yahoo.com 
www.radiowrench. <http://www.radiowrench.com> com 

>> On Behalf Of John Barrett
>> Sent: Monday, November 05, 2007 6:26 AM
>> To: Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com>
yahoogroups.com
>> Subject: RE: [Repeater-Builder] Re: UHF Radio recommendations ??
>> 
>> It looks like I'm going to have a Kenwood TKR-820 shortly :-) 
>> Spent a little more on it than I wanted to, but being the lazy 
>> sod that I am, it seemed a little easier than putzing around 
>> with multiple radios :-)
>> 
>> I'd really appreciate any info on programming the 820 without 
>> having to use the KPT-50 programmer - I've already found some 
>> information, but it would be a great help if I could confirm 
>> the procedure.
>> 

 

 

RE: [Repeater-Builder] Kenwood tkr-820 and tkr-720

[John Barrett]

Dallas Texas area ::-(

 

If I can validate the "remove and reprogram" procedure that I found online,
I'll submit it for the RB website

 

If I can't reprogram it that way, or find someone local to do it - I'll be
buying the KPT-50 :-)

 

At least the chips are still available if I fry one :-)

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of skipp025
Sent: Monday, November 05, 2007 11:25 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Kenwood tkr-820 and tkr-720

 

Kenwood tkr-820 and tkr-720 

> You are going to have a fun time getting the repeater to receive 
> down that far. Those repeaters don't quite have the front end 
> as the newer TKR repeaters have.

The TKR-720 and TKR-820 Repeaters have a pretty good front end for 
what they are. I seem to remember a 3-Section front end that holds 
its own in actual operation. I've got them working down at 143 MHz 
no problama...

There are three known methods to program the tkr-820/720 radios 
and repeaters. The first and the best is using the KPT-50 programmer 
unit (which I as a Kenwood Dealer normally stock) with the matching 
kpg-20 dos software (on a laptop). 

I'm pretty sure one can also use the older Kenwood KPT-20 programmer 
unit... not so easy to find and not so fun to operate. I have a 
KPT-20 and a KPT-10 but why use them when the KPT-50 with the software 
is so... much nicer. 

The third method some people are trying to work out is to remove 
the two eproms from inside the repeater and program them "by hand" 
if you have the proper reprogram unit, the knowledge, a large note-
book and a lot of free time to spare.

If you're in the Northern California Area I'll reprogram your tkr 
repeaters for free. Helps the Amateur Radio people avoid the cost 
of the KPT-50 for a one time job. 

cheers, 
skipp 

skipp025 at yahoo.com 
www.radiowrench.com 

>> On Behalf Of John Barrett
>> Sent: Monday, November 05, 2007 6:26 AM
>> To: Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com>
yahoogroups.com
>> Subject: RE: [Repeater-Builder] Re: UHF Radio recommendations ??
>> 
>> It looks like I'm going to have a Kenwood TKR-820 shortly :-) 
>> Spent a little more on it than I wanted to, but being the lazy 
>> sod that I am, it seemed a little easier than putzing around 
>> with multiple radios :-)
>> 
>> I'd really appreciate any info on programming the 820 without 
>> having to use the KPT-50 programmer - I've already found some 
>> information, but it would be a great help if I could confirm 
>> the procedure.
>> 

 

RE: [Repeater-Builder] Re: UHF Radio recommendations ??

[John Barrett]

I've had some off-list replies from others who have used the 820
successfully.. its even mentioned on the RB Kenwood page, which is why I
jumped on the auction. But I've also heard a few saying what you have
(unfortunately AFTER I won the 820 !!). if it doesn't work out, I can always
unload it and try again.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Mike Mullarkey
Sent: Monday, November 05, 2007 7:48 AM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Re: UHF Radio recommendations ??

 

John,

 

You are going to have a fun time getting the repeater to receive down that
far. Those repeaters don't quite have the front end as the newer TKR
repeaters have.

 

 

 

Mike Mullarkey (K7PFJ)

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of John Barrett
Sent: Monday, November 05, 2007 6:26 AM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Re: UHF Radio recommendations ??

 

It looks like I'm going to have a Kenwood TKR-820 shortly :-) Spent a little
more on it than I wanted to, but being the lazy sod that I am, it seemed a
little easier than putzing around with multiple radios :-)

 

I'd really appreciate any info on programming the 820 without having to use
the KPT-50 programmer - I've already found some information, but it would be
a great help if I could confirm the procedure.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Doug Dickinson
Sent: Friday, November 02, 2007 3:59 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: UHF Radio recommendations ??

 

I like the idea of using some of the old "brick outhouse" type radios. The
MasterII and Micor are about as bulletproof as a radio can get.

 

Another idea that I saw on the web is to use a couple of portable radios
(i.e. MT1000 or P200 Motorola) radios as the Receiver and the exciter and
then use a commercial PA of your choosing. If you add some of the mechanical
folters from an old Micor, you could have a programmable, multi-channel
device for not too much money. It will take a lot more time, than the
modified mobile. 

 

My $0.02 worth. Good luck. This could be a fun project.

 

RE: [Repeater-Builder] Re: UHF Radio recommendations ??

[John Barrett]

It looks like I'm going to have a Kenwood TKR-820 shortly :-) Spent a little
more on it than I wanted to, but being the lazy sod that I am, it seemed a
little easier than putzing around with multiple radios :-)

 

I'd really appreciate any info on programming the 820 without having to use
the KPT-50 programmer - I've already found some information, but it would be
a great help if I could confirm the procedure.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Doug Dickinson
Sent: Friday, November 02, 2007 3:59 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: UHF Radio recommendations ??

 

I like the idea of using some of the old "brick outhouse" type radios. The
MasterII and Micor are about as bulletproof as a radio can get.

 

Another idea that I saw on the web is to use a couple of portable radios
(i.e. MT1000 or P200 Motorola) radios as the Receiver and the exciter and
then use a commercial PA of your choosing. If you add some of the mechanical
folters from an old Micor, you could have a programmable, multi-channel
device for not too much money. It will take a lot more time, than the
modified mobile. 

 

My $0.02 worth. Good luck. This could be a fun project.

 

RE: [Repeater-Builder] UHF Radio recommendations ??

[John Barrett]

I hope so - spent a little more than I wanted to on it

 

Anyone know who might be able to program it in the Dallas/Fort Worth area ??

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jim
Sent: Friday, November 02, 2007 5:02 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] UHF Radio recommendations ??

 

John Barrett wrote:
> Thanks for all the input - I just picked up a Kenwood TKR-820, so I'm down
> to getting the VHF packet rigs and I'll have everything I need :-)

O-good choice!

-- 
Jim Barbour
WD8CHL

 

RE: [Repeater-Builder] UHF Radio recommendations ??

[John Barrett]

Thanks for all the input - I just picked up a Kenwood TKR-820, so I'm down
to getting the VHF packet rigs and I'll have everything I need :-)

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of John Barrett
Sent: Friday, November 02, 2007 10:50 AM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] UHF Radio recommendations ??

 

I wanted to go UHF from the start, but until 2 days ago I was unable to
locate info on backyard UHF pairs. info which I now have. the packet rigs
are on 144.39 and 145.05, so not quite exactly 600kc separation.. I use the
TNC-X and it does not have a "hold-off" input to sync with other devices
without making modifications either in hardware or software, so I'm probably
just going to filter it up real good and test with a spectrum analyzer to
make sure all the intermod products are well suppressed.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jim Brown
Sent: Friday, November 02, 2007 9:07 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] UHF Radio recommendations ??

 

John, for your application I would suggest buying a GE Mastr II mobile UHF
radio and modifying it for repeater use.  It is very simple to configure,
and all the info you will need is on the repeater-builder site.  I have
several of these units in service and have been very pleased with the
results.  If you do not care to do the modification yourself, purchase one
of these units from the repeater-builder folks.

 

In my experience they far out-perform the Hamtronics type units so far as
reliability and desense rejection is concerned.

 

I think you are on the right track for your system.  As you might remember,
I suggested this solution in the first place.  Use a standard VHF duplexer
to couple the two radios to the VHF input of a Comet or Diamond band
splitter and couple the UHF duplexer for your repeater to the other port of
the band splitter.  A dual band antenna will complete the RF configuration
with a minimum of difficulty on the RF side.

 

To avoid complications on the two packet ports, I would configure the system
to not allow transmission on both radios at the same time.  Packet TNCs have
an input to prevent transmission when a signal is being received, and you
should be able to arrange logic to OR the receive signal DCD with the PTT on
the other radio and supply this to the TNC as the DCD signal.  Do this for
each TNC, using the other TNC PTT signal.  This will avoid the possible
intermod product you will generate with the two transmitters keyed at the
same time.  If your two packet frequencies are exactly 600 kHz apart, the
other 2 meter repeater owners in the area will apreciate it also.

 

73 - Jim  w5ZIT

John Barrett <[EMAIL PROTECTED]> wrote:

The major problem I was having is resolved. I've finally got a UHF backyard
pair for my portable repeater :-) No more hassling with trying to pack 4
radios into 1mhz of VHF bandwidth :-)

Since there isn't a way to look at receiver specs and figure how much
isolation is really needed, here I am asking - what is my best bet for
radios to build a UHF repeater? I'm currently looking at a Hamtronics
receiver/exciter pair with separate PA, but I'm pretty much open to anything
I can get at a reasonable price (300-400 for both RX and TX, PA extra if
needed). The repeater controller I will be using has PL built in, so the
radios don't need it. I would prefer 50 watts or better output, 100w max.

Size is important. I've only got about 16" of depth to mount this in, though
there is a way I can get bigger than that if absolutely necessary. If the
equipment recommended has any "front panel" controls, it needs to be 16" or
less front to back. If no controls, then I have a lot more freedom in
mounting.

 

 __
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com 

 

RE: [Repeater-Builder] UHF Radio recommendations ??

[John Barrett]

I wanted to go UHF from the start, but until 2 days ago I was unable to
locate info on backyard UHF pairs. info which I now have. the packet rigs
are on 144.39 and 145.05, so not quite exactly 600kc separation.. I use the
TNC-X and it does not have a "hold-off" input to sync with other devices
without making modifications either in hardware or software, so I'm probably
just going to filter it up real good and test with a spectrum analyzer to
make sure all the intermod products are well suppressed.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jim Brown
Sent: Friday, November 02, 2007 9:07 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] UHF Radio recommendations ??

 

John, for your application I would suggest buying a GE Mastr II mobile UHF
radio and modifying it for repeater use.  It is very simple to configure,
and all the info you will need is on the repeater-builder site.  I have
several of these units in service and have been very pleased with the
results.  If you do not care to do the modification yourself, purchase one
of these units from the repeater-builder folks.

 

In my experience they far out-perform the Hamtronics type units so far as
reliability and desense rejection is concerned.

 

I think you are on the right track for your system.  As you might remember,
I suggested this solution in the first place.  Use a standard VHF duplexer
to couple the two radios to the VHF input of a Comet or Diamond band
splitter and couple the UHF duplexer for your repeater to the other port of
the band splitter.  A dual band antenna will complete the RF configuration
with a minimum of difficulty on the RF side.

 

To avoid complications on the two packet ports, I would configure the system
to not allow transmission on both radios at the same time.  Packet TNCs have
an input to prevent transmission when a signal is being received, and you
should be able to arrange logic to OR the receive signal DCD with the PTT on
the other radio and supply this to the TNC as the DCD signal.  Do this for
each TNC, using the other TNC PTT signal.  This will avoid the possible
intermod product you will generate with the two transmitters keyed at the
same time.  If your two packet frequencies are exactly 600 kHz apart, the
other 2 meter repeater owners in the area will apreciate it also.

 

73 - Jim  w5ZIT

John Barrett <[EMAIL PROTECTED]> wrote:

The major problem I was having is resolved. I've finally got a UHF backyard
pair for my portable repeater :-) No more hassling with trying to pack 4
radios into 1mhz of VHF bandwidth :-)

Since there isn't a way to look at receiver specs and figure how much
isolation is really needed, here I am asking - what is my best bet for
radios to build a UHF repeater? I'm currently looking at a Hamtronics
receiver/exciter pair with separate PA, but I'm pretty much open to anything
I can get at a reasonable price (300-400 for both RX and TX, PA extra if
needed). The repeater controller I will be using has PL built in, so the
radios don't need it. I would prefer 50 watts or better output, 100w max.

Size is important. I've only got about 16" of depth to mount this in, though
there is a way I can get bigger than that if absolutely necessary. If the
equipment recommended has any "front panel" controls, it needs to be 16" or
less front to back. If no controls, then I have a lot more freedom in
mounting.

 

 __
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com 

 

[Repeater-Builder] UHF Radio recommendations ??

[John Barrett]

The major problem I was having is resolved. I've finally got a UHF backyard
pair for my portable repeater :-) No more hassling with trying to pack 4
radios into 1mhz of VHF bandwidth :-)

 

Since there isn't a way to look at receiver specs and figure how much
isolation is really needed, here I am asking - what is my best bet for
radios to build a UHF repeater? I'm currently looking at a Hamtronics
receiver/exciter pair with separate PA, but I'm pretty much open to anything
I can get at a reasonable price (300-400 for both RX and TX, PA extra if
needed). The repeater controller I will be using has PL built in, so the
radios don't need it. I would prefer 50 watts or better output, 100w max.

 

Size is important. I've only got about 16" of depth to mount this in, though
there is a way I can get bigger than that if absolutely necessary. If the
equipment recommended has any "front panel" controls, it needs to be 16" or
less front to back. If no controls, then I have a lot more freedom in
mounting.

RE: [Repeater-Builder] pc board duplexer article

[John Barrett]

Dump a copy of the duplexer article this way if you would. I need something
better than the 4-6" cans I currently have.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of George Henry
Sent: Thursday, November 01, 2007 11:11 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] pc board duplexer article

 

I'll scan the Dec. 2005 article tomorrow and send you both.

George

- Original Message - 
From: "Mike Morris WA6ILQ" <[EMAIL PROTECTED]  net>
To: mailto:Repeater-Builder%40yahoogroups.com>
yahoogroups.com>
Sent: Thursday, November 01, 2007 4:24 PM
Subject: Re: [Repeater-Builder] pc board duplexer article

> At 01:32 PM 11/01/07, you wrote:
>>According to the ARRL web site QST index search, it was April 1979,
>>page 11. I don't have that one, but do have a copy of the 1972
>>6-can duplexer construction article.
>>
>>Somebody out there must have the QST CD-ROM that covers 1979, though
>>
>>
>>George, KA3HSW / WQGJ413
>
> Repeater-Builder has permission from the ARRL to have PDFs from QST
> on the web site. If anybody
> would send me the PDF of the 1972 article or the 1979 article I'll put it 
> up.
>
> I'd also like to get a PDF of the introductory article on regulated
> power supplies that used the Astron schematic as a walkthrough from
> the December 2005 issue.
>
> Mike WA6ILQ
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>

 

RE: RE: RE: RE: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciev

[John Barrett]

Ohh geez - active devices are capable of exhibiting gain. Period. I hate to
sound proprietary, but I started this thread and this is WAY OT !!

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Gary Schafer
Sent: Wednesday, October 24, 2007 11:42 AM
To: Repeater-Builder@yahoogroups.com
Subject: RE: RE: RE: RE: RE: RE: RE: [Repeater-Builder] Re: duplexer
isolation and reciev

 

So according to your definition of "active" that would mean that a regular
old ammeter is an active device as something changes when a signal is
applied.

That would also make a light bulb an active device as its properties change
when a signal is applied. Its resistance changes, it gives off heat and
light.

That would also make a resistor an active device as it gives off heat when a
signal is applied.

A capacitor could also be called an active device by that same definition as
it accumulates charge when a signal is applied. It has changed its state.

73
Gary K4FMX

> -Original Message-
> From: Repeater-Builder@ 
yahoogroups.com [mailto:Repeater-
> [EMAIL PROTECTED]  .com] On Behalf Of
Ron Wright
> Sent: Wednesday, October 24, 2007 7:25 AM
> To: Repeater-Builder@ 
yahoogroups.com
> Subject: Re: RE: RE: RE: RE: RE: RE: [Repeater-Builder] Re: duplexer
> isolation and reciev
> 
> Jeff,
> 
> Beta is the current gain of a transistor, HFE and Hfe. No one would
> design a transistor with a beta of less than one, but they do exist for
> transistors can become defective. It is common for a new transistor to
> have a beta of 100, but after hours of use decrease to 20. A good design
> recognizes this and adapts. They can also decrease to less than 1.
> Usually one replaces them, but they are still acting as a transistor. An
> emitter follower will have power gain only if the transistor has a beta,
> HFE or Hfe, greater than 1, but is active in any case. Having gain,
> voltage, current or power, does not determine if a component is active.
> It is how the component reacts to the energy.
> 
> Yes diodes and transistor have junction capacitance, resistance, but get
> their properties from entirely different means than passive devices such
> as a resistor. Junction capacitance is a function of energy supplied to
> the device. A capacitor does not change its properties based on energy
> supplied, unless one exceeds its specs. A diode does.
> 
> A transistor and diode change their properties based on the energy
> supplied. This makes both active.
> 
> As for the Quantum Mechnicancs this was over 40 years ago. One must know
> high level calculus understanding the wave and heat flow equations to
> follow. On one of my exams the instruction was to come up with the
> equation for current flow in a diode. Only took about 3 pages. The 2nd
> question was how much current was flowing with given parameters, holes,
> doping density, and some others. If you got the first correct it was
> easy. If one goes thru these derivations one can see a diode is a very
> active device.
> 
> 73, ron, n9ee/r
> 
> 
> 
> >From: Jeff DePolo <[EMAIL PROTECTED]  com>
> >Date: 2007/10/23 Tue PM 08:52:14 CDT
> >To: Repeater-Builder@ 
yahoogroups.com
> >Subject: RE: RE: RE: RE: RE: RE: [Repeater-Builder] Re: duplexer
> isolation and reciever n
> 
> >
> >
> >> Sorry, but I totally disagree about a diode not being active.
> >> If having to have gain then many devices such as a transistor
> >> emitter follower with a beta of <1 would not be an active device.
> >
> >I assume you're using the term "beta" to really mean current gain of the
> >stage. On my planet, an emitter-follower stage can't have a current gain
> of
> >< 1. Please draw me a schematic of an emitter-follower circuit that
> does.
> >
> >Or better yet, point me to a data sheet for a transistor that has a beta
> >(hFE) spec of less than one.
> >
> >An emitter-follower is a current-gain stage. Assuming the voltage
> remains
> >constant (or nearly so, minus the junction drop), but current increases,
> it
> >provides POWER GAIN, which DOES make it an active stage.
> >
> >> Maybe if you had studied the equations with Quantum Mechanics
> >> for a diode you might understand this.
> >
> >You don't need quantum mechanics to show that a diode is a passive
> device.
> >But I'll indulge you; please explain how a diode (just a plain old
> silicon
> >junction diode) qualifies as an active device using quantum mechanics.
> >
> >> A diode follows some
> >> of the same equations as a transistor.
> >
> >So? A diode also "follows some of the same equations" as a capacitor, a
> >resistor, an inductor, or even a fuse for that matter depending on how
> its
> >used in a circuit. What's your point?
> >
> > --- Jeff
> >
> >
> 
> 
> Ron Wright, N9EE
> 727-376-6575
> MICRO COMPUTER CONCEPTS
> Owner 146.64 repea

RE: [Repeater-Builder] Re: duplexer isolation and reciever noise budget

[John Barrett]

Yes - I made that suggestion. I'm no RF engineer, but it seemed like an
interesting idea. A circulator configured as an isolator (dummy load on the
3rd port) would be counterproductive, my idea was to hook the 3rd port to
the receive chain, adding the reverse port to port isolation of the
circulator to the existing isolation of the duplexer, and incidentally
splitting a single antenna into separate TX and RX paths. I've got a VHF
circulator here, and plan to load it up on my friend's network analyzer
tonight and see just how far out in left field this idea is :-)

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Ken Arck
Sent: Wednesday, October 24, 2007 12:04 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Re: duplexer isolation and reciever noise
budget

 

At 09:51 AM 10/24/2007, you wrote:

>OK, I have to comment,
>
>An isolator/circulator should not be used in a duplexer at the 
>antenna connector when there are other strong signals floating 
>around the air that can get into the isolator.

<---Uh...a couple of things here:

1) Did I miss something here? Did someone suggest connecting a 
circulator to the antenna port of a duplexer?

2) The whole point of a circulator is to act as a "one-way" path for 
RF. Placing it in the antenna path is a bit counterproductive, no?

3) I disagree with your comments about "strong signals that can 'get 
into' the circulator. Again, that's the whole point, isn't it?

Ken

--
President and CTO - Arcom Communications
Makers of repeater controllers and accessories.
http://www.arcomcon  trollers.com/
Authorized Dealers for Kenwood and Telewave and
we offer complete repeater packages!
AH6LE/R - IRLP Node 3000
http://www.irlp.  net
"We don't just make 'em. We use 'em!"

 

RE: [Repeater-Builder] duplexer isolation and reciever noise budget

[John Barrett]

Yes - this is going on an 16ft boat trailer converted to a flatbed with a
38ft crank up tower mounted on a tilt base that I built. the tilt base,
hydraulic system, and generator are towards the back of the trailer, with a
9ft x 5ft x 3.5ft cargo box system forward of the tilt base. The forward 5ft
x 5ft x 3.5ft of the cargo section is split into 2 shelves for cargo, the
rear 4ft is split with 2 18" deep shelves on each side, and a 65 gallon fuel
tank for the generator in the middle. The bottom shelf on each side holds 10
each 100ah SLA batteries. The top left (drivers) side is power electronics
(transfer switch, 3000W inverter, 140A battery charger, AC distribution
panel, Primary 300A DC power Bus, and the high current DC breaker panel. The
top right side is radio and computer gear to implement local area and point
to point WiFi networks, APRS beacon with optional digipeater capability,
WinLink Telpac and PacLink Postoffice capability, Voice Repeater, and
eventually a 1.2hgz D-Star link. If the repeater ends up on VHF, then I
might consider setting an ATV system on 440, since I won't be using 440 for
anything else on the trailer. Call it the "ham shack on wheels" if you like
:-)  

 

I have asked for a UHF itinerant/backyard pair, been informed that I would
be given a list of pairs to listen on to find one reasonably clear enough to
set up on, and have been waiting over a week for said list. There is no
specifically designated UHF "backyard" pair in this area, but there is one
for VHF - 145.25/144.65, which I have been assured by the VHF coordinator
that I can use.

 

As stated earlier, I would LOVE to setup on UHF for this, but until I get
coordination, I'm moving forward with the VHF at least far enough to get the
2 simplex rigs playing nicely, with a solid plan in place for adding the
repeater should the UHF idea fall through. I'm almost tempted to set up and
scan pairs where I don't have a repeater closer than 40 or 50 miles, just to
get a jump on the UHF coordinator, but I don't have a spare 440 capable
radio to use for a dedicated scanner for a week right now.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of n9wys
Sent: Wednesday, October 24, 2007 11:03 AM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] duplexer isolation and reciever noise budget

 

John,

 

If I'm reading this correctly, you're trying to do this all in a trailer -
yes?  Since you are operating "portable", does your coordinating body have
an "Itinerant" UHF pair you can use for the repeater?  If so, this might
make your situation MUCH easier to engineer. 

 

Mark - N9WYS

 

  _  

From: Repeater-Builder@yahoogroups.com On Behalf Of John Barrett

 snip 

 

The key here is the height of the cans. if they are short enough (less than
30" total including tuning rod), I can do 2 banks, facing different sides of
the trailer.. doubling the number of cans I can pack in. Only one of the
cans I have so far exceeds that spec, and only by a little.. once its tuned
it may be less than the 30" max, or I can trade it off with a shorter can on
the other side to make up the difference.

 

I would prefer to keep all the cans on one side if possible, but it is
looking more and more like it will not be, so I'm willing to give up some
space in the power electronics bay to make space for more cans. 

 

RE: [Repeater-Builder] Re: duplexer isolation and reciever noise bud

[John Barrett]

I've seen dual stage isolators (have one sitting here for 440 just in case I
get a UHF pair to work with), and am actually planning to use them as
exactly that on each transmitter... and I've proposed your idea if worded
slightly differently by suggesting a circulator between the combined output
of my transmitter chain, the antenna, and the input to my receiver chain.

I even suggested sticking a circulator between the RX and TX halves of a
standard duplexer.. get you an extra 20-30db of isolation at very minimal
cost if your antenna is reasonably matched to the transmit frequency. You
might need a harmonic filter between the circulator and antenna, but that
shouldn't be a huge problem. Total additional insertion loss.. perhaps 1db,
and a lot less transmitter getting into your receiver :)

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Nate Duehr
Sent: Tuesday, October 23, 2007 7:52 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Re: duplexer isolation and reciever noise
bud

John Barrett wrote:

> Re: selectivity and rejection: I'm looking at the Icom V-8000, which 
> specs 75db for all of spurious/image/rejection. I have no data on 
> dynamic range or 3^rd order intercept. (haven't seen data like that on 
> any of the radios I've been considering for this system)
> 
> Is there any way to estimate the missing info from 
> spurious/image/rejection data??

Jeff was recommending that you actually MEASURE it, if you're curious. 
I agree.  As one of my RF mentors says, "Are you a thinkin' man, or are 
you a knowin' man?"

With that said, if you're attempting all of this without a spectrum 
analyzer, you're nuts.

You are building a system that would ultimately have multiple devices in 
an "odd" configuration (meaning that your methods of combining don't 
appear to be practiced by anyone here, nor in any documentation anyone 
can find -- probably for good solid engineering reasons?) and one device 
(the isolator) is known to throw harmonics.

Additionally, now you're mentioning that you want to put high-gain 
pre-amps into the mix (which may or may not be inherently stable, 
depending on who's you use -- also your setup will put a LOT of RF from 
your transmitting side directly into them, which is likely to blow them 
up or otherwise make them very unhappy)...

> Is there anything meaningful that can be determined from the info I have 
> available??

No, this is why Jeff pointed out it'd make a lot more sense to measure 
and KNOW than use the manufacturer's paperwork (specs) and GUESS.

You're going to have to see this whole thing with a spectrum analyzer at 
some point anyway, if you have any chance of it being "clean" ... so 
might as well start measuring things up-front if you're dead-set against 
using traditional tried-and-tested combining and filtering methods.  Right?

> No trade secrets now!! Spill all the dirty details J

Wow, the only "trade secrets" being "hidden" might be that the rest of 
us *usually* use completely different best practices for combining and 
splitting that look nothing like what you're attempting.  If you already 
realize that, then there's nothing being hidden here other than perhaps 
a few cringing people hiding behind something sturdy waiting for the big 
"boom" when something blows up over in your general direction.  (GRIN)

Your idea has sucked me in SLIGHTLY, however... you do know you could 
get a FOUR port isolator, right?  (Ha... that's bound to give you some 
REALLY wild ideas.)  Look for "dual-stage" isolators.

Port 1 TX
Port 2 Antenna
Port 3 RX
Port 4 Load to protect TX and keep stuff from going around forever by 
getting into the PA and mixing/amplification.

LOL!  Frankly, I can't believe I just posted that, though -- I think 
you're missing something here...

> That's for carrier attenuation only. Aside from the passive losses in the
> system, you've done nothing to attenuate transmitter noise, which is going
> to be a bigger enemy in your close-spaced frequency assignments.

If you're having trouble getting an image of what Jeff's talking about 
here... look a the output of any FM transmitter with a spectrum analyzer.

It's not a single vertical line.  It's a "mountain" shape with a slope 
on either side.  SKIRTS.

You have to deal with all that RF energy that's NOT directly on-channel 
too, not just the "directly on-channel" RF.  That's some of the "noise" 
Jeff is referring to... or at least it's part of the energy in the skirts...

If you put that into an isolator (which will create harmonics not just 
of the main frequency, but possibly of ALL of those frequencies in the 
skirts!!! 

RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever noise budget

[John Barrett]

I'm basing those isolation figures on a calculator I found online that asked
for the gain of the antennas and the separation (horizontal or vertical)

 

Re splitting the simplex: a circulator with the radio hooked to the input,
the transmit chain on the standard output, and the receive chain feeding the
load port is what I was thinking - a relay would do the job just as well,
but would require changes to the PC based Packet Engine software to support
flipping the relay before and after transmitting. I don't think that's a
built in feature, and source code is not available.

 

Re 4/5 ports: I have 3 transmit frequencies. 144.39, 145.05, and 145.25, and
3 receive frequencies. 144.39, 144.65, and 145.05 - if I keep transmit and
receive on separate chains, I only need a 4 port splitter/combiner on each
chain. if I go full out with all BP cavities, combined transmit/receive
chain for the simplex rigs, and no circulators/isolators, I need a 5 port.
If I understand the products correctly, a standard star coupler is just
resistance on each port to balance the impedance presented, and there is no
port to port isolation. I feel I would be better off with a Wilkinson at
that point because it would give me some additional port to port isolation,
and If I'm reading it right, for about the same insertion loss.

 

I have approximately 18"x18"x60" without moving cans to the cargo bay.
perhaps a little less - I'll have to measure - say enough for 9 5-6" cans,
or as many as 18 of the smaller cans that I have - the cans I have are a mix
from 5" to 8", with the idea that the larger cans would be used where I
needed sharper skirts, on the close spaced frequencies. The key here is the
height of the cans. if they are short enough (less than 30" total including
tuning rod), I can do 2 banks, facing different sides of the trailer..
doubling the number of cans I can pack in. Only one of the cans I have so
far exceeds that spec, and only by a little.. once its tuned it may be less
than the 30" max, or I can trade it off with a shorter can on the other side
to make up the difference.

 

I would prefer to keep all the cans on one side if possible, but it is
looking more and more like it will not be, so I'm willing to give up some
space in the power electronics bay to make space for more cans.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo
Sent: Tuesday, October 23, 2007 6:43 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget

 

> If I do two antennas, the best I can do is about 30db 
> isolation (30ft separation, 6db multi-bay folded dipole 
> antenna on bottom, 9db 2m/440 base station antenna on top), 

If you can get 30 feet of separation, you'll get more than 30 dB of
isolation. More like 50 dB on VHF, 60 dB or more on UHF as a guess. 

> Going to split the simplex radios with a circulator on each.. 

Maybe I'm missing something. I was talking about splitting the transmitter
and receiver apart so you could combine the transmitters separate from the
receivers if you were going to use hybrids as the primary means of
combining.

> I've done some checking around for "stars".. haven't found 
> any - I'm combining three transmitters - so 4 ports ?? 

You have four frequencies (144.39, 144.65, 145.05, 145.25), plus an antenna.
Five ports.

> got 
> some vendors or links I can look at 

Try Delta Electronics, Pasternak, maybe Kings. A 4-port "cross" is easy to
find. It's easy to build stars with more ports in a small die-cast box (the

ideal-sized box would make all of the center pins of the connectors
coincident).

> If I can use the star 
> to eliminate hybrid couplers, that would be great :-) that 
> would leave me with a 2 stage isolator and one or more cans 
> per transmitter.

Split antennas is, by far, the best way to go. Your biggest problem is the
145.05 Tx/Rx versus 145.250 Tx. I'd be inclined to start doing the analysis
assuming 145.05 is on its own antenna, with the remaining frequencies
three-wayed on another antenna using conventional cavity-ferrite combining.

> I don't have t-pass cavities, but since I'm still acquiring 
> cavities, I can get them if warranted. I've got 4 regular 
> band pass cans right now, 2 more on ebay I'm trying to get, 
> and a 6 can helical BR/BR duplexer that I can use for a 
> really deep notch if I need it somewhere (or will become part 
> of the receiver filters if I decide to stack BR filters for 
> receive, as per my previous post)

A helical pass/reject duplexer isn't going to help with the close spacings
involved. You might get lucky and be able to it to get some filtering
between the extremes (144.39 vs 145.25), but otherwise, the notches aren't
going to be sharp enough to avoid degrading the frequencies in between.
Have you swept it to really see what its performance is like (both
transmission and reflection)?

How much room do you have?

--- Jeff

 

RE: [Repeater-Builder] Re: duplexer isolation and reciever noise bud

[John Barrett]

It's kinda tough to measure when you don't have all the pieces in front of
you. I'm space constrained so I'm looking for alternatives to conventional
designs.. 3 harmonic filters take up a lot less space than 3 cavity filters.

I'm attempting to stay conventional up to a point.. we can look at it as
isolated issues -- what is the most space efficient and loss efficient way
to combine 3 transmitters with minimal off channel noise and maximum power
to the antenna... what is the best way to split receive for 3 receivers...
what types of filters and where do they need to be located to get IM and
harmonics under control... those parts I'm trying to stay pretty standard..
where I'm getting weird is how I make the simplex radios look like split
transmit and receive rigs, and how I'd like to run it all off the same
antenna

I've seen 2m FM on a spectrum analyzer, and I have occasional access to an
HP network analyzer to sweep the various components (got a meet scheduled
for Wednesday to go over the 4 cans I already have and the one circulator
that I've gotten in)

I've run into some hitches getting a UHF backyard pair, or I would move the
repeater to UHF in a heartbeat -- already have the duplexer for that, and
that would leave me with a pretty standard BP/BP duplexer setup to separate
the simplex radios, and would additionally get me back on a single antenna.

But I'm in the Dallas/Forth Worth Metroplex area, which means a coordinated
pair is impossible to get, and since I'm portable, I'd be a lot happier on a
backyard pair.



-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Nate Duehr
Sent: Tuesday, October 23, 2007 7:52 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Re: duplexer isolation and reciever noise
bud

John Barrett wrote:

> Re: selectivity and rejection: I'm looking at the Icom V-8000, which 
> specs 75db for all of spurious/image/rejection. I have no data on 
> dynamic range or 3^rd order intercept. (haven't seen data like that on 
> any of the radios I've been considering for this system)
> 
> Is there any way to estimate the missing info from 
> spurious/image/rejection data??

Jeff was recommending that you actually MEASURE it, if you're curious. 
I agree.  As one of my RF mentors says, "Are you a thinkin' man, or are 
you a knowin' man?"

With that said, if you're attempting all of this without a spectrum 
analyzer, you're nuts.

You are building a system that would ultimately have multiple devices in 
an "odd" configuration (meaning that your methods of combining don't 
appear to be practiced by anyone here, nor in any documentation anyone 
can find -- probably for good solid engineering reasons?) and one device 
(the isolator) is known to throw harmonics.

Additionally, now you're mentioning that you want to put high-gain 
pre-amps into the mix (which may or may not be inherently stable, 
depending on who's you use -- also your setup will put a LOT of RF from 
your transmitting side directly into them, which is likely to blow them 
up or otherwise make them very unhappy)...

> Is there anything meaningful that can be determined from the info I have 
> available??

No, this is why Jeff pointed out it'd make a lot more sense to measure 
and KNOW than use the manufacturer's paperwork (specs) and GUESS.

You're going to have to see this whole thing with a spectrum analyzer at 
some point anyway, if you have any chance of it being "clean" ... so 
might as well start measuring things up-front if you're dead-set against 
using traditional tried-and-tested combining and filtering methods.  Right?

> No trade secrets now!! Spill all the dirty details J

Wow, the only "trade secrets" being "hidden" might be that the rest of 
us *usually* use completely different best practices for combining and 
splitting that look nothing like what you're attempting.  If you already 
realize that, then there's nothing being hidden here other than perhaps 
a few cringing people hiding behind something sturdy waiting for the big 
"boom" when something blows up over in your general direction.  (GRIN)

Your idea has sucked me in SLIGHTLY, however... you do know you could 
get a FOUR port isolator, right?  (Ha... that's bound to give you some 
REALLY wild ideas.)  Look for "dual-stage" isolators.

Port 1 TX
Port 2 Antenna
Port 3 RX
Port 4 Load to protect TX and keep stuff from going around forever by 
getting into the PA and mixing/amplification.

LOL!  Frankly, I can't believe I just posted that, though -- I think 
you're missing something here...

> That's for carrier attenuation only. Aside from the passive losses in the
> system, you've done nothing to atte

RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever noise budget

[John Barrett]

If I do two antennas, the best I can do is about 30db isolation (30ft
separation, 6db multi-bay folded dipole antenna on bottom, 9db 2m/440 base
station antenna on top), or I can get close to the same isolation with a
circulator and one antenna.. so I don't see a difference there and one
antenna really simplifies things. (plus gets more gain and height compared
to the dipole array mounted low on the tower).. there is another issue, a
2nd antenna is at best a month away before I can slip it into the budget - I
have the base antenna available now.

 

Going to split the simplex radios with a circulator on each.. anything that
leaks through from transmit to receive will be 30db down and have to get
through the receive splitter and receive filters on the other receivers
before it can be a problem. Also, non-mechanical so removes a potential
point of failure !!

 

I've done some checking around for "stars".. haven't found any - I'm
combining three transmitters - so 4 ports ?? got some vendors or links I can
look at ?? If I can use the star to eliminate hybrid couplers, that would be
great :-) that would leave me with a 2 stage isolator and one or more cans
per transmitter.

 

I don't have t-pass cavities, but since I'm still acquiring cavities, I can
get them if warranted. I've got 4 regular band pass cans right now, 2 more
on ebay I'm trying to get, and a 6 can helical BR/BR duplexer that I can use
for a really deep notch if I need it somewhere (or will become part of the
receiver filters if I decide to stack BR filters for receive, as per my
previous post)

 

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo
Sent: Tuesday, October 23, 2007 4:37 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget

 

> OK - Here are my requirements for the transmit chain. minimal 
> physical space and minimal insertion loss :-) (ok - too 
> bloody obvious) Tuning simplicity is also a factor. I'm 
> combining 3 transmitters at 144.39, 145.05 +/- 0.04 and 145.25

Before we get to what hardware to use, we still need to quantify how much
isolation you really need between each transmitter and receiver. I'll throw
out real rough numbers but they really need to be determined ahead of time:

144.39 Tx noise supression at 145.05 (660 kHz) - 80 dB
144.39 Tx noise supression at 144.65 (260 kHz) - 105 dB
145.05 Tx noise supression at 144.39 (660 kHz) - 80 dB
145.05 Tx noise supression at 144.65 (400 kHz) - 95 dB
145.25 Tx noise supression at 144.39 (860 kHz) - 70 dB
145.25 Tx noise supression at 145.05 (200 kHz) - 110 dB
145.25 Tx noise supression at 144.65 (600 kHz) - 85 dB

144.39 carrier supression at 145.05 Rx (660 kHz) - 80 dB
144.39 carrier supression at 144.65 Rx (260 kHz) - 85 dB
145.05 carrier supression at 144.39 Rx (660 kHz) - 80 dB
145.05 carrier supression at 144.65 Rx (400 kHz) - 80 dB
145.25 carrier supression at 144.39 Rx (860 kHz) - 80 dB
145.25 carrier supression at 145.05 Rx (200 kHz) - 85 dB
145.25 carrier supression at 144.65 Rx (600 kHz) - 80 dB

144.39 Tx to/from 145.05 Tx - 60 dB
144.39 Tx to/from 145.25 Tx - 60 dB
145.05 Tx to/from 145.25 Tx - 60 dB

>From lowest to highest, it looks like this:

144.39 Tx/Rx --260 khz-- 144.65 Rx --400 kHz-- 145.05 Tx/Rx ---200 kHz--
145.25 Tx

Question 1: Are you locked in to a single antenna, or are two antennas a
possibility?

Question 2: If two antennas are a possibility, how much isolation can you
reasonably expect to get between them?

Question 3: Did you decide how you're going to "split" the simplex
transmitters and receivers (digis)?

> Right now by best bet for minimal space is the hybrid coupler 
> approach, but I pay in insertion loss. 

As a real rough estimate, you'd be looking at 10 dB or more insertion loss
for two of the transmitters and 7 dB or more for the third once you factor
in filter losses. If you're willing to take a 7 dB hit on one transmitter
alone, you'd be better off putting up two half-height antennas (3 dB gain
reduction) which will buy you 20-30 dB of isolation right there, and you'd
be almost guaranteed to come out better in ERP and sensitivity even
including the 3 dB antenna gain hit.

> loss is the T-Pass, but the T-Pass is starting to cut heavily 
> into my available space --- I'm already looking at 6-9 cans 
> on the receive side and would prefer something with NO cans 
> on the transmit side.

No cans on the transmit site - forget it. You've got 100 dB+ of noise
supression to make up somehow.

> Despite the space issues I'm still considering the T-Pass 
> because of the improved spurious signal suppression. Getting 
> the cans is another issue - could I use a regular band pass 
> can with a coax T rather than an actual T-Pass can ??

You could do a five-port star. If you don't already have cavities with
T-pass style loops in them, there's no reason to try to build using that
design.

> Can you list out some of t

RE: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever noise bud

[John Barrett]

That much I had figured out from the basic duplexer setup. I’m just trying to 
figure how to do it without 12 or more cans by taking advantage of the 
isolation provided by broad band components such as circulators in the path 
between TX and RX (broad band in this case meaning minimal variation within the 
1mhz window where all the frequencies are located). If I can hold it down to 6 
or 9 cans by using circulators and isolators, then I can probably make 
everything else fit :-) 

 

I’m almost getting to the point of saying to heck with cans on the receivers at 
all – I’ve been looking at preamps, and I can easily get 24db gain before the 
receiver filters… that gives me enough head room to start looking at helical 
reject filters again – even though each receiver will need 6 helical cavities 
per frequency rejected. I can get that with a standard 6 can mobile duplexer by 
going end to end and ignoring the common port… it would take 2 of those filters 
per receiver on the simplex radios, and 3 on the repeater input, but that is 
still a lot less space than 9 cans… 

 

Interestingly, unless I can find a preamp that is a little less “hot”, I may 
even have to look at some attenuation after the preamp to keep everything 
within limits. I’ll need less than 6 db from the preamp to overcome the receive 
splitter and the insertion losses from the additional filters

 

I would then have no space problem using T-Pass cans on the transmitter 
combiner which reduces my combiner losses and gets me more power to the antenna.

 

  _  

From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of 
Fred Seamans
Sent: Tuesday, October 23, 2007 1:58 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever 
noise bud

 

  

John: There are two things that you must protect you repeater receiver from. 
One is the on frequency signal, which will come from the repeater transmitter 
noise output and the second one is the blocking signal which prevents the 
repeater receiver from receiving the desired signal, which will come from the 
repeater transmitter main carrier output. The first has to be eliminated at the 
transmitter output signal, while the second is eliminated at the receiver input 
source. Both areas usually require between 70 and 80 db rejection each!

 

Fred W5VAY

 

- Original Message - 

From: John Barrett <mailto:[EMAIL PROTECTED]>  

To: Repeater-Builder@ <mailto:Repeater-Builder@yahoogroups.com> yahoogroups.com 

Sent: Tuesday, October 23, 2007 11:39 AM

Subject: RE: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever 
noise bud

 

I’m trying to understand your figures, and I got lost some place.

>From the transmitters… I’m max 50w (+47dbm) into the isolator

-1db from the isolator

-3db from the combiner

-30db from the antenna circulator (assuming the antenna is matched)

-3db from the receive splitter

-60 to -90db from the receiver cavities

Total isolation = 97 to 127db (as good or better than most stock duplexer 
setups)

Putting my transmit signals at -50 to -80 dbm

The receiver has 0.15uV sensitivity, which is -123dbm, which puts the 
transmitters well above the receivers “floor”

However, the receiver specifies 75db spurious/image/intermod rejection which I 
take to mean that any off channel signal -48dbm (-123dbm sensitivity + 75db 
rejection) or less should be completely ignored by the receiver, as it will be 
attenuated below the receiver floor in the IF. Anything stronger than that will 
start to cause de-sense, swamping any on-channel signals at the same power or 
less.

That’s what I need confirmed – if the receivers stated sensitivity + 
spurious/image/intermod rejection = maximum adjacent channel signal before 
de-sense kicks in.

Is there an RF Engineer in the house ??



  _  

size=2 width="100%" align=center tabIndex=-1> 

From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of 
Ron Wright
Sent: Tuesday, October 23, 2007 6:31 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever 
noise bud

There will be some reflected power from the antenna. And this reflected power 
will be wide tx band noise also which will affect the receiver.

If you are putting power into the isolator tx port there will be reflected 
noise and 30 db will not be enough. With the TX -80 db down and 30 db from 
isoloator that is only 110 db. It will swamp the receiver. 

Not sure why isolator cause harmonics for it has no non-linear components. It 
might cause tx to generate harmonics. Isolators are on the output of many 
repeater transmitters including my UHF Micor and it is built to work directly 
into an antenna although most applications use a duplexer which will give some 
harmonic suppression.

Using the dummy load port for the receiver might good idea. One way of getting 
TR re

RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever noise budget

[John Barrett]

OK - Here are my requirements for the transmit chain. minimal physical space
and minimal insertion loss :-) (ok - too bloody obvious) Tuning simplicity
is also a factor. I'm combining 3 transmitters at 144.39, 145.05 +/- 0.04
and 145.25

 

Right now by best bet for minimal space is the hybrid coupler approach, but
I pay in insertion loss. best for insertion loss is the T-Pass, but the
T-Pass is starting to cut heavily into my available space --- I'm already
looking at 6-9 cans on the receive side and would prefer something with NO
cans on the transmit side. 

 

Despite the space issues I'm still considering the T-Pass because of the
improved spurious signal suppression. Getting the cans is another issue -
could I use a regular band pass can with a coax T rather than an actual
T-Pass can ??

 

Can you list out some of the other options that I might be able to squeeze
onto my trailer ??

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo
Sent: Monday, October 22, 2007 9:41 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget

> Commercial installations usually use either a harmonic filter 
> and 3db hybrid coupler, or a special type of band pass cavity 
> to couple the output from the isolator to the feed line. 
> (This info from an RX TX application note on transmitter combiners)

Well, that's just two out of a myriad of ways of combining, duplexing,
multicoupling, etc. Hybrid-ferrite and TX-RX's T-pass are by no means the
only two ways of combining transmitters.

RE: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever noise bud

[John Barrett]

I'm using strictly band pass filters on both transmit and receive, with at
least one filter on the output of each transmitter (after the isolator), so
something is being done to knock down any off-channel outputs from the
transmitters and isolators.. the V8000 specifies -60db or better for
spurious output, add on another 30db or so for the band pass filter in the
combiner, 30db or so for the circulator isolation, plus path losses before
anything spurious that is on a receiver frequency can make it to the
receiver front end. so better than -120db. given a +47dbm signal, that's no
better than -80dbm, more likely -90dbm at the receiver - good enough or do I
need more??

 

Re: selectivity and rejection: I'm looking at the Icom V-8000, which specs
75db for all of spurious/image/rejection. I have no data on dynamic range or
3rd order intercept. (haven't seen data like that on any of the radios I've
been considering for this system)

 

Is there any way to estimate the missing info from spurious/image/rejection
data??

 

Is there anything meaningful that can be determined from the info I have
available??

 

No trade secrets now!! Spill all the dirty details :-)

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo
Sent: Tuesday, October 23, 2007 12:05 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and
reciever noise bud

 

> Total isolation = 97 to 127db (as good or better than most 
> stock duplexer setups)

That's for carrier attenuation only. Aside from the passive losses in the
system, you've done nothing to attenuate transmitter noise, which is going
to be a bigger enemy in your close-spaced frequency assignments.

> However, the receiver specifies 75db spurious/image/intermod 
> rejection which I take to mean that any off channel signal 
> -48dbm (-123dbm sensitivity + 75db rejection) or less should 
> be completely ignored by the receiver

No, you're thinking dynamic range (blocking) and/or selectivity, but quoting
the spec for spurious and image rejection.

The spurious spec is generally a function of the "purity" of the receiver's
LO. If the LO has spurs, new mix products will be generated in the mixer,
and some of those undesired mix products can end up falling at the IF center
frequency. In other words, you're creating spurs within the receiver
itself.

The image spec is largely a function of front-end filtering. The tighter
the front-end filtering, the further attenuated image frequencies will be
before reaching the mixer.

The intermod spec is mostly a function of dynamic range of the mixer (or RF
gain stage if one precedes it), typically quanified by the third-order
intercept point.

> That's what I need confirmed - if the receivers stated 
> sensitivity + spurious/image/intermod rejection = maximum 
> adjacent channel signal before de-sense kicks in.

No.

> Is there an RF Engineer in the house ??

Several.

--- Jeff

 

RE: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever noise bud

[John Barrett]

I’m trying to understand your figures, and I got lost some place.

 

>From the transmitters… I’m max 50w (+47dbm) into the isolator

-1db from the isolator

-3db from the combiner

-30db from the antenna circulator (assuming the antenna is matched)

-3db from the receive splitter

-60 to -90db from the receiver cavities

 

Total isolation = 97 to 127db (as good or better than most stock duplexer 
setups)

 

Putting my transmit signals at -50 to -80 dbm

 

The receiver has 0.15uV sensitivity, which is -123dbm, which puts the 
transmitters well above the receivers “floor”

 

However, the receiver specifies 75db spurious/image/intermod rejection which I 
take to mean that any off channel signal -48dbm (-123dbm sensitivity + 75db 
rejection) or less should be completely ignored by the receiver, as it will be 
attenuated below the receiver floor in the IF. Anything stronger than that will 
start to cause de-sense, swamping any on-channel signals at the same power or 
less.

 

That’s what I need confirmed – if the receivers stated sensitivity + 
spurious/image/intermod rejection = maximum adjacent channel signal before 
de-sense kicks in.

 

Is there an RF Engineer in the house ??

 

 

 

  _  

From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of 
Ron Wright
Sent: Tuesday, October 23, 2007 6:31 AM
To: Repeater-Builder@yahoogroups.com
Subject: Re: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever 
noise bud

 

There will be some reflected power from the antenna. And this reflected power 
will be wide tx band noise also which will affect the receiver.

If you are putting power into the isolator tx port there will be reflected 
noise and 30 db will not be enough. With the TX -80 db down and 30 db from 
isoloator that is only 110 db. It will swamp the receiver. 

Not sure why isolator cause harmonics for it has no non-linear components. It 
might cause tx to generate harmonics. Isolators are on the output of many 
repeater transmitters including my UHF Micor and it is built to work directly 
into an antenna although most applications use a duplexer which will give some 
harmonic suppression.

Using the dummy load port for the receiver might good idea. One way of getting 
TR relay.

73, ron, n9ee/r

>From: Keith McQueen <[EMAIL PROTECTED] <mailto:kb7m%40arrl.net> >
>Date: 2007/10/23 Tue AM 12:10:47 CDT
>To: Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com> 
>yahoogroups.com
>Subject: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever 
>noise budget

> 
>The danger I see with this is when your antenna goes bad (and they all do 
>eventually), your receiver will be hit with the full reflected power of the PA 
>almost certainly turning it into a smoldering doorstop. Keith McQueen801-224- 
><mailto:McQueen801-224-9460kb7m%40arrl.net> [EMAIL PROTECTED] -Original 
>Message-
>From: Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com> 
>yahoogroups.com [mailto:Repeater-Builder@ 
><mailto:Repeater-Builder%40yahoogroups.com> yahoogroups.com] On Behalf Of John 
>Barrett
>Sent: Monday, October 22, 2007 7:47 PM
>To: Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com> 
>yahoogroups.com
>Subject: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever 
>noise budget
>
> 
> 
>An isolator wont cause intermod, but it may cause harmonics. Commercial 
>installations usually use either a harmonic filter and 3db hybrid coupler, or 
>a special type of band pass cavity to couple the output from the isolator to 
>the feed line. (This info from an RX TX application note on transmitter 
>combiners) 
> 
>I’m proposing a novel application of the circulator (an isolator without the 
>dummy load on one port)…. Instead of the dummy load, the 3rd port feeds the 
>receiver chain… the transmit chain will still use more or less conventional 
>combining techniques to merge the signals from the 3 transmitters… the 
>output from the transmitter combiner goes to the input of an additional 
>circulator, the circulator output goes to the antenna as you would normally 
>expect for an isolator, and the “load” port goes to the receive chain 
>instead of a dummy load. Since the path from the transmit chain port to the 
>receive chain port is “reversed” compared to the normal signal flow in a 
>circulator, it will incur 20-30db of loss, depending on the circulator specs. 
>So long as the antenna is well matched, there will be minimum reflected power 
>fed back into the receive chain. My “window” for all the transmitters and 
>receivers is less than 1mhz, so matching the antenna shouldn’t be a huge 
>problem. 
> 
>From: Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com> 
>yahoogroups.com [mailto:Repeater-Builder@ 
&

RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever noise budget

[John Barrett]

Keith: A very good point - and multiplied since there will be 3 receivers
involved :-) Perhaps a good reason to stick with 3 cans per receiver,
instead of 2, since that will give me the same protection any standard
duplexer would, and even more isolation when things are working right, at
the cost of a little more insertion loss. Depending on the insertion loss of
the cavities in the receive chain - I'm looking at 6 to 9db of loss between
the splitter and the cavity filters.

 

It makes putting a preamp before the receive splitter an interesting
possibility, to make up some of the losses further down the chain, at the
cost of intermod in the preamp, which might be covered with a single band
pass filter right before the preamp (1mhz wide, centered on my receive
window). though that wont stop intermod with my own transmit signals. Still,
if the antenna were to go bad, its more likely the preamp would smoke before
enough got through to smoke the radios :-)

 

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Keith McQueen
Sent: Tuesday, October 23, 2007 12:11 AM
To: Repeater-Builder@yahoogroups.com
Subject: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget

 

The danger I see with this is when your antenna goes bad (and they all do
eventually), your receiver will be hit with the full reflected power of the
PA almost certainly turning it into a smoldering doorstop.

 

 

Keith McQueen

801-224-9460

[EMAIL PROTECTED]

 

-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of John Barrett
Sent: Monday, October 22, 2007 7:47 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget

An isolator wont cause intermod, but it may cause harmonics. Commercial
installations usually use either a harmonic filter and 3db hybrid coupler,
or a special type of band pass cavity to couple the output from the isolator
to the feed line. (This info from an RX TX application note on transmitter
combiners)

I'm proposing a novel application of the circulator (an isolator without the
dummy load on one port).. Instead of the dummy load, the 3rd port feeds the
receiver chain. the transmit chain will still use more or less conventional
combining techniques to merge the signals from the 3 transmitters. the
output from the transmitter combiner goes to the input of an additional
circulator, the circulator output goes to the antenna as you would normally
expect for an isolator, and the "load" port goes to the receive chain
instead of a dummy load.  Since the path from the transmit chain port to the
receive chain port is "reversed" compared to the normal signal flow in a
circulator, it will incur 20-30db of loss, depending on the circulator
specs. So long as the antenna is well matched, there will be minimum
reflected power fed back into the receive chain. My "window" for all the
transmitters and receivers is less than 1mhz, so matching the antenna
shouldn't be a huge problem.



  _  


From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright
Sent: Monday, October 22, 2007 8:19 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget

I am not sure why an isolator would cause intermod. Usually there are not
active or non-linear components in them and they are often used to prevent
intermod by preventing outside signals from coming in thru the feedline into
the transmitter.

In the past commerical sites would often require an isolator for this reason
with strong transmitters close by. In better repeater equipment an isolator
was built in.

73, ron, n9ee/r

>From: Jeff DePolo <[EMAIL PROTECTED] <mailto:jd0%40broadsci.com> com>
>Date: 2007/10/22 Mon PM 07:27:09 CDT
>To: Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com>
yahoogroups.com
>Subject: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget

> 
>> This isn't guessing - its called RESEARCH
>
>When I said guessing, I was talking about quantifying the performance of
>your radios rather than guessing how much isolation you need. In other
>words, make measurements to actually determine how much noise supression
and
>carrier attenuation you need using the actual frequencies involved. Once
>you know how much isolation you truly need, then you can work backwards
from
>there to determine the filtering requirements.
>
>I still think using an isolator is going to cause you new problems with
>respect to IM into your receivers unless you have adequate filtering
between
>the isolator and antenna, which I believe you have no way of acheiving if
>I'm understanding your layout right (i.e. isolator is connected directly to
>the antenn

RE: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever noise budget

[John Barrett]

An isolator wont cause intermod, but it may cause harmonics. Commercial
installations usually use either a harmonic filter and 3db hybrid coupler,
or a special type of band pass cavity to couple the output from the isolator
to the feed line. (This info from an RX TX application note on transmitter
combiners)

 

I'm proposing a novel application of the circulator (an isolator without the
dummy load on one port).. Instead of the dummy load, the 3rd port feeds the
receiver chain. the transmit chain will still use more or less conventional
combining techniques to merge the signals from the 3 transmitters. the
output from the transmitter combiner goes to the input of an additional
circulator, the circulator output goes to the antenna as you would normally
expect for an isolator, and the "load" port goes to the receive chain
instead of a dummy load.  Since the path from the transmit chain port to the
receive chain port is "reversed" compared to the normal signal flow in a
circulator, it will incur 20-30db of loss, depending on the circulator
specs. So long as the antenna is well matched, there will be minimum
reflected power fed back into the receive chain. My "window" for all the
transmitters and receivers is less than 1mhz, so matching the antenna
shouldn't be a huge problem.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright
Sent: Monday, October 22, 2007 8:19 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget

 

I am not sure why an isolator would cause intermod. Usually there are not
active or non-linear components in them and they are often used to prevent
intermod by preventing outside signals from coming in thru the feedline into
the transmitter.

In the past commerical sites would often require an isolator for this reason
with strong transmitters close by. In better repeater equipment an isolator
was built in.

73, ron, n9ee/r

>From: Jeff DePolo <[EMAIL PROTECTED]  com>
>Date: 2007/10/22 Mon PM 07:27:09 CDT
>To: Repeater-Builder@ 
yahoogroups.com
>Subject: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget

> 
>> This isn't guessing - its called RESEARCH
>
>When I said guessing, I was talking about quantifying the performance of
>your radios rather than guessing how much isolation you need. In other
>words, make measurements to actually determine how much noise supression
and
>carrier attenuation you need using the actual frequencies involved. Once
>you know how much isolation you truly need, then you can work backwards
from
>there to determine the filtering requirements.
>
>I still think using an isolator is going to cause you new problems with
>respect to IM into your receivers unless you have adequate filtering
between
>the isolator and antenna, which I believe you have no way of acheiving if
>I'm understanding your layout right (i.e. isolator is connected directly to
>the antenna with nothing in between save for a harmonic filter).
>
> --- Jeff
>
> 

Ron Wright, N9EE
727-376-6575
MICRO COMPUTER CONCEPTS
Owner 146.64 repeater Tampa Bay, FL
No tone, all are welcome.

 

RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever noise budget

[John Barrett]

I got your post before, and since then I have acquired a 2m circulator, and
a 50 ohm dummy load for an antenna. My network analyzer says that it does
exhibit the 30db isolation that I'm looking for.. I can insure that the
isolator sees that load with a 2m antenna tuner which I already have, or a
custom built loading circuit if needed - the frequency range that needs to
be covered is very narrow - less than 1mhz wide.. so I should be able to get
a good match across the entire range.

 

You say "makeshift" but it gets me about the same isolation that splitting
the rx and tx antennas does for the space I have available to split the
antenna, or the same amount of isolation as a single cavity (which would be
multiplied by 3 for my 3 receivers).. so I'm just as well off and the
circulator is as cheap if not cheaper than the 2nd antenna, and definitely
cheaper than 3 cavities in terms of both cost and space. it also gets my RX
and TX at the same height and the same gain. definite benefits. And even if
I don't achieve full 30db isolation, I can make up the difference elsewhere
in the system - trading off cavity bandwidth and insertion loss to get the
additional isolation needed

 

To date I have acquired the repeater controller, 4 cavity filters, 1 2m
circulator, and 2 of the 4 radios I'll be needing.. still a bit more to go
before I can do a full systems check - at least one more circulator and one
more radio before I can setup a minimal test system (1 simplex radio + the
repeater). I've got 2 more cavities on the way that should get me all I need
for the receiver filters.

 

So, until I have a few more parts, it would help to have some sides of how
receiver specs will impact the required isolation needed.

 

This isn't guessing - its called RESEARCH

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo
Sent: Monday, October 22, 2007 3:11 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever
noise budget

 

> Transmit and receive paths will be separate with 30db of 
> isolation (either split antennas, or a 30db isolation 
> circulator just before the feed to the antenna)

I posted a followup to one of your previous messages regarding using
isolators as a makeshift way of getting more Tx to Rx isolation, using the
reject port to feed to a receiver, and the problems therein. For some
reason, that post never showed up.

Anyway, the 30 dB of theoretical isolation that you refer to is never going
to be realized in your application. The isolator's spec of 30 dB that
you're quoting is from antenna to transmitter, assuming an ideally-matched
reject load. You're using the isolator differently; that spec doesn't
apply. In your configuration, the Tx to "Rx" (reject port) isolation is
only as good as the return loss of the antenna; consider that a 1.5:1 VSWR
is only 14 dB return loss. Maybe you'll do a little better than that, but
you'll probably never get the full 30 dB.

And there are a whole slew of other issues related to IM and harmonic
generation within the isolator.

> That brings the transmit power down to +17dbm (55mw) before 
> any other splitting and filtering to get to the 3 receivers

What about noise supression? At close T/R spacings, the noise supression
requirement is likely going to be higher than the carrier supression
required.

> Am I blowing smoke ?? Is there a way to figure from the usual 
> receiver specs just how much signal can be handled before 
> de-sense occurs ??

A typical 50 watt solid state 2m repeater typically needs 80 dB or more of
noise supression at 600 kHz split, and about 80 dB of carrier supression
(both figures plus or minus maybe 10 dB depending on the radios used). If
your Tx is closer than 600 kHz to your Rx, you're going to need
proportionally more noise supression; 100 dB at 400 kHz spacing would
probably be a good guess. Carrier attenuation likely won't need to increase
substantially until you get appreciably close to the Rx frequency, like
maybe within 200 kHz as a rough ballpark guess (it will likely vary quite a
bit depending on the quality of IF filtering in the radio).

Instead of guessing at all of these numbers, why not quantify them if you
already have the equipment you're planning on using.

--- Jeff

 

RE: RE: [Repeater-Builder] Re: duplexer isolation and reciever noise budget

[John Barrett]

Time to reopen this subject just a little !!

 

I'm currently looking at Icom V-8000 radios for the simplex and repeater
radios (0.15uV sensitivity (-123dbm) and 75db spurious/image rejection)

 

The most any transmitter in the system will ever be running is 50 watts
(+47dbm)

 

Transmit and receive paths will be separate with 30db of isolation (either
split antennas, or a 30db isolation circulator just before the feed to the
antenna)

 

That brings the transmit power down to +17dbm (55mw) before any other
splitting and filtering to get to the 3 receivers

 

I need to understand the sensitivity and rejection numbers on the radios a
bit better. I would think that sensitivity + rejection would indicate the
strongest nearby signal that the receiver front end can handle without
de-sense .. which would mean (if I'm not totally blowing smoke) that the
V8000 could handle a nearby signal at -50dbm. leaving me 67db of isolation
that I need to account for in the splitter/filter system connected to the
receivers.

 

Am I blowing smoke ?? Is there a way to figure from the usual receiver specs
just how much signal can be handled before de-sense occurs ??

RE: [Repeater-Builder] duplexer isolation and receiver noise budget

[John Barrett]

OK - the problem may have just gotten beyond easy solution...

 

I just checked with the repeater coordination folks, and if I'm going VHF at
all, I'm looking at a year or 2 for a coordinated pair in this area, which
pushes me off to the 145.250 / 144.650 "backyard" repeater pair.. which puts
me smack dab in the middle of the APRS and winlink frequencies :-)

 

So if I'm going to attempt that, I'm going to have transmitters on 144.39,
145.01-09, and 145.25.. and I have to protect receivers on 144.39, 144.65
and 145.05

 

At this point I'm probably going to stick the repeater up on the UHF
"backyard" pair (once I find out what it is !!)

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Joe Montierth
Sent: Friday, October 05, 2007 7:43 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] duplexer isolation and receiver noise budget

 

I think you need to identify what your priorities for this project are.
If it's not cost, then there are several ways to do this thing. It
seems like your biggest concern might be physical size of the cavity
package.

If that is the case, what I would do would be to get a repeater pair in
the 147MHz range, the upper meg of 2M. If that is possible you could
get two 2M duplexers, one for the 147 repeater, and another for the
144/145 frequencies. Now you have everything combined into two antenna
ports, one for the 144/145 stuff and one for the 147 repeater.

Next, you need a way to combine these two ports into one antenna. This
could be done with several notch type cavities, or a wideband pass type
duplexer.

The duplexer solution would be easier, and take less rack space. There
is a company called DCI that can build you a custom BP duplexer that
would cover the 144/145 on one port and 147 on the other. Should be
able to make it with 60 to 70dB of isolation between the two ports, and
about 1.5 to 2 dB of insertion loss.

Now depending on the duplexers that you choose, it should all fit on
less than one standard 6ft rack, maybe even half a rack.

You should end up with 75+ dB of isolation from any port to any other,
and probably about 3 to 3.5 dB of insertion loss, which is a little
much, but acceptable for this type of operation.

The bad news is the cost. This could be in the 6K range, give or take,
maybe as little as 3K, if you can shop around for the 2 duplexers, and
are not overly concerned about the size.

Contact www.dci.ca and tell them what you are trying to do, and what
they could engineer a solution for the wideband duplexer part of this.
They probably can't do anything for the 2 close spaced pairs, and that
is where Telewave, dB Products, Sinclair, TXRX, etc will come in.

It should work out OK, but using two antennas would be simpler and
cheaper, but maybe that isn't an option.

Joe

--- John Barrett <[EMAIL PROTECTED] <mailto:ke5crp1%40verizon.net> net>
wrote:

> Finally found some good diagrams for a 3 cavity bandpass filter at
> Telewave,
> and it looks like I can get 80db down with 6db of insertion loss
> using 5"
> cavities, which may be acceptable as I can make it up at the antenna
> if
> needed. Then it seems I can get the last 10db (if not more) by
> kicking up to
> a 6" or 8" cavity to steepen the skirts.
> 
> 
> 
> http://www.telewave <http://www.telewave.com/pdf/TWDS-5012.pdf>
.com/pdf/TWDS-5012.pdf
> 
> 
> 
> So bandpass CAN be made to work. the question then becomes: Is there
> a way
> to do it with less than a dozen cavities ??
> 
> 
> 
> Using notches seems to be counterproductive as I would need 2-3 notch
> cavities per radio per frequency to notch (call it 3 recievers vs 2
> transmitters, or 6x3 - 18 reject cavitites)
> 
> 
> 
> Do I really need the cavities on the repeater transmitter (which will
> never
> be used for receive). might not a Wilkinson splitter/combiner do the
> trick,
> bringing at least that one transmitter down 20db before hitting the
> cavities
> for the 3 recievers
> 
> 
> 
> Bring on the "other" ideas :-)
> 
> 
> 
> 
> 
> _ 
> 
> From: Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com>
yahoogroups.com
> [mailto:Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com>
yahoogroups.com] On Behalf Of Eric Lemmon
> Sent: Thursday, October 04, 2007 9:50 PM
> To: Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com>
yahoogroups.com
> Subject: RE: [Repeater-Builder] duplexer isolation and receiver noise
> budget
> 
> 
> 
> John,
> 
> It might be instructive to let the big-name combiner companies make
> proposals to solve your dilemma. Send a request for proposals to
> Telewave,
> TX-RX, and RFS/Celwave to see what they would recommend. Don't t

RE: [Repeater-Builder] Re: duplexer isolation and reciever noise budget

[John Barrett]

I don't have a coordinated pair at this time, and someone on my local
repeater mentioned something about
uncoordinated/unprotected/test/"community" pairs in 144 and 440 bands.. so
if you know what they are, that's probably where this repeater will live
until I get coordinated (if I get coordinated - NE Texas is pretty packed
up).. So until I get more information, I guess I should be focusing on
isolating the 2 digital rigs.

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of skipp025
Sent: Friday, October 05, 2007 4:51 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: duplexer isolation and reciever noise budget

 

Before I give you an answer I'd want to know where the repeater 
is going to be placed. Operation in the 146 and higher portion of 
the band is going to be a heck of a lot easier than a repeater 
in the 145 segment. 

both aprs and winlink radios on the same antenna are going to require 
some serious and unique protection methods. 

To talk about the cavity size question/issue... you'll notice the 
cavity Q is much higher for "most" larger diameter cavities. So pretty 
much anything you are going to want to hunt down is going to be 
the larger high Q cavities on the order of 8 inch min typical. 

s. 

> "John B" <[EMAIL PROTECTED]> wrote:
> I'm attempting to design a system that will have a VHF repeater (freqs
> not yet determined) sharing an antenna with 2 packet radios (APRS on
> 144.39 and Winlink on 145.05, either of which may be active as a
> digipeater at any time).
> 
> I'm currently considering a bandpass-only "quadplexor" to isolate the
> radios from each other.. each radio running through a bandpass filter
> tuned to its frequency only (that includes the transmitter and
> receiver for the repeater), on the theory that it is a lot easier to
> pass one frequency than it is to reject 3 others.
> 
> Assuming that none of the transmitters run more than 50w, how many DB
> down do I need to be outside of the passband to minimize desense for
> any of the 3 receivers ??
> 
> Any other suggestions on how I might handle this hookup would be
> greatly appreciated. I'm nearing completion my trailer-mounted 40ft
> crank up tower, and I'm having some problems budgeting space for a
> filtering system with 12 bandpass cavities without cutting into
> general cargo space.
>

 

RE: [Repeater-Builder] duplexer isolation and receiver noise budget

[John Barrett]

Finally found some good diagrams for a 3 cavity bandpass filter at Telewave,
and it looks like I can get 80db down with 6db of insertion loss using 5"
cavities, which may be acceptable as I can make it up at the antenna if
needed. Then it seems I can get the last 10db (if not more) by kicking up to
a 6" or 8" cavity to steepen the skirts.

 

http://www.telewave.com/pdf/TWDS-5012.pdf

 

So bandpass CAN be made to work. the question then becomes: Is there a way
to do it with less than a dozen cavities ??

 

Using notches seems to be counterproductive as I would need 2-3 notch
cavities per radio per frequency to notch (call it 3 recievers vs 2
transmitters, or 6x3 - 18 reject cavitites)

 

Do I really need the cavities on the repeater transmitter (which will never
be used for receive). might not a Wilkinson splitter/combiner do the trick,
bringing at least that one transmitter down 20db before hitting the cavities
for the 3 recievers

 

Bring on the "other" ideas :-)

 

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Eric Lemmon
Sent: Thursday, October 04, 2007 9:50 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] duplexer isolation and receiver noise budget

 

John,

It might be instructive to let the big-name combiner companies make
proposals to solve your dilemma. Send a request for proposals to Telewave,
TX-RX, and RFS/Celwave to see what they would recommend. Don't try to
design it for them; just give them the frequencies, power outputs, receive
sensitivities, feedline type and length, and make/model antenna, and let
them come up with their own plans. I think you will be surprised that more
than one solution may do the job.

My gut feeling is that your requirement to use just one antenna may be a
killer, cost-wise. I can think of several combining strategies, but I don't
think multiple bandpass cavities is going to work. I think you'll need more
notches than bandpasses in any viable combining plan.

73, Eric Lemmon WB6FLY

-Original Message-
From: Repeater-Builder@ 
yahoogroups.com
[mailto:Repeater-Builder@ 
yahoogroups.com] On Behalf Of John B
Sent: Wednesday, October 03, 2007 10:51 PM
To: Repeater-Builder@ 
yahoogroups.com
Subject: [Repeater-Builder] duplexer isolation and receiver noise budget

I'm attempting to design a system that will have a VHF repeater (freqs
not yet determined) sharing an antenna with 2 packet radios (APRS on
144.39 and Winlink on 145.05, either of which may be active as a
digipeater at any time).

I'm currently considering a bandpass-only "quadplexor" to isolate the
radios from each other.. each radio running through a bandpass filter
tuned to its frequency only (that includes the transmitter and
receiver for the repeater), on the theory that it is a lot easier to
pass one frequency than it is to reject 3 others.

Assuming that none of the transmitters run more than 50w, how many DB
down do I need to be outside of the passband to minimize desense for
any of the 3 receivers ??

Any other suggestions on how I might handle this hookup would be
greatly appreciated. I'm nearing completion my trailer-mounted 40ft
crank up tower, and I'm having some problems budgeting space for a
filtering system with 12 bandpass cavities without cutting into
general cargo space.