[Repeater-Builder] Re: off site extra RX

[rtc_0001]

I'm going to suggest another "Poor man's voter" 
despite the probability that someone, somewhere, 
has already done so.

I was thinking you might go ahead & build your 
2nd rcv site with a one way link to the main tx.  

However, you would rely on the link activation 
to "vote" the rx signal into the tx audio path.

In operation, the link rx at the main site will
force an audio gate to route the link rx audio 
to the main tx.

A careful setting of the squelch at the remote
rx will allow the main site rx to do most of the 
work but when the main site isn't hearing the 
portables well enough, the remote rx will. This 
is when the link audio gets switched in. 

There'll be a period of trial & error tweaking
of the remote's squelch but it can be done.You'll 
still want to make efforts to equalize the audio 
freq responses of all paths involved. I'm sure
you can find a way to make the switching fast.

Its not an ideal solution but it keeps operation
mostly transparant to the users.  ie. They don't
need to remember to change PL's or channels.


--- In Repeater-Builder@yahoogroups.com, "Chuck Kelsey"  
wrote:
>
> Someone else suggested the "poor man's voter" by simply requiring a 
> different PL tone for the other receiver. Users simply need to know 
> which tone to use for each area.
> 
> The other solution is to simply link in a low profile repeater at  
> the desired location. This could even be on a different band.  
> Again, users would need to understand this as well.
> 
> Chuck
> WB2EDV

[Repeater-Builder] Re: off site extra RX

[rtc_0001]

I don't know the RLC controller per se'.
If it has a voter panel in it I'd say ok.

If you don't have a voter panel I'd say 
the idea is very "iffy".

You don't want the same rcv audio being 
summed from two different sources unless 
you take very special precautions. If 
those precautions are not employed,
you will have distortions & echos.

Problem #1: Unless you incorporate an
adaptive delay into each audio path, 
you'll have audio arriving out of sync
from the various rcvrs.  This is where
your echos will come from.   

Problem #2: Your audio will probably 
comprise unequal freq responses due the
different rcvr & link characteristics.

You'll need to "equalize" the audio paths 
so they sound the same no matter which
source is feeding the main tx.

About the only way your idea can work w/o
all the extra devices is if the two (or more) 
audio sources were never live simultaneously.

Other than the last scenario, you'll have your
work cut out for you in the attempt to make it
sound decent.

Just my thoughts on the matter.


--- In Repeater-Builder@yahoogroups.com, Rick Szajkowski 
 wrote:
>
> Question for the group
> 
> The repeater is on the out side of town .. coverage in town is ok 
> but could be a lot better TX is GREAT

> Idea ..  can I put a RX (vhf ) site in town and piggy back that to 
> a UHF radio and then feed that into a RLC controller to be linked  
> to the main repeater port or will that cause problems ?
> 
> I just want to bring up the 'handi' coverage in the down town core
> 
> I have access to a roof top that will do what I want to ..
> 
> any Ideas ?
> 
> Thanks
> 
> Rick

[Repeater-Builder] Re: DB4062 in non-standard application

[rtc_0001]

At first blush it looks possible if you have an isolator somewhere in 
the tx lines of each device & you're willing/able to suffer some 
performance degradation.

A lot depends on the actual frequencies & power involved.
How the node is configured for antenna ports would also play in.


--- In Repeater-Builder@yahoogroups.com, n...@... wrote:
>
> At 1/8/2009 13:19, you wrote:
> >The local CAP group has a DB4062 duplexer. (6- 8" cans) Somehow they 
are able to operate a VHF repeater and a packet node all on one antenna 
using this set of BPBR's. Does anyone have an idea as to how they would 
have plumbed the duplexer to make this happen?

[Repeater-Builder] Re: Alexander Batteries "Optimizer" Info / Manual available on line?

[rtc_0001]

I wasnt aware that the newer chemistries needed an optimizer.

>From some reading, Im led to believe the newer stuff doesnt have 
memory issues & due the limited charge/discharge cycles available in 
some chemistries, you don't really want to cycle them too often.

[Repeater-Builder] Re: Helper Instruments

[rtc_0001]

Necessity is the mother of invention.

You are not alone in the universe my friend.
rtc.



--- In Repeater-Builder@yahoogroups.com, n...@... wrote:
> 
> ...and everyone thought I was nuts for using a Regency scanner as a 
> deviation monitor & signal generator.
> 
> Bob NO6B
>

[Repeater-Builder] Re: Six Meter Repeater Noise Issues

[rtc_0001]

In the repeater case, disable the tx, put an ISO-T in the line with a 
dummy load in place of the feed-line.

[A] Set the generator for 12db sinad or 20db of quieting.
Note the generator level.

At this point you could key the tx to see if there's anything odd in 
the duplexer..Make sure the dummy load can handle the tx power.

Next, remove the dummy load & reconnect the feed-line.

[B] Perform the same generator level set as above.
Don't key the tx yet, just note the gen level.

Depending on the site noise level, the setting should be close to [A].

If not the same or nearly the same, suspect outside noise at the site.

Key the tx, if the noise worsens, suspect a corroded antenna or bad 
connector at the antenna or on the radio end of the cable. Also, it's 
possible the coax is noisy as well. 

rtc

[Repeater-Builder] Re: Astron P/S question

[rtc_0001]

Every linear Astron I've ever owned had an issue with vhf getting 
into the regulator thru the 12vdc output leads.

I've always cured the issue by putting a 0.01 cap across the output 
studs & another to the chassis from the pos stud. Additionally, you 
could put one from the neg stud to the chassis as well. 

You may need to experiment with the value.

Always worked for me. 

I dont recall mine ever blowing the fuse though.

Blowing the fuse could mean the regulator was off in lala land where 
it couldn't sense an overcurrent condition or control the output 
voltage thus causing the scr to trigger.
rtc



--- In Repeater-Builder@yahoogroups.com, "n9wys" <[EMAIL PROTECTED]> wrote:
>
> For the learned group here.
>snipped. 
>  
> Now - here's the WEIRD part.  when I was at the tower with another 
tech and replaced the fuse the time before the last failure, we tried 
to use his DMM to check the P/S fuse for continuity.  His meter acted 
as if the battery was dead - but later investigation revealed that 
the meter was getting hit with RF from another transmitter at the 
site.  So I'm thinking that the RF problem may or may not be directly 
related to MY transmitter.  (There is VHF 100W MICOR transmitter 
directly next to my equipment rack that is on 161.325, and transmits 
24/7/365.) 
> 
> 
> Thanks,
> 
> Mark - N9WYS
>

[Repeater-Builder] Re: How to set up a basic crossband repeater system in Public Service

[rtc_0001]

Reading comprehension must be on holiday here.

In the original post, the licensing "thing" was brightly illuminated.

As to the mechanics of the situation: you probably don't need 
anyones' external controller to accomplish this task.

As I posted, you simply mate the appropriate I/O's & program 
accordingly.  What you do want is a service monitor to help in 
adjusting the final values of resistors & caps that you will need to 
match the audio paths.

To control using dtmf will likely require a little head scratching on 
your part but I'm betting a latching relay tied to the signaling 
alert I/O pin will afford you the on-off you want.

The hardest part to it all will probably be getting the audio levels 
set & the tonal quality right.

I wouldn't be overly concerned about overdeviation unless someone has 
screwed with the factory alignment in any of the radios.

Again, to make life much easier, you want a service monitor on hand 
while setting the I/O levels & tone quality.

As to the duty cycle of the gear: You know this is not a very busy 
system & even a (2)mobile repeater will work, especially if it's got 
a fan.  Those lil F221 mobiles are good units & failures are very few 
unless stressed from outside sources.

An outside source would include lightning, power main surges/noise, 
building collapse, bad antenna/coax...etc.


--- In Repeater-Builder@yahoogroups.com, "bkcarter33" <[EMAIL PROTECTED]> 
wrote:
>
> My local Community Emergency Response Team (CERT) has recently 
> obtained a UHF repeater (ICOM CY-F221S).
> 
> It has two ICOM F221S radios linked together in a nice rack mount 
box.
> 
> It has also been set up with a remote mic and speaker off of the 
> outputs on the chassis back panel.
> The CERT group is licensed for the UHF repeater frequencies and 
they are in the public service band. They also have a simplex VHF 
> frequency in the PS band (old police frequency) licensed.
> 
> They have a number of Motorola HT radios (CP200) that operate on 
the simplex VHF frequency.
 
>snipped
 
> Thanks for any help you could provide me,
> 
> 73
> 
> Bryan Carter
> KE7GVJ
> Kaysville CERT Administration
>

[Repeater-Builder] Re: How to set up a basic crossband repeater system in Public Service

[rtc_0001]

You probably already know you need to find tx audio input, squelch 
gated rx audio output, ptt & COS or TOR.

COS is carrier operated relay & TOR is tone operated relay.
Preferably you'll use TOR as the active low output to key the vhf ptt.

There's software settings to make these I/O's as you need them.

It is necessary to adjust audio levels into & out of each radio.
This can be done with series resistors or attenuator pads.
Chances are you'll need to use caps to equalize the audio as well.

Ideally you'll have a service monitor available to check all this.

In lieu of the SM, you can carefully compare between the uhf & vhf 
sides for best match of tone quality & levels.

Wish I had the tech info near me but it's all at work.

You might find a way to use the dtmf decoders in each unit along with 
some type of latching relay to perform your control functions.

I'm pretty sure there's I/O for the dtmf decoder available on the 
accessory jack.

--- In Repeater-Builder@yahoogroups.com, "bkcarter33" <[EMAIL PROTECTED]> 
wrote:
>
> My local Community Emergency Response Team (CERT) has recently 
> obtained a UHF repeater (ICOM CY-F221S).
> .snipped...
> I would like to accomplish the following and would love to receive 
> some guidance from someone who has the knowledge to instruct me:
> I would like to set up a cross band link for them from the UHF 
> repeater, to a VHF radio:> Thanks for any help you could provide me,
> .snipped...
> 73
> 
> Bryan Carter
> KE7GVJ
> Kaysville CERT Administration
>

[Repeater-Builder] Re: 900mhz , DTR, 906 to 923.75 MHz FHSS

[rtc_0001]

I would be carefull in applying an antenna other than a rubber duck.

It seems to me these radios fall under a class of non-licensed but 
having rules specifying no external antennas other than the type it 
came with.

I suspect those rules preclude an antenna connected by coax.

I'm not entirely versed in fcc rules nor where this particular radio 
fits into them but I thought I'd throw this at you as food for 
thought.


--- In Repeater-Builder@yahoogroups.com, "Brian R. Chapman" 
<[EMAIL PROTECTED]> wrote:
>
>  Just for the heck of it I plugged one of my Radio Shack simplex
> repeater controllers into the DTR-650. The plug is not quite
> correct(I'll be checking the print) but this will work. I have a set
> of the DTR-650's on loan testing their functionality. The pair I 
have
> has the integral antenna. Can someone tell me what type of antenna
> connectors the ones with removeable antennas have? Are they SMA like
> most other Moto's?  I imagine with a small PS and a battery
> eliminator(lighter cord false battery) connected to a kp-20 on a
> mountain top out here in NV  this scheme might work pretty well!!!
> Just set the units up for group call.  "73"
>Brian nb9e
>

[Repeater-Builder] Re: Good Repeaters?

[rtc_0001]

The Vertex is a good commercial repeater but be careful.
There were two versions & differ mainly in the PA section.

The older version had a bipolar xsistor PA while the newer has a rf 
hybrid module.

Neither of those repeaters is 100% duty cycle unless you cut the 
power in half & even then I'd be wary of HD use.

The older Vertex would overheat the collector lead & unsolder itself 
while burning the pcb. Much the same as the GR300s/Maxtracs & 1225's.

The newer Vertex is still a bit tender when presented with a poor swr 
& heat.

It has a fairly sensitive receiver which can be tuned a little better 
in software. If it'll go to the ham band is unknown to me. Haven't 
tried.

I will put one on the bench in the afternoon and see if it will.

I don't have anything to say about the Kenwood 851 because I haven't 
put one in service.



--- In Repeater-Builder@yahoogroups.com, "John Transue" 
<[EMAIL PROTECTED]> 
wrote:
>
> I see several Vertex Standard VXR-7000 repeaters and one or two 
Kenwood TKR-851 repeaters for sale on eBay. Are these good repeaters 
for a ham repeater? Do they have known weaknesses or defects?
> John Transue
>

[Repeater-Builder] Re: Recommended commercial radios that use SMT technology - to convert to 2m rpt

[rtc_0001]

The older "foreign looking" radios have several stages of helical 
tuning in the front end & mixers. Much better selectivity than the 
newer sm "track tuned" front ends.

You could, of course, buy a filter for this but why? since the older 
units come with a good one.

Interfacing with the the older units is not much different than the 
newer sm types except perhaps the newer ones have dedicated acc ports.

As far as driving an amplifier goes, you can still do that with the 
older, higher powered boxes by interfacing with earlier stages in the 
pa's. If you do it right, you can retain the swr protection & power 
output monitoring/leveling of the original radio while using the 
external pa. 

--- In Repeater-Builder@yahoogroups.com, Cort Buffington <[EMAIL PROTECTED]> 
wrote:
>
> I may sound a bit like a broken record here, but I really like  
> Motorola GM300s and R1225s for these jobs. Particularly the 10W  
> versions of both. Heat stays under control with a 10W radio much  
> better than the higher powered ones (even turned down).

[Repeater-Builder] Re: 455khz filter for Mastr II discriminator audio

[rtc_0001]

One would think the input to your controller is already bandpass 
filtered for the "super sonic" audio frequencies it needs to perform 
squelch gating.

Is there a possibility of a dc component on the tap-off point that is 
influencing the input to the controller or...is the tap off point at 
such a hi-z that you're inadvertantly loading it down too much & 
causing the level of "noise" to drop below what the controller needs?

I find it difficult to believe that the controller can even "see" a 
455khz signal on the discriminator input.  Equally difficult to believe 
is that there actually is some 455khz energy available on the squelch 
control.

Re: [Repeater-Builder] Repeater input getting interference FROM a TV?

[rtc_0001]

I have had a tv cause interference to a system before.
It was in an Illinois cnty jail.

The interference wasn't there until this one tv in a cell was turned on 
and tuned to a certain channel.

I thought it was cable company leakage until they came out & together 
proved otherwise.

The interfering signal was strong enough to penetrate the concrete/ 
steel building structure & it echoed around inside the building so much 
I had a great deal of trouble homing in on it.

Had to go outside & look inward.

Had a heck of a time tracking that one down.

[Repeater-Builder] Re: Motorola R1225 versus Kenwood TKR-750

[rtc_0001]

It's not so much a defect as it is asking the rptr to do more than it
was designed for. It may be a 45 watt PA but in rptr use, medium to HD
rptr use, drop it down to about 25 to 30 watts out of the PA.  Enjoy
what you get thru the duplexer. Asking for more will melt the PA.

The earlier units had a temp controlled fan that only came on when the
PA was about to melt.  The next generation of power supplies came with a
switch to turn the fan on permanently.

You will probably be able to fix them without the manual. Most of the
time the PA transistor collector got hot, melted the solder & the chip
caps moved (slid down the pcb due to gravity).

I repaired these on a regular basis without needing new parts unless the
damage literaly burnt the pcb around the collector lead.  I removed the
chip caps, removed the solder on the collector tab & trace & resoldered
it all back in with silver solder.  This, along with turning the factory
output down, made them last a long time even under HD casino use.

I think it took me maybe 45-60 mins to get it all apart, fix it,
reassemble, reinstall. Lots of times I did it in place at the customer's
premises.  rtc







> -Original Message-
> From: Repeater-Builder@yahoogroups.com

> Sent: Friday, July 13, 2007 11:08 AM
> To: Repeater-Builder@yahoogroups.com
> Subject: [Repeater-Builder] Re: Motorola R1225 versus Kenwood TKR-750
>
> Hi Eric,
>
> 
>
> I just pulled three 1225 uhf repeaters from two different locations
> and they all have the same failed tx pa problems. Wonder if there's
> a minor pa defect problem (like there was in early version one tkr
> repeaters) or it's just bad customer karma time. I've got to find
> a service manual before we open them up...
>
> cheers,
> skipp

[Repeater-Builder] Re: crystal/channel element compensation..

[rtc_0001]

Every radio today uses a crystal as its reference, hence frequency
stability.

Some Pll's compensate for temperature using the uprocessor, a lookup
table & a DAC.

I can't think of any off the shelf units that still heat the xtal unless
its an option.

I found little wrong with xtal heating in the older units...other than
whoever installed the xtals might not have been careful or smart enough
to re-establish the physical connection between the xtal & the external
heating element (usually a resistor & a thermister).

Sometimes an error was made in the ordering of xtals. Some models of
radio came with heaters & some of the same models didn't. You had to
know which you wanted before ordering.

Not only were tube type radios using heaters, back in the day, but solid
state mobiles & even a few solid state Ht's did too.

[Repeater-Builder] Re: Cable formula

[rtc_0001]

--- In Repeater-Builder@yahoogroups.com, "Jeff DePolo" <[EMAIL PROTECTED]> 
wrote:

> > Do you have any thoughts on why or how a well designed Z
> > match could produce cable
> > radiation?
>
> For the feedline to radiate, there would have to be currents flowing
on the
> shield. It would seem to me the only way to get that to happen would
be if
> there was an imperfect shield connection at the mating connector at
one end
> or the other. Most Z-matchers I've dissected use a length of wire as
an L,
> with shunt trimmer caps. Assuming the enclosure itself is bonded well
to
> the connectors at either end, I can't come up with a good reason why
such a
> device inserted in a transmission line would cause shield currents to
flow
> absent a connector issue.
>
> --- Jeff

How about an instance in which there's a thru hole ground connection
from the inside to the outside of the case. e.g. a bolt from a floating
pcb ground plane or a capacitor that protrudes thru the case & is nutted
on the outside of the case.

If that bolt is not well bonded to the inside of the case, it can carry
rf current to the outside that is not in phase with current at the
connectorized ends.  As the length of the bolt or rivet increases, so
does the Z & phase difference between the pcb groundplane & the insides
& outside of the case.

Now you have at least 3 circulating currents. The pcb groundplane
itself(end to end), the pcb thru the bolt to the inside of the case &
last, the unintended pcb thru the poorly bonded bolt to the outside of
the case.

Yes, I do enjoy playing Devil's Advocate. Hey! It's a slow Sunday.

[Repeater-Builder] Re: PL-259 type 50 ohm terminations?

[rtc_0001]

Some of those N type terminations use a screw in connector / adapter.

I've unscrewed the N's from mine in order to thread in a N female to UHF
male adapter on many occassions.  Your terminations may be able to do
this?

rtc

--- Original message --
> From: "skipp025" [EMAIL PROTECTED]
> > Re: PL-259 type 50 ohm terminations?
> >
> > Anyone know any place/source selling 50 ohm terminations with
> > a PL-259 type connector. I've got a ton with N connectors
> > but would be interested in picking up some of the 5 to 50
> > or 100 watt pl-259 connector loads.
> >
> > thanks up front for your reply posts...
> >
> > cheers,
> > skipp

[Repeater-Builder] Re: HELP - Photo collection: Name this PA !

[rtc_0001]

It's a Motorola hi duty cycle hi power repeater/base PA for 800mhz.

Lo drive requirement & 75watts out constant duty. You could push it to
an intermittant 100 watts if you added a cooling fan. I've rebuilt a few
of these but a long time ago.

FedEx had a bunch of these for their mountaintop data/voice repeaters.

What is it you need to know? I'll be going from memory so go easy on me.

--- In Repeater-Builder@yahoogroups.com, "Chuck Kraly" <[EMAIL PROTECTED]> 
wrote:
>
> I am thinking it is from the Micor series. I want to say low power 800
but not exactly sure

[Repeater-Builder] Re: paging system

[rtc_0001]

I was under the impression that as long as the transmission was one of
direct benefit to the ham community at large, it was not considered
broadcasting in the usual sense.  Hence, you have W1AW & the other news
caster org.

I don't know that short duration control tones are illegal provided they
don't interfere or last for more than a certain time frame & the
intention of sending the control tones was for the direct benefit of the
Ham & non-ham community.

I could be wrong, I've never been much on rules & regs being the bit of
a scofflaw that I am.

[Repeater-Builder] Re: IC FR4000

[rtc_0001]

Aside from any possible receiver deficiencies, you might want to
consider that the Vertex VXR7000 has a pretty weak PA section.

The earliest ones came thru with a discrete transistor PA. They became a
problem like so many other PA's in that the collector current was too
much for the pad & melted the solder & surface mount caps off.

The next step was to add a rf module. This was ok but they didn't
resurface the aluminum PA extrusion to accept the module directly.
Instead, they created a new pcb & added a copper heat spreader plate as
a retrofit to the existing aluminum heat sink.

The problem there is the copper heat spreader doesn't have enough
contact area to the aluminum heat sink to remove the heat from the heat
spreader fast enough.

I still use the VXR7000 in new installs but not in areas of high use. I
still keep several of the retrofit kits & rf modules & install them as
the old units die.

Lastly, the internal duplexer, unless tuned with a return loss bridge,
can present a poor swr to the PA module & pop it prematurely. I've run
across a few that I tuned with a tracking generator & attenuators that
looked good in all other respects but once the factory cables are
attached, the output drops & the tuning goes off. You have to kinda'
fudge the tuning once the factory cables are attached to get the power &
isolation back.

I also noticed the internal duplexer as sold with the unit (Sinclair) is
very temperature sensitive. If I mistakenly hold my palm on the duplexer
while tuning, that cavity will be tuned wrong once it cools down to room
temp.  The heat from the power supply & the PA will warm the chassis &
the duplexer & throw the tuning off.

If you can, use an external duplexer. It won't detune itself due to the
heat buildup & offers better isolation/less loss.

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

> On Jun 2, 2007, at 12:35 PM, barrypal wrote:
>
> > Anyone running the Icom repeater in the ham bands? This question has
probably come up before buy I couldn't find it. I am considering the
Icom 4000 or Vertex 7000 for my ham repeater.

[Repeater-Builder] Re: OT: Need to find a product to develop goodwill at a tower site(s

[rtc_0001]

I might have a cheaper answer to it all but it depends on what radios
exist in the fleet.   If they are anything like the Kenwoods, they'll
have built in dtmf & 2 tone encoders/decoders.  I believe some Motorola
mobiles have this as well.

Program the units to encode either dtmf or 2 tone on a front panel
button.  I've done this with the Kenwood mobiles & port's.  If you have
Fleetsync or MDC signaling that will work as well...Provided you have
the rcvr for it.

The key click counter is ok as well. I regularly sell & install S-Com's
AGI1100's in airports just for pilots to remote dial a phone line &
other functions using the proper number of ptt's.

If you go with the ptt counter, use the Pl/dpl detect or TOR (kenwood)
output instead of a carrier det only.  This way, you are actually
counting the correct PL/DpL hits & not a noise or distant co-channel
user.

If you build a ptt counter, bear in mind that commercial units offer a
programmable window of opportunity within which your ptt's must arrive
or the system resets.   The usual windows are setup for 1 ptt per second
for the number of ptts necessary.  If any of the ptts arrive outside
that window, you have to start over.

Other than the rather pricey (for this job) S-Com units, I don't know
who else makes such a device commercially.  In my applications I require
very dependable, bullet-proof units that I can set & forget for years. 
I haven't had an S-Com AGI1100 fail yet after the hundreds installed or
the years in service.