[Repeater-Builder] Decibel Antenna question

[Captainlance]

Hello All.
We obtained a new in box DB408D-B antenna, it is really a pair of DB404, 3.8 db 
antennas on a common mast with 2 feeedlines, equal to a DB408 split in half. My 
question is,m we want to use it as a single 408 antenna. how do we combine the 
2 halves? I was told that they used to make a phasing harness, but no longer do 
so. I called Andrew tech support, and got nowhere, they have NO old drawings of 
these antennas. We also were given a used harness, a "Y:" shaped affair, with 
what Appears to be an impedance matching transformer in one leg, 2 legs marked 
"IN" and one marked "OUT". All 3 have male "N:" connectors. Any ideas?
Lance N2HBA

[Repeater-Builder] Re: Midland 70-0375c Questions

[skipp025]

Re: Midland 70-0375c Questions

Hi Eric, 

Not the 100 watt 0375 but I've got a number of the lower powered 
25 & 35 watt radios doing repeater and linking projects. 

The 100 watts is a bit more than I need or want from the radio 
so I use the lower powered models. But yes, they can work as repeater 
sections if you reduce the power level. 

Consider the yahoo Midland Group. 

http://groups.yahoo.com/group/MidlandLMR/


cheers, 
skipp  

> "achowalogen457" <[EMAIL PROTECTED]> wrote:
> Gretings, 
> I may be showing my inexperience, but has anyone ever used the Midland 
> 70-0375c radios to build a repeater.  I seem to find this model radio 
> fairly common and it can be tuned to the 6m band.  I'm just not sure 
> that it would be a good choice for a repeater.  Anyone have any 
> thoughts on this?  I appreciate anything I can get, good or bad.
> 
> Thanks and 73,
> Eric
>

[Repeater-Builder] aea cp70-422n

[Ian]

hi guys .I have the above diplexer in use but it was tuned to 76mhz and 
we have it retuned according to the manual and it is  in use at 78mhz 
but the swr from the tx814 is reading 3 to 1 on my meter and it was 
turning the vswr circuit on and very little power was being 
transmittered .I tried a shorter length of rg223 in the tx diplexer 
path with a higher swr and it activated the alarm so it looks like i 
will need to increase my cable length .would it make any improvements 
to adjust the tuning loops.ie shorten them a bit or is is better to try 
different lengths of cable to lower the swr and dont modify the 
loops .thanks ian

[Repeater-Builder] Midland 70-0375c Questions

[achowalogen457]

Gretings,

I may be showing my inexperience, but has anyone ever used the Midland 
70-0375c radios to build a repeater.  I seem to find this model radio 
fairly common and it can be tuned to the 6m band.  I'm just not sure 
that it would be a good choice for a repeater.  Anyone have any 
thoughts on this?  I appreciate anything I can get, good or bad.

Thanks and 73,
Eric

RE: [Repeater-Builder] dtmf encoder - decoder chip number

[Ken Arck]

At 09:27 AM 4/9/2007, you wrote:

>Hello, for DTMF IC you can find Clare M-8870 or Teltone M-8870.

[Repeater-Builder] Re: Need Mirage B 215G Schematic

[skipp025]

Pretty generic amplifier really. Pop the cover off and count 
the main power transistors and record the part number. With 
that much power gain it's sure to be a multi stage amplifier 
like the common one-driving two transistor layout. Probably uses 
the mrf-247 or equiv. type transistor. 

Most of the web stuff for this Model Spec 5 watts input for 
about 150 out.  I'd drive it with 5 watts and see what the output 
is before I assume something is wrong. 

MFJ now owns Mirage Amplifiers so you can find most of their manuals 
available for free download. 

http://www.mfjenterprises.com/mirageamp/manuals.php 

I don't see the B-215g manual listed... but I do see a similar 
B-315g manual. You could also email or call them to request the 
B-215g manual. 

cheers, 
skipp 

> [EMAIL PROTECTED] wrote:
> My Mirage B 215G amp is only putting out about 40 watts with 3 
> watts drive. Looking for the schematic. Any one has one you can 
> email to me? Thank you.
> Rod KC7VQR
>

Re: [Repeater-Builder] dtmf encoder - decoder chip number

[DCFluX]

MT8870 is currently the most popular.

Direvitieves are MT8880 and MT which add DTMF encoding capability.

Other harder to find chips that are out of production are the SSI-204
and SSI-202

On 4/9/07, skipp025 <[EMAIL PROTECTED]> wrote:
> What is/was the part number for the popular dtmf chip somebody
> is/was looking for a short time back?
>
> skipp
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>

RE: [Repeater-Builder] dtmf encoder - decoder chip number

[Eric Vincent]

Hello, for DTMF IC you can find Clare M-8870 or Teltone M-8870.

 

Maybe you can ask for samples.

 

73’ Eric VE2VXT

 

   _  

De : Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] De la part de skipp025
Envoyé : 9 avril, 2007 11:46
À : Repeater-Builder@yahoogroups.com
Objet : [Repeater-Builder] dtmf encoder - decoder chip number

 

What is/was the part number for the popular dtmf chip somebody 
is/was looking for a short time back? 

skipp 

 


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[Repeater-Builder] Re: Tuning duplexers with sweep generator?

[skipp025]

> "w6nct" <[EMAIL PROTECTED]> wrote:
> I was recently told (by another ham) that I could ONLY tune up 
> my 70cm duplexer cavities using something called a "tracking 
> generator". 

Then consider the rest of what you hear from your ham friend with 
a skeptic ear. There are a number of different ways to tune and 
adjust various types/styles of duplexers and cavities. 

> For some reason, I thought that my father used to tune up resonant
> cavities using a sweep generator, oscilloscope, and a frequency
> counter; but I don't recall the exact setup he used.

It's one method of making a tracking or sweeping display of your 
cavity/duplexer assembly. The Wavetek Method (same series) I have 
here is not as exact as using other specilized test equipment but 
any port in a storm will probably work well enough. 

> I inherited his Wavetek (Model #1080, 1GHz) sweep generator,
> oscilloscope, and frequency counter.  I also have access to an
> IFR-1100 service monitor, if I need it (i.e., can be borrowed 
> from a friend).
>
> Can I tune up my 70cm duplexer cavities using the equipment I have?

Probably... but other minor equipment you have might also be handy. 
Like a receiver, watt meter, 50 ohm terminations/dummy load(s). 

> If so, could someone please indicate the test setup and procedure.
> Thank-you.

Before that... tell us what type of duplexer or cavity/cavities you 
want to adjust?  

cheers, 
s. 

[Repeater-Builder] Re: Tuning duplexers with sweep generator?

[w6nct]

Ron;

Thank-you for your comments and suggestions.  

I didn't get around to trying to tune then with just the audio of a
receiver to go on; fortunately I got the Sweep/Marker Generator and
Oscilloscope setup to work.  I really like how the display output is
linear (vs log.); I think that it makes it easier to read/adjust. 

I didn't have the problem you described with the narrow notch.  I'm
not sure if it is because of the linear (vs. Log.) display, or perhaps
the cavities I was using.  It might also be because I tuned each
cavity individually first, before looking at them in series.  Either
way, it seemed to dial right in.

I haven't done the final tune (of the entire duplexer system) yet; as
I am still trying to get the interconnecting cables cut just right. 
Perhaps the situation you describe might show up more notably during
the final tune when the pass and reject behavior is more pronounced
(e.g., narrower BW,...).  Either way, I'll keep my eye out for it.  

Another Ham here asked me about reading the "actual bandwidth" of the
cavities (referring to a 3db or 6db point, or something like that). 
To be honest, I wasn't quite sure what he meant or how I might do it;
but I suspected that it is just the width at a certain number of DB
from the peak (of the pass or notch).  The Sweep/marker generator does
seem to have data to indicate the signal strength (in db); so I am
guessing that I can actually do it if I was more familiar with the
Wavetek 1080 and how to read the vertical display it generates (I'm
still looking for the manual).

<<< vern >>>

[Repeater-Builder] dtmf encoder - decoder chip number

[skipp025]

What is/was the part number for the popular dtmf chip somebody 
is/was looking for a short time back?  

skipp 

[Repeater-Builder] Re: Tuning duplexers with sweep generator?

[w6nct]

I haven't received it yet.  You might want to double check the
TO-address you used (S/B:  [EMAIL PROTECTED]).  Occasionally, my eMail
bounces; but I haven't figured any reason for it.  If it does, please
try again.

Thx.

<<< vern >>>


--- In Repeater-Builder@yahoogroups.com, Mike Morris WA6ILQ
<[EMAIL PROTECTED]> wrote:
>
> I've responded to this message off-list.
> 
> 

[Repeater-Builder] Motorola Squelch IC

[rande]

Was someone looking for a Motorola M7716 squelch IC?

I just found a new IC I was going to use for a bi-level squelch board 
and never got it built.

Please reply direct.

Randy

Re: [Repeater-Builder] Re: Tuning duplexers with sweep generator?

[v44kai]

Hi vern.
I will also like a copy of your setup there too, as I also have an 
interesting setup that only uses two transceivers capable of switching txing 
and rxing on the two freq's that the cavities would be tuned to, of coarse 
they are modify with discriminator output and a signal level output.

Got the setup from a Harris tech, and retired army tech.

All one will need, is a good pairs of eyes and one good ear, and a little 
knowledge about tuning cavities.  Have tune, and retuned them for years, big 
and small without any problem, and when they are checked with a service 
monitor with the whole works, (tracking generator, spectrum analyzer etc) 
there are on the button.

v44kai.Joel.


- Original Message - 
From: "rtoplus" <[EMAIL PROTECTED]>
To: 
Sent: Saturday, April 07, 2007 10:08 AM
Subject: [Repeater-Builder] Re: Tuning duplexers with sweep generator?


> Thanks Vern...I would like to see your setup, if you don't mind.
> Email me at your convenience.
>
> Have a great weekend
> Bob, GMRS WPVV845, Amateur KG4WAD, LMRS WPXC892
>
>
> --- In Repeater-Builder@yahoogroups.com, "w6nct" <[EMAIL PROTECTED]> wrote:
>>
>>
>> Thank-you; it has been an interesting learning exercise for me.
>>
>> For the detector, I actually used a little gadget box circuit that
> my
>> Dad had made up years ago.  When I first found it (unlabeled) in
> his
>> electronics stuff, I didn't know quite what it was.  Like so many
>> other little boxes he had, he used to toss a handfull of components
>> into a small box and use it when he was testing something out.
> When I
>> was young, they always seemed like magic and mystery.  It was only
>> after several years at college that I could even start to figure
> out
>> the mysterious little circuits inside.
>>
>> The particular setup I used was much like N5ESE's QRP Dummy Load
> with
>> it's built-in RF Detector (http://www.io.com/~n5fc/dummy3.htm);
> but in
>> my case, I used a standard "T" connector to combine my Dad's
> detector
>> and a separate 50 ohm dummy load (also in a gadget box).  I
> stumbled
>> on N5ESE's version when I was trying to convince myself of what my
>> Dad's actually did; especially since Dad's was wired a bit
> different
>> from the others that I had seen.
>>
>> At Gary Schafer's (K4FMX) recommendation, I also put a 6db pad
> between
>> the sweep/marker generator and the cavity's input.
>>
>> If you like, I can sketch out the whole test setup; just let me
> know
>> with an off-group message ([EMAIL PROTECTED]).
>>
>> Enjoy.
>>
>> <<< vern >>>
>>
>
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>

Re: [Repeater-Builder] Re: UHF Micor Exciter Output Level??

[Kevin Custer]

I FOUND THE PROBLEM!!!

It was the lack of keyed A- that the exciter gets from the Time Out 
Timer! The conversion instructions I was using did not address that.


Use these instructions, and do away with the TOT:
http://www.repeater-builder.com/rbtip/stationmod.html

Kevin

Re: [Repeater-Builder] LMR feedline revisited and revised!

[Nate Duehr]

On 4/6/07, allan crites <[EMAIL PROTECTED]> wrote:


 Jeff DePolo, Gary Schafer, Nate Duehr, and Burt Lang,



Thanks for the kind words, Allan -- but I really didn't add much to the
topic other than to direct folks to information publicly available via
Amphenol's website.

It's been just as entertaining/educational for me to read along as anyone
else, I'm sure... the folks here who've posted real RF engineering work on
the topic shouldn't be weighed down with my name attached to them!  (GRIN)

I "are" just a ham here, but I do like to read and study the information
from the folks who make a living doing this stuff... they've learned far
more the "hard way" than I'll ever learn about the topic of repeaters!

Nate WY0X

Re: [Repeater-Builder] Re: UHF Micor Exciter Output Level??

[Mike Morris WA6ILQ]

At 12:12 AM 04/09/07, you wrote:
>--- In Repeater-Builder@yahoogroups.com, Mike Morris WA6ILQ
><[EMAIL PROTECTED]> wrote:
> > Assuming you have the controller hooked up properly,
> > and the station modded properly, I'd assume that if you
> > have one cracked joint you may have more.
> > I'd redo EVERY receiver and exciter joint, starting with
> > Keyed voltages (i.e. Keyed A-).
> > Yes, it's going to be a very boring hour or two, but put
> > some good music on the CD or MP3 player in the shop
> > and get a large mug of your favorite beverage and start
> > melting solder...
> > Large 52 oz mug on my very messy bench:
> > 
> > I picked that up at a 7-11 about 5 years ago... and they
> > now make a 64oz mug...
> >
> > Been there, done that... had to resolder every pin in a
> > Micor station backplane where that slot was occupied..
> > the receiver, exciter, station control card, squelch gate
> > card, and single-tone card (that slot was being used
> > to hold a 4-tone Pl decoder card).  The station had a
> > Scom 7K controlling it.
> >
> >
> > Don't make any assumptions until you are sure that the test
> > bed (i.e.the unified chassis) is solid. Until I did the resoldering
> > that station was very intermittent. The station was sitting on a
> > hardwood floor, and you could walk past that station and it
> > would drop out, or have "rattling" audio, or work normally until
> > I spent one saturday morning resoldering those slots...
> > Read the checklist - builder.com/rbtip/checklist.html>
> > and the line "Locating and fixing the intermittent that only
> > shows up at 4am on sundays during a full moon"... that
> > station was the inspiration for that line...
> >
> > Mike WA6ILQ
>
> >
>Hi Mike.
>
>First of all, How did you get a picture of my bench Actually, my
>mug is smaller, but my bench also has the optional empty Triscut box.
>
>I followed one of the sets of instructions from RBTIP. I thought that
>it would be easier to use the "no cards except the station control
>module mod" due to the fact that the docs were there, it was simple,
>and I was handing this off to another Ham who will have to maintain
>the thing. I was thinking K.I.S.S. The controller works as it should,
>things just went downhill when I realized that the output was gone.
>It was weak even for a dummy load.
>
>With regard to the backplane. I am half done with the re-flow. I'll
>finish the rest later. I found one bad joint at the COS point, I am
>sure that the others aren't far behind. I am not going to drag this
>thing a hundred miles to hang it in the rack just to have it take a
>dump on the hill. Been there. Theres nothing like being on Donner
>Summit modding a GE MVP Squelch Board with a butane soldering iron in
>high winds.
>
>Well, at least now with the temporary mock-up, I have about 2 watts
>out of the tripler. Things are looking up.
>
>Time for bed. Work comes early.  Thanks for the response.
>
>73 de John

Watch that tripler / low-level amp - they are somewhat fragile
electrically, and Moto isn't making any more of them.

While this article is for the mobile, it's worth reading:

Lowering the voltage sounds like a good idea as long
as you have enough drive...

This is for the station:

Dunno if the station has the "headroom" that the mobile does.

Mike WA6ILQ

[Repeater-Builder] Re: UHF Micor Exciter Output Level??

[John Everson]

--- In Repeater-Builder@yahoogroups.com, Mike Morris WA6ILQ 
<[EMAIL PROTECTED]> wrote:
> Assuming you have the controller hooked up properly,
> and the station modded properly, I'd assume that if you
> have one cracked joint you may have more.
> I'd redo EVERY receiver and exciter joint, starting with
> Keyed voltages (i.e. Keyed A-).
> Yes, it's going to be a very boring hour or two, but put
> some good music on the CD or MP3 player in the shop
> and get a large mug of your favorite beverage and start
> melting solder...
> Large 52 oz mug on my very messy bench:
> 
> I picked that up at a 7-11 about 5 years ago... and they
> now make a 64oz mug...
> 
> Been there, done that... had to resolder every pin in a
> Micor station backplane where that slot was occupied..
> the receiver, exciter, station control card, squelch gate
> card, and single-tone card (that slot was being used
> to hold a 4-tone Pl decoder card).  The station had a
> Scom 7K controlling it.
> 
> 
> Don't make any assumptions until you are sure that the test
> bed (i.e.the unified chassis) is solid. Until I did the resoldering
> that station was very intermittent. The station was sitting on a
> hardwood floor, and you could walk past that station and it
> would drop out, or have "rattling" audio, or work normally until
> I spent one saturday morning resoldering those slots...
> Read the checklist - 
> and the line "Locating and fixing the intermittent that only
> shows up at 4am on sundays during a full moon"... that
> station was the inspiration for that line...
> 
> Mike WA6ILQ

>
Hi Mike.

First of all, How did you get a picture of my bench Actually, my 
mug is smaller, but my bench also has the optional empty Triscut box.

I followed one of the sets of instructions from RBTIP. I thought that 
it would be easier to use the "no cards except the station control 
module mod" due to the fact that the docs were there, it was simple, 
and I was handing this off to another Ham who will have to maintain 
the thing. I was thinking K.I.S.S. The controller works as it should, 
things just went downhill when I realized that the output was gone. 
It was weak even for a dummy load.

With regard to the backplane. I am half done with the re-flow. I'll 
finish the rest later. I found one bad joint at the COS point, I am 
sure that the others aren't far behind. I am not going to drag this 
thing a hundred miles to hang it in the rack just to have it take a 
dump on the hill. Been there. Theres nothing like being on Donner 
Summit modding a GE MVP Squelch Board with a butane soldering iron in 
high winds.

Well, at least now with the temporary mock-up, I have about 2 watts 
out of the tripler. Things are looking up.

Time for bed. Work comes early.  Thanks for the response.

73 de John