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Posted: 7/1/2012 8:35:38 PM EDT
it's a bit of a shame, really.  After 15 years of trying to get the XYL to get her tech ticket, I've finally given up.  We've got the county 2m repeater literally within touching distance, but no-go if she won't take the test.  So, I bought a GMRS license and couple of the mobiles CJan turned us on to.





I'm considering putting my own GMRS repeater on the new tower when it goes up.  There's a couple of them around us, but the owners I've asked are pretty hostile to us using them, which is their right.  Mostly they're farmers with only a peripheral understanding of RF, but I understand their major complaint:  "if I wanted to listen to your wife talk to your kids while I'm on my combine, I'd be using a CB".  Fair enough.





Many questions:





What equipment do I need?  I know I need the repeater itself, a duplexer (Knowledge-free in this area), power supply, antenna, and cable.  Antenna will be a vertical (recommendations please) hanging off the side of a 45G, up about 60-65'.





Base of tower will be about 100-120' from the house.  I know losses at UHF add up fast, but will losses on LMR-400 type cable be so bad that I need to go w/ 600 or something else?





What repeater and duplexer do you recommend, and why?  What skills and/or tools will I need to set all of this up?  Is there a way to use old/surplus/whatever equipment to do this on the cheap?  Again, if she would take the freaking test, I'd be putting this $ towards an IC-7600, but no go.





What regular maintenance is required?  Or will it just "run"?





Assuming the county is pretty much flat (it isn't, but this will be at one of the highest locations), what kind of range can I expect w/ 25w (?) and a 6-9db gain antenna just above the trees at 65'?  Assume the other side is a 40w mobile w/ a mag-mounted 3db gain stub on the center of the roof.  What about a 4w HT w/ a standard duck on it?





What should I be asking about that I'm not?





Thanks guys/gals,


-Slice



 
 
Link Posted: 7/1/2012 11:42:20 PM EDT
[Last Edit: 7/1/2012 11:45:36 PM EDT by Gamma762]
Originally Posted By HomeSlice:
I understand their major complaint:  "if I wanted to listen to your wife talk to your kids while I'm on my combine, I'd be using a CB".  Fair enough.

Are they going to be listening on their fillings or something?  It's their tower, but maybe a little information on the subject might be helpful.

What equipment do I need?  I know I need the repeater itself, a duplexer (Knowledge-free in this area), power supply, antenna, and cable.  Antenna will be a vertical (recommendations please) hanging off the side of a 45G, up about 60-65'.

Base of tower will be about 100-120' from the house.  I know losses at UHF add up fast, but will losses on LMR-400 type cable be so bad that I need to go w/ 600 or something else?

100 foot run to the base of the tower is only viable if you're really not looking for high performance out of this system.

Duplexors really need a controlled environment, so putting some kind of enclosure closer to the tower is a challenge.

What repeater and duplexer do you recommend, and why?  What skills and/or tools will I need to set all of this up?  Is there a way to use old/surplus/whatever equipment to do this on the cheap?  Again, if she would take the freaking test, I'd be putting this $ towards an IC-7600, but no go.

There are a zillion choices in gear, lots of used stuff on the market but you need to know what you're dealing with to make sense out of it.

I recommend avoiding the notch type small duplexors;  any quality bandpass+reject type UHF duplexor should be fine, sinclair or wacom were my preferences but other good choices too.  Tuning a duplexor isn't rocket science but does require equipment that you're not likely to have or have available to you - spectrum scope and tracking generator, usually found in a service monitor.  You can make a repeater out of two mobile radios, or buy an actual "repeater".  I don't know if GMRS is required to change to narrowband on Jan 1, if not there is probably a ton of gear that's getting sold off right now that would work.  If it does need to be narrowband, then you have to make sure the equipment is capable of that.  I don't know what the ID requirements are for GMRS, if they don't need to announce an ID then there are plenty of low cost "repeater maker" controllers that you can use.  If they do need to ID, you'll need some kind of repeater controller that can generate the ID.

When buying LMR radio equipment the ability to program the radios is a vitally important feature, so tends to point one towards say Icom which has readily available programming software, and away from say /\/\ which is a massive PITA.

What regular maintenance is required?  Or will it just "run"?

Assuming the county is pretty much flat (it isn't, but this will be at one of the highest locations), what kind of range can I expect w/ 25w (?) and a 6-9db gain antenna just above the trees at 65'?  Assume the other side is a 40w mobile w/ a mag-mounted 3db gain stub on the center of the roof.  What about a 4w HT w/ a standard duck on it?

What should I be asking about that I'm not?

Thanks guys/gals,

http://www.repeater-builder.com may be information overload but lots of good info there.

What mobiles did you buy?
Link Posted: 7/2/2012 5:52:54 AM EDT
Thanks for the info Gamma.  Will do some reading.  Can I get by w/ the repeater 100' away from the base of the tower if I use some super-duper coax?



The mobiles I bought are icom F2821's...






 
Link Posted: 7/2/2012 11:30:45 AM EDT
Originally Posted By HomeSlice:
Can I get by w/ the repeater 100' away from the base of the tower if I use some super-duper coax?

Sure.  Probably cheaper to build a shelter.

All depends on what kind of performance and range you're looking for out of the system.
Link Posted: 7/2/2012 1:13:20 PM EDT
[Last Edit: 7/2/2012 2:32:50 PM EDT by EXPY37]
Edit, chg VHF to UHF. Also, IIRC GMRS needs the deviation set to the 'new' narrow band. If the radio you find is 'wideband' usually there is info in the service manual on changing some components in the modulation and demod sections to narrow it up. Not too hard once you figger it out.

Slice, for the duplexer look on ebay for a VHF one, not the compact type but they will be about 30" long, to help ident the right one. About $200 to $300.

For the radio, consider Tait repeaters. There are some on ebay, just looked and no good deals today tho... A nice one on today is $800, too much, but the seller might take less. It's due to be relisted, he may lower the $$.

At 65 feet on flat terrain, you are going to get a lot of opinions, but if no intervening terrain, I think 30 miles is doable. More if you have advantegous terrain.

I'd locate the repeater and duplexer at the base of the tower. The Tait equipment has everything built into the unit to remote it even over a balanced audio pair with a DC control. I wouldn't use coax in a long run to the house unless you don't care abt optimum performance.

As far as temp issues, you aren't likely to have any in my exp.

The unit will just work with little intervention.

I'd run it off a 12vdc battery [2 golf carts hooked up per your question in another post] and charge the battery from the house -to help with lightning protection. Or use a $300 solar panel.

I walk the walk too...   If any questions...

Link Posted: 7/2/2012 1:28:48 PM EDT
GMRS is UHF, not VHF, so VHF duplexers and antennas are not going to work.



If anything, it makes the job simpler since UHF duplexers are little bigger than a laptop computer.

















Originally Posted By EXPY37:


Slice, for the duplexer look on ebay for a VHF one, not the compact type but they will be about 30" long, to help ident the right one. About $200 to $300.



For the radio, consider Tait repeaters. There are some on ebay, just looked and no good deals today tho... A nice one on today is $800, too much, but the seller might take less. It's due to be relisted, he may lower the $$.



At 65 feet on flat terrain, you are going to get a lot of opinions, but if no intervening terrain, I think 30 miles is doable. More if you have advantegous terrain.



I'd locate the repeater and duplexer at the base of the tower. The Tait equipment has everything built into the unit to remote it even over a balanced audio pair with a DC control. I wouldn't use coax in a long run to the house unless you don't care abt optimum performance.



As far as temp issues, you aren't likely to have any in my exp.



The unit will just work with little intervention.



The antenna could be a couple of Cushcraft 2 meter beams modified and pointing in opposite directions if a perfect omnidirectional pattern isn't required.



I'd run it off a 12vdc battery [2 golf carts hokked up per your question in another post] and charge the battery from the house -to help with lightning protection. Or use a $300 solar panel.



I walk the walk too...   If any questions...









 
Link Posted: 7/2/2012 1:39:30 PM EDT
Also I suggest not to bite off the whole enchalada at once.

First get the repeater radio and the duplexer and manuals and get familiar w/ them. The Tait that's on ebay is a Series II and can be pgm'g via PC. The cable is abt $30 on ebay. SW is online.

The older Series I radios are cheaper and need an EEPROM  pgm'd and I think easier.

An alternative to get started is to get an inexpensive repeater controller and interface any receiver with an type accepted transmitter. It could be one of your mobiles or HT's to get started.

There are controllers on ebay but I'd pay $100 or so for one of the NHRC ones. Easy to use.

Oh, the duplexer you maybe should look for would be a 4 cavity. I looked on ebay and they are around 400 to 500 now. Mine was 300 IIRC.

A nice one just sold.



Link Posted: 7/2/2012 1:44:21 PM EDT
[Last Edit: 7/2/2012 3:14:21 PM EDT by EXPY37]
Originally Posted By JC_Conn:
GMRS is UHF, not VHF, so VHF duplexers and antennas are not going to work.

If anything, it makes the job simpler since UHF duplexers are little bigger than a laptop computer.





Originally Posted By EXPY37:
Slice, for the duplexer look on ebay for a VHF one, not the compact type but they will be about 30" long, to help ident the right one. About $200 to $300.

For the radio, consider Tait repeaters. There are some on ebay, just looked and no good deals today tho... A nice one on today is $800, too much, but the seller might take less. It's due to be relisted, he may lower the $$.

At 65 feet on flat terrain, you are going to get a lot of opinions, but if no intervening terrain, I think 30 miles is doable. More if you have advantegous terrain.

I'd locate the repeater and duplexer at the base of the tower. The Tait equipment has everything built into the unit to remote it even over a balanced audio pair with a DC control. I wouldn't use coax in a long run to the house unless you don't care abt optimum performance.

As far as temp issues, you aren't likely to have any in my exp.

The unit will just work with little intervention.

The antenna could be a couple of Cushcraft 2 meter beams modified and pointing in opposite directions if a perfect omnidirectional pattern isn't required.

I'd run it off a 12vdc battery [2 golf carts hokked up per your question in another post] and charge the battery from the house -to help with lightning protection. Or use a $300 solar panel.

I walk the walk too...   If any questions...



 


HAHA -my bad... Thought it was VHF.

In that case, change everything to UHF, there's a Tait repeater on ebay for $700, even more reason to put the repeater at the tower, there's a UHF 'Motorola' duplexer on ebay now for $200 [same one as was in my old repeater years ago, still have it, threw the radio out after the ham club wouldn't even return my calls to give it to them...]

Since it's UHF, your vertical should be OK. Range won't change much from VHF. On my old UHF repeater I had a gasfet preamp and could often talk over flat terrain abt 10-15 miles w/ an MX300. Across an urban area. Ant height abt 40'.

Try to pick up a Bird 4110 IIRC mini watt meter off ebay for abt $40 or so to keep in the line. They are a super deal usually, use one all the time and can zoom an IP cam on it and monitor from far away.



Link Posted: 7/2/2012 1:53:55 PM EDT
[Last Edit: 7/2/2012 2:03:46 PM EDT by EXPY37]
There's a VariNotch duplexer on ebay for $375. Prolly better than the Motorolas but not sure. I'd buy it for the extra $ tho.

You'll likely find putting up your own repeater a rewarding and fun experience. Keep us posted!



Link Posted: 7/2/2012 2:07:38 PM EDT
Cell phones are what women want to use....not repeaters. LOL
Link Posted: 7/2/2012 2:25:26 PM EDT
Originally Posted By K9-Bob:
Cell phones are what women want to use....not repeaters. LOL

This is what I'm afraid of for the OP.

If she's refused for 15 years to take the simple test for an amateur license she probably doesn't want to talk on a radio.  You'll end up thousands of dollars into a project and not getting any benefit from it.
Link Posted: 7/2/2012 5:35:56 PM EDT





Originally Posted By EXPY37:






Slice, for the duplexer look on ebay for a VHF one, not the compact type but they will be about 30" long, to help ident the right one. About $200 to $300.





For the radio, consider Tait repeaters. There are some on ebay, just looked and no good deals today tho... A nice one on today is $800, too much, but the seller might take less. It's due to be relisted, he may lower the $$.





At 65 feet on flat terrain, you are going to get a lot of opinions, but if no intervening terrain, I think 30 miles is doable. More if you have advantegous terrain.





I'd locate the repeater and duplexer at the base of the tower. The Tait equipment has everything built into the unit to remote it even over a balanced audio pair with a DC control. I wouldn't use coax in a long run to the house unless you don't care abt optimum performance.





As far as temp issues, you aren't likely to have any in my exp.





The unit will just work with little intervention.





I'd run it off a 12vdc battery [2 golf carts hooked up per your question in another post] and charge the battery from the house -to help with lightning protection. Or use a $300 solar panel.





I walk the walk too...   If any questions...








I'll check those out on ebay, thanks for the tip.





After checking into the prices of some of that hardline, it's looking like a shack at the bottom of the tower is going to be cheaper.
Originally Posted By Gamma762:



http://www.repeater-builder.com may be information overload but lots of good info there.




Great link, thanks!
Originally Posted By EXPY37:





Since
it's UHF, your vertical should be OK. Range won't change much from VHF.
On my old UHF repeater I had a gasfet preamp and could often talk over
flat terrain abt 10-15 miles w/ an MX300. Across an urban area. Ant
height abt 40'.





That'd be plenty adequate if I could get 7-10 mi out of it.  I can't climb a tower, so I want to make sure that everything that goes up on it can work for years w/o maintenance.
Originally Posted By Gamma762:





Originally Posted By K9-Bob:


Cell phones are what women want to use....not repeaters. LOL



This is what I'm afraid of for the OP.





If
she's refused for 15 years to take the simple test for an amateur
license she probably doesn't want to talk on a radio.  You'll end up
thousands of dollars into a project and not getting any benefit from it.






This is really a pricing and design exercise at this point.  I'm going to put the tower up anyway, I'm pretty sure of that.





The area where this will be has pretty crappy to no cell coverage.  The thought process is we can cut the kids loose in the woods w/ an HT, and be able to talk to them, even if we're in town or at a nearby friends house.





Right now i'm in the pricing/design/feasibility study phase (which is all free, and helps me learn anyway).  It kind of pisses me off a little, since there's a 2m repeater in the front yard.  If it gets to the point where it'll really cost as much as a 7600, then I'm going to have to think real hard about which one of those is going to show up...
 
 
Link Posted: 7/2/2012 5:54:40 PM EDT
[Last Edit: 7/2/2012 5:59:30 PM EDT by EXPY37]
Well, then start small with a NHRC 'peater controller and 2 of your MURS GMRS whatever, HT's and put them on top of your house separated well away from each other.

I find I can avoid serious desense on a cheap scanner when xmitting with a 1 watt HT 20 feet away.

Get the duplexer and hook the HT's to it and an antenna on your house roof. I don't see why you need to be on a tower for your requirements especially if you're on higher terrain..

The UHF repeater pairs are 5 mc apart IIRC and the deals for duplexers on ebay are hard to beat. You can probably tune them well enough using your existing radios and some cheap attenuators with a bit of coaching.

Link Posted: 7/2/2012 5:58:56 PM EDT
[Last Edit: 7/2/2012 6:04:26 PM EDT by EXPY37]
You don't need a 'shack' at the tower, just an enclosure that's watertight abt the size of a  suitcase.

You otta be able to put one together for less than 1000. Mine cost ~250 for the radio, 300 for the duplexer, 70 for a crummy Cushcraft antenna, and 20 feet of LMR200 or 400 or whatever. The 1/2 inch stuff and conx. It's wunderful.

Link Posted: 7/3/2012 4:04:10 AM EDT
For a repeater look at the kenwood TKR-820. If you get one I can program it up for you. It uses a eprom programmer and can be moved to ham if the gmrs thing does not work. Usually the motorola duplexers can be had pretty cheap on ebay. And watch around there is going to be a ton of stuff dropped soon due to narrowbanding. And for coax look at showmecables they have some 50ohm andrews aluminum 7/8 hardline pretty cheap. Depending on where in IN you are it may be cheaper to do pickup from St. Louis than have it shipped.
Link Posted: 7/4/2012 1:31:12 PM EDT
Have you confirmed that you do not get the range you want on simplex while using hi-gain mobile antennas?
Link Posted: 7/4/2012 2:48:20 PM EDT
Thanks for the offer Jazz, I may take you up on it!



Grog, I haven't tested it yet.  The tower is still a concept ;-)




 
Link Posted: 7/4/2012 6:47:50 PM EDT
The repeater builder site has tons of good info (non-repeater as well) but I would suggest tesing your coverage on simplex before you spend a ton of money.  

Mobile to mobile, base to mobile, whatever you would envision using.  Tossing an HT to the kids and being too far away would likely not work well at all, but if that's a low possibility and the other coverage works well I'd say work with what is paid for (providing you have most of what you need so far).
Link Posted: 7/4/2012 8:57:53 PM EDT
[Last Edit: 7/4/2012 8:59:11 PM EDT by Gamma762]
http://www.ebay.com/itm/180921206923

$175 BIN, would need crystals (I think about $25) and duplexor retuning.

Originally Posted By HomeSlice:
Grog, I haven't tested it yet.  The tower is still a concept ;-)

I think he means mobile-to-mobile range.

Originally Posted By Jazzemt:
And for coax look at showmecables they have some 50ohm andrews aluminum 7/8 hardline pretty cheap. Depending on where in IN you are it may be cheaper to do pickup from St. Louis than have it shipped.

Link?
Link Posted: 7/4/2012 9:45:56 PM EDT



Originally Posted By Gamma762:


http://www.ebay.com/itm/180921206923



$175 BIN, would need crystals (I think about $25) and duplexor retuning.




Originally Posted By HomeSlice:

Grog, I haven't tested it yet.  The tower is still a concept ;-)



I think he means mobile-to-mobile range.




Originally Posted By Jazzemt:

And for coax look at showmecables they have some 50ohm andrews aluminum 7/8 hardline pretty cheap. Depending on where in IN you are it may be cheaper to do pickup from St. Louis than have it shipped.


Link?


How big of a deal is retuning the duplexer?  Presumably it has one since it only has one antenna jack?



As for testing, What I'd like to try is getting my hands on a decent base antenna, somehow getting it up in the air as far as I can temporarily (15-20'?), and then seeing how far out I can reach a mobile or HT.  Because of the terrain (there's a pretty big valley), I think if you were down there w/ an HT, then range w/o a repeater is going to be pretty limited.



~$200 is really reasonable for what I'm wanting to do...



As for the hardline, I might be willing to make the trip to StL for that stuff –– I'm in SE IN, but I'm always up for a road trip...



Thanks, guys!

-Slice



 
Link Posted: 7/4/2012 9:50:55 PM EDT
Originally Posted By HomeSlice:
How big of a deal is retuning the duplexer?

Any duplexor you buy will have to be tuned to whatever frequencies you are going to use.  Call around to local 2 way radio shops, or ask at a ham club if anyone has access to a service monitor and can tune duplexors.
Link Posted: 7/4/2012 10:01:33 PM EDT
[Last Edit: 7/4/2012 10:02:59 PM EDT by EXPY37]
Slice, tuning a duplexor is a critical job even w/ the right equipment.

It is possible with an expedient setup as I posted above.

But like already mentioned, if you can find someone to do it locally, that will save you a lot of time at the expense of not learning how to do it yourself.

$200 is a hell of a deal for a working repeater.

Over the years we've found International Crystal in OK  to be a reliable xtal supplier to work right the first time.

Link Posted: 7/4/2012 10:06:54 PM EDT
For testing, why not stick a 450 mobile ant on your chimbly with a ground plane under it?

A trash can lid would do fine with a mag mount. Since you already have the radios, you could be testing real fast.

Link Posted: 7/4/2012 10:07:41 PM EDT
Great.  Thanks guys...




 
Link Posted: 7/4/2012 10:19:46 PM EDT
Do the rules for the GMRS service require the repeater to ID itself via CW every 10 min?  Seems the ones around here –– some do and some don't, at least from my observation so far...
 
Link Posted: 7/4/2012 10:34:17 PM EDT
[Last Edit: 7/4/2012 10:38:20 PM EDT by Gamma762]
The part of Standard radio that made crystals was spun off into its own company after Standard was sold.
http://www.frequencymanagement.com/ used to be the crystal manufacturing part of Standard.  I'd give them a call and check on cost of crystals.

That info from the Standard page on the repeater-builder website, which also has the service manual for that repeater online.

Originally Posted By HomeSlice:
Do the rules for the GMRS service require the repeater to ID itself via CW every 10 min?

It would appear the answer is no.
95.119 Station identification.

(a) Except as provided in paragraph (e), every GMRS station must transmit a station identification:
(snip)
(e) A station need not identify its transmissions if it automatically retransmits communications from another station which are properly identified.

http://home.provide.net/~prsg/part95ae.htm#95.119
Link Posted: 7/5/2012 7:55:42 AM EDT
Originally Posted By Gamma762:
http://www.ebay.com/itm/180921206923

$175 BIN, would need crystals (I think about $25) and duplexor retuning.

Originally Posted By HomeSlice:
Grog, I haven't tested it yet.  The tower is still a concept ;-)

I think he means mobile-to-mobile range.

Originally Posted By Jazzemt:
And for coax look at showmecables they have some 50ohm andrews aluminum 7/8 hardline pretty cheap. Depending on where in IN you are it may be cheaper to do pickup from St. Louis than have it shipped.

Link?


Looks like they don't have the hardline anymore but they do have their lmr600 from 1.50 to 1.13 a foot. Depending on how much you buy.


http://www.showmecables.com/product/ShowMeCables-Low-Loss-600-Cable-Per-FT.aspx



The al hardline from andrews is called FXL-780
Link Posted: 7/5/2012 8:10:34 AM EDT
But...

a) Except as provided in paragraph (e), every GMRS station must transmit a
   station identification:

    (1) Following the transmission of communications or a series of
        communications; and

    (2) Every 15 minutes during a long transmission.

Link Posted: 7/5/2012 8:44:50 AM EDT
[Last Edit: 7/5/2012 8:47:44 AM EDT by EXPY37]
Gamma, how does control of a GMRS repeater get handled?

Does a remote shutdown of the transmitter via some code from a remote unit need to be included?

Also, here's an inexpensive ID'er.

http://www.hamgadgets.com/index.php?main_page=product_info&products_id=108
Link Posted: 7/5/2012 9:44:50 AM EDT
[Last Edit: 7/6/2012 3:24:22 PM EDT by Gamma762]
Originally Posted By EXPY37:
Gamma, how does control of a GMRS repeater get handled?

Does a remote shutdown of the transmitter via some code from a remote unit need to be included?

By comparison to the amateur service, there is little in Part 95 about such things.  And as I mentioned before, ID is not required on the repeater.  I've never seen a Part 90/95 repeater with an IDer, and the only remote control I've ever seen is for turning on and off different subscriber pl/dpl tones.

Considering that he's talking about installing the repeater at his home, the power switch will be readily available.

Something I mentioned earlier which bears repeating however, is the question of whether GMRS stations must change to narrowband by Jan 1 2013.  If they do, it's pointless to buy an older piece of equipment like that Standard, or this Motorola, or anything similar that isn't capable of narrowband.
Link Posted: 7/6/2012 1:24:17 AM EDT
Do NOT use LMR type feed-line in a full duplex application. Use LDF5 hardline at a minimum.
Link Posted: 7/6/2012 11:44:08 AM EDT
Originally Posted By DOUGHERTY03:
Do NOT use LMR type feed-line in a full duplex application. Use LDF5 hardline at a minimum.


Why?

Link Posted: 7/6/2012 3:06:43 PM EDT
[Last Edit: 7/6/2012 3:07:18 PM EDT by Grog]
Narrowbanding will not apply to GMRS (part 95), part 97 (amateur) or even part 80 (marine).  It does cover part 90 (business & public service land mobile) .  

That is one reason some gear is absolutely dirt cheap, and will work well for various part 97/95/80 uses (need a cheap MURS receiver for 154.570 & 154.600? Wire up an old Maxtrac.
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