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#21 Tim

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Posted 18 July 2014 - 07:16 PM

yes Jerry's black swamp 550 is working great and we put the black swamp 575 system on the air only to find that we have unlicesed users on simplex 3 blocks from the system and once they get reprogrammed we will start using it, we only did this to be nice because of who it is and I'll let Jerry tell you about that LOL



#22 jimenezl

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Posted 27 October 2014 - 09:43 PM

Hello all, Did I read correctly, that the baofeng 888 is part 95 compliant?
Thanks,
Louis
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#23 zap

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Posted 28 October 2014 - 02:53 PM

Power doesn't always translate to distance. 

 

A couple of things to remember, the biggest attenuator to FM communications is the ground. Path loss on a 50W GMRS radio, a commercial grade receiver, and 1/4 wave antennas is nearly 6000 miles. However, this number goes south quickly when you start talking about punching through urban environments, trees, hills, etc. With GMRS, you're pretty much guaranteed a successful transmission if there is unobstructed line of sight. More power means greater risk for desensing the receiver (what good does it do to have a repeater that can be heard for 100 miles but only talked to for 35?) which means adding extra filters, more antenna separation, etc. 

 

The 675 and 700 repeaters in Lubbock. The 675 repeater is on the tallest building for 120 miles. The antenna is 360 feet off the ground. It's running 50W at the transmitter and 40W at the antenna (which is a DB420).That's 477W ERP. It fizzles out about mile marker 41 on I27 (it's located at marker 4 roughly). The 700 repeater is a good 70 feet below it running 32W (23W at the DB420)...it fizzles out around mile marker 38. The two sites are 1000 feet away from one another. 70 feet is what mainly makes up that extra 3 miles.

 

95% of the time, you'll never notice the difference between a repeater running 200W or one running 25W if it's in a good location.


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#24 mel

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Posted 29 October 2014 - 01:21 AM

Did I read correctly, that the baofeng 888 is part 95 compliant?

 

I read that too...but alas a search on https://apps.fcc.gov...nericSearch.cfm  =
There are no applications on file that match the search criteria specified: 
Grantee Code: ZP5 Rule Part Exact Match: Selected First Rule Part: 95 

 

Same with 95a. So the search for the cheap, legal, full power gmrs HT continues...



#25 quarterwave

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Posted 29 October 2014 - 11:06 AM

Power doesn't always translate to distance. 

 

A couple of things to remember, the biggest attenuator to FM communications is the ground. Path loss on a 50W GMRS radio, a commercial grade receiver, and 1/4 wave antennas is nearly 6000 miles. However, this number goes south quickly when you start talking about punching through urban environments, trees, hills, etc. With GMRS, you're pretty much guaranteed a successful transmission if there is unobstructed line of sight. More power means greater risk for desensing the receiver (what good does it do to have a repeater that can be heard for 100 miles but only talked to for 35?) which means adding extra filters, more antenna separation, etc. 

 

The 675 and 700 repeaters in Lubbock. The 675 repeater is on the tallest building for 120 miles. The antenna is 360 feet off the ground. It's running 50W at the transmitter and 40W at the antenna (which is a DB420).That's 477W ERP. It fizzles out about mile marker 41 on I27 (it's located at marker 4 roughly). The 700 repeater is a good 70 feet below it running 32W (23W at the DB420)...it fizzles out around mile marker 38. The two sites are 1000 feet away from one another. 70 feet is what mainly makes up that extra 3 miles.

 

95% of the time, you'll never notice the difference between a repeater running 200W or one running 25W if it's in a good location.

 

Great points to reiterate. I have talked to people about these time and time again. People that know enough about radio to be dangerous often think more power is better. but with these repeaters, location is everything. If your portable radio is 4 watts and the antenna height is about 5 feet when transmitting, and you can make the repeater just fine...then your repeater only really needs 4 watts at the antenna to get back to you the same. Of course, there can be other factors, but this is why those little 12w UHF industrial repeaters always worked well at manufacturing plants, you put them on the smokestack or the water tower, etc...and you had all the range you needed for the job at hand. 

 

When I worked for M we had a big plant that had 6 or 7, 25 watt UHF repeaters going....set it and forget it. I don't think we ever went back for anything on those until we moved them once. 

 

On a wider scale, we had a volunteer fire system with the "100 Watt or die" mentality. Over the years they had gotten more and more portables until that was the primary radio, and the mobiles they now had were 45 watt dash mounts. The repeater was at an awesome site, so we had their repeater set for about 50 watts, and you could always hear it at around 20 miles further than they could talk in...but that was ok, no need to talk in on a portable from 2 counties over! They never knew it wasn't running at 100 watts, they couldn't tell. 

 

The worst case of this not being heeded was a manufacturing plant on about 300 acres...with 6 VHF repeaters, and antennae on the roof (about 40 feet off the ground) and among various exhaust stack, piping, railings, AC units, etc....all things that deflect and attenuate signals. They had a "guy" that insisted on big power. Well, with 6 VHF repeaters running constantly during the busy day, that place, and a 1/2 mile around it, is a giant intermod factory! They recently narrow banded, of course, and I was told they dropped the power to 50 at the base except one repeater that's at 75-80 because the head Maintenance guy wants to hear it at his house 20 miles away....boo hoo...I'm sure this place provides him a cell phone. I heard they were advised to reduce the power...not sure if it was for the intermod issue, or the FCC reduced their power. Either way....that's up to 12 VHF frequencies on the air at once! I would venture to say 10-15 watts would work just fine on those repeaters. After all the years, still can't see why they are on VHF at all...but this point, they should be on a UHF or 800 trunk, which could be put on a on-site tower and be easier to service, etc. Oh well, not my money.



#26 wqxr365

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Posted 18 May 2016 - 05:15 PM

New to GMRS and I'm in the Aera of this Clyde repeater. I can hear the repeater, but can't get in due to the PL tones being listed. Does anyone know the tone, or who I need to contact to get permission on the repeater??

73,

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#27 SteveC7010

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Posted 19 May 2016 - 06:54 AM

New to GMRS and I'm in the Aera of this Clyde repeater. I can hear the repeater, but can't get in due to the PL tones being listed. Does anyone know the tone, or who I need to contact to get permission on the repeater??

73,

WQXR365

 

It is already listed in the repeaters database including the operator's email address. Send him a note. If you allows you on his repeater, he'll give you the tone info.


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#28 wqxr365

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Posted 19 May 2016 - 09:50 AM

It is already listed in the repeaters database including the operator's email address. Send him a note. If you allows you on his repeater, he'll give you the tone info.

Thanks for the reply. I didn't see the email address. Which database are you referring to?

I'll do some searching as well.

Thanks again!

Edit: I found it, thanks!!

#29 ASRM

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Posted 30 May 2016 - 07:19 AM

Thanks, Jerry - Sounds as if that system might have more usable range than the local Sheriff's system... but, that is common with many GMRS systems.

 

;)

Isn't that amazing? I know ours out does most of the Public Safety systems around us (we even cover better at 10 miles from the site than theirs do with the repeater in the town or county), I am shocked at times that some shops don't feel this is an officer safety issue. Makes you wonder if there is something more to it, though I can understand ERP and restrictions placed that Part 90 and PS deal with that we GMRS folks are not restricted with.






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