zap

I looked at building some out of TK880's but I couldn't find the little pigtail anywhere (I guess Kenwood's version of the OPC-617 that my Icom's use). 16 pin Moto's are easy, $10 cable from China, programming the pinouts and you are GTG (minus the duplexer/antenna setup).
 
It's very rare to see low duty repeaters in commercial operation that aren't based off of mobile radios. Especially in applications where a desktop unit isn't needed (GE MASTR II and Kenwood TKR desktop units). The Icom CY-series of repeaters are mobile based as are the GR series from Motorola (GR1225 excluded), think I've even seen a GR style from Moto based off the CDM line. 
 
Two mobiles can be put together to form a repeater. In some cases with older (crystal controlled) mobiles, you can actually make the receiver and transmitter run full duplex and convert a mobile to a repeater. Examples of this are Motorola Micor, GE MASTR II, Motorola Mietrek…

Stand-offs are easy. Go get a stick or two of unistrut from the local hardware store, some conduit (whatever you may need for antennas to clamp to) and the appropriate unistrut clamps (for clamping to the tower face). And if you need to side mount a DB antenna then you just use the appropriate strut clamp to clamp the antenna directly to the unistrut (both top and bottom if necessary) Works like a charm.

They actually are.
 
You have to dig up the service manual (it's online) and remove a zero ohm resistor on the back of the control head board and then enable the function  in the software. Then and only then can FPP be used.

MDC on input. Change the input tone (keep the output the same, try dpl and pl combos).
 
 
Sent from my iPhone using Tapatalk

I live in Round Rock. I typically keep my issued service monitor in my truck. PM me if you need help or duplexer tuning. I will say, highly recommend using a Band-Pass/Band-Reject type duplexer if your site is to be collocated with other UHF repeaters.
 
I'd run a rtl_power plot for the repeater spectrum and see what comes out…I may do that (Brushy Creek area here) and see what I find.
 
 
Sent from my iPhone using Tapatalk

So here's what you are looking at from an average shop.
 
$50/ hr in travel charge
$100/hr tech time
$150/hr system tech time (things like testing repeater, checking for desense, tuning duplexer)
$200/hr engineering time (this will be the whole networking of the system)
 
Plus, material.
 
Then there is the whole networking aspect. IP? Link radios? Remember, hiring professional services means professional solutions so you'd be looking at NXU-2s and at a very minimum Ubiquiti PtP radios (assuming ISP connections are not available and LOS between sites is).
 
You're likely looking at $1500 to $2000 to setup the repeater at your home and another $3000-$6000 for getting everything networked.
 
 
Sent from my iPhone using Tapatalk

The thing I don't like about the antenna farm, stopped listing things as dBd or dBi.
 
The antenna farm also resales directly off of Tessco for a good portion of their products. LMR antennas you can generally get much better pricing from Tessco or Hutton.
 
 
Sent from my iPhone using Tapatalk

Hard to go wrong with Laird. They've been in the LMR business for awhile.
 
Sent from my SM-T713 using Tapatalk

Keep it at 25W. GR1225's are notorious for burning up PA's.
 
Out of curiosity, when was the last time the duplexer was checked for desense?
 
 
Sent from my iPhone using Tapatalk

Keep it at 25W. GR1225's are notorious for burning up PA's.
 
Out of curiosity, when was the last time the duplexer was checked for desense?
 
 
Sent from my iPhone using Tapatalk

The problem with the Maxtrac, the PA actually backs down in power based on a timer in the logic board. The GM300 on the other hand used a thermistor to control power. 

Try manually jumping the PTT pin to ground on be Kenwood.
 
 
Sent from my iPhone using Tapatalk

Try manually jumping the PTT pin to ground on be Kenwood.
 
 
Sent from my iPhone using Tapatalk

Ironically, this post gave me an interesting (dangerous) idea. Simplex repeater, P25 receive, analog transmit. Subs are programmed to receive analog and transmit P25.
 
Sent from my SM-T350 using Tapatalk

Simplex repeaters could be interesting if the receive and transmit tones were different. Essentially, subscribers RX on tone A and TX on Tone B. Repeater TX on tone A and RX on tone B. Keeps people from hearing the same thing twice.
 
 
Sent from my iPhone using Tapatalk

Motorola R1225.
 
 
Sent from my iPhone using Tapatalk

Probably more experimentation going on the commercial side right now than anything. Sent from my iPhone using Tapatalk

Does technology exist that will operate there, yes. However, there is a statement which only allows analog voice communication in Part 95.
 
 
Sent from my iPhone using Tapatalk

I'm sure this has topic has been on here before, but hear me out.
December 26th, 2015 my city was hit by an EF4 Tornado, and guess what the first thing was to go? The Power.. Your probably wondering where the encryption part comes in right..? Let me put this in order for you.
 
I have a Motorola XTS3000 800MHz Model II that scans my cities Public Safety Trunking System,
 
So I was in my room as usual, playing games and talking to friends on Skype, when I noticed the lights flickered, at the time I didn't think much of it, then it happens 2 more times within 3 minutes, so I get up and go to the living room and see my parents and my older brother watching the news. The weatherman is stating there is a tornado watch for Dallas County, and this thing was far away from my city, I live in Northeast Dallas and he was reporting the storm in far South Dallas, so we didn't think much of it, and I go back to my room playing and talking to friends on Skype. A short 10 minutes go by and the power goes out for about 5 seconds then flips back on, I opened the door to my room and my dad and brother were opening it just as I was, and said "We're getting your bed and moving to the laundry room!" Before leaving I grabbed my Motorola XTS3000, flicked it on and then ran to the laundry room, passing by the living room I see on the TV it says "Tornado Warning for Eastern part of Dallas County" and continued my way to the laundry room, mom was already in there and my brother and dad got back with the mattress and we all sat down, power went it again and we began listening to my radio as it scans through PD and FD talkgroups, we hear:
 
"40 hold all traffic, 50, I can still see it, looks like its North of 66, still East of Dalrock"
"500 to all units, be advised we've lost power and our phones in here, we're going to try to get some off duty employees in here to help us out!"
 
then FD tones out the FD for an entrapment and the reply is
 
"Firecom from Station 3 be advised the station does not have power--" and then he literally cuts out
 
During this whole time we have NO Cell Service, nor do we have any AM/FM Radios to listen to the weather service, so here we are, stuck with my 3000 listening, trying to figure out where this thing is, and guess what.. That radio may have saved our lives, think of someone equivalent to us out there, with either a scanner, or some type of device to listen to the PD/FD.. That may have saved their life. Lots of cities came from all over to help out with the disaster.
 
Then the next few months pass and I set a schedule to meet with the city who runs the system and talk to him and his team about the new system that is coming up and ask them specifically what the backup plan was if the current system went down, great example was the tornado.
 
Anyway, the whole deal is that my city is encrypting ALL of their talkgroups, PD and FD, all of them, every single one of them.. That is what they decided. Yes I 100% understand the things these officers go through and the risk they take, I back them up 110% but to encrypt FD? Like, I submitted an FOIA Request to gather the radio audio, and heard they told all the stations of the weather situation, so when you think about it, that could save someones life, by listening to that broadcast, as the power was down, so no way to look it up on the internet or receive updates. I suppose they assume everyone has an AM/FM Radio? I mean we did at the time, lost in the garage.. Lol..
 
What do y'all think about encryption when it comes to Public Safety Communications, because think of if they were encrypted when it hit.. And don't even get me started on encryption when it comes to Interoperability, I suppose that's where the Statewide 800MHz IOP Channels come into play..

All Stat is dependent on Asterisk's app_rpt.
 
Only IP link with analog audio I have going currently is through two Simoco SDB680 repeaters. Native interconnection, will integrate with any SIP so it could theoretically be used for app_rpt linking.
 
 
Sent from my iPhone using Tapatalk

Ironically, this post gave me an interesting (dangerous) idea. Simplex repeater, P25 receive, analog transmit. Subs are programmed to receive analog and transmit P25.
 
Sent from my SM-T350 using Tapatalk

The problem with any cable that uses 'foil' as the inner shield is that over time it will begin interacting with the braided wire shield and become 'noisy'. This doesn't happen immediately and may take many months to develop, but it isn't a question of "if" as much as a question of "when..." :
 
For detailed information, see here: http://www.repeater-builder.com/antenna/double-shielded-coax.html

Have you considered using a Baofeng 888 as your RX radio?, it will consume less power, weight less and you can tap the COR/COS easilly , that's what I plan to use on my solar repeater. ID-O-MATIC as the repeater controller too.

I'll also add, I've been seeing a lot of issues with mobile duplexers here lately (even Celwave/RFS). Anything much more than 35W and they start de-sening even though they are rated at 50W. 

I'm just gonna point this out, Motorola PA's are notoriously narrow in their efficiency. A 40 watt rated PA on a Radius series mobile is 23% efficient from 40W to 25W, beyond that its efficiency dwindles. The 25W version is 24% efficient from 25-10 W (but has the same heat sink as the higher power model). In retrospective, the 20W GE custom MVP is 29% efficient from 8-20W.

What do I mean by efficient? I mean that the output in RF is that percentage of the total power drawn in current. That means for your average 25% efficient radio you need 4 times the power output just to provide power. It also tells you how much heat is being generated from the circuit (conservation of energy).

When it comes to solar powered repeaters, one is better off running 10W or less and focusing on antenna systems. Avoid the Chinese junk (even antennas) as you want something you only have to buy once. Quality feedline, (avoid LMR in a full duplex environment), and proper installation. General rule of thumb is your solar system needs to be able to carry your load in snow shedding.


Sent from my iPhone using Tapatalk