Radioguy7268

Some DPL codes can be "falsed" by tone codes on certain panels. I recall seeing DPL 125 being falsed by tone code 1A on a Zetron 38 panel years back. Drove me nuts, because the interfering signal originated almost 90 miles away. I was looking at reprogramming nearly 80 mobiles if I had to switch codes. A little experimentation on the bench led to us switching tone panels and reducing receive system sensitivity a few ticks. One trip to the tower site & 30 minutes later, problem resolved.

There's so much good stuff out there in the way of used Part90 Commercial gear.... I've got a couple PM400's, an XPR5550 (shop truck), an old TK-880, and an assortment of portables that run the range from Vertex through Motorola. I've always been a fan of the M1225 for starter gear. It's small enough, has decent specs, and the software is very easy to use. I've picked up units off eBay for under 25 bucks for low power (25 watt) 4 channel models. The 20 channel display units usually run higher, but almost always under $100 for clean working units. The M1225 series was also type accepted for Part 95, which calms some people's fears. I have to admit that having access to all the software and cables makes things pretty easy for me, but unless you're looking at current model top of the line stuff, the software is pretty easy to come by, and most of the mobile cables you can make yourself if you can follow a diagram on Batlabs or Repeater-builder.

411 is a Digital Private Line code. It is transmitted along with your voice on the frequency you operate on. Normal operation is that the radio would transmit and receive with the same DPL code. This acts as a "mask" or Filter - helping to reduce or eliminate unwanted noise on your channel. It is useful when other user groups are operating on the same frequency, and you don't want to hear their traffic. With a properly set up DPL code, your radios will only hear (and talk) to each other. If your radio operates without a DPL or Private Line code (Carrier Squelch mode) - then you will hear all traffic on the received frequency. However, if you transmit without the correct DPL code, then there's a pretty good chance that the other users in your fleet (which are all programmed to only open their audio circuits when code 411 is received) will not hear your transmission. That's the simple level explanation, there's more to it, but that's enough for now.

I agree with your comment about Digital emissions, the FCC has been pretty clear that GMRS is supposed to be analog voice in a clear & unencrypted state (foreign languages allowed - as long as your ID is in English or CWID). However, when it comes to Part 90, I'm pretty sure that an FB6 private carrier repeater license can be used any way that a paying customer chooses to use it. I've never seen a single action from the FCC since the deregulation in 1980 for "casual communication" on Part 90 frequencies. I've got more than one licensed FB6 (and FB8) system, and I've never cared what a customer talked about. I also don't think the FCC ever asked to look at my books and see how much I was charging those FB6 customers. I think the definition of "Private Carrier" is fairly loose. I just told the Frequency Coordinators that I was planning to offer airtime service to my customers.

I'm not aware of any current crystal manufacturers, and the pricing of crystals was pretty much making them obsolete even before you counted the cost of labor to install and tune. I've still got an old Micor station that's been modified for a CSi multi-tone panel, and it was rocked on a Biz band frequency of 462.175. I've kept it around with the idea of tweaking it over to GMRS, but I never got around to it. I've got enough projects I'm behind on already.

And the hits just keep coming.... Apparently, there was video of the collapse as it happened. The video is grainy, but apparently shows that the workers knew something was wrong. Shocking tower collapse video shows an erector just two seconds away from death. https://www.youtube.com/watch?time_continue=88&v=oH-ER8yFJfs More video, along with the story: http://wirelessestimator.com/articles/2018/shocking-tower-collapse-video-shows-an-erector-just-two-seconds-away-from-death/

Update: Inside Towers has an update on the outcome of the OSHA ruling. https://insidetowers.com/cell-tower-news-contractors-error-caused-death-osha-reports/

Some people make things way too complex. Overanalysis = paralysis. As for CWID, yes, a repeater can and will transmit morse code on the output (462.xxxx) frequency. If you really read deep into the rules, I suppose that you can make a case that the mobile unit which transmits into the repeater on 467.xxxx should also be identifying. A simple verbal call sign identification would serve that purpose, but I'm also not aware of a single case of the FCC ever taking action against some one who only identified on the GMRS repeater's output. There are tone panels out there which will CWID based upon the tone/PL/DPL in use. In short, you can have different CWID's for different users, and pre-program them into the repeater based upon the user's PL tone. A pretty easy way to have multiple users identifying off a single repeater. There are plenty of type accepted Part 95 radios out there, but they're not all being sold new anymore. Wanting brand new limits your choices, for sure. There's also no FCC action I've ever seen that the FCC took against someone for using re-purposed Part 90 radios, and there's been a few letters and tacit admissions posted by the FCC where they realize that people are using surplus Part 90 radios and repeaters for GMRS. Does lack of enforcement = legal? Probably not, but I'll still keep using Part 90 gear until such time as the FCC tells me to stop. Over the air, there's little way to tell what type of radio someone is using. I guess some people like to know exactly who is talking & wish for an easy way to identify such. I view an automated CWID as being legal, slightly more anonymous, and a whole lot easier to use for my family. We don't need to spend 10 seconds identifying ourselves before we see if Mom wants milk on the way home. We let the automated CWID take care of all that after we're done talking.

It is EXTREMELY poor practice to put up an "open tone" or carrier squelch repeater that will activate upon any activity on a particular frequency.

Depending on the exact location and situation - as well as the type of Duplexer you might be using, a Preselector is probably more of a Nice to have, as compared to a Need to have. But, if you're buying a used repeater, get one with a Preselector if you can - especially if the price is within $50 or so. Buying a Preselector after the fact would probably run you @ $200 + tuning. If you have a really good duplexer (meaning a properly tuned 6 cavity bandpass/bandreject) the benefit you would get from a Preselector is minimal. If you were running a typical compact flatpack notch duplexer - the benefit would be amazing. The front end (receiver) of an MTR2000 is worlds better than most any '2 mobile radio based' duplex repeater package out there. The MTR2K converts received signal into PCM (Pulse coded modulation) digital signal for all it's internal processing, and the internal noise level introduced by the machine is nearly non-existent. You get a clearly reproduced voice -- even with a weak input signal from a distant mobile. Trouble areas are minimal - but if you're getting one off eBay, be super careful. If you can wait on them, you will often find people selling off a batch of them as they part out an old UHF trunking system - recent pricing between $450 and $650. The power supplies can be troublesome on the 100 watt units - but I've picked some up for a few hundred dollars that had known power supply issues, and then turned around & grabbed a huge 26 volt DC rack mount power supply for $100 or less (plus the $50+ for shipping the beast). Nice way to eliminate a known problem spot & put a 100 watt repeater on the air for less than $500. Motorola doesn't support them anymore, and many of the components are designed as "bricks" - so you can swap around a receiver, a power amp, a power supply module, but each component is sealed up & considered non-serviceable by Mother M. I don't think I've ever seen any schematics or break downs to component level. Software is a little old & cludgy, but I've still got a winXP machine that runs it well enough. The last time I programmed one - I realized it had been nearly 5 years since I'd touched one for a customer. A testament to the "set it and forget it" nature of those machines. Basic single user repeater mode is pretty straightforward. If you try to run a multi-tone panel things get a little more complicated, but the method to do it has been well documented and doped out.

Isolation between transmit and receive can be achieved if you have enough spacing between the 2 antennas. The trouble is, horizontal spacing requires about 300 ft to get 60dB of isolation in UHF, which isn't really enough. Vertical spacing only requires about 25 ft height difference for decent theoretical isolation in the UHF GMRS band. But, I'd still run a bandpass can on the receive side. http://www.repeater-builder.com/antenna/images/vertsep.jpg

The MTR2K is a VERY nice repeater package. Built as a giant aluminum heat sink, it will handle 100% duty cycle at 40+ watts of power all day long 24/7. It will run on standard AC power from the built in power supply - or you can run DC power directly using the power pole connectors on the back. You would (normally) need to provide a duplexer. (Unless you're running a split antenna system - one antenna for transmit, a second antenna for receive). Many MTR2000's would come with a built in high performance preselector to help filter out receive side noise or interference. Repeater-builder.com has a complete and well written breakdown on the MTR2000. I've had quite a few of them running in commercial service 24/7 for nearly 20 years. I did have to replace one of the power supplies a few months back, as it finally gave up the ghost. 30 minutes later, it was back up and running without missing a beat. IMHO, it's the best repeater package Motorola ever built - a compact performer that will run up to 100 watts all day long. Software is getting old & is totally unsupported anymore. Make sure you can source the software (or find someone locally to program/test it) before you take the plunge.

Also to add: I see by the callsign that the OP is located in NYC, and I'll assume that the repeater is on the rooftop of a building in the NYC area. There's a ton of RF energy in and around NYC. A Notch style duplexer is designed to be decent protection against the repeater's own frequencies. An inexpensive Notch style duplexer is NOT good at high concentrations of RF - such as at a mountaintop repeater site, or at a downtown urban area with tons of transmitters and intermod. A duplexer should absolutely be tuned to a specific pair of frequencies. I'll avoid arguing over how some people try to cover the entire GMRS range with one single duplexer. If they're doing it, they're not doing it very well. Putting a UHF cavity filter on the receive side of the duplexer (between the high side duplexer connection and the actual receiver) would help to deaden down some of the RF noise that might otherwise overload the front end of the receiver. I would also avoid putting a pre-amp on a setup like this. You're probably just going to be amplifying noise - as much or more than your desired signal. I have bought (and tested) a few of the Chinese duplexers off eBay. The quality of equipment and tuning varies. Generally, you're getting what you pay for. The better units from China tested out as good as most compact notch style duplexers I've seen from Sinclair or Celwave. I would not recommend using a notch style duplexer at a High RF site location - as mentioned. If you can't afford the real deal Bandpass/Bandreject Duplexer, then try to get some tuned bandpass cavities/cans.

Dennis - make sure that your transmit radio is going to the LOW side (462.xxx) of the duplexer. Also check your cables between the radios & the duplexer. If you're getting decent range when you eliminate the repeater from the scenario - you know your cable & antenna are most likely good. Now try doing what Rich recommends & just use a regular mobile palm mic on the transmit radio to key up the base frequency & transmit - going as a repeater normally would, through the duplexer & out through the antenna. If you start to see a problem there, you know it's something with the transmit radio (off frequency most likely) or possibly the duplexer and/or cables. If the transmit radio being keyed by itself gives you the 5 mile range, but going back to a repeater function gives you problems, you can just about guarantee that it's de-sense or a terrible setup on the receive radio. Using a portable 1225 "board" as the receiver doesn't sound like a sure fire path to success. The 1225 radios would easily suffer from de-sense in a heavy RF environment. I'd want to get the repeater into a shielded box & separate the receiver from the transmit radio as much as possible (A few inches and a little shielding could make all the difference).

There's some drone video up on www.ky3.com which is the local news station there in Missouri. The broadcast video shows a 2nd tower still standing near the location of the collapsed tower. I believe the newscaster mentions this tower being closer to 1900' tall. I have no knowledge if that's correct or not. Devastating. It's amazing that only one person was killed, but sad that it happened at all. Work was being done to reinforce the tower - apparently in anticipation of some upcoming re-pack work. This is the 2nd tragedy that I know of being blamed on re-pack work, the other one being earlier this year a tower near Miami where 3 workers were killed when rigging failed.

In disclosure, I sell both Motorola and Kenwood brands for a living. Motorola used to be the King, high on a hill above all others, but they haven't had that prominent of a position since the 1980's IMHO... There are plenty of pretty good brands out there besides those 2. Baofeng isn't one of them. Now, the question asked was not about Ham - it was about Part 95 GMRS, which actually has some specific standards. Baofeng doesn't meet those standards. If you've seen one on a Service Monitor, you've seen that for yourself. It's not even a question of how close they come - it's how far they still are. They don't hold a center frequency with stability, they generate spurious emissions with every transmission, and they have lots of hum and audio distortion in analog mode - which is what we're using for GMRS. Now, I've got some of those cheap radios, and they're good for portable scanning, and they have a few capabilities that some of my $800 DMR radios don't have. I've used them. Ten or 15 years from now, we'll probably remember when those brands were just young upstarts. They'll be building some decent equipment. They're not there yet. Experimental, sure. But that wasn't the question that was asked.

The trouble with Baofeng (and a bunch of the other cheap chinese radios) is that they have poor specs and no consideration for actually keeping their transmission on frequency - and not throwing out spurious energy onto other adjacent and nearby frequencies. The specs that they do publish are at best optimistic, and when you compare them side by side on a service monitor with an actual well built radio, you see that they're nowhere close to what a real radio can do. You will also see that the receiver is easily overloaded if you key up with another nearby radio on a different frequency. Search "direct conversion radio" on Youtube and you'll see a few videos showing the effect.

In the Part 90 world, the wording "Fixed station" refers to an FX1 designation, which most people would consider a Control Station. Usually a mobile in a tray attached to a power supply (often, and wrongly called a base station). That unit is used at a stationary location to communicate with a distant repeater (often using a directional Yagi antenna). Limiting the power of an FX1 was designed to keep people from interfering with distant repeaters on the same frequency pair. In the old 800/900 Mhz SMR world, it was also used in conjunction with the "20 foot rule" which kept the elevation above ground of an FX1's antenna in a reasonable range. I'm not aware of the term "Fixed station" being defined anywhere in the Part 95 rules, but it makes sense to me that power limitations on a repeater's input are designed to limit interference to distant repeaters on the input frequencies. If you're operating on the 462.xxx output frequency (lower side of the pair) - then you're an FB designation, a Fixed Base - or an FB2, which is a repeater.

Make sure you've got the duplexer connected properly (LOW to transmit, HIGH to receive) and you don't have a cable or connector issue on the jumpers. To me, that's your likely problem from what you're describing.

I just sent a couple of M1225 mobiles down to Texas for one of your members with all 5 sites programmed in. Sounds like you're building some good momentum. The coverage certainly looks impressive!