WRKC935

From a technical and hardware standpoint. Where are the radio's going to come from? While some hams bought up the low band commercial gear for ham use, most of that has flushed through and is gone. Repeaters..... There haven't been low band repeaters built since the days of the MICOR, at least by Motorola. They had tube finals that are now obtainium. Yes, I know 3 guys are gonna pop in here and talk about the 4 they have on the shelf. So that's 12 tubes. Where are the rest of them going to come from? So then it's NEW radios. From a new source. No one on the commercial front is producing radios any more, and unless they ca see selling millions of them, none of the big commercial guys are gonna go back to that. And even if they did, you're talking about radios that will be over a grand to purchase. So then you have the chi-com stuff that will need to be filling the void. They don't currently support the platform. The dual band and single band chi-com radios that are in the pipeline are the same radio they produce as the UV-5R and other common chi-com radios. They are HIGH BAND VHF and UHF. And that appeals to a number of people. Even they aren't producing VHF -LOW transceivers. So new product for how many people? Remember that you can decorate a Christmas tree with Baofengs for less than the purchase of the tree, on sale. Everyone bought a number of them and they toss the guts in a new case, toss some better firmware at it and give it a new model number and they flock. If it's JUST a GMRS radio, and I am betting that the FCC will be watching, it's not gonna be 40 bucks for a portable and 125 for a mobile. And have you ever SEEN a duplexer for low band VHF? Let alone priced one. They are HUGE, and they carry a HUGE price tag. I don't know that the GMRS community is going to take to repeaters costing 10 grand or more with a duplexer and antenna, and 500 dollar mobiles. Oh, and Low Band antenna's.... that's not going on a 1 1/4 inch mast pipe on the end of your house either. And repeater / real base station antenna's are 40 plus feet of vertical real estate. But the bare minimum 1/4 wave is still 8 or so feet. And that's gonna be unity gain. Honestly, I see this as an idea by someone for a radio service that doesn't really know radio.

As I have said several times on here. GMRS is radio facebook, radio chatroom. It's how many are using it. It's a social gathering spot for people that just want to chat. The reason GMRS and not HAM is HAM requires testing and more effort. With GMRS, you pay your money and you get a license. And the codgers involved with ham radio aren't always real welcoming to the younger generation either.

And for the sake of the discussion, there is NOTHING stopping you from putting a repeater up, on one of the frequencies they are using and talking on it. And this is for the same reason I gave before on them backing themselves into a corner. They have a linked repeater system and have overlapping coverage of a number of the pairs if not all the pairs. But again, who are they going to call? The FCC? I seriously doubt it. Because again, backed into a corner with no recourse. What are they gonna tell the FCC? They going to admit they have all the pairs tied up with linking? That they are running a for profit business selling air time on GMRS? I personally dealt with this in Ohio. At first I was willing to try to work with the guy. But he started telling me HE had the pairs and I could only run a short antenna and low power. His repeaters (turned out to be paper repeaters) were well established. When I started looking into his repeaters, and found his business license and it stated he was for profit selling air time on GMRS, I picked the two pairs he was on and parked repeaters on both pairs. He wasn't happy. I invited him to call the FCC and told him I had all of it documented including his state business license where he was selling air time for profit. It never went any further.

Gee that sounds like a ham radio conversation. Seriously, at a bare minimum the way to report it is saying that the repeaters are being keyed with out the person accessing them being within the coverage footprint of the repeater. This is causing harmful interference on that frequency / frequencies in a specific location or area. That is spelled out in the blurb the FCC put on the their web site about why they don't want people linking repeaters. No way to monitor the frequency in use before accessing it and causing interference. Mind you I am all for linking GMRS repeaters, and have even come up with ways to mitigate this and other issues that were cited as being the problems with linking. But the FCC says the rules are what they are, so until they change the rules, I don't link repeaters. Now I will say this, that group has backed themselves into a corner. If someone is interfering with their linked repeater system, they have ZERO recourse to deal with it. It's like having a house full of drugs and calling the cops because someone stole their bag of weed. The FCC is the only governing body with GMRS. If they call the FCC, then they open themselves up to being looked at for what THEY are doing. So that's not really an option for them. Local police and government in general have no ability to enforce FCC regulations. So, the option they are left with is the redneck thought process of "I'm gonna *insert dumb redneck statement of violence here* and that will get it done. Of course the problem with that is the local police DO have the ability to deal with that. And although I'm not sure what Georgia's laws are but if they are like Florida then doing that sort of thing might involve a free trip to a hospital or even the grave yard. While people may claim that they will just go drag them into their yard and throw them a beating, it's rarely done for that reason. And can escalate quickly if they do. And the police will still not give a rip about the GMRS interference, the assault, battery, menacing and all that WILL get a response.

I see this question so often that this almost needs to be a direct post about it so it can be referenced. I came up from CB radio many years ago where guys would think that if they had a 1:1 match that they had somehow accomplished something almost magical and akin to hitting the lottery. Or they would brag about how they had a 1 to 1 match and how great their radio system worked and nothing could come close to it's performance. The truth is far less dramatic than that. And when you really start to understand signal levels, delta of signal levels, meaning how much difference in signal level A from signal level B actually is and what the perceived and actual effects of that level difference is, you quickly find out that it ain't much. Now you meter actually SHOWS the percentage of signal forward VS reflected which is SWR. SWR is the RATIO of forward vs reflected power. Of course reflected power is power that is NOT being radiated by the antenna. Some same it backs up to the radio and is burnt off as heat, others will tell you it reflects from the radio back to the antenna and is then radiated (which is BS and due to phase changes would really DECREASE your signal) and there are a few other stories out there of what becomes of the reflected power.. but the crux of it is, it's not going out the antenna as signal. So then we get into the discussion of decibel or dB. And here's where the rubber really hits the road. Because while the radio is rated in WATTS for transmit, the receiver is rated in dBm for receive. And the whole idea of GMRS radio is talking to others. The other guys receiver is what you are trying to effect a response from. And NO amount of power matters if there is no one listening on the other end. That is referred to HAM radio at this point... no one listening. So a cool little tidbit of radio is that wattage can also be expressed as dBm. Now, some might know something of decibels from school and that it's a logarithmic number that is a delta or difference from some other value. That's where the little 'm' comes in on dBm. The 'm' in this case is 1 milliwatt and it equals 0 dBm. so the 'm' sets the reference point of the delta. Positive numbers are values above 1 milliwatt and negative numbers are values BELOW 1 milliwatt. So then we can start looking at something recogniziable. 0dBm = 1 milliwatt 0.001 watt 30dBm = 1 watt 33dBm = 2 watts 36dBm = 4 watts 39dBm = 8 watts 42dBm = 16 watts 50dBm=100 watts 60dBm = 1000 watts Couple things to see here. A change of 3dB is double / half the original power. 10dB adds or removes a zero from the value and 30dB of change is 1000 times or 3 zeros So for every 10 dB of change, you add or subtract a zero or move the decimal place up or down. Now we have that established. We can get into receivers and receiver sensitivity. Most GMRS radios are going to hear down to -115 to -120dBm range. Now that's pretty wide, but that range covers from the crappiest radio to the best UHF receivers you will find. Then we get to the 12dB Sinad which is a 12dB signal to noise ratio receiver test. This is the intelligible signal (receive audio) being 12dB above the background noise in the sound coming out the speaker. Still has some noise but is fully understandable. This falls around -108 to -105. Then there is full quieting at -100 to -90. That is a dead silent signal where only the intelligence (spoken word) is heard in the receiver. These are in 10dB hops. Remember the 10 dB rule right. It's a signal level change factor of 10, one decimal place. Obviously smaller changes can be measured with test equipment. But your NOT going to HEAR a difference in the speaker with less change than the 10 dB hop. So NOW we get to SWR. And we start looking at signal change based on SWR or 1.5 , 1.75, 2, and 3. Anything over 3 is bad. And it's not really effecting the signal levels mean as much as it's creating a problem for the radio that's transmitting. All numbers are based on 100 watts transmit power. 1.50 : 1 SWR is 4 watts reflect and 96 watts radiated or a 0.1773dB difference from a 1 : 1 match 1.75 : 1 SWR is 6.7 watts reflect and 93 watts radiated or a 0.3152dB difference from a 1 : 1 match 2.00 : 1 SWR is 11 watts reflect and 89 watts radiated or a 0.5061dB difference from a 1 : 1 match 3.00 : 1 SWR is 25 watts reflect and 75 watts radiated or a 1.25dB difference from a 1 : 1 match SO... it takes a signal change of 10dB to HEAR it, and these changes are less than 1dB change until you get out in dangerous territory. So from a perfect match to a 2 : 1 match makes basically NO difference in the signal the other guy hears. These are the numbers. All this is on the web, and yes I use a calculator for it because math SUCKS. But it doesn't lie. But this is how I can sit down and figure out if you give me distance, antenna gain at both ends, cable loss at both ends and receive signal strength, I can tell you how much power you are running. There are some other things not mentioned like path loss that are taken into account (that's the distance portion) but it's all numbers once you have a good understanding of it.

The services that would be limited by FCC rule are the services that have height limits on antenna's. CB would be a good example. A CB antenna per the rules is limited to 50 feet AGL. So you couldn't use CB radios in an aircraft. Commercial radio under Part 90 would be another since at least repeater antenna's are both power and height limited per the issued license. GMRS really has no AGL restriction. The only thing in the rules regarding height is that if a mounting structure (tower) is over 200 feet that it be registered as an obstruction and properly lit within the guidelines of the FAA regulations for it's height. Ham radio is the same way. They aren't really height limited, they just need to follow the 'hazard to navigation' regulations that the FAA has for towers exceeding 200 feet in most area's and whatever regulation is imposed in area's around airports where there are additional restrictions.

An 'In the weeds" explanation of a trunked radio system, at least the MSI P25 version. The way this all works, at least at 700/800 Mhz, is every frequency is assigned by the FCC a channel number. These channel numbers are set in steps of a specific channel spacing and start frequency. With VHF it's not that way, VHF requires the channels to be programmed into the radio with TX and RX frequencies and the channel number is assigned by that programming. So as mentioned there is a 'control channel' that is effectively a data channel. All radios use this to connect to the system. When a radio is turned on it finds the control channel of the closest site and then announces it's presence. The system will acknowledge that radio and do one of three things. It will OK the radio to be on the system, it will deny access or it will if told to by the system admin send a stun / kill command to that radio and disable the radio. If the radio is allowed on the system, that system will process the radios request for access to a specific talkgroup. The radio talkgroup is remembered by the system and the site it's connected to. When that talk group becomse active the control channel will tell the radio to go to the specific assigned channel for the traffic and begin listening. It will pick the channel in b ased on a couple things. First is the standard round robin assignment. The next available channel on the site is used. But certain channels can be set to NOT use that talk group, so it can skip certain channels. It can also use lowest channel TX time to equalize the TX loading on each channel based on total time of transmit for each channel at a site. Now, since you didn't mention that you had to reprogram your scanner, your not hearing different conversations on a specific channel that was only for police previously, or any of the other stuff. I am gonna say that you are probably NOT listening to a trunked radio system. Back to the programming and channel assignment. When you setup your scanner, if it's 700/800, you will only need to put in the control channels and the stepping information. The scanner will know what frequencies are assigned to what channel numbers with that information. If they used VHF or UHF frequencies, you may / will need to program all used frequencies manually. Refer to Radio Reference for programming information on your specific system for more information

You are STILL not going to be able to have them on the same frequency if they are linked. In order to do that, they need to be run by simulcast controllers. They need a GPS referenced timing standard and frequency standard. There is a lot more to it than just linking them together. And I promise you adding height to your tower will be cheaper. Not to mention that they will need a stable connection between them. THe Internet ain't gonna do it, you will need s Microwave shot between them so there isn't the changes in latency (link delay) that is present in Internet linking.

OH,, PA's are FUN. Driving past the football team and yelling out " RUN FOREST RUN" in a really goofy way. Rolling up on a deer in the road and barking at it. They fall on their ass while pooping all over the place. "Driver, put down the phone and drive your vehicle" in some sort of official sounding voice can get the phone tossed in the back seat, hands at 10 and 2 and the guy or gal looking around for the cop car. I skipped the CB PA setup and went right to the 100 watt siren for a cop car / fire truck. The air horn function also works very well to get peoples attention. Siren function was disabled, but the radio pass through was also handy for sort of what the OP was talking about. Far as his situation. The 4 watt amplifier in a CB radio driving a single speaker isn't going to put out much audio over a wide area. Find a few tripods, get some horn speakers attached to those tripods and find a 70 volt professional audio amp to drive them. Speaker horns should be 70 volt as well. Then plug a mike into it and run some wires. That would be your best bet. A single point PA speaker to cover a wide area doesn't work for two reasons. First is that the level of sound in close would be too high if you wanted it to carry very far. Second is tied to the first, you don't have control over the surrounding noise, so it would need to be really loud to overcome the baseline noise. Spread out speakers that are not crazy loud will get you heard without scaring the deaf and dead.

Yeah, hams are fun when they end up with commercial radios. It is technically legal to program ham stuff in a Part 90 radio since they can basically use anything for a radio that will work on the frequency band they are allocated. For a long time they wouldn't program anything ham into radios at my shop. Then they figured they would have me do it since I was a ham. I wrote a 1 page agreement and instruction sheet for getting a commercial radio programmed with ham stuff. It basically stated that the owner was required to provide a spreadsheet with the column's that were laid out for TX and RX frequencies, TX and RX PL/DPL tones, channel alias, a column for channels in the scan list for the zone, high and low power and a couple other things. Then if they wanted anything commercial with transmit, they would need an MOU on letterhead from the person listed on the license or a chief or high ranking official with the agency or department that owned the frequency. The MOU's and the channel lineup would be kept on file and if a programming discrepancy was noticed that the sheet would be checked against what was in the radio. If it matched what was provided, they would need to pay to get it changed. We weren't going to be researching PL /DPL, TX frequencies or any of that. What was on the sheet was going in the radio. IF the sheet was wrong, the radio would be wrong. It set a price for a single zone with 16 to 20 channels. If multiple zones were requested, and it explained how to create the spreadsheet for that, it would be done on an hourly rate with one hour minimum. Which was at that time 130 an hour. I had a copy of it laminated and put at the front desk for the greeter / customer service person to have them read when they came through the door. It also had the contact info for the state agency that was in control of the state radio system and that they would need to get a radio ID from them and an MOU for the talkgroups they wanted if they were requesting access to the state wide trunked system. I already knew that they wouldn't issue ID's to private citizens directly and that some agency that was on the system would need to sponsor them to have a radio on the system, so that wasn't gonna happen. But when you establish a policy, and put price tags to it. It stops them cold. Oh, and we charged $500 for codeplug creation for a state wide system subscriber. Which is what we charged everyone else. Most of them would leave in a huff, a few would do it, and we were happy to have their money and their understanding of what they were going to get for it. I finally decided we weren't going to do anything with the ham DMR stuff or it would be strictly hourly rate to program with a 2 hour minimum. Because DMR on commercial radios when they want a bunch of group calls and crap takes a LOT of time to create. And the codeplug was a one off. What one guy wanted in his radio wasn't going to be in 100 radios, just his. The next guy would want different stuff in different places and it was all a big PITA so they were going to pay for it. And we didn't and don't program ham radios, if it didn't say Motorola on it, we weren't touching it.

I don't disagree, but I'm not sure where the lies and misinformation statement comes from. There are regulations on the books that restrict the stuff we are talking about. The FCC choosing to ignore the enforcement of those rules doesn't void them. And there are things that many of us do that violate those rules. The big one is running channels 14-22 wither wide band of in a radio that will not turn down to the legal power level. Then there are the guys with high power XTL's and such that don't turn their power down, running 100 watts on GMRS, either simplex or through a repeater. Hell, I will admit to the fact my one GMRS repeater is putting 75 watts out the back of it. Mind you it's going into a high loss transmit combiner, and that 75 in results in 18 out the other side. But it matches the receive very well at that level so I don't talk out farther than I can hear with mobile coverage. Portables can hear it farther than they can talk back to it, but that's a 10dB difference in power output causing that. And since it says NO LINKING I can't even add receive sites to equalize the portable coverage at this point. And again to your statement, who would know or care if I put up satellite receivers that were linked and voted back to the transmitter. The point is there are rules. You should at least TRY to follow them. Even if others don't.

No strawman to it. It might NOT have been what you were referring to, but I can promise you that even today with statewide 700/800 radio systems the ARES guys STILL 100% believe that they should have access to that system and every analog public safety repeater on the air. And it's not just the ARES crowd. The number of average hams that 100% believe that little blurb in part 97 about 'any means at your disposal' means talking to the Po Po is completely acceptable and expected. I had this discussion with a couple hams about 10 years ago. They were adamant that was what it meant. I had to talk to the FCC on business related stuff and ask them as a side question about it and that is exactly what they said. Ham operators can use any HAM frequency in the ham allocation during an emergency. But that was it. They went further to state that modifying a Part 97 (ham) radio was against the rules and at no time should a part 97 radio be used on part 90 frequencies. They also said that even if they were using commercial part 90 radios, that without prior authorization being issued that they would be in violation. They emailed me all of this and I actually printed it out and had it laminated and would stuff it in the face of the hams that were convinced they were authorized by the regulation to talk to the public safety dispatchers on their channels, from their personal radios, if there was an emergency. I run into this about once a month. Someone will bring a radio into the shop they want loaded with public safety frequencies they got from radio reference. Half of the stuff isn't even on the air any more. Hell, some of it I pulled from service. We just tell them that they need letters from the fire chief / sheriff / someone on letterhead with an MOU and we will be happy to program them in. Without the MOU in hand they get nothing.

Here we go with the 'I need to mod my radio so I can talk to the Po Po, just in case." This has been asked and answered many times. That rule means that you as a Novice ham operator can get on the Extra class frequencies if you hear someone there and ask for assistance in the event of an emergency. Hammies think it means they need to MARS mod every radio they have so they can talk to public safety dispatchers. And that's not it. YOU ARE NOT SUPPOSE TO HAVE A RADIO WITH PUBLIC SAFETY CHANNELS IN IT. So regardless of any means, you aren't suppose to posses those means to begin with. Ham radios are NOT Part 90 and are NOT to be modified except for MARS operation. Again, I am agreeing with Randy here. And still can't believe it. What is Joe hammie gonna do when he tracks down that evil deplorable wanna be that's operating on their beloved local hammie repeater? Are they gonna march up to their door and beat on it with their ARES badge and bandoleer of radios so they look like a dork version of Poncho Via? Are they gonna wear their ARES yellow vest and puff out their chest and with all that fake authority tell them to stop doing it? Or are they gonna really take it too far. Pull the guy out of his house and beat the hell out of him on his front lawn? Then find out it was his neighbor doing it as he's sitting in jail for felonious assault? Maybe he will send him an real official looking letter with the ARRL logo and even his local club logo demanding they cease and desist. Cause the FCC ain't gonna do much unless it's pervasive and they get LOTS of complaints

In this sort of application, there is something to be said for commercial radios. It was mentioned 'did I just bump the channel knob' and that's a thing if you have one. Personally I would be looking at a CDM750 for this specific application and dealing with the 4 total channels that can be programmed in it. I realize that as you travel track to track and races to race that others might be on the same channel and you might need to move. But 4 channels should actually be enough to have something usable for the event. Of course the high dollar race teams all have a licensed frequency, so they don't tend to have issues with others interfering with their comms. The other thing with a CDM750 or similar radio is the quality of construction. Race cars are not luxury sports sedans with leather and adjustable 'comfort systems'. They beat you and vibrate and generally are a rough ride. I remember the difference in my Camaro just building in the cage and tying the subframes (unibody 2nd gen). Even with the mostly stock suspension system the car suddenly rode more like a log wagon and less like a pony car. And the solid motor mounts didn't help much either. CDM750's are dirt cheap since they are only 4 channels. No one wants them, they all want the CDM1250s and 1550s. I would be interested to hear how that radio holds up in a purpose built race car over time.

Does the radio work on other repeaters? That is as good as a watt meter for testing if the repeaters are similar distances away or the one that does work is farther.