WRKC935

Update to your request. I am ACTIVELY working on getting a shell script together that will run on an instance of Debian with ASL loaded on it to convert it to the mygmrs system and get the web management and all the rest working. Once this is done, it will be a simple as loading Debian, then loading ASL and copying the script to the machine and executing the script. I will have detailed instructions for doing this. Now there will still be some other configuration that you would need to complete. Things like setting the correct drivers to be loaded for the repeater / radio interface would need to be figured out by you. But I will say this is all based on AllStarLink that Hams have been using for years. There is a TON of online information on getting ASL setup and running, but there of course are several things that need to be done to make it work with GMRS.

Well, there are two types of interference. The first being interference FROM the vehicle / device / whatever that would interfere with the operation of a radio in close proximity to the device. This would typically be noise generated from the device / vehicle that would either show up in the receive of the radio or in come cases show up on the transmitted audio of the radio being used. Second type is the radio transmissions getting into the electronics of the device / vehicle and causing erratic operation or even damage to the electronic control systems of the device. Both are a possibility, but only one can possibly be harmful or expensive to deal with. That of course being the device reacting to the RF field generated by the radio. At handheld power levels, this is going to be very rare as the electronics on something like a mobility scooter would need to be tested for certain levels of RF exposure to be allowed to be sold as having those issues when going past a police car, fire truck, semi truck with a legal radio system or even a radio station could NOT put the user in danger of the loss of control of the scooter. The type of modulation used in the radio transmission can also effect the reaction of the equipment in question. FM signals typically present the lowest probability of causing issues due to the nature of the continuous signal level during a transmission. Other modes of transmission like DMR, CW, SSB and possibly AM could have effects on sensitive equipment that FM wouldn't bother. There is a LOT to all this, but I will say that since a mobility scooter is a 'medical device' the testing requirements on it are typically going to be rather high. A kids power scooter / E-bike / whatever may or may not have the same level of ability to deal with RF being near it.

Yes, I am running a Pi. Yes, there are 'pinch points' with doing so, and there are additional pinch points depending on the audio interface that you choose to use. Your best option, unless you are a heavy Linux user and have a very strong understanding of AllStarLink / HamVoIP then you are FAR better off to just use the image provided here on the forum and run that image on a Raspberry Pi. Will the software run on another platform? Short answer is yes. But you need to know the modifications for taking the ASL software and getting it talking to the right servers. And I will tell you this now. There is ZERO support for doing it from members and administration of this board / forum. NONE. There are a few of us that have attempted it and failed, and a few more than are doing it that don't talk about it. So either you are gonna KNOW how to do it, and make it happen or you are going to pull your hair out trying. And just because the image for a Pi is available that it's all just gonna load and run. I can tell you from experience in the last week that's NOT the case. I just reloaded the image on a Pi for the third or fourth time tonight attempting to get it running correctly. MODIFICATIONS First mod to the Pi image is putting in your node number and password into the correct places in the files on the image. These are the rpt.conf file and the iax.conf file. And for some reason I can't figure out the image is not pulling the updated rpt_extnodes_gmrs file from the main servers. Now this file is the list of all the nodes that is used as a sort of DNS 'hosts' file and a list of available nodes you can connect to. So that file does two things. BOTH are extremely important for getting things to work. If you don't have that file, and it's not updating every 10 minutes, then the software doesn't have any info on what nodes are out there for you to connect to. Second issue is the port configuration in your firewall. This too is sort of important if you are going to use the website to manage your node. It is where you can go and easily connect your node to the other nodes. Then there is the configuration of the audio interface for connecting your repeater to the software so you can actually get your repeater connected. This is another issue I am fighting. If you get the little repeater that is on the webstore, and the interface for it, and buy the image written to the memory card, then it's all configured for you. If you go any other route, you are on your own to figure it out. And while I did get the CM108 interface working correctly on the Pi, I had to refer to other documentation from teh ham radio world in order to get that going. And keep in mind that I am a professional commercial radio tech and have been for about 15 years. Prior to that I was in IT for 14 years and I fought the thing getting it up and running. So, if you don't know Linux and don't have experience with ASL / HAMVoIP it's going to be a serious learning curve unless you can find someone that is versed in these things.

YOu are going to want to put an antenna as high as possible for best performance. Since you have an HOA and I am going to assume that you have approached them for a variance on their by-laws and failed, the next and most reasonable option is an antenna inside the attic space. This will work reasonably well if you don't have a metal roof. Obviously a metal roof will significantly limit your ability to get RF through it. Another option is a small dish for TV. But be warned that you will need to research the federal regulations allowing for a small dish or off air antenna for folks that are in an HOA and their by-laws 'limit' that. Due to it being a path for emergency communications, the FCC has mandated small dish and off air antenna's be allowed in all instances. But you are going to need to get copies of those federal regulations in hand and present them to the HOA for review before doing anything else. They will no doubt what to verify it before making a ruling. And depending on the caliber of people running your HOA, they may or may NOT take well to being forced by anyone including the federal government to grant a variance. At the point you basically role up the rules like a newspaper and slap them in the face with it. They WILL crawl up your hind parts and file for a new address in there. They will watch you like a hawk, making sure to enforce EVERY other regulation and by-law they have on the books. And of course fine you as often as is possible until you sell out and move. But it's an option, so I figured I would mention it. After all the HOA isn't going to know what antenna is for what. But, first option is filing for a variance with them and seeing if you can put up something on an eve of the roof on a small mount.

But with regard to the bright lights from the gas station on the hill. If that lighting is creating a hazard to motorists, then you are looking at your state DOT or possibly NTSB for regulation and enforcement traffic issues.

Not even certain if you are actually asking if the FCC has enforcement over visible light, or if they can enforce a non-licensed RF user. It's all sort of gray here. Far as record of them going after non-licensed operators using RF spectrum, yep, they are called pirate radio station operators. They come up from time to time in the FM and AM broadcast band. The FCC does go after them, there is a history of this, and it continues to be the case. Now, specifically, lasers and aircraft. I think you have the wrong agency. I would be looking for the FAA not the FCC to be involved here. It's a danger to flight operations. You mentioned a tower or something that is generating output in the 400 to 700nm range. Well that's the 'visible light' spectrum. What sort of radiation is present? Is it a danger to flight operations? Is there a standing NOTAM for this area? Outdoor concert venue's are sometimes marked as no-fly zones at night due to visible light lasers being used during a performance. And there are other instances where they can't use lasers in outdoor venues, or they have a combination of NOTAM's and regulation for the maximum angle the lasers can be with regard to the horizon. Again, nothing to do with the FCC. All that is done through the FAA. There is a bit of crossover with the FCC and the FAA however. And that comes from tower obstruction lighting. The FAA sets the requirements for when a tower is required to be lit. First regulation is a structure above 199 feet in height. There are a very few instances where this requirement is waved, like being in the presence of other towers that are lit and taller than your structure, but for the vast majority, if you are 200 foot or higher, you have lights. There are pages of additional regulations involving obstruction lighting, but since this mostly effects radio towers, the FCC is the registration arm for those regulations. They issue the ASR numbers for the towers. So, if you could explain your issue, link to something posted you read about or give a better explanation of what it is you are talking about, that would help to figure out what's going on here.

as long as it works it's a good setup

Nevermind Couldn't delete

The easier way, depending on your repeater is to directly use batteries to power the repeater. Most repeaters are going to have a 12 or 24 volt power supply and many of them have a specific battery input for backup power. Since I don't know what specific repeater you are running, I can't give a specific answer to this. With a high power (100 watt) MTR2000 the power input is 24 volts and it's a connector right on the back of the repeater. It does require an external battery charger to keep the batteries up, typically these are an ARGUS charger. The low power (25 watt) version of the MTR is 12 volts, also requires an ARGUS charger for 12 volt power. If you have either of those I have chargers and power cords for them. Many kenwood repeaters have a battery hookup that will charge the backup batteries. Refer to the manual for your model. For those units that have neither, there is still hope. There are external modules that connect to a power supply, an battery and the load or repeater. These modules will power the repeater off the power supply and also allow the power supply to charge the batteries. When a power failure happens the load side just reverts to the input with power available, so there is no 'switchover' the unit just keeps going until power returns or the battery voltage drops below a certain value and then the unit drops the load to protect the batteries from being discharged too far. Yes, that's a thing. I have worked with this stuff a LOT. To the point my 5 ham and GMRS repeaters, the network routers and switches, and microwave links I use for Internet connectivity are all running off a large bank of batteries and NOT directly off 110 utility power. The utility comes into the battery charger that in these types of systems is called a rectifier. It powers the 48 volt distribution system and charges the batteries. This rectifier is rated for 260 amps. The batteries consist of 4 parallel strings of 105 amp hour 12 volt AGM batteries. The 48 volt power comes out of the distribution panels and goes to the equipment that requires 48 volts for operation. It also feeds a 48 volt to 24 volt converter that runs to a distribution panel and out to the repeaters and other 24 volt equipment. I am currently working on a 48 volt to 12 volt converter and distribution panel to replace the 75 amp supply and string of six 75 amp hour batteries that power the 12 volt equipment and base radios. I can currently go over 24 hours on battery before I need to get the generator going. But of course it's on a transfer switch and auto starts as soon as the power fails. SO I don't go to battery, except during the transition from utility to generator. I will then fail to battery once the generator fuel supply is expended. So I can go with no power for 72 hours before I need to fuel the generator. It's diesel and I have 8 cans sitting to go get fuel if I need to.

Well if you are looking to 'do your own thing' I will say this. It's not as hard as you might think, but there is some knowledge required. Since no one wants to reinvent the wheel so to speak, it's really going to be easier to use what others have done and adapt it to your own use. All that is being done with mygmrs and gmrslive linking is a 'rebranding' and repurposing of something called All Star Link or HAMVoIP. The basis of that entire system is a open source IP PBX called Asterisk. This is a office type phone system that someone wrote to replace his ageing PBX in his office and then decided to put the source code out in the open for others to use. Another gentleman wrote the 'rpt' part add on for Asterisk that created a manner to connect radios and repeaters into the PBX in what could be defined as a conference call. So when you link two repeaters or radio's together, it's like two phones, with one calling the other. THere is a bit more to it but that's the really basic way it can be described. When you connect a number of radios and repeaters together it's treated as a conference call at that point. The limitation is the amount of bandwidth available for the traffic being shipped from place to place and the processing power of the computer it's running on to process and ship the audio and telemetry (PTT and COR) from site to site to site. Now that's established. ASL or All Star Link is open source. You can go download the servers, hubs and all the manuals and set about modifying it to do what YOU want it to do. There are a couple things that you need to know. First is that the typical downloads are setup for non-computer people to use. So they are preconfigured for the databases of the HAM nodes out there and the info for them to connect together. All that needs to be removed or modified to make it work in YOUR specific application. And although there is no specific requirement for Internet access, linking sites together must be done with IP for this to work. Now you can use microwave links between towers that have LOS or Line Of Site between them and forego the Internet all together. But that might not be what you are desiring to do. But it's going to require someone with significant ASL and Asterisk experience to get this all going. It's not a plug and play solution. USING ANOTHER SYSTEM There is the possibility of using a preexisting system to do the linking where you just create nodes on the system for each repeater and then connect the nodes together. You do NOT want to create loops while doing this. So the easiest way is select one node to be the 'hub' and connect all your other repeaters to that node. Then you are allowing others to do the 'heavy lifting' on the back end so to speak and riding their system. SO this is a possibility. Now, I will say this. There is a way to go into the rpt config files and ONLY allow certain nodes to connect to your node. So it you want to like 5 repeaters together, with node numbers of 1 thru 5 and node 3 is the 'hub' you set repeaters 1,2,4 and 5 to only allow connection from node 3 and node 3 you limit to the other 4 node ID's. Then if I get to playing around with my node that's numbered 10 and I attempt to connect, I will get rejected because I am not in your allowed node list. By default, most systems update their node lists every 10 minutes, so that would need turned off or a different node list would need created that was static (not updated) and the rpt.conf file location would need modified to point to that list and and not the master list for the system. And there are other ways to go about that as well. If' it's a few repeaters, you can just set the system up to not connect to anything and then go back and individually allow the specific nodes you want in to have access. So there are a couple options that are out there and are NOT crazy expensive. If you want to look at third party hardware, I would advise you to look at the nx2-u units from JPS. I THINK that those can be configured for point to multipoint connectivity. which would fit into what you are talking about for a small system but those ain't cheap.

Motorola does have RAC for analog, but it's can be scanned. A better option is to spend the money and get a part 90 license then you have better options. First is you can run DMR (MOTOTRBO) and run a digital RAC and run basic encryption. It would also allow you TWO talk paths on the same frequency. Something that's no possible with analog radio. And the other thing with a part 90 commercial license is if others come in, outside of your family unit, they can use the license under your authority. You can 't grant a non-family member access if they don't have a GMRS license.. so day workers and laborers that are not family can't use the radios. The basic encryption will also keep your radio traffic semi-private. The 6 digit numeric RAC code will keep all but the most determined off the repeater. And it really sounds like it would be a better option for your specific application. The issue is that you are so limited with analog radio. And there is a greater limitation with the lack of encryption due to the regulations of GMRS. I know that someone brought up using a trunking controller that would look at radio ID's to grant or deny access to the system, but there again, I don't know the regulations specifically for GMRS would allow that. Would it work, sort of, until someone with a scanner that could display the LTR data was used to pick apart the information and then it's going to be screwed with if you are really expecting issues with others trying to gain access. I wouldn't typically go to these length's but you seem adamant in you post about it to the point you foresee issues before you even have equipment on the air. And in truth, if you haven't bought any equipment for this yet, now is the time to look at other options that better match your listed requirements. Personally, I am a P25 and AES encryption guy all the way. That will always work and NO ONE gets to listen in. But none of that fits within the rules governing GMRS.

I am thinking that the national HUB's are just what's established. That being said. For a statewide hub, or group hub, you have a couple options. First is to just use one of your NODES as the 'hub'. Link all the other repeaters in the group to that NODE and run it that way. Second option is to build out a Pi without the audio interface and attached repeater. You will need to register it as a repeater on the site and then assign it a node number once it's created. This could also act as a NODE, but I will warn you that you will get people requesting access to it thinking it's a repeater. I took mine 'down' off the site becasue of that. I kept getting requests for access since it displays as a repeater. People will not bother to read the listing first and verify what they are requesting access to. Now, if you are a Linux guru and a ASL guru, you can in theory download the image, and load it up on a Pi and then look at the changes to ASL and see what's been done to it and mimic those changes on a Debian instance with ASL loaded on it in a x64 platform. I have had no luck with that but I am not even versed on either Linux or ASL. So your mileage may vary. If you are knowledgeable on both, and get it working I would LOVE to know what the steps are to making that happen.

Going back to the idea of GMRS for communications. If you are looking to map coverage of a repeater in the area, try RadioMobile. Just google it. That will generate coverage maps. Be sure to use LOW GAIN repeater antenna's if there is a lot of up and down or you are placing the antenna significantly higher than any part of your expected coverage area. High gain antenna's will cause issues when close into the repeater if it's a lot higher in elevation. If you are looking for this to be a solution when cell is down, you need to consider why cell service would be down. Cell towers require a couple things to operate. First is power. If the cell sites have no power, will your repeater. If not, it's is not going to work unless you power it off some other source, or have a backup source when the power is out. Second is connectivity to the outside world. Cell sites can't communicate with the phones if they have no connectivity to the outside world. Think of it like an Internet outage. A repeater in local service would NOT be effected by an Internet outage, but a linked repeater or repeaters will have issue if they are reliant on Internet connectivity to link between the different sites. Now the HAM and NVIS stuff is all great for base to base communications. But that is HF frequencies. You are NOT going to build an NVIS antenna for GMRS and have it work. The problem is that the UHF frequencies will NOT bounce off the Ionosphere. They will just go right past it and out into space. So NVIS doesn't work for GMRS.

Does anyone have a VMWARE instance of the ASL mygmrs linking software up and running? If so would you be willing to share it? I am working on configuring a State level HUB for Ohio. Have an ID and all that, I just need to get the Raspberry Pi software off the ARM platform and on to an X64 platform so it's easier to manage and run. And I would rather save my Raspberry Pi's for repeaters, which this isn't going to be, at least I hope not.

I am wondering how you would seal with receiver at the subscriber level. If you put a transmitter on the air in the same band as another radio in receive with 30 feet of each other, the transmitter will overload the receive of the other radio and it goes deaf. GMRS isn't just in the same band, the whole thing is only 175 Khz wide for the repeater channels. There isn't a UHF duplexer made that will deal with that sort of spacing. So how would you even think that it was possible? Full duplex can't exist at those tight channel spacing. Just not reasonable to build the filtering for it. Cell and other technologies had Megahertz of channel spacing available to pull it off. The analog 800 band is 45 Mhz. The 700 band is 30Mhz, and the 902 ISM band is 27Mhz for ham and I believe it's more for the commercial users. It's simply not possible to do on GMRS.

Yes, but I don't believe that you have an ERP limitation on 15-22 that you are required to meet. That being said, it's always a 'best practice' regardless of regulation to only use the minimum amount of power needed to establish a solid communications path with the other party. Using power levels beyond that can cause interference for other users of the service. But there is no specific regulation stating that requirement.

There is just SO much wrong with this. Gonna go full on with the math here so it makes sense. And this is gonna be based on that if the antenna in question has 11dB of forward gain that it has an 11dB null off some part of the pattern, most likely the back side off the corners. Second assumption is the repeaters in question are running full legal limit power of 50 watts minus a standard combined loss of 3 dB for feedline and duplexer losses and a 6dB gain antenna. So conversion of 50 watts is 47.0 dBm for ease of the math. Real conversion of 50 watts is 46.9897dBm so I rounded up to save time. Mind you that a 3dB change is a doubling or halfing of power. So, 47 dBm minus 3dB is of course 44dBm OR 25.11 watts. Getting that out of the way. So we have a 44dBm signal going into a repeater antenna with 6dB of gain. So that's 50dBm or 100 watt's ERP if you want to go that route. ERP is Effective Radiated Power. Look it up for a better explanation. Now we need to consider path loss. Path loss is the amount of signal drop between the two antenna's ( repeater transmitting antenna, and your receiving antenna). The path loss calculator used for these calculations. https://www.pasternack.com/t-calculator-fspl.aspx?utm_campaign=Power_Combiners&keyword=&gad_source=1&gclid=Cj0KCQiAkKqsBhC3ARIsAEEjuJj7ApOIs_PMeM7_yH6hraxqwaoC9i42tDkgTTaSKcF2Q5qN0GSO0coaAtBGEALw_wcB Path loss on a 9 mile path for 462.550Mhz is 109dB. So we take 50dBm and subtract 109dB which leaves up with -59dBm. Your receiver will open with a tight squelch setting at about -110 to -105dBm signal level. So lets add the null to the -59dBm signal level and we get -70dBm. This is when the signal null is the greatest when the antenna null is turned to face the transmitted signal. So your radio will open up at -110 to -105dBm and you have a signal level of -70 dBm at the antenna. Even with another 3dB of signal loss in your coax feeding the receiver, you STILL have a -73dBm signal level hitting your receiver. To put into contrast the difference between -103 and -73 dBm which is 30dB of course. If you have a 1 watt transmitter, and you amplify the 1 watt by 30dB, you now have 1000 watts. It's THAT BIG of a change in signal level. And your receiver is hearing that much more signal than it needs to in order to open the squelch up and hear the signal. So, is your yagi defective? I am gonna say NO. And this is the math that proves it's working. If you ever worndered how the FCC can sit in your neighborhood and gell how much power your CB radio is putting out without needing to walk in and test it with a watt meter, these equations are it. You measure signal level off of a calibrated antenna into a signal level meter or spectrum analyzer and calculate it back. Your antenna of course is clearly visible above your house, and it's design will indicate a reasonable gain number to apply to the math to figure out just how much fire you are putting in the wire. And mind you, don't take my word for all this. There are two RF engineers on this board, One has posted in this thread. If he chooses to pipe up he can verify this math is correct and why you are hearing the signal off the side of your beam. And also verify that even if the repeater output was reduced to 1 watt, you would STILL hear it off the side of your beam. The math don't lie. I would ask him, if he reads this, that if it's the case, that he bump the answer over on the top left of the post here. It makes my numbers look a bit better. And I will continue to do that for him as well. Gonna toss this link in here too, gives a better explanation of a yagi and how it effects signal pattern for both receive and transmit.

While SOME might think that you need to bring your own group to the party so to speak, and chatting it up with other users isn't the thing to be doing, there are those of us that believe that's a lot of BS. While don't have near the number of repeaters that some do in Indiana or Illinois, I am growing the system in Ohio as I can. And our rules are pretty simple. Some ask that you gain permission for the use of their repeaters but grant to all comers, and then there are others like me that take the approach of it you have a license, by all means use it and I will speak to you if you are NOT using it correctly otherwise have at it and enjoy. Mind you that repeater system reaches across 4 states and covers most of Indiana, much of Illinois, and parts of Ohio. And we all work together to make sure it's available for all that are willing to use it and have a license to do so.

A lot of that is going to depend on the bonding more than the surge suppressor. As mentioned elsewhere, the BONDING is done for safety reasons and to keep all the equipment at the same voltage potential. So single point grounding of all equipment on the operator position is KEY in keeping the equipment running after a strike. If you have a strike hit any piece of the equipment , it should ALL jump to the same potential as the gear next to it. If that happens, you stand a better chance of it surviving. If one piece of gear jumps to 10KV and the rest stays at 0 volts, POOF. And you get a big fireworks show on your desk to boot. And one of the things that I had a hard time with when discussing grounding was how does a number 2 or number 6 wire really deal with a hit. It's tens of thousands of amps and millions of volts. But what was explained to me is there really is no way that you could pass that amount of current across a conductor that size for any length of time. But if the time was short enough, it would hold that sort of current. The other part was once you are in the structure, and the site has proper grounding, those smaller conductors are NOT exposed to those sorts of currents and voltages. If a single DC floating antenna takes a direct strike, the maximum voltage across the cable from center conductor to ground is the breakdown voltage of the cable. You can't put 100KV across two terminals that are 1 inch apart. The voltage will arc over and limit due to the arc, and that arc will short the rest of the voltage to ground. And that breakdown voltage is only present until the arc starts. Once an arc starts, it's no longer an open circuit. You have current flow and therefore a load against the potential. Welders will recognize this with simple stick welding. You have to fight to get the arc to establish. And a typical stick welder open circuit is about 60 to 80 volts. Once the arc is established, the welding voltage drops down to about 20 volts. And you can pull up several inches from the welded material and maintain the arc, still having a really low voltage present between the welding electrode and the material. Same thing with a coax cable on a tower that is hit. The center will arc over to the shield and the voltage gets limited between the shield and the center conductor. Of course the shield is grounded to the tower at the base of the antenna, where it transitions off the tower to the structure, at the entry point of the structure on the outside and then at the surge suppressor just inside the structure. At least that's the way it's done on commercial towers. In addition, it's grounded not less than every 100 feet coming down the tower. Back to the number 2 wire and the 100K amps and a gazillion volts. Lightning is swift. It's a LOT of power being dispersed very quickly. So the wire will heat up, but it's not an instantaneous thing. And since the duration of the voltage drop across the conductor (which is the actual voltage across the wire and NOT the total voltage present during the strike) is so quick, the relatively meager conductor size in actually ample to pass the voltage across it and into the ground. Now, something else that's NOT being considered. Since the cables are all grounded to the tower and everything else and all that is bonded together, the tower carry's a LOT of the power to ground via the metal structure and the metal in the concrete base of the tower. In other words, the single antenna cable of the antenna that gets hit, never really see's the entire blast of lightning, it's spread across a number of other conductors to ground.

Grounding bonding and the like are NOT to deal with a direct strike. The first and foremost reason to ground and bond is safety for the operator. And that is where the bonding part comes in. If you install a tower, toss a couple ground rods in the ground and connect them to the tower and do NOTHING else you create a bigger issue than if you just did nothing. And here's why. Your house, building or whatever has an electrical service connected to it. Part of the code for that service being connected is there is a safety ground. So that service has one or two ground rods connected to it (newer builds require 2 rods). You radios are plugged into that service and that ground. That ground is connected to the case of your radio and then the antenna is ALSO connected. That antenna is connected to the tower and the tower is grounded with a second set of ground rods. A ground strike that hits neither the tower or the electrical service will induce a pulse that will spread out across the ground as it disperses. Since the two different grounds are at different places, they are at different voltage potentials as the strike disperses in the ground. But you have connected them together with your radio being the fuse in the middle. So it goes poof. If the radio is NOT connected to the electrical ground, but is connected to the tower, but other equipment is sitting there on the desk that is connected to the electrical ground, then it will arc across from one device to the other, OR if the radio is connected to a computer or some other device that is on the electrical ground via data cables, then one device has a different voltage potential than the other across the data cable,,, again POOF. None of these are 'direct hits' They are all ground strikes that fry your gear due to lack of proper bonding between the different pieces of equipment connected to the different grounds. Specific to tower grounding. For a small tower for GMRS / HAM radio use, and NOT a big commercial tower, the reason for grounding the tower is NOT to deal with a direct hit, it's more to prevent the hit from coming at all. As we have all been told over and over. Lightning will take the path of least resistance. If you have an ungrounded tower, that tower can build a static charge on it with reference to ground. The tower is more conductive than the tree's around it, and it's now at a higher potential due to the static charge. That makes it the path of least resistance and therefore the most likely target for a strike. Anything connected to that tower is going to become part of the dispersion of that strike. So you ground it. Grounding the tower brings the entire tower back to the same voltage potential as the rest of the surrounding earth and therefor makes it no more of a target than anything else there because the grounding pulls the static charge off the tower, and in reality will not let it build up to begin with. Lightning suppressors. Lightning suppressors perform two different tasks when they are properly installed, and don't do anything if they are not installed correctly. They first and foremost need to be grounded. That ground needs to be right at the entry point where the cable enters the building. But the shield of the cable needs to be grounded on the outside of the building just before it enters the building as well. The surge suppression part of the device is to short down any voltage higher than the trigger voltage of the suppressor in use. This is typically about 100 volts. If any part of the tower is hit, every part of that tower and anything connected to it will have a voltage induced on it. That induced voltage will create a magnetic field (like a transformer) that will induce voltages on any other conductor near it including the center conductor of any coax on the tower. The suppression is to short that to the shield of the cable and then to the grounding system it's connected to. It's NOT to deal with a singular hit on a specific antenna on the tower. If that happens, the radio connected to that antenna will go POOF. BUT if the grounding is done correctly and the bonding is right, that will be the only radio damaged. If not, then the lightning will come down and tear up lots of stuff.

Try the Johnstown600 repeater if you have an elevated outdoor antenna. It's possible to make it but it's gonna be difficult.

I mention the rules thing for one reason only. If it's not brought to to the forefront in the initial discussion, then it will be discussed, debated, and pontificated by a number of folks that may or may NOT have a solid understanding of it and possibly convey partly or completely incorrect info that then needs corrected. This always seems to turn into a thing, threads get hijacked, dead horses beaten. It's just a thing that happens with online forums. Nothing new or exciting, just a continuance of the norm. Unless you are connecting your .5 watt radio to a 30dBi gain 20 foot dish and purposely creating interference for others I seriously doubt that the FCC is gonna come knocking. That being said. You mentioned both dBi and dBd gain numbers. Gonna give a quick explanation of each, because it's not common knowledge. dBi is gain over an isotropic radiator. This is the default 'paper' reference antenna that radiates RF in all directions at all angles equally. It's basically a free space radiator that has a sphere of RF eminating from it. I know that I used a lightbulb as an anology, and it's not quite correct since it can't radiate out the bottom of the lightbulb, but it's a good point of reference for most all other directions. dBd is gain over a dipole. Dipole is simple, and does exhibit gain over an Isotropic radiator since it's pattern doesn't include significant radiation off the ends of the antenna. That power has to go somewhere, so the increased radiation at certain angles give the antenna some amount of gain over the paper antenna in those directions. One of the other interesting things with antenna's an gain as opposed to amplifier gain which of course is an active component of the RF string is the amplifier is typically uni-directional with it's gain. Take a typical amplifier with a 10dB gain design. You put in 1 watt and 10 comes out. This will make you be heard farther than before. But it does nothing for your receive. Now, gain in an antenna doesn't so much 'boost' the receive signal. The signal is what ever it is at the antenna. Once again, we bring in the light source. The light isn't brighter for the directional antenna vs the onmi directional antenna. It's the same level. I am not going to bore you with math and what is referred to in the big antenna college text books as power density. I am gonna go back to the simple light source. So what a directional antenna does to increase your ability to 'hear' a signal is it darkens everything else out other than what it's pointed to. Take a flashlight outside at noon, you can see it at 100 yards. But you can't see a candle at the same distance. There is too much other light source (noise) to see the candle. But take the same candle out at midnight, and it can be clearly seen as a light source at the same distance. The directional antenna does this by ignoring the light (signal) from every other direction and only looking at the candle. A receive amplifier can't do that. It's going to amplify the signal some, but it's going to amplify all the other signals that we don't want as well.

Yeah, there have been 800Mhz radios that were produced with PL-259 connectors. Sure there is some loss. The N connector is a better option, but it's a situation where the performance difference isn't significant enough to matter in most real world situations. There are people that believe that little bit of loss is going to keep them from being able to communicate, or give them an edge on getting some rare DX contact in the case of the ham radio guys. But the truth is you would never notice. But I will say that installing PL259 connectors on RG-8 sized cables is a pain as opposed to an N connector. We use the Times Microwave LMR400 / LMR600 EZ connectors and that specific cable at work as a standard unless heliax is used, and the connectors go on quickly with the proper prep tool.

So there are some issues using a beam specifically with simplex operations. First issue is beamwidth of the antenna. Think of an onmi-diredctional antenna as a bare light bulb, the light comes out in all directions pretty much equally. Then we get into a short yagi of 3 or so elements. That's like having a flashlight. It's a directional beam of light that spreads out as the distance increases but is still very directional as compared to the bare light bulb. Now we get into the longer boom yagi's. And while 7 elements isn't really a big beam as opposed to some of the 30 element ones that ham's use for Satellite work, it's still significant forward gain. That's gonna be like a cheap red laser that up close is just a dot, but at a distance, the dot might be a foot or two across. You need to point that dot at the other person you are trying to communicate with and hold it on them throughout the communication as it progresses. And the more elements, the smaller that 'dot' is that you need to hold on the other party. Because once they are out of the dot, they are no longer able to communicate with you. Second issue is more of a regulation thing. While the repeater channels are NOT ERP regulated and any sort of antenna system can be employed for these simplex channels, some of the simplex channels are indeed ERP regulated and the ERP is a calculation of antenna gain and input power to the antenna. A 10 watt radio into a beam with 3dBi of gain is the same ERP as a 20 watt radio connected to an antenna with 0 dBi of gain (typically an omni-directional antenna). If you get into 6 or 9 dBi of gain, your .5 watt radio is no 2 watts, or 4 watts, when you are regulated to .5 watts of ERP and FRS is always regulated on ALL channels hence the reason an FRS radio has an antenna that can't be removed and connected to a different antenna.

BTW, I believe that the XTL and APX will address up to 4 heads. There is a way to set the head number on each head and they get daisy chained from head to head. The power would be a bigger issue at that point as I don't know I would want stand along power supplies running each head creating a ground loop on the data cable between the heads and the radio.