DONE

Not exactly.... It wasn't that he was complaining, it was that he REALLY got indignant when I blew it off and DIDN'T at first act like it was some huge deal and react accordingly. And It's my understanding that the group or whatever he is with was about to put up a repeater. Went and had a discussion with the property owner, and had everything sealed up. Then somewhere in the discussion the property owner dropped an F-bomb and they immediately decided they were NOT going to do anything there because he used a bad word. Now I am getting that third hand. But this dude was on a tear about the guy up north being drunk on the repeater and really felt I needed to do something about it. And since at first I wasn't, he seemed to get irritated with me because it came out of my repeater. He understood that it was a linked system and the guy getting wild was three states away. He didn't care.... I needed to react. So I did.... Scorched Earth. Which was WAY over reacting. But I was mad. I am ok with someone disagreeing with me. I am ok with him being offended by cussing drunks.... What I was actually mad at we HE decided I was wrong for not being really mad and offended that some guy in Wisconsin was drunk on a linked repeater system I have a node on. And when I told him I heard part of it, earlier in the evening, he was really indignant. I am good with someone having a different belief structure than I do. What I am NOT ok with is when they try to force their belief structure on me. Which is basically what happened here. I SHOULD have ask him if he got the guys call sign and then told him to contact the FCC about THAT guy. But I sometimes over react a bit. And pulled the plug out of pure irritation over his nonsense. On a side note. The repeaters are BOTH back on the air. Now, if I hear him on my repeaters again, I may well tell him he's not welcome to use them any more.... But I may not even bother with that. And regardless of how technically reliable a system is. If it's not YOUR system you shouldn't 100% rely on it. Because someone can decide to pull the plug.

Yeah, really... And I ended up moving from 625 to 600 because of it. I suppose I should have added that in there somewhere. He was there first but was so inactive, I had no idea. Easy enough to change frequencies. Bit of programming and a retune of the combiner port.

Now, what LScott and a couple others were talking about. RAC or repeater access code, which is a Motorola thing that sounds like MDC but isn't will control the access of a repeater if enabled. First thing you need to know about it, it's only a Motorola thing. So if you go down that road, only Motorola radios, WITH RAC ability will be able to access your repeater. I suppose you COULD setup a single channel LTR trunking system and use that to control access. But again, You are limiting access to a few radio types. Standard conventional radios will not run on LTR. So you would need to be very specific in the radios you choose to buy. My take is different. If I am putting up a GMRS repeater, it's gonna be open. I would rather pull the plug on it than need to go through dealing with all the crap of trying to put split PL's or RAC or any of that crap on it. If I need to talk on the radio to someone else and I need it to be that tightly controlled, I will get a commercial repeater pair and load up some encryption in my radios and disappear. Or just call them on the phone. It's just simpler. If you are so worried about unauthorized people getting on your GMRS repeater, turn the stupid thing off and find another way to communicate.

Oh,,, geeze. Long day. So first off. I couldn't give a rip about the guy in Wisconsin getting blasted and then talking on the repeater,,, even if it was MY local repeater. I am guessing he ruffled a few feathers. I didn't hear him on today before I pulled the plug, and my guess is that he got up this morning and remembered what he did and out of pure embarrassment stayed off the air. I believe there were a few comments made about him being blitzed as the night wore on. But again, don't care.... not my problem. Others may feel differently, but that's my stance. So what spun me into a rant filled tizzy. I had a user of all 3 of the repeaters at the site contact me on one of the OTHER repeaters, not the 600 that's linked. And he started in about the way the guy was drunk and using vulgarity (his words) on the repeater. I replied that I had heard part of it and was aware. I explained that it was a linked system and that I had little control over someone in the middle of the night, 3 states away acting the fool on the linked repeater system. This for some reason didn't seem to be the response he was expecting. Reading between the lines of what he was saying, he expected me to be equally offended and that it was totally unacceptable that someone acted that way and something needed to be done. But I wasn't doing it and that was unacceptable in his mind. So I reacted. I keyed the radio up, told him he was right, and further more, since he was obviously offended by the FREE REPEATERS that I provide to the community, and that I would just pull the plug and he would no longer be offended. Or if he was he wouldn't have me to complain to about it. Yes, to put it plainly, I was pissed that I was getting this passive aggressive holier than thou crap for someone I provide free GMRS repeater access to. So I reacted in the most polite and politically correct manner I could muster. I pulled the plug on two of the three repeaters. Ultimately, here's the real truth. People say and do things that are not acceptable at times. God knows I have, more than a bunch of times. Now I haven't done it on a repeater, I refrain from that out of respect for others. But I have more than a bunch of times went into a cuss word filled rant when something broke, didn't work as planned, got away from me and fell, fell on me, fell near me and was expensive, and a whole list of other reasons. That's the way SOME people are... and I accept that. Smack your thumb hard enough that the skin tears on the bottom side, not the side you hit, and try to refrain from letting the colorful adjectives come spewing forth. If you can do that, you are a better man than I. But people are people. If you choose to NOT partake of the booze ( i personally don't) then cool. If you choose to have a couple, that's fine. And there are instances that a few turns into a few more and you might start acting dumb. Again, human nature, and I ain't gonna judge. Ol boy decided I personally needed to be offended by the acts of another. And HE wanted to push HIS belief structure on ME. THAT ain't gonna happen.

So I ran, by accident, a repeater without a PL for a short time. The problem with that is when others have a machine on that frequency, even though they are running PL, they will bring up their machine and your machine since having NO PL will allow your repeater to be accessed with ANY PL because it's not monitoring for a specific one. This of course can generate hate and discontent when your repeater has a wide coverage footprint and it covers that guys footprint. He can't use his repeater because you are covering him up or at least are generating some amount of frequency noise and interference with his signal. So are you LEGALLY required to run a PL? It depends and not because there is a specific rule about running PL but instead the rules governing harmful interference with other users equipment. That right there, they're rules for. You can't interfere with other users on purpose. Not running a PL on a repeater when you KNOW there is another repeater on the frequency is purposeful, since you know how to minimize the interference.

I just finished a conversation on one of my repeaters about the antics of an operator on the system last night. Like I personally have any control over it. But then I realized I do have control of it. By yanking the cord out of the wall feeding power to the repeaters. At this point Johnstown675 and Johnstown600 (the linked repeater to midwest) are off. And may well be for good. So here's what NOT to do. When you are a GMRS user, and you are using someone else's repeater FOR FREE because they make a serious effort to provide and maintain equipment for you to use. Don't complain to them that someone 3 states away on a linked system was acting the fool, cussing and drunk on the repeater system. It's a REALLY good way to make them mad. For them to decide it's NOT worth the trouble to keep the equipment on the air and then decide to just pull the plug. For those of you in this area that were using the link and the 675. The jury is still out on what I am gonna do going forward. You have ONE person to thank for it being gone. And that's for you to figure out. But I ain't listening to people complain to me about the actions of another on a linked system. And if you happen to be the guy that complained.... CONGRATULATIONS!!!!!! You got the repeaters shut down. SO there will be no more bad words on the repeater, since there will be no repeater. RANT OFF>...

Hi George. Yes, it's a modified version of All-Star specifically for GMRS. The version of the software is a bit behind the current version of All-Star but it works well. Since you mentioned being familiar with All-Star you shouldn't have too many problems with setting it up, but I will tell you it's NOT exactly the same, and you do need to follow the directions pretty close. The system admin has posted copies of the image used on a Pi for getting it running. You will need to fill out a request for access elsewhere on this site to get that ball rolling. He will provide you with a node number and password to get on the system. Most of the nodes on this system are connected via the RTCM but I can tell you if you hold your mouth right and setup to correct voltage divider for the input of the interface, a CM108 can be made to work. But it certainly takes a bit of effort to get it done and the audio quality of a 1 dollar USB sound card doesn't stack up to the RTCM. My personal setup is an MTR2000 repeater (Johnstown600) with a CM108 interface and a Pi. I am considering switching the Pi out for a VM running on a server for handling the software. But I haven't pulled the trigger on that project yet. Good luck and if you run into problems get on here and ask. Those who are into this will no doubt be happy to assist.

Exactly. And all I was getting at was if you are speaking spanish because you want to then your legal. If you are doing it to obscure the message content then technically it's a problem. But there again, you do it all the time. So the only one that would know what the motivation was for speaking another language is you. And that gets into the whole 'no duty to self incriminate' so again you are covered. My other point was using MDC isn't encryption if it's not specifically being used to mask meaning. And simply sending a radio ID is certainly NOT masking anything.

Pertaining to the discussion of MDC being a form of 'encryption' It's really not. FCC specifies that it's illegal to modify the transmission 'to obscure the meaning of the communication' MDC doesn't obscure anything. And even being 'proprietary' doesn't hold water. I don't own a fusion radio or a DStar radio. So since I can't hear it, is it being specifically obscured so I can't hear it as a ham operator, and is it being done specifically so I CAN'T hear it? Of course the answer is no. And if you were to program up a GMRS radio with MDC status messages and broadcast them, are you obscuring the meaning? Not unless you specifically will NOT allow others to know what those status messages are. If you were to set up 16 status messages in MDC and then POST them here on the board, they aren't obscured. If you are only using MDC as unit ID's for your radios, nothing is being obscured, it's your radio ID. And MDC is limited to what it can send. It's not packet of another digital mode where you are shipping text messages with it. The status messages are assigned a specific number that is universal to the protocol. If STS16 is 'A$$CLOWN on repeater" then it's not obscured if posted. And it's universally STS16 message on the MDC protocol. Now I can' have STS16 as "I Love You' to be sent to my wife. It's still STS16. Of course if you have it as something else, then your radio will display something different. But again, I am using it to communicate with my wife and you are using it to warn others of shenanigans on the repeater. But they are BOTH STS16 in MDC. Now, if a number of us were to get on the repeater and start speaking Russian, is THAT 'encryption'. If we are doing it do others CAN'T understand what we are talking about, then yes, that's encryption, not because we are using the Russian language, but because we are SPECIFICALLY using it to obscure the meaning on purpose so others CAN'T understand the meaning of the communications. But if we have a Wednesday night net to keep our multi-lingual skills up to par and speak Russian for most all of the net then it's perfectly legal. It all goes back to intent. I honestly believe the only reason that we aren't allowed ANY form of encryption on ham specifically, even on WiFi links is the FCC doen't want to field the telephone calls about it from the old farts that would be raising hell about it because they can hear it on their old tube radios. I have no doubt that when VHF went to FM the old codgers were mad because their AM VHF radios wouldn't hear it. And it was gonna be the downfall of ham radio. Now I am not saying GMRS should be allowed P25 C4FM modulation and AES256 encryption. But DMR and building a nationwide network with IPSC (Ip site connect) would be nice, but also not really needed. So I really think it's about intent at the end of the day. But I will also say this about MDC. One of the features with MDC is Radio Stun. Which enables you to send a command to a radio with an MDC ID to basically turn it off. It's used commercially to disable rouge radios and stolen radios that pop up on the system. And it's pretty effective. Yes, you have to have a radio or console that will transmit that command, but that stuff IS out there in the wild.

Well, I specifically put a repeater up on 675 with a PL of 141.3 because that WAS at one time the designated traveler channel and traveler tone. The only other listed repeater in the area was the clown with the for profit business selling air time. So I figured it was the right thing to do. I honestly don't care if y'all decide it needs to be different, the repeater is on it air and I ain't changing it. And to sort of quote WROZ250. Why are we rehashing this AGAIN??? Dude saw a video on YouTube and decided that it needed to be discussed in it's own new thread after we generated how many pages of discussion on this topic? I'm sorry but I am all for requiring your first 5 posts to require being approved by a moderator and a rule in place saying that you have to search the site before posting a new topic. One of the boards I moderate has a back end that when you type a topic for a new post, there is an area that populates with similar topics right below it. And it will ask you if you want to post an already discussed topic. Moreover, if you DO post a topic that's already been beaten to death, it gets added to the other thread or deleted and you get a strike for posting it.

Yes, that is true. I suppose I should have clarified that and said it was partly to minimize interference with co-channel users. And what I was referring to were the typical FB2 licenses. I also deal with FB6 and FB8 and we even have a few 'market frequencies" that are fully exclusive use in our market. Problem with those is they were paging frequencies. Of course the ERP on those was silly high, I believe 1KW output. Oddly we have a couple on the mentioned tower site with the antennas at 700 feet. Our co-channel owner in Indiana still uses the 'input' frequency as a link freq for paging and in the spring tends to get into our receivers pretty good. And please don't get me started with the coordinators. We had 3 customers in a 10 mile radius with the same repeater pair and two of them were DMR licenses and of course just tore each other up. Swear those guys at times use a spinning wheel like the "Price is Right" to choose what they are gonna grant someone with zero effort to do actual coordination.

There are several reasons for side mounting. First is increased gain based on height. A taller antenna will talk farther. But unlike GMRS and HAM commercial radio operators are limited by their license on how far their equipment can be talked on from the tower. It's typically on the license as a radius in KM. Legally you can't operate at a distance further than your license allows. To limit that a properly designed system will only talk that far or only slightly more. Another reason for limiting coverage is system design. If you have a DMR system that has multiple sites, you want to limit how far each site talks so the subscribers will vote the sites and switch to the better site as it approaches it. If the system was installed by the old guard types that believe it needs to talk as far as possible, it will not work right. We have such a system that the 100 watt repeaters are turned down to 20 watts. Why 20, because they will not go any lower and it still talks farther than it can hear. Antenna is 675 feet AGL. Cable length is 780 feet and 7/8. Cable loss is 6 dB. Combiner output is 5 watts, and it's DB-420 antenna's. It can be heard forty miles away in some directions but it will only hear for 30 miles and less in some directions. Now that is as extreme as I have seen. But my crap talks and hears at 30 miles on a bad antenna with 6 watts forward and 3 watts reflected on the current antenna. Antenna height is 110 for transmit and 240 for receive. Vertical Real Estate (commercial tower space rental) is calculated by the foot, and by the load. The higher you are and the more you load the tower the more you pay. A tower also has a limited amount of wind loading that it can take. If you significantly exceed that rating bad stuff happens. So it's also a juggling act with the renter to figure out how high they NEED to be for the coverage they want without needing to pay for unneeded height. While we sit and discuss the cost of antenna and line, we typically don't consider the reoccurring cost of rent. We look at a DB-420 and 300 feet of line costing 3 to 5K installed with a side mount arm and wring our hands at the idea of that expense ONCE. When there is a 600 dollar difference PER MONTH for a higher or lower place on a tower, that 5K number seems mundane compared to the cost savings going lower on the tower if the coverage is adequate for the customers need.

Yes, 200 feet is a magic number. And it's not a huge deal to exceed 200 feet, depending on location, but you do need to have FAA approved obstruction lighting on it and it needs to be registered. We deal with that at the site and it's just a hoop to jump through. But if you are considering going that high you need to contact the FAA / FCC before beginning construction. They have to grant you permission to do it and they will need to do a location study to verify it's not too close to an airport or in a flight path.

Got the last of the racks cleared tonight. The last two are sitting at the door at the site to be taken outside and around back for storage. I ended up moving some stuff around as there was a request by the site owner to setup a specific rack for receivers (scanners). We have a 24 port receive multicoupler that was tested from 50Mhz to 1Ghz. It's got a small amount of attenuation below 100Mhz, but nothing bad, around -1dB. This will go in the top of the rack and allow up to 24 receivers within that frequency range to be connected. Which is a plus for me since I have a number of scanners that I feed into dual receive cards on the console system for monitoring of various things. With basically ALL public safety in my state being on one system (OHIO MARCS) I have to have multiple P25 trunking scanners running to follow stuff and segregate the different services (police and fire) and locations so things don't run together. I have 4 running currently and will be looking for one or two more at Dayton this year. There is very little left on VHF and UHF around here outside some commercial radio and ham / gmrs. The ham stuff is covered with either single channel radios dedicated to a specific repeater or frequency or a radio with 14 channels that are controlled via tone remote. My simplex VHF ham radio is an MTR with an antenna relay configured as a base station with 14 frequencies. Having that sort of option is nice.

I should have mentioned that I would be willing to act as NCO once I get stuff back up and running at the tower. And I may want to talk to someone about running a separate node that would be directly connected to my dispatch console and only used for CO duties.

Since this got pretty well hi-jacked pertaining to the R-Pi and the current cost and availability, I will throw this in. I am interested to see what may replace the Pi as the standard for the 'maker space' and other DIY development efforts. There are a number of SBC's (single board computers) filling that space that may be a bit more expensive, but in some cases are FAR more capable. And I have had mixed results with the Pi. For development and experimentation the Pi is a good platform. But for production gear, I prefer the Beagle Bone. Same numbers as the Pi performance wise, but they just seem to be more stable. And depending on how stable I want it, I am not above loading Buster (Debian Linux that the R-Pi OS is based on) on a VM instance and running it all in a VM container. Recovery with snapshots is very quick and you can do a recovery remotely, where a memory card failure at a remote site requires a trip there.

Split tones are pretty good indication of a CLOSED repeater. And of course some radios will not support the split tones. I would go with a single PL tone, and I would be looking hard at 141.3 which is the 'traveler tone'. But I would program up a radio and try bringing up any local repeaters with that configuration prior to reprogramming the repeater.

Yeah, we have that here in central and southern Ohio. He has a number of sites registered on here that I can promise he's not on. When I put him call in google to do a bit of research I found his commercial for profit business license. If you do a search in Ohio for repeaters and turn on the dead and old repeaters you will see the state littered with his 'dream system'. The one tower he has listed near me is a State of Ohio site. I have been in the site numerous times and even moved the gear out of the old structure and into the new building when they brought it in. No GMRS repeaters and have never been in the last 14 years. I truly believe that he sat down on AntennaSearch.com and found tower and then got on here and listed a bunch of repeaters that were never installed. Not sure what the guys deal is, and really don't care. I would LOVE for him to file against me with the FCC for interference though. Figure I will send them PDF's of his business license and his dream tower map and see what they think of someone trying to run a business selling GMRS access and having every pair supposedly tied up in half the state. But yes, I fully believe that if you are gonna tie up a pair with a 30 mile radius of coverage footprint, you need to allow ANYONE that has a license to use your gear. Now I will FULLY admit that I do have a 30 mile radius (60miles across) coverage footprint, and that's with a bad antenna and only running 6 watts up the transmit line. And I do have 3 pairs tied up, not just one. I am on 725 675 and 600. I was on 625, but I found that there were two repeaters in my footprint and I immediately moved off to 600. And if that one don't work out I will move again. But my stuff is open. And I encourage folks to use my gear. I don't want it to just sit there and ID once in a while and do nothing else. If I wanted that I would have put up ham repeaters. No one seems to use them any more. And in truth, I have one VHF ham repeater on the air and a UHF repeater waiting in the wings to be turned up once I have the rack swap complete at the site. And it's gonna be on the same antenna system as the GMRS repeaters so it's coverage will be decent.

Only if the guy with the bigger repeater is an a-hole. Because real men will accept that someone else was there first and chance frequency. Like the Johnstown625 repeater becoming the Johnstown 600 repeater. To the actual question. There isn't a coordinating body like there is for commercial and amateur radio. The individual repeater owners are expected to work together to coordinate their repeater pairs to minimize interference with other users. This can be difficult as there is no standing database that has ALL the GMRS repeaters in it. There are a number of them on here, and quite a few on RepeaterBook.com but neither database has everything. My advice is to listen with an outdoor antenna with a radio or scanner programmed with NO PL or DCS in it so you will hear ANY transmissions. If you find a busy repeater, then that's not the pair to be using. If you hear some traffic but it seems to be off in the distance it might work if you are going to setup a limited coverage system. But you are going to need a quiet frequency if you are putting up a repeater with a large coverage footprint. When putting up a big system, and there are no quite pairs, try locating the owner of one of the small systems and see if they are willing to forgo having a repeater and instead just use yours. And if you are putting up a large coverage repeater, make it OPEN for all users. You are 'consuming' a resource when you put up a repeater. That being one of the 8 pairs that we have available to put repeaters on. If you are locking down 100 square miles with your repeater, no one else can use it, so don't be 'that guy' and not share the repeater.

Well, it just so happens..... I have BOTH the 5000's in 3 bands and the 2500's in 3 bands. The one 5K is an 800 system radio and the equivalent 2500 is 900 and used for ham Durability is about the same. Price is similar. I like my 5K's because I have an XTVA in my van which allows me to drop any of the three radios in and have a handheld control head and external speaker. I have a multiband commercial antenna on it so it works with all three bands. Programming is no harder than setting up a CCR Baofeng, due to their almost hostile software. The 5K's are a bit larger and heavier than the 2500's but I run a fire rig (shoulder strap and leather case) with a commander mike (has volume and channel control on the mike. Not sure that the commander mike will work with the 2500's but I have never tried. If you are a system owner / operator on the network, the one nice thing with either of the radios is you can program 'phone numbers' into the radio. Now actual phone numbers on GMRS with a phone patch is a no no... But setting up the node DTMF commands so you can connect and disconnect to the different main nodes is nice. You just select the command you what and push the PTT. The radio will send the command string and your node will do it's thing. Accessories is another thing that commercial radios have that the CCR's and ham stuff lack. I have bank chargers that my radios set in. I can charge 6 radios or batteries at a time. Never seen that with a Baofeng. And the overall quality if so much better with the commercial stuff, and the apex of that is the 5K's for their manufactured window of time. Of course they have been phased out and replaced with the APX radios and those are a whole different animal. But they are seriously expensive. I have less invested in all my 2500's and 5000's than a single APX 7000 costs. The other thing with the programming is the files are portable. You can read your radio, email me or someone with my skill set your 'codeplug' (programming file) and I can edit it and setup the radio how you ask for it to be done and then I email it back. This is helpful when learning to program and not knowing exactly what you are doing. Just some thoughts to consider.

Old racks and the new ones. Sent from my SM-N960U using Tapatalk

yes it is

Have a couple things cooking in Johnstown at the site. First is we acquired 12 matching equipment racks for the site. For those that have seen the pictures of the hodge podge of equipment racks I currently have this is a MAJOR upgrade. So for those needing an equipment rack or 6, I have plenty that need new homes. Of course as equipment is moved from rack to rack it will be down. So if you are experiencing an outage, it's only temporary. I reprogrammed the Johnstown625 machine tonight. It's now the Johnstown600 machine. I found out that I was stomping on a guy two towns over and I first and foremost do NOT want to interfere with anyone else. He has been licensed since the FCC actually granted you repeater pairs you were allowed to use. 625 was one of his pairs and he was established so I vacated. Another interesting discovery while doing the retune. I have an SWR of 5:1 on the transmit antenna currently. Gonna rig the tower this weekend and hopefully get new line run and a different antenna in place on the tower. It has seemed to be a bit noisy at times and I really wasn't paying close attention. That of course is going to change. I will be putting a power monitor on the antenna system so I know when there is a problem going forward. I also figured out I have a 10dB loss in the transmit combiner. That works out to 50 watts in and 6 watts out to the antenna. It's actually sort of funny that the thing talks 40 miles in most directions with that sort of power output. I am giving some consideration to trying to space the antennas horizontally apart far enough at the top of the tower (needs to be 30 feet I think) so the coverage will more or less overlap. Not sure if I can do that and not shadow the antenna's due to the horns still being on the tower.

I don't have issue with a national net once a month to give guys a chance to chat with others outside their normal operating area or system. But there are some concerns I would have with control operators and backup control operators being on the same node or even the same repeater if the links bounced. A net is of course run by the CO. If all of a sudden there was no CO, the net work fall apart, and if that happened a couple of times the net would just fall apart. I would advise that there be a CO for each major node at minimum when the nodes are tied and the net starts so someone can keep things going while the links reset or to run the net on their node so things don't spiral out of control. Of course those CO's would need enhanced control ability to drop individual repeaters off ANY node that became an issue during net operations. Beyond that, there should be a preplanned set of topics to discuss and all the normal net stuff, again so that there is a reason to join the net to begin with. That of course is a problem with HAM nets. Lack of compelling topics to keep people engaged. Once people stop showing up, there is little use of having a net.

The CM108 is a very inexpensive replacement for the RTCM interface that is used for AllStar and the myGMRS linked repeater systems. Going into this, I will say that if you can't solder, are not computer savvy, and don't have some sort of test equipment, it will make doing this EXTREMELY hard to accomplish and you will fight with getting the audio at an acceptable level. The CM108 (which is actually the part number for the USB chip) is a USB audio interface with I/O (inputs and outputs) that can be used for connecting a radio to a Raspberry Pi. I am not going to go through all the soldering and wiring stuff since it's WELL documented on the web. I will tell you that you will need the PTT output and the COR input for interfacing to a system. While the speaker level output voltage is very close to what is needed to drive a LINE input on a radio (not a direct Microphone input) the Microphone INPUT will need a voltage divider network to get the output from basically ANY radio down to a level that it can process. I set the interfaces BOTH to a -10dBm level into a 600 ohm load on a TIMS set. And while a TIMS set is not 100% needed, it is MUCH easier to get a fixed level to start with before connecting the interface to a repeater for final adjustment. With a -10dBm signal being generated into the mike input, you will need a 20 to 1 voltage divider or a 50K pot on the input. The two resistors to use for a 20 to 1 divider would be a 20K ohm and a 1k ohm. The 1K resistor and the 20K resistor get wired in series. One end of the 1K resistor gets grounded and the floating end of the 20K resistor is fed the incoming audio. The connection point between the two resistors feeds the input of the CM108. This is fed from the RX audio from the repeater, it's best to just use unfiltered audio and allow the Pi and the CM108 to process the audio. For the TX audio, for the -10dBm I mentioned before the setting on the CM108 configuration is 990 in the simpleusb-tune-menu. Which I will get to in a minute. But that provides a good relative level to feed into a repeater. The repeater I interfaced to was an MTR2000. I did NOT use the wireline interface with the CM108 because true wireline is a balanced input, meaning there is no real ground and 'positive'. Like a twinlead antenna cable. The output of the CM108 is unbalanced, meaning it has a ground wire and a 'positive' wire that the audio rides on. connecting a balanced input or output to a balanced input or output WILL cause hum, noise and headaches that you will NEVER solve with your audio quality. The RTSM does have balanced outputs and WILL work with the wireline interface to a repeater. But if your repeater doesn't have a wireline input, it can also cause hum and other issues. So remember that all inputs and outputs need to be balanced or not, mixing them is NEVER a good idea. You can do it via impedance matching transformers, but that further complicates the build. SIMPLEUSB-TUNE-MENU and SIMPLEUSB.conf These are two files that are in the distribution for Asterisk that setup the actual CM108 interface. And they can bring you heartache and pain. The first issue that you will encounter is that the interface will not accept audio without BOTH a core input and a PL being received on the audio line. These settings are in the simpleusb.conf file in the /etc/asterisk directory. To edit the simpleusb.conf file you will log into the Pi and type 'sudo nano /etc/asterisk/simpleusb.conf . This should bring up a test file that willhave a number of different things in it. The parts that you are looking for are the 'rxboost = ', and the 'ctcssfrom = '. These need to be set to rxboost = 0 and ctcssfrom = no. The one that will give you headaches is the 'ctcssfrom=no' because it's set for 'ctcssfrom=usb' which means it REQUIRES the PL or CTCSS tone be present on the input audio line (receive audio). If you have filtered audio and not discriminator (flat) audio coming from the repeater, and have the CTCSS tone set elsewhere in the configuration of the Asterisk, it will NOT receive. Setting that to NO turns that function off and allows the 'carrierfrom =' setting to control the RX from the repeater into the interface. THIS IS REALLY IMPORTANT because it don't work if you don't change this. You are advised to use 2n2222 transistors to invert and isolate the inputs to the CM108. The information on doing this is again on the web in a number of places. But they will protect the interface board that can't deal with the 5 volt output from the repeater to the CM108 that should only ever see 3 volts input. These little interfaces will allow you to connect to many different repeaters besides Motorola units that have a wireline interface and will also also allow you to connect to an MTR repeater that doesn't have the wireline card installed in it. These are getting harder to come by since they haven't been made in a number of years. I am FAR from a guru on this. But i have worked on countless numbers of MTR's over the 15 years of being a two-way tech. Feel free to ask questions and I will do my level best to answer them. But there are others here that know FAR more than me about the Linux image and other parts of the myGMRS network of repeaters.