MarkInTampa

The GP-9NC (GMRS/MURS) is rated 153-157MHz and 460-470MHz. The straight GP-9 and GP-9N (ham version) is rated 144-148 and 440-450MHz.

I have both of these antennas. 30ft mast, 50ft LMR400. In my case, the GP9 worked better on VHF and the GP6 better on UHF. Don't know if it is the location of the antenna, the oak tree 20ft away or what but I had a better experience with the GP6 over the 9. I dropped my mast to 15ft and the GP6 made it just fine though the Cat3/4/5 hurricane that hit me last week in Tampa. Don't have to worry about the oak tree....it didn't. Power is still down, no air conditioning sucks.

Me back in the day with a Siltronix 1011D that popped up on my sisters FB page yesterday...

I've broken the ring many times. From a hour or two when installing new switches to a week or so at a time when one of my guys drove a underground fiber warning post right through the fiber before it was fixed. Every switch that part of the network has passive fiber coupling, if the switch or power goes down the fiber is coupled together to keep the fiber live bypassing the switch. Also all are on large UPS's, IP accessible power strips, etc. Every pullbox for the fiber has at least 50ft spare cable looped in it. The strange thing is the way different districts test things. The UPS's all have ethernet ports and are connected to the network. One district will test remotely once a month and send somebody out it it fails and another district actually have crews that go to the site to test the UPS and visually verify batteries are not bulging, connectors are good, etc on a monthly basis.

The fiber network runs in a redundant ring and is divided by 7 districts that run and maintain their own fiber within their district. Some of the districts even have redundant operation centers. For example district 1's primary operations center is in Ft Meyers and the backup is in Bartow 90 miles away. With additions of cameras, traffic detectors, EDMS (electronic digital message signs - and each one of those have a camera focused on them to confirm operation) and the like over the last 10 years that are all IP based and consume a ton of bandwidth fiber is the way to go.

Two different groups run them so I couldn't tell you for sure. The SARNET system runs across the FDOT's (Florida Dept of Transportation) microwave network and towers. I've been to a few of the tower locations - it was kind of strange. The microwave network runs T3/DS3 (54mbs) protocol as a backbone, then divided into T1/DS1 (1.5mbs) lines and then further divided into 56/64k lines. There was even a old analog rotary dial telephone connected using a ancient PBX adapter that still worked at each location. It was like looking at a telco room from the 1960's. DOT is really well connected in Florida using both microwave and fiber they own. Almost everything that ran on the microwave is now running on fiber. Up until 5 years ago almost all the interstate was covered with fiber and have PTZ cameras installed every 2 miles and MVDS (Microwave Vehicle Detection System) every mile with the exception of 130 mile or so stretch of I-10 between Jacksonville and Tallahassee and that's what I helped put in, now it's close to 100%. Now almost everything that was running microwave has been switched to fiber and the microwave network is basically abandoned except for the SARS repeater system. I talked to one of the FDOT IT directors awhile back and they wanted to scrap the microwave network that they don't use and didn't want to have to pay to maintain the towers and system anymore but it wasn't in the cards yet. I'm not sure how long SARNET will stay up or if DOT will allow them to run across the fiber - time will tell. BTW - you can listen to SARNET through Broadcastify: https://m.broadcastify.com/listen/feed/35392

It's covered even better by SARNET (https://sarnetfl.org/)

GMRS Live to shut down on Monday, Sept 30. Statement is on his webpage... https://www.gmrslive.com/

The reason I think it was a simple timer (at least in the case of the radios) is that it makes the most sense. If you are going to detonate all at one time, how else are you going to do it? DTMF maybe, but at what frequency (or frequencies)? Individual or in group addressable, again what frequency and why if you are going to blow 'em all up at the same time would it matter? A simple timer in a battery pack would be undetectable to the radio, it's programming, it's operation, ID or frequency. Once the secret of exploding radios came out (with a boom - sorry, had to say it) I think it was a one and done thing, the enemy knows what to look for now.

I may be proven wrong (it wouldn't be the first time) but I don't think the radios (or pagers the day before) were doctored at all, the batteries were. If your intelligence department finds orders for pagers, batteries or radios being shipped to a known enemies address that acts as a liaison for those in the field, can pose as the vendor or intercept the order and you sent them a battery that had a simple timer and a small explosive charge to go off at a predetermined time. You wouldn't even need the radio or pager turned on, wouldn't have to hack the radio or anything and a heck of a lot simpler to pull off.

The Comet GP-9 2m/70cm antenna sucks for GMRS. I don't know how the GP-9NC (the GMRS version) does on 70cm. The GP-6NC (GMRS/MURS) version works great on 2m/70cm/GMRS though... GP-9 UHF SWR seep followed by GP-6NC UHF and VHF sweeps, same coax (50ft LMR-400) and pole (up 35ft)...

Just make sure you are at least 3.5ft away from the antenna...

If I had to guess there is a really strong repeater around 40 miles away already on 725 with excellent coverage up 400ft that can be accessed from the 575 repeater location with a good radio. Far enough away that occasional local traffic on a different tone on the input of 725 won't really effect it but close enough that you wouldn't want them on the same output. Both are by far the strongest repeaters in the area.

There is ship traffic that causes occasional interference on the Tampa 575 repeater. It has a alternate input of 467.725 as well as the primary input of 467.575. The primary input (467.575) is part of the ITU standard for UHF vessel communications and the repeater overlooks the port of Tampa. The ship traffic doesn't key the repeater but does mix in with normal GMRS traffic so they shut down the primary input if it becomes a problem. FYI - ITU UHF standards for vessel communication coexists with two GMRS repeater inputs, 467.550 and 467.575 as well as GMRS channel 8 (467.5625)

You would think so... Repeater A has been around for 5+ years and is the dominate repeater in its area. Repeater B popped up about a year ago and almost instantly I notified the owner about the issue (within a day or two of it going up) and asked if could change the tone and he never responded. I tried to be a good trooper but if I accidently hit his repeater (and the repeaters networked to it) when using repeater A there isn't much I can do about it. I sent a link to the repeater A owner of repeater B's linked status page so if there is interference on their repeater they can at least see if it's a user of repeater B doing it. It doesn't happen often, the band has to be open just a bit then it becomes a bit of a problem or confusion to users on both repeaters. Folks on one of the repeaters or the other are hearing just one side of the conversation and wondering what's going on and from where I sit I hear both.

I sit between two repeaters on the same tone and frequency. 35 miles from repeater A, 25 miles from repeater B and the repeaters are around 60 miles from each other. Repeater A is up 400ft and hits me full scale. Repeater B is up around 50ft and is fully readable but just above the noise floor and is networked with far more (but very little local) traffic. They are far enough from each other that most of the time there is no issue except when you get folks trying to use one or the other when operating between them (like myself) or there is even a slight band opening. I do get a bit of heterodyning most of the time on repeater A on receive if repeater B is transmitting but not to bad. I have to bring up the system status page of repeater B on the web and drop my power to 5 watts to verify that I'm not keying it at the same time, 50 watts and I will. If there is a REALLY strong band opening I have talked on up 4 repeaters on the same frequency and tone with one being 160 miles away as long as nobody is using the other 3. Gotta love 141.3 and 4 squelch tails! There is somebody local out here that is running a encrypted DMR repeater on 462.700. It's driven at least 3 GMRS repeaters off that frequency because of interference. Its been reported by quite a few folks to the FCC but nothing has been done in the 1.5+ years its been on the air. Oh well, just subtract one frequency from being used, not much you can do about it. The City of Tampa also has a grandfathered GMRS repeater on 462.625 that ID's every 10 minutes but in two years I've yet to hear anybody actually use it. Its CTCSS decoder has been screwed up for years, it will repeat on the wrong tone (or any tone) one or two times (mostly at the beginning of a transmission) and then behave by not repeating on the wrong tone. It's also driven a few local repeaters from using that frequency. Subtract another frequency from being used.

I'll usually listen to the net with my 2nd VFO listening to the input frequency of the repeater. I'm 35 miles west of the repeater and find it interesting to see who I can hear on the input. If I can hear them I could probably talk simplex with them. For grins, I mapped out the check in's of one of last months net by callsign...

One of the local GMRS repeaters out here run a SkyWarn (storm spotter thing) every Tuesday. They run the same basic preamble that WRYZ926 posted, something like "This net is to test our equipment incase of an actual emergency. All licensed GMRS users are encouraged to check into the net, if you are SkyWarned trained or a CERT member please let us know your info when checking in". There are usually 25-35 folks that check in per week. It's actually a pretty good turnout for a stand alone repeater I think. A lot of the 2 meter nets have less check in's.

From the admin of GMRSLive posted today....

The squelch tail is set by going to "Common", select "Timer" and adjust "Repeat Hang On Time". Default is 2 seconds I think. The tail beep is set on the main screen channel setup under the option "Court Blip" (short for Courtesy Blip). It can be on or off for each channel. Here is a link to the manual if you don't already have it... https://www.motorolasolutions.com/content/dam/msi/docs/vertex-standard/manuals/vxr-7000/VXR-7000_OM_ENG_EU_E13671108.pdf

It should be opposite - TX on 462.625 and RX on 467.625 Also click on "Help" then the "Index" tab - Help in most older software it doesn't work but in CE27 it still does. It give a brief definition of almost all the settings.

I never used the icons to upload or download from the radio, read they were revered and others said it wasn't. I clicked on "Radio" on the top of the screen and "Upload" to send to the radio or "Download" to get the config from the repeater. Easy way to tell, by default when opening CE27 it opens in VHF band mode (at least mine does) and switches automatically to UHF band after reading the radio config.

Another one down....

The may be a stupid question, but.... The FCC page show that linking repeaters is not allowed but what about linking two or more base (fixed) stations that in turn key up a repeater? The repeater wouldn't be linked but the fixed station would be.

The FCC changed the GMRS operations page last week. Now shows this.....(https://www.fcc.gov/wireless/bureau-divisions/mobility-division/general-mobile-radio-service-gmrs#:~:text=You must cooperate in the,or through a repeater station)