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^^^^^ Is 100% accurate. It baffles my mind when folks say they need a 50 watt repeater and all they have are 4 wat handhelds. We used to deal with this in the LMR world all the time. Balance of a system is not only good practice but can help reuse frequencies also. We had multiple factories in one city all using the same frequency. All of them were far enough apart the 5 watt TX repeaters did not interfere with the other sites. Our C-C SAR repeater on UHF is set for 10 watts at our antenna on TX. We only have UHF portables and no mobiles. Rarely does one who can talk to the site not hear the site. Even my testing with a mobile was great. When you can see the antenna from miles away no need to have a ton of power. In the GMRS world with limited repeater frequencies this is something all should remember.

Sounds like the problem I had with the 1st mic that came with my KG-1000G when they first same out. BuyTwoWay Radios made up for it and sent me a new one at no charge. New mic corrected the problem immediately.

The main reason 90% of repeaters use a duplexer is because of ISOLATION, not because of power loss. As others here have said, yes you can work it with 2 antennas, but you will likely still need additional filtering. If all you can measure is wattage & SWR, you are never going to appreciate what true isolation and improved receive sensitivity (and selectivity) can do for your repeater. How's that saying, when your only tool is a hammer, every problem looks like a nail? I guess in the radio world, when all you have is a watt meter, every problem looks like a lack of power. If you have enough RF power to reach out to whoever you want to talk with, but they can't reach you back because your repeater's receiver is being drowned out due to poor isolation (likely from your own transmitter) - then what's the point? You've now got a bunch of time and money invested in a one way paging system. The point of having mobile transmitters is to allow them to talk back. I'd gladly give up 3 dB of transmit power in a duplexer if it offered 100dB of isolation. Most of the affordable compact notch duplexers will only give you about 65dB of isolation with a 5 MHz split. Add a tuned bandpass cavity or two to the receive side, you'll pick up even more isolation - and you'll still be ahead of the 45 or 55 dB isolation of a split antenna system with 20 or 25 ft. vertical spacing. Oh yeah, and if you do a split antenna system, don't use braided cable for your coax. You'll leak somewhere around 6-10% of the signal with most decent brands - even worse with the cheap knockoffs that use a loose weave for the coaxial braiding. Think about where that 6-10% of your signal is going as it travels up the tower. Even the real Heliax hardline has some RF signal leakage, but it's about as good as you can get in an imperfect world.

I have high hopes of becoming a mutant zombie, carrying a radio that I protected inside a cream can I buried.

Ditto. I'll probably just walk out the front door so I can watch the military base two miles away get blown to hell, and wait for the shock wave.

Nobody was.

Well, if it's DC to daylight and beyond, then a Faraday Cage isn't what you are looking for. It's one thing to block RF signals. If we are talking about trying to attenuate Alpha, Beta and Gamma radiation then it's a whole different ball game. ANd the truth is ONLY plate steel, and LOTS of earth are going to work. So let's quit screwing around and get a go fund me together for a dozer and a BIG track hoe and most likely a portable concrete plant and start building AT&T style bunkers and skip the discussions of ammo and trash can's with aluminum tape around the seams and lids. I mean if we are going to be ridiculous, lets just get to it and skip the silliness all together. Here's the problem. If you are looking to block stuff that will kill you anyway, what's the point unless you have other means of protecting yourself for event's like you are referring to. And if you DO have those means, they will certainly protect radios that are around you went it happens.

LMR400 is good, you can also get LMR400UF (Ultra Flex). The 400UF is a little easier to work with since the center conductor is stranded, and has pretty much the same properties as regular LMR400 (see chart below), with only a slightly bit more attenuation, (which I doubt anyone will notice in the real world). For antennas, most will know that I'm a big fan of the Browning base antennas. I started with a Tram 6140 (a.ka. Browning 6140), and moved up to the BR-6155. Just mount it and go, no tuning required. During the day, over flat terrain I'm regularly hitting repeaters at 40+ miles with only 15w. At night that extends out to 60-70 miles. Antenna is only about 30-35' AGL, and is fed by 50' of ABR Industries LMR400UF. The Laird base antennas (450-470 MHz) are also very good, though more expensive than what is effectively the same performance you get with the Browning. Something to point out, check the connector on the antenna side. Some UHF antennas with have a Type N (female) connector on it, not (UHF) SO-239. So you will need an adapter at one end or the other.

You need vertical separation for a dual antenna setup. Unless your doing a combiner and receive multi-coupler I don't see the value in the dual antenna setup. A good duplexer will have a small amount of loss and in the end work much better than the dual antenna setup. There is alot more to this discussion than just antenna. The repeater is another big item that needs to be figured out. A repeater made from cheap mobiles will be worse in a dual antenna setup than a purpose built LMR repeater. In the LMR world a lot of sites use dual antenna. My one SAR site uses a receive multi-coupler with a DB408 at 35' up a tower. The TX antenna is thru a TX combiner at 15' off the ground. With the filtering on both TX and RX I see no desense at all on 75 watt Quantars on GMRS and our SAR channels. Another site we have an ICOM FR4000 with a BPR duplexer. Out of the duplexer is a 30 watts into 1/2" LDF 150 up the tower. Again no desense at all and there is multiple LMR repeaters at this site. Both sites have great coverage for the area and both serve specific purposes. If I didn't have other SAR LMR frequencies at the first site we would have a duplexer. Normally the cost of feedline and antenna will be the same cost of the duplexer.

I use the Tram 1486 because it is not very expensive, it's relatively high-gain, and it does not look like an alien spaceship on the roof. It was also easy to trim/tune - I got 1.01:1 SWR on the first try. You should use good/decent coax, but do not listen to "some people" that will try to convince you that you MUST USE hardline or Heliax, or some other $45/ft coax. I am using LMR400, which is plenty "good enough". You should ground both the mast and the coax (using a lighting suppressor type inline ground block), but i wont get into the details about how/what to ground them to as no doubt "some people" will be starting ongoing arguments over proper grounding techniques any minute now.

You should come to L.A.. Its a shitshow and its every man for himself.

As the title says, I'm trying to outweigh the pros and cons of using a duplexer or not for a planned repeater. I see through research that there is a power loss going through a duplexer in one form of another and that's to be expected when trying to tx and rx at the same time on one antenna. Space isn't an issue to run 2 antennas, and I would think that I'd have less loss in both directions doing it this way even with twice the amount of coax. I've read somewhere that the rx and tx antennas should not be on the same horizontal plane. Is this a myth or fact? I can go to 20 different sites and get both answers. How do I know how far apart to put them, or is "as far away from each other as you can possibly get" the theory here? I'd like input from someone who has actually tried this both ways (duplexed or not) and their real world results, and not just opinions. Thanks!

GMRS was dead near me so I got my amateur license. Now I have many, many more channels to hear silence on

What you don’t?

Heard this a few months ago: one guy: I gave my wife my credit card, but not sure why she wanted it other guy: sounds like idiocy is afoot!

It's not a real question if you intend to run a real, reliable repeater. Some loss is part of the game. Good equipment reduces that issue. I setup a split repeater once, antennae were separated by 150' horizonally, and about 30 feet vertically. Just a pain in the ass to maintain, and still needed a can on the receive side. You don't have to buy a $10k repeater setup, but going cheap will result in cheap operation.

I would suspect that the problem is either I. The microphone, mike cable, or in the mike jack, but it’s really hard to tell from a forum post. Sometimes those little spring fingers in the RJ-11 jacks pop out of their slots causing problems. Sometimes wires break or the insulation pulls apart, leaving the wires to rub together and make noise. And sometimes itnone of the above but a bad solder joint on a circuit board. Hopefully the new mike will take care of it.

https://www.goodreads.com/quotes/14977-i-know-not-with-what-weapons-world-war-iii-will

I work and live inside a ground-zero strike zone. If something happens here, I'll be gone, and so with the people I love. Ive just come to except that living afterwards is a non-starter. So I don't bother with any of this crap beyond internet discussion and the occasional experiment.

How Texas became known as The Friendly State East Coast GMRS... not so much!

I suggest trying another microphone. What happens if you speak into the mike?

If the cable is less than 25 feet a higher-grade cable won't buy you much.

I can 100% tell you through experience, if you don't use some serious filtering, like found in a duplexer, vertical separation isn't enough unless you plan on using very low power... like 5 watts. I have a portable repeater system the doesn't use a duplexer. At 5 watts, it can have both antennas about 100 feet from each other and it works locally with limited issues. However, if I want to run 50w, or even 200w, I have to separate the two antennas by about 400 to 500 yards to avoid desense issues. I also have a fixed repeater with a duplexer sharing 1 antenna. The duplexer cooks off about half the power, both transmitted and receive. However, antenna placement is going to impact performance more than transmitted and receive losses in the duplexer. You would have to cut your power 4 times to see a single s-unit of loss. Most people who don't run a duplexer, don't do it for performance benefits, mostly because it's not a noticeable benefit. It's done to save money or to provide rapid diversity in deployment and changing frequency or even bands without having to re-tune or replace the duplexer every time. Such as my portable field unit.

Repeater users rarely can hear local traffic on simplex. Only when simplex stations are close to the said repeater user. That kind of interference from the repeater is a fact of life and unavoidable. Move to another freq if you are on simplex.

I think the statute of limitations has passed and I can tell this story: Years ago I picked up the pair of ICOM R-7000 and R-71 receivers at a garage sale for $50. The UHF model did not have the cellphone frequencies blocked and, it still being analog, I used to enjoy spending Saturday nights listening to guys calling their girlfriends from their cars!

Not noticeably. You will lose a little more gain, with the additional cable and connectors. But it will be marginal. Usually, more of a problem with longer runs, say +50 feet. Then coax choices and connector choices start being critical, to reduce loses. Many of us have long runs of lmr400 with connectors that cost almost as much as the cable. Only to have jumpers of 3-5 feet of rg58 (due to the flexibility and size). By the way chances, are the mount you are using has rg58. Most f150 guys just use the third brake light mount due to convienence of routing and installation. The ones I have spoken to have said they feel it isn't optimal. But easy of install and not drilling was worth it. Not sure if any of them tried bonding the mount (ground strap) or if they are even isolated (to prevent dissimilar metal corrosion). One fire dept guy on his f350 went with an aluminum cap and drilled out the cap for 4 nmos. He likes to listen to the boys when he is off duty and will go to call if he thinks he can help. Sent from my SM-S901U using Tapatalk

So, your CERT Net was going on and while it was going on when someone checked in you could occasionally hear someone else on the receive frequency. In other words, when your receiver broke squelch because the repeater transmitted a tone, you could hear the folks in the background who were trying to talk on the simplex receive frequency, is that right? Could anyone else on the CERT Net hear them, or were they local to you only? Before you started the Net, did anyone listen with squelch off to hear if the channel was in use? When you did hear them, did you transmit on 462.675 MHz and announce, politely, that the frequency was in use? They could have been on GMRS or FRS. Except during an emergency, they have as much right to be on the channel as your CERT Net. We share the repeater receive frequencies with simplex users of both GMRS and FRS radios and while it would be ideal for each of us to listen with squelch turned off to hear if a frequency is in use before transmitting, there is no GMRS training that covers that. It sounds like folks were just using their radios and it happened at the same time as the Net. If they were using a different tone from you they might not have even heard you. As far as it being “a violation”, no, it wasn’t, at least in my opinion. No more than the Net operators were in violation for transmitting on a channel that was in use already by a couple of folks with their radios. And since you liked seeing the actual regulation regarding emergency use, here’s the one that requires shared use: § 95.359 Sharing of channels. Unless otherwise provided in the subparts governing the individual services, all channels designated for use in the Personal Radio Services are available for use on a shared basis, and are not assigned by the FCC for the exclusive use of any person or station. Operators of Personal Radio Service stations must cooperate in the selection and use of channels in order to avoid interference and make efficient use of these shared channels.

I’ll second that.

This is where my money is.

If the simplex channel is trying to check into the net, why not go back to that person on simplex and give them the correct channel they should be using? They think they are on duplex and using the power allowed for a repeater channel.

Was there an emergency? If there was, 95.1731(a) says: (a) Emergency communications. Any GMRS channel may be used for emergency communications or for traveler assistance. Operators of GMRS stations must, at all times and on all channels, give priority to emergency communications.

A KrakenSDR and a couple of local angry GMRS users can usually make it stop... fairly quickly..

Go read the blog entry and decide for yourself. Note this change to 95 E, which is referenced in the letter posted on that blog: § 95.1749 GMRS network connection. Operation of a GMRS station with a telephone connection is prohibited, as in § 95.349. GMRS repeater, base and fixed stations, however, may be connected to the public switched network or other networks for the sole purpose of operation by remote control pursuant to § 95.1745. Note that it says "may be connected to ... other networks for the sole purpose of operation by remote control ..." Remote control means things like turning the repeater on or off, changing the power level or tones, etc. My interpretation of that is, "You can hook your repeater up to the Internet, but only for remote control". In other words, not to link it to other repeaters for voice traffic.

Its a nifty little radio, but unless everyone else in your party also has one, most of that nifty'ness doesnt matter. As for basic use and fars, it's pretty much the same as any other radio.