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I really appreciate all the informed responses! The truth is that I can afford more, but the logic of the question was really the crux. After doing some more measurements, my cable run is likely to be considerably longer than I had originally expected, so I’ll probably go LMR400. My chimney has a metal top that I’m considering a mag base for, but I’d have to pull It down if I ever (extremely rarely) wanted to use the fireplace. I see the other option as a long piece of pvc tube with some guy wires, but that doesn’t get nearly as tall as my second story chimney. I’m pretty sure that standing at the closest upstairs window to Dallas that I’m already hitting repeaters close to downtown with the longer (included in the GM30 plus kit) whip, so I’m betting that I’ll be ok no matter what.

I agree, but I think it buys more than it used to. On our road home to Butte from Phoenix this past week quite a few places were advertising for help. At convenience stores the starting wage appears to be $21.00/hour. So $100 worth of stuff is now equivalent to about five hours of work. When I was a sophomore in college (1974), I worked on a farm for $15/day and they were long days. Within a couple years I got a job at an appliance store for $1.25/hour. Compared to what my wages would have purchased then, five hours will buy a much better radio, antenna, and cable than it would have then.

Any chance you can enlighten us on the equipment you used and the techniques to tune it in this particular instance? Details like brand names and models of the equipment so I can looke them up and see them type of details. Unless you don't want to give up your secrets LOL.

Thank you for the kind words. It was my pleasure! I'm glad I was able to help.

I agree. It's not so much that you need special stuff as much as $100 doesn't buy $100 worth of stuff any more.

Never expected it to. It's absolutely a compromise. But what it does is allow you to figure out what channel might work best for you in your area. And when you figure that out you can commit to a tuned duplexer. Of course when I first started out I didn't know squat about any of this stuff. And that was a little bit more than a year ago when I got a pair of HTs. But I'm a quick learner and generally don't need to ask questions because I can find answers myself. But duplexers are simple and complex at the same time and it took many vids before I understood how they worked. I always knew what they did. I'm excited to see if it'll improve my reception. We have 2 repeaters nearby. Commercial repeaters all gussied up with the best of the best. And you can tell by how they receive, very sensitive. While mine being much closer wasn't that sensitive. Kinda frustrating. Hoping for a similar sensitivity with the better tuned duplexer. Of course the commercial ones have the advantage of being 700ft+ in the air while mine currently sits at 40ft.

Outstanding! We look forward to your test results. As mentioned by many of us, a duplexer tuned for all of the GMRS repeater channels will not work as well as one tuned for just one channel.

my Notification window would not work. Zooming over and clicking did not open it.. Its working now though

EchoLink and Zello are the only phones apps i'm aware of. EchoLink never did accept GMRS or non HAM Bands.. I'm just saying, the only way to IP link now would be via a repeater system linked via IP.. Couple months ago i did read that a group was working on a Linx based version of (copy) of Zello, they probaly will end up getting that to work on Adroid phone and older jail broke iPhones. Personaly, i think it sucks that phones we 'own' are tied to the manufactures App sorces.. We should have open rain to run what ever software we choose.

It was very brief but I got the same thing accessing on an iPhone this morning.

Same thing. Did either of you report it to Rich? I did anyway. I think he’ll forgive me if I’m duplicating your reporting.

Also I got an “expired password” pop up when trying to access the repeater map. Anyone else? Or did I get taken by a hacker pop up?

Something is haywire with the home page you normally get when accessing MyGMRS.com. Normal graphics are absent and there are words on top of words at this time.

Yep, I can't wait to do a real world test when I put it back in the RPT50 Btech. Right now I have a wide band tuned duplexer in it that they sent as a replacement. And this duplexer worked much better than the one I gave Marc to tune. As soon as I swapped out I noticed a marked improvement in reception. Not sure how it's tuned, if it's the same tuning as the one I gave to Marc or something else. It's probably tuned better than the original just from the fact I could get better reception out of it. I've done a lot of real world testing with my current setup. I know where I can hit it and where I can't and where it's iffy. It's the iffy spots I'm hoping to see better results. And Marc I just want to say it so the people here see it too. Thanks for doing this. I appreciate your effort and I'm looking forward to putting it to good use. I know you just wanted to play with your toys, but it's hopefully going to be a real world difference for my repeater. This way we can both have our fun. And just think, now I'll have that other duplexer.....

Ya, 2 months ago.

@WSIK532 the entire process from setup and initial testing to the finalized range test and cleanup was about 2 hours. The actual tuning itself only takes a few minutes.

@marcspaz How long did it take to tune it?

Wait what? you doing a giveaway... Cool!

Well, define 'abandoned'. There are a number of towers that are owned by someone, all over the US that are not currently active, but are not by what I believe you are inferring, abandoned. Many are indeed owned by the major vertical real estate companies like Crown Castle or American Tower. Some are owned but private individuals or businesses that are not in the vertical real estate business, but do own the property a tower sits on. You are no doubt asking because you want to put up a repeater and think if you can find an abandoned tower, that you can just roll up in there and get to work putting up a repeater on it and no one will care. Well, good luck with that. First issue is there isn't a piece of property anywhere in the US that's not owned or claimed by someone else already. And if there is a tower on it, someone put that tower there. As a person that manages and maintains a tower. Like a real tower, not a 20 foot pipe on the end of my house, but a 240 foot microwave tower sitting on 1.3 acre's of land with a building. Here's what you face, IF you can find an abandoned tower or one that someone will allow you to have full access to. First is an electric bill. Because you simply are NOT going to find some rich benefactor that will not only allow you access to their tower, but pay your power bill as well. Second is the building condition. If it's truly abandoned, and unused, then it's not being maintained. So the roof will leak, the door may or may not even close. You may face it being full of animals, birds and lots of poop. Bird poop will give you an incurable disease. Don't remember what it's called, but look it up, it's a thing. So getting the building ready to put a repeater in might require a hazmat suit and respirator to just be in and out of the thing. And mold.... yeah, gonna be plenty of that too. Now, getting the power turned back on may well require permits, and civil engineering plans with PE stamps to obtain the permits. We had to do that too. More money. If the crack heads have been there stealing wire, then you are rewiring the building. Again, been there and done that. More money. Then there is the tower. What shape is it really in? Is it a guyed tower, or free standing? Is it rusted or in reasonable shape? Guyed towers will hide dangers. The anchor heads will rust just below the ground and you will not see that if you don't dig them up. Simply attempting to climb a tower with that issue may cause the tower to fall, with you on it. Then there is the base pier, the grouting and all that other stuff that since you are asking this question, you know nothing about. You don't posses the knowledge to even judge the structural integrity of the tower to begin with. This can create TWO issues. First is simple. If you are on the tower and it falls, you die. Second issue is you have someone else on the tower and it falls, they die, and you get sued by both the tower owner in front of 12 people that have equally no clue about a tower but know YOU were allowed to access it and it's down and someone died. And not only will the family of the dead guy be suing you, but so will the tower site owner to claim you were at fault, and responsible, but also to protect himself from that family from coming after him. Just depends on who gets to the court house first with the lawyers to file the suit. A friend told me once ' I can't afford free" and free towers typically very few can afford, and they don't figure that out until they have made some level of commitment to do something with a site that they have no business being involved with. But I will tell you this. There are NO FREE ABANDONED towers anywhere that you are gonna just walk into and put up a repeater at without significant cost. And remember that we haven't talked about repeaters, cable, antenna's or any of that yet.

@marcspaz Great Job! i know @LeoG will be excited!

I'm not going to try any unlocking I was just curious.

Mines says 5R-M8 GM-V02

Hey folks! For people looking for an affordable duplexer that works well, I may have a solution for you. For those of you who have been following the thread, you may be aware that our friend @LeoG had a problem with a duplexer in his B-Tech repeater. They exchanged it for him, but I offered to take a look at the duplexer, hoping that we could get a spare available, or a second for another machine. I have to say, I am impressed. The duplexer is a SGQ-450D. It is a traditional six cavity mobile duplexer, made in China, and the cost is about $115-$120. When I first got the duplexer, I connected it to a VNA. The unit looked like it was tuned perfectly, the notch and SWR were great... it was just on the wrong frequency, preventing it from working on GMRS. I connected it to a radio and a dummy load, checking both sets of filters, and it worked perfectly. The downfall with duplexers setup like the ones installed in the B-Tech repeaters isn't the duplexer itself, but rather the tuning. What companies do to make these wideband (and what I found with this duplexer), they tune the 3 receive cavities to slightly overlap instead of perfectly align. Also, the 3 transmit cavities to slightly overlap instead of perfectly align. What you end up with is about 500KHz-700KHz of filtering at about 45dB-50dB on each side, for a max of about 100dB of isolation. While not terrible, it leaves a lot of room for improvement, which is easily accomplished if you align all 3 cavities to work on the same frequency. @LeoG asked to have the duplexer aligned to 462.600/467.600. On the high side, I was able to get a minimum of -85dB notch centered at 462.600MHz. On the low side, I was able to get a minimum of -87.4dB notch centered at 467.600MHz. That is better than -172dB of isolation... almost double what the previous tune was. Here are the final tune-up results. Isolation = > -172dB Transmit SWR = 1.08:1 Receive SWR = 1.18:1 Loss due to SWR = 0.0064dB Total Insertion Loss is <1dB For a test, I hooked it up to my portable repeater while at my house. I got the same range as with my personal duplexer. For comparison, these specs are on par with my SinTech/Sinclair duplexer, which is priced 4 times higher than the SGQ-450D. The duplexer will be shipped back to Leo next week. I am looking forward to his real-world feedback after the tune-up. Below are a few images of the duplexer and the tuning results.