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That's more important than you think. Remember one of the functions of a duplexer is to "isolate" the RX and TX sections since they are both using the same antenna. A receiver can only tolerate a small level of signal before the AGC, automatic gain control, in the radio reduces the internal signal level to keep it within the operating range of the electronics. The gain can be reduced to the point were a weak signal is reduced to a level where the FM detector can't work. That's desense in action. As strange as it sounds some repeater owners discovered that REDUCING transmitter power improved the receiver sensitivity! Why is that? Well consider the duplexer has a FIXED attenuation. Those cheap Chinese duplexers don't have a lot to begin with anyway. So if the transmitter power is increased the signal level feed into the receiver's front end increases too. As I mentioned if it gets too high then the AGC kicks in big time and your receiver goes deaf. That's why higher power repeaters use duplexers with 100db or more isolation. They have to use it to keep the signal level into the receiver below the point were desense occurs. Finally if the repeater is installed at a site with a bunch of other high power transmitters, which are in close proximity, all that power is trying to get into your repeater's receiver too. The duplexer has to keep all that crap out as well.

I have used one and it worked great. If you get it from your link they will tune it the the specific frequency you want when you order it. Just dont put the full 50W through it as it probably wont last long.. If you burn it out using a 50W radio they will replace it within the warranty period, but if you limit your power to ~30Watts or so, it will last much longer.

Oh, one other important point that very seldom gets mentioned is the quality of the coax cable. I'm NOT talking about signal loss in the cable. Coax cables are not perfect and will leak a little RF along their length. When your TX and RX cables are in close proximity signal leakage from the TX side coax can get into the repeater's receiver section AFTER the duplexer. That sort of defeats the whole purpose of using one. Smart repeater builders will use multiply shielded coax cable for this exact reason. Yeah, it might be more expensive, but it's the difference between a great performing system verses a poor one.

Or, spend $800 to $1000 and get a purpose built repeater with a decent receiver front end that won't desense, and cooling fans to boot. Public Service announcement: your "50 watts" won't perform any better than a properly configured 10 watt repeater when you are talking back in with 5 watt portables. Especially if you're talking through a cheap compact duplexer that's probably rated at 65 or 70 dB isolation (and that's when it's properly tuned).

Newly licensed GMRS user here! WRXX896, looking to learn and have some fun and it seems I've got a repeater near my area as well. I've been into HAM radio for many years (KC0RJX) and I came to GMRS to include the rest of my family in on the fun of pushing the PTT button on radios

@jsneezy, the Midland (5/8λ stacked) will be far superior to either the Nagoya or the Tram, hands down. If you want a good UHF-only performer that's not as tall, the Laird BB4503 (Black) or B4503 work great, but have to be tuned (trim the bottom of the mast). They are both 5/8λ, and about 10" tall, and work very very well. I normally use the BB4505C (32", also 5/8λ stacked), but when clearance is a concern I swap in my BB4503. With the BB4503 I have no problems hitting repeaters (250-300' AGL) at 30-40 miles with only 15w. *The Midland MXTA26 will not require any tuning.

Lscott that was a very good explanation! Thanks. Cleared up a couple things for me. I'm not wanting a repeater but like learning.

1 thread (pun intended) about a screw and there's a run on the store. hahahaha

You get what you pay for. Some find out the hard way why something is so cheap.

"Public Service announcement: your "50 watts" won't perform any better than a properly configured 10 watt repeater when you are talking back in with 5 watt portables. Especially if you're talking through a cheap compact duplexer that's probably rated at 65 or 70 dB isolation (and that's when it's properly tuned)." That's like the number 1 thing I try to get people to understand when they get into radio. Power out of the repeater has nothing to do with talk in range (if desense is out of the picture).

I had the 430-450 version of that base loaded 5/8, and that worked very well also. Was picking up a 70cm repeater at something like 100 miles out, and it worked great for overhead clearance on my truck. I also clarified my other post to indicate it was the tram 1181 that didn't work so well for me

Put it in reverse and it's Driver Returns On Foot. To get back on topic, I think the KG-UV9GX is going to be the better of the two, partly because of that sexier wrist strap, but also the fact that it's superhet.

Were you outside with clear skies? Many GPS signals tend to be too weak indoors. (By design, GPS is a spread spectrum signal just above the noise floor at the frequency used).

Finally mounted the plate. Baking sheet turned upside down clamped on edge in 4 locations to the aftermarket cargo basket with the ghost in the middle as shown in the image. Was able to talk about 15 miles simplex with very good signal on initial contact sitting in the driveway with only slight relative elevation. Also was able to use repeater successfully as well. I'm probably good for now. Thanks for all the help.

For UHF/VHF (GMRS) I just use the Surecom SW-102 off of Amazon. Gives you SWR, power, and shows the transmitted frequency. For cutting off the shelf whips and the like it works great. I also have a variant of the Nano VNA. It it more finicky to use, but does work and gives you tons of information. I use that when making HF antennas. Not necessary IMO for GMRS stuff. The surecom is easy to use right out of the box. And for the price I think it's worth it. Are there better? Sure, but you'll pay more than you probably paid for your radio... just my 2 cents from my experience.

Nanovnas are awesome. Especially, when building antennas. But overtly complicated for most. They do have some what of a steep but fast learning curve to them. Most just buy a surecom, really more then enough. Fairly fast and not complicated. If really serious, you start looking at rigexperts and up. But they are $$$. Sent from my SM-S901U using Tapatalk

Many scanning systems provide three options: Carrier Operated (resume when carrier drops), Time Operated (resume after n-seconds EVEN IF THERE IS STILL TRAFFIC), and Stop Scan on traffic. Some radios may have a secondary control for CO -- specifying a pause before resume. You'd have to check the manual/menus for the radio to see if such exists. (Based upon the PDF -- the only option seems to be scan on/off, and from your description, the only mode is CO). The KG935 offers TO/CO/SE (Stop, they call it SEarch) options, but states that CO will continue as soon as the signal is lost The AT-D878UV+ (dual band amateur) has TO/CO/SE, but states that CO resumes 2 seconds after signal loss. BTech GMRS-V2 TO/CO/SE CO "after a factory preset time with no signal it resumes scanning" (TO is "factory preset time out...") DB20-G (mobile unit) scan modes are 2SP, 5ST, 10ST, 15ST -- SP is the only option for CO mode, 2 seconds after signal drop; ST is TO mode choices.

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.

Just a caution to be civil here. This thread has the potential to get political fast, and that's not okay here. For casual listening to the protesters, I have no issue with sharing that information. I do have a problem with using that information for nefarious purposes, however. Just like how it's okay to share information for monitoring police and the military within the confines of the law, but once you try to use it for nefarious purposes that goes out the window and becomes a problem here.