Fumei UHF 400-470MHz 50W Duplexer for Radio Repeater with Preset Low Frequency 462MHz & High Frequency 467MHz & N Female connectors

Good little duplexer! I'm using it for a low-power mobile repeater, and it's working fine. Initial tuning out of the box was garbage (like only a -60 dB notch on the low side, though a -100 dB notch on the high side), but that didn't matter because I was going to tune it myself anyway. Tuning was straightforward with my HP 8714ES VNA, if a bit touchy. Breathe on the tuning screws while the jam nuts were loose and the null would shift a hundred kHz. Took a while to get it dialed in, and it was a challenge to tighten down the jam nuts without moving the notch, but again, there weren't any real surprises. All pretty standard stuff. See the attached photos for the post-tuning transmission as measurement by my VNA. Managed about a 90 dB notch and about a 1.5 dB insertion loss on both legs. Construction seems nice and solid.

Absolutely, do not purchase this. If you attempt to modify it, you will not achieve an insertion loss of less than 10 to 15 dB, even with a 5 MHz split. While you can tune it, the insertion loss is the key factor. You would be better off using a dual antenna instead of buying one of these cheap, poor-quality duplexers. With such an insertion loss, your range is acceptable if your repeaters are high enough to say a couple of hundred feet in the air. And if you have a GP nine, which comes with 11.5 dB of gain on UHF, you’re still only looking at about 5 miles. I don’t even have to do the math; I can simply know that for every 1 dB increase in value, the sound doubles. Therefore, you definitely don’t want any insertion loss, which is practically impossible. I’ve seen things as low as .5 dB, but anything above two is a significant loss of range. So, 2 dB of sound would be 4 times more powerful than 0 dB. And if you’re looking for a reliable option, consider buying one of the BCD440 duplexers from Bridgecom. It’s true that you get what you pay for, but it’s worth the investment.

So far so good, I have seen reviews that have not been very positive but during testing I have found that the one I have received works very well right out of the box. I am using a Ra87 repeater setup and the SWR is coming in at 1.02 on the low end and 1.05 on the high end and the 40 watt radio is coming out of the duplexer at 24 watts, so I am very happy with the one I received, I am about to purchase the 30 watt version to use with a bug out five watt hand held repeater setup. I would recommend at least giving them a try especially if you are on a tight budget.

Rejection was good but no matter how I tried I couldn't get better than 3dB insertion loss even at the sacrifice of isolation. 50% power reduction is a steep loss. I know it's not a Cellwave but was hoping for < 2dB at least.

OK, so I purchased the 30w version of this unit first, and after receiving two defective ones, gave up and got this 50w version instead. Very pleased with this unit. The factory tuning was close to the claimed 462.000 MHz and 467.000 MHz frequencies, but was not spot on (see the photos). I needed this tuned for 462.550 and 467.550 and was able to tune it up in about 10 minutes (most of that time was spent making connections and setting up the analyzer). I was able to achieve a ~100dBm notch on the desired frequency (both high and low), and about a ~1.1dBm insertion loss on each side as well. While I would prefer the insertion loss be lower, it is acceptable considering the size and price point of this unit.

Unit came well tuned to GMRS with the diplexer able to cover all frequencies and separate the high/low by more than 30dB isolation as delivered. May be able to improve from there for a specific freq pair if desired as the curves showed a local null could be found but to cover all freq pairs this well out of the box is great.

These are just too physically small to work well. I get a LOT of desense when used with an Icom DStar repeater. A pair of full-sized cans provides much better isolation. Note: don't buy one of these thinking you're going to tune it with your nanovna. You need a decent bench VNA or a quality lab spectrum analyzer to optimize all six cavities. But even then, you may not be happy with the performance.

Great product it was tuned for low 462.000 and high 467.000 from the factory. I ordered it without a specific tune because I tune them myself. Good little duplexer price point. Would highly recommend

Good for mobile use. Not meant for high interference locations. It has band reject tuning only. Serves me well.

Very good item. Just wish they didn't leave it on the front door anybody could have picked it up as it was very expensive. And was instructions to leave it in a different place

On duplexer page showing 2 Fumei duplexers 50 and 30 watt version, same model number, no difference in the design including size and weight.....