Chinese 50W UHF Duplexer

[WX5812]

Although these are highly frowned upon, I see several people use them rather it be temporary or permanent. There is also mixed reviews.
How do these act when pushing them with a full 50W @ 5Mhz spacing?
When tuned properly what are you seeing power at with 50W input.
Let me hear your success and/or failure story.

 

[KK4JUG]

I haven't used a duplexer in years BUT, by your own admission, they're "highly frowned upon." That would immediately raise a huge red flag to me.

 

[WX5812]

I haven't used a duplexer in years BUT, by your own admission, they're "highly frowned upon." That would immediately raise a huge red flag to me.

Frowned upon is a rather gray area.. it really depends who you ask. Of course they are cheap. So are baofeng, but nearly everyone has one..this is a hobby with endless experiments… now if this was a Wacom or Motorola duplexer then it would do no point to ask any question because the name says it all.
I just know some folks use these cheap duplexers and I was just wanting to get their opinion of them when you run them with maximum allowed power which is 50w for this particular Chinese UHF model on Amazon.

 

[mmckenna]

I got stuck with a couple of Bridgecom repeaters at a remote site. I'm running them at 10 watts. They all have these Chinese mobile duplexers in them. Due to the location, I can't put in a larger set of cans.
They are OK. Never have run them higher than 10 watts, though.
They don't have as much isolation as the larger ones. These are considered a "mobile" duplexer and they give up performance for size.

I'm sure someone can put it into more technical details than I can, but the less than ideal isolation between the ports with the higher power is going to result in less performance/range from your repeater.

Yes, they work, just like a Yugo can drive down public roads, and you can technically use an adjustable wrench as a hammer.

One thing to remember about buying duplexers on line:
You may pay for, or be given for free, the tuning, but usually shipping a tuned/adjustable mechanical device like this through the mail results in them getting banged around and going out of tune. If you buy one of these, or any duplexer, you will want it tuned on site by someone who knows what they are doing if you want the best performance. Don't pay for them to be tuned by the vendor, then bounced around in a truck for a few days. You won't be happy with the results.

 

[tweiss3]

They will probably be ok for most uses, but they are lossy. I also wouldn't suggest running them at the 50W limit. I have a Fiplex DCL4533A2N (UHF) in my repeater, and there was a 2-3 watt difference between the output on high (50W) vs low (25W). I decided to leave it on low since that is safe for the finals (100% duty), and 19.3W into the hardline isn't too bad.

 

[TylerMK]

I've run one with a Motorola GR1225 at 30W with great results. The same duplexer on an Icom or Yaesu repeater at 20W was horrible. I think if you have a decent quality repeater and keep the wattage fairly low you'll be fine.

 

[vagrant]

Not all Chinese mobile duplexers are the same, but my experience with two of them were similar.

The Chinese UHF mobile duplexer I use has performed very well using a Yaesu DR-1X low level repeater at 5, 20 and 50 watts from miles away and not under the antenna. I am able to remotely adjust the power, so that power level testing was done at the same time. Also, the last time I tuned it the loss was nice and low, I think 1.2 and at least 80 dB of rejection. I will check it again when it warms up here, but no troubles with it. I believe it was $100 shipped via eBay and I purchased it five years ago. It has N connectors as well. During the test I used analog and C4FM from handhelds and mobile radios. I think the other UHF flatpack duplexer was getting at least 70 dB of rejection. I sold it as it was no longer needed. I use an Agilent 8935 (E6380A) with some 6 dB pads to tune my duplexers.

Note - I do not use that mobile duplexer at a tower site. The RFI it would give and receive would be unneighborly. Still, the location where it is used also has another Yaesu repeater and zero problems when both are blasting away simultaneously. I should note that the VHF duplexer is a Telewave TPRD-1484...so yeah no problems.

 

[N4GIX]

I once owned a UHF Bridgecom repeater, and was very unsatisfied with the lack of performance from the mobile duplexer they had installed. I was unable to get much better than -50 dB rejection, which is really poor. I wound up selling it to a ham in Oregon who installed it on a mountain top tower.

 

[K5MPH]

If you are talking about the cheaper notch duplexers I use these for my mmdvm repeater they are rated at 50 watts the radio pairs I am using are Cdm-1550 for the repeater and are set at 30 watts out and have had no problems at all,with all that said I would like some day to change over to Band Pass duplexers with less loss it depends just how much money you want or can spend ..........