Chinese duplex repeater?

[office888]

Has anybody tried one of these setups yet?

Radio-Tone Duplex repeater controller VX-170 FT-270 new - eBay (item 220665534862 end time Oct-06-10 08:32:52 PDT)

VHF 6 CAVITY DUPLEXER for radio repeater N connector - eBay (item 220671339737 end time Oct-18-10 12:50:01 PDT)

Seems like a cheap way to make a portable duplex repeater setup, or even a little home base repeater.

 

[n8fgb]

I saw them as well. They lack an ID'er though.
Rich

 

[office888]

I saw them as well. They lack an ID'er though.
Rich

It wouldn't be that hard to make a simple ID'er...you could make one pretty easily out of radioshack parts and splice it in.

 

[spickus]

You did see the 3.5 Mhz split?

 

[office888]

You did see the 3.5 Mhz split?

It's still inside the amateur radio spectrum, although somewhat large.

What do you expect from an $80 duplexer?

 

[ke7vvt]

Cooool.

 

[Shockwave]

The duplexer is similar to the type used in police and fire vehicles to form their vehicle repeaters. Used to boost the signal of a handheld radio through the mobile radio. They don't have the rejection of larger cavity filters and that's why the split is so wide to reach 75 db isolation. Power is limited to 50 watts but that's assuming the transmitters are extra clean, free of spurs or IMD and the receivers are highly selective. Most commercial Two-Way radios meet this requirement while most amateur equipment will fall somewhat short of the goal here. This may be why we see it marketed with 5 watt 2 meter HT's.

With respect to the controller, don't expect this to work like your local 2 meter repeater. Since there is no carrier or PL operated squelch line at the mic or speaker jacks, what switches it between TX and RX? It says DTMF and is either triggered by that or VOX. Either one can be annoying. You may want to do more investigating on the controller because I don't know as much about it as the duplexer. I wonder if it requires another DTMF code to turn it off after each transmission, if it has a timer that holds it keyed, or if it's detecting audio?