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K9CCH
06-27-2014, 09:21 AM
What would a duplexer on a UHF/VHF be used for?

K7SGJ
06-27-2014, 09:36 AM
For combining a uhf and a vhf radio to use a single feed line for a multiband antenna. They are also available to combine a HF output with VHF and UHF radios (Triplexer) to run everything down one coax for a multiband antenna much like you would do in a mobile situation where you don't have an antenna for each band.

My 857 has the option to run HF +6 Meters out one jack, and the UHF/VHF out another jack, (it has a built in selectable duplexer) or you can select the option of running everything out one jack if you are using the ATAS 120 or equivalent. I have it set to run HF/6 to the ATAS 120, and VHF/UHF to a UHF/VHF antenna because at times I only use the VHF/UHF portion of the radio.

NQ6U
06-27-2014, 10:28 AM
What La Rata said.

At Field Day last year, we used a triplexer along with some bandpass filters to allow three people to share a single tri-band Yagi—each on a different band, of course. It worked quite well, even if it did mean that all the work I put into building my 15m Moxon turned out to be for naught.

XE1/N5AL
06-27-2014, 11:55 AM
^^^But who got to "drive" the Yagi?

WØTKX
06-27-2014, 12:13 PM
Hmmm. AFAIK, the FT-857 does not have a duplexer built in.

You have to install an external one to use a single feedline on an ATAS-120.

Moot point. Duplexers are about $70, triplexers are about $10 more.

K7SGJ
06-27-2014, 04:12 PM
Hmmm. AFAIK, the FT-857 does not have a duplexer built in.

You have to install an external one to use a single feedline on an ATAS-120.

Moot point. Duplexers are about $70, triplexers are about $10 more.

You are correct, there is a menu setting that tells the radio the ATAS 120 is being used for 1.8-440 so it will tune the antenna properly, unless the VHF/UHF is going to a separate antenna. But you do have to use a diplexer to combine them onto one coax when using the ATAS for all bands.

K9CCH
06-27-2014, 04:33 PM
I posted a WTB thread on the swamp for a VHF/UHF radio and someone locally replied. He has a Kenwood TM 733A with a Diamond duplexer for sale in original boxes. Wants $200 for the kit.

I knew it had something to do with multiple feeds, I just didn't know exactly what it was for.

WØTKX
06-27-2014, 05:06 PM
That's not a bad deal. I like that radio, almost bought one.

K9CCH
06-27-2014, 05:35 PM
That's not a bad deal. I like that radio, almost bought one.



I bought that FTM350AR for $450 or $500 and it was WAY too much radio for me, even though it was quite a pretty radio. So I figured I'd put something cheap and easy in the Jeep and start back at the basics and grow from there to see how much I use it.

If I find myself using it a lot, and moving forward again with the hobby, then I'll look at upgrading later. I dont need all the bells and whistles right now.

So this 733A is used, and I'm trying to decide between it, or a Yaesu FT2900R.

K7SGJ
06-27-2014, 06:24 PM
I posted a WTB thread on the swamp for a VHF/UHF radio and someone locally replied. He has a Kenwood TM 733A with a Diamond duplexer for sale in original boxes. Wants $200 for the kit.

I knew it had something to do with multiple feeds, I just didn't know exactly what it was for.

That really is a very good price for that radio, and I believe it has cross band repeat on it which can be useful.

NQ6U
06-27-2014, 08:53 PM
^^^But who got to "drive" the Yagi?

Nobody. One interesting thing about living in the extreme southwestern corner of the US is that 90% of potential Field Day contacts are more or less on the same beam heading.

K9CCH
06-28-2014, 04:40 PM
Decisions decisions....

Would you buy a,

-Kenwood 733A with duplexer and separating kit for $200
-Yaesu FT7800R with separating kit and Lido floor mount for $200
-Icom V8000 for $100
-Yaesu FT2800m for $95.

I'm leaning towards the 2800 because it's the cheapest, or the Kenwood because of the dual band cross band repeat.

The Kenwood is opened up to TX wherever it receives.

K7SGJ
06-28-2014, 07:26 PM
If it will get beat to shit in the Jeep, or stands a good chance of getting ripped off, go cheap. If it will be secure, and you think you will use the xband repeat, the Kenwood is a good buy. I use the xband repeat around here, because there are too many mountains and I'm too far away for most of the repeaters in Phoenix or northern AZ using a handheld. I mostly use xband on the swap net on 144. With a 50mw handheld going through the Yaesu FT8900 in xband mode, running high power to the multiband antenna, I can hit most anything.

K9CCH
06-28-2014, 07:52 PM
The only reason I could ever see myself using cross band was if I were at the beach and wanted to walk away from the jeep with my baofeng. Or if I want to talk with the baofeng from inside my house. But then I have a J pole on the roof so that is a moot point.

I'm thinking about going with the 65w $95 option, and saving the rest to put towards an HF setup.

65w would allow me to hit all the 2m repeaters around here just fine.

K7SGJ
06-28-2014, 08:10 PM
good choice