Will this work...

[tkiuntke]

or am I missing something?

Is it possible/realistic, whatever, to use one of those 50 watt Celwave reject duplexers as a directional coupler for sweep testing?

Just a wild hair that I thought up, any ideas?


Thanks

Toby
KC0FRU

[jackhackett]

a duplexer and a directional coupler are quite different things.

[xmo]

When you say "sweep testing", I assume you are referring to the sort of tests that one can perform using a spectrum analyzer and tracking generator or the equivalent instrument functions that are built into certain service monitors such as the HP8920 or GD R2600 series units.

The item you need is called a signal separation device. Two primary types are available, directional couplers and directional bridges. One popular model of directional bridge [AKA return loss bridge] is manufactured by Eagle. They have several application notes on their web site that will help build your knowlege on the subject:

http://www.eagle-1st.com/notes/note_toc.htm

The current model of their bridge is kind of spendy, but RF Image has obtained some of the earlier model and is offering them at an attractive price:

http://www.rfimage.com/eagle.html

[tkiuntke]

Thanks XMO, that's great info! Trying to learn the in and outs of this testing method as it's becoming more and more attractive to be able to do. Thanks again!

Toby
KC0FRU

[440roadrunner]

There's a vast amount of info on the web that can help you, although it can be difficult to find.


The above mentioned Eagle site has a lot of info

Another good place is the (used to be HP) now Agilent technical pages. It can be intimidating to find. There's a lot of stuff there.


http://www.home.agilent.com/agilent/fac ... =80029.k.0


http://www.home.agilent.com/agilent/fac ... c=eng&sm=g

QST has a return loss bridge at it's "technical pages" but you do have to be a member to download it---I believe I've seen the very same project elswhere on the web.


I CANNOT find that project. I know it was posted somewhere.
Here's one:

http://www.pollak.sulinet.hu/elektro/hidak/hidak.htm


Here's some reading I found from Mini-circuits

http://www.minicircuits.com/pages/pdfs/coup7-2.pdf


This appears to be the back door to their tech notes

http://www.minicircuits.com/pages/pdfs/

Search the web also under stuff like "hybrid combiner", "hybrid coupler", "directional coupler", "return loss bridge"

[xmo]

Indeed Agilent is following HP's fine tradition of creating an extensive range of application notes and product information that teach technology basics as well as their solutions.

Here is one that discusses directional couplers and bridges:

http://www.home.agilent.com/upload/cmc_ ... erview.pdf

And here is an application note that discusses the tracking generator option for the ESA series spectrum analyzer:

http://cp.literature.agilent.com/litweb ... -1650E.pdf

This note shows how to make transmission and reflection measurements. Much of this information would be applicable to other similar instruments.