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Old Dec 14, 2011, 11:18 AM
Build Fly Crash Repeat
crezzee's Avatar
Worcester UK
Joined Nov 2004
774 Posts
If anyone in the UK is building one of these, how about swaping some SMA patch cables in return for a couple of these detector diodes.

http://uk.rs-online.com/web/p/produc...633D4E4F4E4526

PM me if interested
Cheers Ian
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Old Dec 14, 2011, 11:32 AM
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GregSilver's Avatar
United States, FL, Plantation
Joined Nov 2005
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Anyone willing to contribute and make a PCB layout for this?

I might be willing to contribute and CNC the boards for people. I have time to cut about 10-20 boards a week.
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Old Dec 14, 2011, 12:12 PM
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i think i found the cheapest source for the coupler, but only for 900-1200, at 12 shipped worldwide:

http://www.ebay.com/itm/310209833363...fvi%3D1&_rdc=1
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Old Dec 14, 2011, 02:00 PM
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Too big the price to abandon 5.8Ghz.
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Old Dec 14, 2011, 04:00 PM
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Canada,Quebec
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Quote:
Originally Posted by Martinba77 View Post
I am just wondering now if I found a Dual Directional Coupler for my Frequency, then can I have a double (vF/vR) reading and attach directly into two voltage displayers and have the two numbers simultaneously? And then make a nice wood box and have put toghether nicely inside with the two displays facing outside to the front of the box?
Mmmm, maybe this make no sense at all!

Martin
Yes, it make lot of sense

-Hugo
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Old Dec 14, 2011, 04:30 PM
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SW England
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If you are not interested in frequencies above 2.4GHz, than you can make something like this

http://pe2er.nl/wifiswr/

or this

http://www.frars.org.uk/cgi-bin/render.pl?pageid=1085

Nigel.
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Old Dec 14, 2011, 11:44 PM
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United Arab Emirates, Dubai, Dubai
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I have built this one : http://pe2er.nl/wifiswr/ with just RF head PCB modified to fit into the square made of 3 SMA panel connectors soldered together. Works great on 5.8GHz too. I think it is not as accurate as power coupler based but good enough for home use.
EDIT: also - I used only 3 OpAmps - didn't use the one with NULL pot on it.
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Last edited by Leszek_K; Dec 15, 2011 at 12:06 AM.
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Old Dec 15, 2011, 12:29 AM
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Any issue if the components are soldered in the air without PCB, if skills permits ?
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Old Dec 15, 2011, 02:22 AM
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Quote:
Originally Posted by RENATOA View Post
Any issue if the components are soldered in the air without PCB, if skills permits ?
It can be done with good soldering skills...

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Old Dec 15, 2011, 02:34 AM
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Leszek_K's Avatar
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Renatoa - I assume your question was directed to me - didn't try that. PCB is double-sided as in a picture. Still needed a little vane capacitor to balance the bridge..
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Old Dec 15, 2011, 02:37 AM
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United Arab Emirates, Dubai, Dubai
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Quote:
Originally Posted by Hugeone View Post
Yes, it make lot of sense

-Hugo
In that case it would be easier to add some differential amplifier and show SWR directly.
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Old Dec 15, 2011, 04:34 AM
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I see that someon use a 50ohm resistor for port 4 ( coupler )....why ?
When you buy a coupler....Isnt port 4 terminated ?


Thanks
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Old Dec 15, 2011, 07:35 AM
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IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
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@renatoa - You can also build a wheatstone bridge circuit with 3 X 50 Ohm resistors on a PCB board and tap between the measurement junction for the reading. In any case you need a ground plane for reference or the circuit will resonate. So a backed PCB board makes it easy.

-Alex
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Old Dec 15, 2011, 09:41 AM
ELECTRIC R/C
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INNERKIP,ONTARIO,CANADA
Joined Feb 2006
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Mini-HowTo SWR meter - A DIY project

Quote:
Originally Posted by piopio View Post
Is this diode OK for swr-meter ?

http://www.rs-components.co.id/diode..._from_store=id
Thanks
The Max forward voltage is very low for this item.!
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Old Dec 15, 2011, 09:51 AM
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Amherst, VA
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^yes it is. It's a Schottky diode. It's supposed to be low. That is the voltage drop when working in the forward mode.

-Alex
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