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Old Dec 13, 2011, 08:25 AM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
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Mini-HowTo
SWR meter - A DIY project

It's been a while since I made a tutorial so I figured it's time for another one. This is my DIY SWR meter. The complete build and operation instructions can be found here: http://fpvlab.com/forums/showthread....urself-project

It is made of 5 parts:

Directional coupler
Microwave detector diode
Resistor
Capacitor
Short RG316 jumper

You must be a master at soldering to build this, but it's cheap and works all the way up through 5.8GHz. That's right, a 5.8GHz SWR meter. Finally!

SWR is calculated as follows:

p = Vr/Vf

SWR = 1+p/1-p

Videos of how to use it:

Forward power
IBCrazy's DIY SWR meter - Forward power (1 min 0 sec)


Reverse power
IBCrazy's DIY SWR meter - Reflected power (1 min 23 sec)


Good luck and have fun with this one.

-Alex
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Old Dec 13, 2011, 08:56 AM
never mind the boll⁣⁣⁣ocks
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Australia, NSW
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ooooh

im off to google what SWR is lol
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Old Dec 13, 2011, 09:03 AM
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United States, CA, Salinas
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Quote:
Originally Posted by brosius85 View Post
ooooh

im off to google what SWR is lol
SWR: Standing Wave Ratio. It's a means of determining how closely matched the antenna system impedance is to the transmitter. "Perfect" SWR is 1:1. "Typical" for amateur radio is between 1.2:1 and 1.5:1.

Ask a silly person, get a silly answer...
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Old Dec 13, 2011, 09:32 AM
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United States, CA, Santa Cruz
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woo thanks man! This looks like a col project to finally test my antennas that don't really look "right"
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Old Dec 13, 2011, 10:25 AM
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Does it work with 5.8GHz item ?


thanks
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Old Dec 13, 2011, 12:30 PM
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Is this diode OK for swr-meter ?

http://www.rs-components.co.id/diode..._from_store=id


Thanks
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Old Dec 13, 2011, 02:21 PM
Engineer for Christ
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Amherst, VA
Joined Jun 2006
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^That should work fine. I used an Agligent HSMS-286K. This stuff is very hard to spec out, sadly...

-Alex
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Old Dec 13, 2011, 03:26 PM
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SW England
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Quote:
Originally Posted by brosius85 View Post
ooooh

im off to google what SWR is lol
More accurately it's a VSWR bridge/meter.

Also, careful using RG316 at 5.8GHz, it's not rated to that frequency.
For 5.8GHz, you need CLF200 or similar/better.

Well done again Alex.

Nigel.
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Old Dec 13, 2011, 04:17 PM
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Is it good CERAMIC capacitor 0,01uf (or 0,1uF ) 100V ?


thanks
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Old Dec 13, 2011, 09:41 PM
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Awesome! I've been waiting for this. Thanks IB!!!
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Old Dec 14, 2011, 12:26 AM
Ikaruswannab
Joined Sep 2009
968 Posts
Hi Alex,

Can you suggest a parts list for this project??
Thank you for sharing.
Teo
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Old Dec 14, 2011, 12:29 AM
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parts list is over on the 'lab
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Old Dec 14, 2011, 02:05 AM
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Originally Posted by volto View Post
parts list is over on the 'lab
site seems to be down cant access it ...
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Old Dec 14, 2011, 02:26 AM
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awesome. now upsize the parts so you can knock out about 150 for the website. too lazy to solder!
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Old Dec 14, 2011, 03:07 AM
It just keeps getting better!
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Eureka, CA
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Outstanding!
Just what I've been waiting for.
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