This LED SWR meter any good?

I am only looking for a simple circuit that will let me know if my antenna is matched fairly close. NOT looking for total perfection. Any idea what the proper way to use/adjust it is?
Thanks.

The circuit it will not work as a SWR meter, because there is no directivity in the coupler used.
You need a transformer or coupled lines to do the job.
Here is an example:
http://www.py2mg.qsl.br/Arquivos_PDF/PONTESWRQRP1.pdf

Thanks for the reply. It just goes to show that people place bad /non-working schematics on the internet.....why they would waste their time I will never understand. I have everything for the schematic you told me to look at. The 10pf trimmer is used for fine tuning? Anything else you can tell me about this circuit before I build it? Usage/design etc....

Thanks

Looks like a bridge circuit to me, which could be used to measure the load impedance.
Bridge circuit - Wikipedia, the free encyclopedia

before you start building, you should really tell us what freq you are interested in using the meter on

yup exactly and you wont measure SWR with a bridge ! :)


OP have a look here for a real SWR meter :)

VK5AJL - Build your own micro-stripline SWR meter - the only way to measure SWR.


Dave

That link was perfect. Very informative. Thanks.

Not during regular operation, of course. You would use a coupler for that.

But as a "measurement instrument", bridge is fine (and broad band) to measure antenna input impedance.

"But as a "measurement instrument", bridge is fine (and broad band) to measure antenna input impedance. "


So If I was to make that bridge, I would connect it to my transmitter and antenna and it would let me know if the antenna is a good match for the transmitter by the LED not lighting up?

The configuration is not a bridge. Is just a simple diode detector followed by an LED which will indicate just the peak forward power.

You can see here a simple impedance bridge.

Red = one arm of the bridge
Blue = other arm of the bridge, consisting of 51 ohm and antenna

Diode is between the arms, and will see RF power if the bridge is out of balance (i.e. antenna <> 51 ohm)
Rectified signal will then light the LED