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s-meter useless?

Jan 31st 2022, 08:02


Joined: Sep 21st 2021, 15:12
Total Topics: 0
Total Posts: 0
I recently received a Yaesu FT-7900R transceiver in the mail. Setting it up I find it reads 9 every signal received. Have I missed something in the manual? No way every transmitting station near or far is a S-9. Any suggestions how to use this S-meter? A setting I can change? Or just out of luck? Reviewed as the best mobile transceiver in the U S and the most popular with Hams. Not so popular with me.
Jan 31st 2022, 08:30


Super Moderator

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
This radio is popular because it has a high resistance to intermod, something that is hard to do.

But, as our 2010 Product Review noted, this is an update of a radio reviewed in 2004. Back then most hams accepted that S-meters weren't accurate. Yaesu had no spec for S9. We measured 5.3uV on 146 MHz and 6.3 uV on 440MHz.

An SDR design can provide much better S meter accuracy, but a hybrid design with expensive filtering is needed to get both good IMD performance and an accurate S meter. As far as I know this is only done with the most expensive base stations.

Zak W1VT
ARRL Senior Engineer

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