The M-802 has no true SWR indicator. During transmit, it shows relative power output. During recieve, it shows relative received signal strength.
The "Tune Indicator" shows the antenna
tuning condition, and when the "SWR" appears it means the "SWR has worsened". Useless.
From the manual:
"SWR” appears when the antenna SWR worsens during
transmit, depending on the transmit output power. If it
appears, check your antenna system.
I strongly believe that EVERY SSB installation
should have a good cross-needle power/SWR meter installed in-line 100% of the time. A good one these days is the Daiwa CN-101L....about $99 online or from HRO, and worth every penny.