Someone suggested changing antennas but mine would always check out fine on the meter at the radio repair shop. The $45 antenna for the Pointer ELT is right next to the $850 Granger antenna so I switched antenna connectors. The $45 antenna worked great. Range was 3 times what it had been before and it worked for hours without problems.
The Granger antenna is an angled blade that sticks up through the dorsal fin. This is some mickey mouse arrangement that Marchetti adapted years ago. My last SF260W, which was experimental, had a whip antenna that was under the dorsal fin. So I spent three hours making an adapter plate and mounted the ELT antenna under the dorsal fin. Then I started to put the dorsal fin back on the plane and discovered that there are internal braces on this fin that were not on the SF260W. So I spent another hour putting everything back like it was and ordered a Granger substitute which only cost $295 to go inside and through the dorsal fin.