Skip Goulet said:
I bought one of the early PA300s back in the early '80s when they first came out, and just didn't like it. It just didn't sound like a "true" Federal siren. The yelp had too much of a "wah-wah" sound, and I didn't like the wail, either. Couldn't fault the hi-lo or air horn, though!
It depends on what your definition of a 'true Federal siren' is. Over a twenty year period (early 1960s to early 1980s) the sounds of Federal electronic sirens changed dramatically.
PA5/PA10: sound closer to a mechanical siren
PA15/PA20: more electronic sounding, but still low-pitched
Early PA15A/PA20A (B, C, and D series): low-pitched slow rising wail tone, true "wah-wah" yelp tone
Late PA15A/PA20A (E series), PA150/PA170/PA200/PA1000: high-pitched fast-rising wail tone, "yow-yow" yelp tone
Early PA300: high-pitched slow rising/fast falling wail tone, fast falling yelp tone.