RayUpdate on these interesting signals. I'll post images later, but I caught BOTH examples in one 10 minute time frame this weekend. Each had a similarly irregular timing interval and variable degree of "chirp". Signal strengths were also comparable. In fact it made me wonder if the same TX is responsible for both groups of transmissions, and has some bimodal instability.
Generally, conditions were very good here at PVC during weekend monitoring. 7P and TSN were very consistent and frequently audible for long periods. NC, OV and others were present. The tight grouping at the 13,555.5xx watering hole was made abundantly clear in a couple of captures. Longer path signals were received well after local dark.
Ed