It appears that the parish is a farm community. For all you city folks, farm communities tend to be staid; and farmers tend to be out in the fields working - and during the summer, an 8 hour day may be about half the working day. Listening to any radio which takes concentration (in other words, something besides background music) is not going to score, let alone score highly. I am not the least bit surprised that the interest by the “elders” was less than “break the door down and let me at it”. It is not a matter that the radio station may have something to offer; it is that there is no time to accept.
we had a young man from a fundamentalist/evangelical background in RCIA this year, and yes - he was on fire. He wanted to start a chaplet to St. Michael.
All well and good, but people in our parish by and large say devotional prayers privately, not in large or even medium size groups. We do have a rather small group which says the Rosary, but I suspect he would be rebuffed if he were to approach them with the suggestion - and probably part of that would be “you have never participated with us, and you are coming with suggestions of what we should do?”.
As noted, if it amounted to putting up a flyer or a small collection of materials from Relevant Radio, I am not sure why he would need to go to anyone except the priest for permission; and no idea what an “ambassador” would have for any other functions.
I suspect there are activities/groups within the parish in which he could participate, and that might be wise before he charges off with a new activity that he engage with one or more and become familiar with the parishioners - and they with him.