They are ALL line of sight. They ALL work on FM frequencies, therefore they can only operate on line of sight. Only AM frequencies can utilize the skip zone and bounce the signal off the ionosphere. Some, however, have a bit more power thus they can transmit a cleaner signal for a little farther distance without interference from small objects.

Gary

https://youtu.be/70zVgVyWtYs

Starting about 6:52

What that tells you is they are working with the maximum amount of power they can work with on those bands, legally. Depending upon the frequency, there are limits as to how much power the transmitter can use. For example, handheld marine VHF radios are limited to just 5-watts transmit power, while base stations are limited to 25-watts. I can contact another station at a distance of about 1 mile with my handheld VHF radio, but with the 25-watt radio I can reach someone 15 miles away.

Same is true for the VHF and UHF frequencies used on wireless mics. Those that utilize frequencies that allow higher power can fire out up to, I believe, 1-watt, which is a lot for a wireless mic. Consequently, if the receiver has a decent antenna system, it can pick up signals with reasonably high quality at longer distances, even when there are concrete block walls between the transmitter and receiver. Place a steel wall there and nothing will get to the receiver because it is an RF shield, where concrete allows some RF to penetrate to the receiver.

I suspect the next big breakthrough with wireless mic technology will be mics that operate on 3G and 4G frequencies, which currently are used by broadband radar and cellular telephones. The clarity will be incredible and the reception should be exceptional.

Hope this helps,

Gary

Tx Gary for the additional explanation. I could have gotten by with the cheaper model but got such a good deal price difference was negligible.

Tx again