This is an intruiging problem. Carhamptons transmit antenna system is a simple cardioid colinear array (pics on mb21) so a fault with the transmit antenna, while likely to cause a pattern change, would result in a noticable change in signal strength but not quality. The only things that can cause a quality loss to this extent on all three muxes are local interference, adjacent channel interference (these days often 4G) or as Chris SE has discovered - a strong co-channel interference source. Looking at the postcodes and the bearings from them to the relay, and to Kilvey Hill, it does look like that is the case here!
It looks like a somewhat imperfect level of spectrum planning! Plus, remarkably bad luck in that all three channels are co-channel with Kilvey Hill!
I suspect, as mentioned, the way to alleviate this is with some clever use of receive antenna pattern, bearing, and use of available shielding (positioning on side walls etc to try and block Kilvey)
one thing to note though - Kilvey is only part way through the 700MHz clearance process, at some point in the future that process will be completed. Ive no idea whether that will be a further frequency change or not
Saturday 3 August 2019 5:12AM
This is an intruiging problem. Carhamptons transmit antenna system is a simple cardioid colinear array (pics on mb21) so a fault with the transmit antenna, while likely to cause a pattern change, would result in a noticable change in signal strength but not quality. The only things that can cause a quality loss to this extent on all three muxes are local interference, adjacent channel interference (these days often 4G) or as Chris SE has discovered - a strong co-channel interference source. Looking at the postcodes and the bearings from them to the relay, and to Kilvey Hill, it does look like that is the case here!
It looks like a somewhat imperfect level of spectrum planning! Plus, remarkably bad luck in that all three channels are co-channel with Kilvey Hill!
I suspect, as mentioned, the way to alleviate this is with some clever use of receive antenna pattern, bearing, and use of available shielding (positioning on side walls etc to try and block Kilvey)
one thing to note though - Kilvey is only part way through the 700MHz clearance process, at some point in the future that process will be completed. Ive no idea whether that will be a further frequency change or not