Hi guys .I have a small problem that i have been trying to
sort out for a while now .I have 5 repeaters operating on one of my
sites
3 vhf low band and 2 uhf band.The frequencies are as follows
VHF
A-TX 70.300MHZ RX 72.800MHZ
fitted with 4 1.5 meter by 4 inch meter tins-most likely a notch
diplexer 3db colinear ant FM828E
B-TX 70.5875MHZ RX 73.0875MHZ fitted with 4 1.5 meter
by 4 inch meter tins-most likely a notch
diplexer 3db colinear ant
FM828E
C-TX 70.725MHZ RX 73.225MHZ fitted
with a new band pass/band reject possibly a
varinotch 3db colinear ant
FM828E
UHF
D- TX 473.575 RX
478.775MHZ fitted with
mobile notch diplexer 6mc450s 6db colinear ant MAXON
PM150/SM4450SC
E- TX 489.1MHZ RX 483.900MHZ fitted
with 6ld450s diplexer 6db colinear ant MAXON
PM150/SM4450SC
All coaxes are Heliax from antennas to Diplexers with N
connectors
Interconnecting cables between diplexers and radios are
rg223u
A and B are a 1.5 meter apart with C in the middle
All antennas are mounted aprox 50 cms or more away from C or
each other .
D and E have a 1.5 meter between them
ie-
D
A
C B
E
I am at times having desense (ie scratch ) especially in windy
weather occuring on repeaters B and D.It doesn't seem to affect the
desense wether the transmitters are txing or not .There isnt any problem
of the repeaters affecting each other ,they all work great just the
problem of scratch coming and going .A,C and E do get scratch on
occasion but no where as bad as D and B.D and B works great
sometimes (clear with no scratch)and then reception
will slowly develope major scratch and then slowly clear up
-possibly electrostatic or wind moving the antennas ?.I have been
fixing loose bolts on the windmill tower to stop problems incase
of tower twist and this affecting service.I am wondering if there are
any futher sugestions .
Thank You,
Ian Wells,
Kerinvale Comaudio,
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