Thanks Eric .The uhf diplexer is a 6mc450s and it has been tuned to the
makers procedure (tuned for the notch and not pass).The notches came up with
ease around 70 db each side and the db loss at the pass frequency was around
1-2 db .I am using a hp8921a with the duplex out and ant in connections
These mobile notch duplexers are supposed to do between 400-520mhz but as
you say maybe they are built to suit the particular frequency for the client
.There are plently of them available and they quote they are supposed to
cover the frequencies.The interconnecting cables cannot be changed and are
molded into the design of the duplexer. I have been able to remove the top
screw plate from the one I am having problems with and have found one of the
insulating tubes has a burnt hole through it so a spark of rf could jump
from the tube to the adjusting screw and has burnt the tip of the screw
black so this could be the cause of the static and loss of power because it
was in the TX pass side.I will look at making a new insulator tube and test
it again . I have other flat pack duplexers in use and they work perfectly
I have been changing them slowly over to 6LD450s notch duplexers because
they seem to work better than the mobile flat packs.
Thank You,
Ian Wells,
Kerinvale Comaudio,
361 Camboon Road.Biloela.4715
Phone 0749922574 or 0409159932
www.kerinvalecomaudio.com.au
