Like Herb is pointing out, one of the problems with stuff bought off the
shelf (from DXE or others) is the lack of documentation.
I have been waiting more than 3 years - so far without luck - for a real
documentaione of the DXE NCC-1 which is a very good phasing unit but int the
end one sertainly needs a good schematic if somthing goes wrong. So far they
have failed to deliver.
Len
SM7BIC
I would avoid any attempts to do relay switching by supplying voltage down a
coax cable but rather use two coax runs. The relay, blocking cap, diode and
associated circuit in my case with two DXE boxes have deteriorate within
less than a year to be useless, mostly due to electrolysis and zillions of
ants attracted apparantly by the voltage or relay coil vibration when pulled
in. (Yes I covered all the edges with
silicon sealant) DXE refuses to send me a print to repair the board
for what reason I don't know, thus making repair very difficult. They
worked well when I got them but are useless today. Another
disadvantage of having a blocking cap in the signal line is that you can not
determine the coax run continuity through the windings of toroid back to the
shack with a common VOM. This is an easy troubleshooting tool that is not
possible via the DXE system.
Herb, KV4FZ
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
|