Actually a 2C ICOM is internally compensated and will not compensate
any other ICOM it's Compensation pin is not connected internally.
All ICOMS will stay with in 2 parts per million with in the "
normal temp range". It's when you get to the "extreme" rang of temps
that the compensation takes over. Before you slam me read your
manual carefully.
Here is what it all means:
EC = "Externally Compensated"
5C = "Internally Compensated to remain with in 5 Parts per million
and will compensate all other ICOMS except 2C.
2C = "Internally Compensated only and will not compensate external
ICOMS and will keep it's frequency with in 2 parts per million"
73
AC0Y
--- In [email protected], "edctexas" <[EMAIL PROTECTED]>
wrote:
>
> --- In [email protected], "kg4wmp" <[EMAIL PROTECTED]>
wrote:
> >
> > I could find nothing
> > specific on why a radio whould need 4 (or more) 5C's and 1 EC.
Do
> > they take an average over several crystals or something or was
this
> > a function of multiple channels?
>
>
> Normally a mobile set only needs one 5C or 2C ICOM. The EC units
are
> slaved to the correction that the 5C creates for itself. The radio
> could have the buss cut and use separate Master and slaves for TX
and
> RX. It is not normally recommended to use multiple 5C units.
This
> will cause the units to fight each other. Theeir temp. comp. will
> not be correct. But on low band and for ham use, put in what you
got
> and use it. Some of the MII repeaters in this area don't bother
with
> any temp. comp. at all.
>
> The master ICOM has a selected thermistor and resistor combination
> which produces a correction voltage to a tuning diode (varicap).
If
> I remember right the 2C units have to have the parts selected, but
> the 5C units don't. The EC units have the tuning diode and get
the
> correction voltage from the master. If two masters are tied
together
> the voltages fight.
>
> Some guys use EC ICOMs and modulate the varicap. Its good FM but
> generally low deviation. Most repeaters source their +10V from a
> separate source for TX and RX. This separation prevents any RX
side
> noise from adding spurious to the TX. Simplex transmitters don't
have
> the problem as the RX is off during TX. Repeaters do have the
> problem without this extra separation.
>
> More GE trivia! WE can take this off line if you'd like more poop.
R-
> B website that Kevin has is a great source book. Once you get a
> manual your off. Many mobile use the same key. I'm not sure if
the
> station key or the mobile key is stamped BF-10 anymore. Nearly
any
> 2way shop has a ley to unlock it. I'd just use the master key
> (electirc drill). Then vaccuum the mess out of the radio.
>
> 73 Ed K3SWJ
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/Repeater-Builder/
<*> To unsubscribe from this group, send an email to:
[EMAIL PROTECTED]
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
