[Yaesu] IC756 and Yaesu Quadra amp - Band Data Interface design?

Tue, 19 Feb 2002 08:11:09 +0200

Hi Jerry

The LM3914 is a simple and ellegant voltage controlled switching device.

The question is how will you select the exact switchover voltage for each
output on the LM3914?

Icom uses a strange series of voltages for switching, typically 6.1, 5.3,
etc
(I cannot remember the exact range).  The input range of the LM3914 can be
set, but I do not think one has control over the switchover point of each
output.  I have not used the LM3914 for many years.

I once built an automaitc antenna tuner for a disabled Ham and the band
switching on the tuner was done in the same manner you have in mind.  I used
a set of LM339 votage comparators, with a reference voltage supplied by an
accurate reference voltage IC, to perform the switching.  Each comparator
was set to the exact Icom band switching voltage.  This scheme was bullet
proof and did not drift at all, due to the accurate reference voltage IC.

The LM339 data sheet provides all the information to use the IC.

Regards
Deon ZR1DQ
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----- Original Message -----
From: Jerry Flanders <[email protected]>
To: <[email protected]>; <[email protected]>
Sent: Tuesday, February 19, 2002 4:40 AM
Subject: [Yaesu] IC756 and Yaesu Quadra amp - Band Data Interface design?

| I am getting a Yaesu Quadra amp to use with my IC-756PRO exciter. I know
| they can be used together, and lots of guys are doing so. BUT - I have not
| heard of anyone making up a band data interface to go between them to set
| the quadra to the band the PRO is on automatically. It appears that most
of
| the guys let the quadra count the freq to set it up, and others set the
| quadra manually.
|
| It appears that a LM3914 in dot mode and a set of diodes in a matrix is
| most of what is needed for a true band-data interface. Has anyone tried to
| set this up?
|
| Jerry W4UK
|
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