RadioBanter - View Single Post - Add bands to Yaesu FTDX-400

Barry OGrady[_3_] · July 24th 14, 09:51 PM posted to rec.radio.amateur.boatanchors

On 24 Jul 2014 10:02:05 -0400, (Scott Dorsey) wrote:

Barry OGrady wrote:
I recently obtained a Yaesu FTDX-400. I have operation and
service manuals but I can't find how to add bands.

Just looking over the manual for a minute, it looks like the band switch
selects one of eight crystal positions, and that output is beat with the
VFO and the modulated signal to form the output.

According to the manual, all eight positions are filled, and there are three
empty positions at the end. It looks like the trimmers are all in place if
the manual is any judge.

So, it looks to me like if you want to add bands, you would first need to
fill those three positions and set the trimmers.

The bandswitch also switches several other stages. You'll notice the last
three positions of S1e, S1f, and S1g are disconnected and you will have to
connect those to the appropriate points on the filter networks for the bands
you are using. But I suspect nothing would have to be added other than
jumpers.

It would be an interesting exercise.

Perhaps not worthwhile.
It does have three empty crystal positions so logically I would need
to add the appropriate crystal for each band,
It does sound like I'm asking the impossible for such an old radio
but the facility is there.
Perhaps the information is on an amateur forum somewhere.

--scott

--
There is something outrageous about such a huge body of evidence being
put together, then being confirmed in all kinds of other scientific
disciplines, particularly genetics, and having other people just sort
of deny it for reasons that have nothing to do with truth.
– Matthew Chapman, Darwin's great-great-grandson.