[Elecraft] K3 to Yaesu Quadra Band Data 2 question

[Joe Subich, W4TV]

> However, I have received emails from a few K3 owners saying they
> indeed HAVE successfully used INPUT 2 with a second HF transceiver
> but none have testified to resolving the issues Joe alludes to
> below.

The Exciter 1/Antenna 1 default is a limitation of the switching in
the Quadra that is not "solvable".  However, as long as one is not
trying to use the Quadra for SO2R (needs to receive on Exciter 2
whilst simultaneously transmitting or receiving on Exciter 1) that
is not a barrier.

The real issue is the single F.SET output.  F.SET is connected to
the K3 "Key" input to provide a carrier for adjusting the Quadra's
automatic antenna tuner in response to pressing the F-Set button
on the Quardra control panel.

The Quadra's original design clearly included separate F.Set outputs
on the 15 pin "Band Data 2" jack - with switching done by RL7501 on
the Connector Unit board.  However, when the FT-1000D and later MP
required a specific resistance to ground rather than a contact
closure to ground for the "TUNE" function, the second output was
changed to provide the resistive pull down and the relay was used
to engage F-Set rather than switch the F.Set line.

Other than the F.Set and SO2R limitations, the Quadra works just fine 
with two exciters.  The Band Data 2 cable schematic is *identical* to
the Band Data 1 cable documented on N0SS's web site *except* that
the DIN8/262 is replaced by a DA15P - the pin numbers are the same
on either connector.

K2ESE has developed a modification to the Quadra that resolves the
F.Set issue - if you can find it on the web.  In essence the K2ESE
modification taps the internal "exciter select" line and routes it
to an external opto-isolator and relay to switch the F.Set signal
between the two exciters.  Once could certainly do the same "job"
by adding an opto-isolator and rewiring RL7501 but of course that
is major surgery as opposed to routing the "exciter select" line
to an unused pin on the "Band Data 2" jack and doing the switching
externally.

Two other notes:  1) the exciter using Band Data 2 must be connected
to Input 2.  This has one side effect - if the *only* exciter is using
Band Data 2, the exciter can not be used if the Quadra is turned off
(as opposed to standby).  2) the PTT inputs of the two Band Data jacks
are connected in parallel and the *unselected* input (exciter) is open
circuited.  One must be careful not to transmit on the unselected
exciter (thus one imperative for switching F.Set instead of the default
parallel operation) although connecting the "Inhibit" line to the K3
and setting MENU:TX INH => HI =Inh will prevent the K3 from generating 
RF if it is not selected!

73,

    ... Joe, W4TV


On 10/10/2013 2:31 PM, KENT TRIMBLE wrote:
> Additional Quadra information . . .
>
> According to a phone conversation I had several years ago with Yaesu
> Support, the Quadra's INPUT 2 was intended to accommodate a six-meter
> exciter, not another HF rig.  Because of internal changes made by Yaesu
> during final design planning (literally at the last minute) to
> incorporate other applications, INPUT 2 does not support the same
> features as INPUT 1.  However, I have received emails from a few K3
> owners saying they indeed HAVE successfully used INPUT 2 with a second
> HF transceiver but none have testified to resolving the issues Joe
> alludes to below.  Neither Tom Hammond nor I pursued further INPUT 2
> issues for the simple reason that I had no interest in using it.
> Moreover, Elecraft's KPA500 was in the final development stages and I
> knew I would be using it with the K3.  To my knowledge, Yaesu has never
> addressed these INPUT 2 issues and the circuitry remains the same as
> originally designed.  If someone has information to the contrary, please
> let me know.
>
> As for Dick's eyesight problems (join the crowd), I suggest taking a
> look at the appropriate Winford Slim Breakout Board
> (http://www.winford.com/products/brksd15.php) as an easy alternative to
> cabling.
>
> 73,
>
> Kent  K9ZTV
>
>
>
>
> On 10/10/2013 10:01 AM, Joe Subich, W4TV wrote:
>>
>>> I'd like to have my 2nd K3 control the Quadra via the Quadra's Band
>>> Data 2 connector. I'm wondering if this is possible,
>>
>> Yes.  Note however, there are some issues in using two exciters -
>> particularly the lack of switching for the TF (tuning) output from
>> the Quadra.  There are a couple modifications on-line that add an
>> external relay to provide that function.
>>
>> Also note that Exciter 1 (Band Data 1) and antenna 1 are automatically
>> selected when the Quadra is off/bypassed.  Exciter 2 will have no
>> antenna and the Inhibit line is forced high (no RF from Exciter 2).
>>
>>> if so, if anyone manufactures the needed cable to go between the K3's
>>> accessory connector and the Quadra's Band  Data 2 jack?
>>
>> Not to my knowledge.  Further,  do not recall any published info on
>> wiring such a cable - it was not included in N0SS's work - although
>> one could derive the information from the Quadra Service Manual or
>> the general interfacing documentation at VA7OJ/AB4OJ's Quadra web
>> site.
>>
>> Yaesu offer the CT-178 Connection cable for connecting the FT3000
>> to the Quadra.  One could modify that cable by replacing the DA15P
>> on the exciter end with the appropriately wired DE15P.  Similarly,
>> one could modify the Yaesu CT-118 cable for the FT-450/950/1200 and
>> Quadra by replacing the miniDIN-10 on the transceiver end with the
>> appropriately wired DE15P.
>>
>> 73,
>>
>>    ... Joe, W4TV
>>
>
>>
>> On 10/10/2013 1:29 AM, RLVZ at aol.com wrote:
>>> Hi Guys,
>>>
>>> Wondering if anyone has successfully used a K3 to control a Yaesu Quadra
>>> by using the Quadra's Band Data 2 jack?  My K3's has  been controlling a
>>> Quadra via the Quadra's Band Data 1 and it works  well.  But I'd like
>>> to have my
>>> 2nd K3 control the  Quadra via the Quadra's Band Data 2 connector.  I'm
>>> wondering if this is  possible, and if so, if anyone manufactures the
>>> needed
>>> cable to go between the K3's accessory connector and the Quadra's
>>> Band Data 2
>>> jack?  (I've got eye problems and cannot wire  small cables)
>>>
>>> Thanks & 73,
>>>
>>> Dick- K9OM
>
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