K3s / P3 baud rate, poor man's 2nd receiver

[Henk de Vries (hdv)]

Hi all,

 

Using my home-made RS232 sniffer in order to capture K3s frequency
information while my K3s is exchanging information with Wintest I found some
non-obvious behaviour of the PC - K3s USB baud rate that might interest
others as well.

 

The set-up is PC <a> USB <b> K3s <c> RS232 <d> P3 <e> (PC port of P3)

<x> = connector/port

 

Normally all baud rates are 38400 bd.

The link <c> RS232 <d> is 38400 bd and cannot be changed.

 

When changing the baud rate of the P3 (with P3 menu) the rate on <e> becomes
the selected rate (as expected), so 4800, 9600 or 19200 bd.

However also the rate on <a> (USB) <b> is changed to this rate.

 

So the P3 is always in control of the baud rate towards the PC, no matter
the connection towards the PC; via USB port on the K3s or via RS232/PC port
on the P3.

However, when the P3 is switched off, the <a>USB<b> rate reverts to the
default setting of 38400 bd (of the K3s).

 

I thought it worth mentioning, because this behaviour is not explained in
the K3s or P3 manual.

Applications running on the PC will stop unexpectedly when a non-default
baud rate is in use and the P3 is switched off.

 

Going through the schematics I found the reason for this behaviour.

The USB info is routed to a dedicated IC where it is split in an audio
stream towards the K3(s) and a data stream.

The data stream exits the IC as RS 232.

 

Depending on the cable connector which is plugged in the RJ45 socket of the
K3(s) it is determined if the RS232 signal is processed internally or routed
to the P3.

(a short in the connector indicates "P3 present" towards the K3s, although
just the cable is plugged in). The cable used is the supplied CBLP3Y.

 

In the P3 the RS232 signal coming from the K3s is received on the PC port.
Using the XCVR port on the P3 the RS232 info is looped-back to the K3s (via
the same cable and RJ45 port)

There is RS232 rx/tx electronics involved in the P3, so the input rate (P3
selectable) can be different from the output rate. (fixed at 38400)

 

Due to the USB to RS232 conversion and routing via the P3, the P3 is in
control of the baud rate of the whole chain towards the PC, including the
USB port.

However when the P3 is switched off a relay connects the P3 PC and XCVR port
(circumventing the internal rx/tx RS232 electronics) and the baud rate is
now determined by the input port of the K3 (38400 bd fixed)

 

It seems a bit odd to convert the USB data stream to RS232, but TMO this
set-up is chosen to maintain compatibility between the "old" K3 <> P3 RS232
way of working (with P3 <> PC connection) and USB K3s or K3 KIO3 USB upgrade

 

Btw, I am using my RS232 sniffer (built around an Arduino and MAX232) to
capture IF and FB data words from the K3s, extract frequency and split
information and convert that to Yaesu CAT protocol.

This way my Yaesu FT 847 is slaved to the K3s (for all bands).

However I use the slaved FT 847 only for tx-ing on 2 meter, while the K3s +
2 meter converter is used as receiver. (due to this Arduino software
solution I did not need to build a transmit mixer from 28 -> 144 + 50W
amplification chain)

 

The K3 can be set in A1 (auto information) mode (IF info only) in case
Wintest is not used/available.

However these A1 single data words are sometimes missed by the software.

I choose to make the set-up a bit more robust and run a small home-made .exe
which generates IF and FB "GET's" on the USB link towards the K3s when
Wintest is not in use.  

(it would be best if the K3 could send A1 information on a periodic basis.)

 

One of the options is to use this set-up as a "poor man's" 2nd receiver on
HF. The FT847 follows the K3s everywhere.

Only an additional simple audio switch is needed to get main, "sub" or
diversity reception.

 

Schematic and software (with lots of comments) are available for free for
those who want to build/experiment themselves. (Arduino IDE and Dev C++
compiler or similar are needed)

Contact me off-list if you are interested.

 

73 Henk

PA0C

 

 

 

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[Nr4c]

No need to waste a lot of time on this. Set all to 38400, the default speed for the P3 to work well.

Sent from my iPhone
...nr4c. bill

> On Oct 12, 2018, at 3:28 PM, Henk de Vries (hdv) <[hidden email]> wrote:
>
> Hi all,
>
>
>
> Using my home-made RS232 sniffer in order to capture K3s frequency
> information while my K3s is exchanging information with Wintest I found some
> non-obvious behaviour of the PC - K3s USB baud rate that might interest
> others as well.
>
>
>
> The set-up is PC <a> USB <b> K3s <c> RS232 <d> P3 <e> (PC port of P3)
>
> <x> = connector/port
>
>
>
> Normally all baud rates are 38400 bd.
>
> The link <c> RS232 <d> is 38400 bd and cannot be changed.
>
>
>
> When changing the baud rate of the P3 (with P3 menu) the rate on <e> becomes
> the selected rate (as expected), so 4800, 9600 or 19200 bd.
>
> However also the rate on <a> (USB) <b> is changed to this rate.
>
>
>
> So the P3 is always in control of the baud rate towards the PC, no matter
> the connection towards the PC; via USB port on the K3s or via RS232/PC port
> on the P3.
>
> However, when the P3 is switched off, the <a>USB<b> rate reverts to the
> default setting of 38400 bd (of the K3s).
>
>
>
> I thought it worth mentioning, because this behaviour is not explained in

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