[Elecraft] [K3] SO2R Controllers

[Paul Young]

This is long and way off topic, but I feel some comments made in previous
postings were misleading or incorrect.  I hope Eric will end this thread if
it goes
further.  Further discussion probably belongs on the CQ-Contest reflector.

I designed the YCCC SO2R Box and I am one of the people who support it.

---
Support of the YCCC SO2R Box (Plus)
---

As far as I know, every unit which has been assembled is running – I’ve
repaired
a couple but most hams have no trouble and several have told me they enjoyed
building it.

The schematic and parts list are on the web.  Anyone with electronics
knowledge
and basic test equipment can troubleshoot the hardware.  There’s enough
information to build one from scratch if anyone wants to.  And I’ve heard
from one
ham who did.

The firmware hex files have been posted, including the bootloader.  I have
not put
source code on the web because I have no way to support firmware that
someone
else has modified.  I have given the sources to several people who have
asked for
them.  And I have published the native USB protocol.

If for some reason I can no longer provide support I’ll publish the source
code so
that someone else can.  And in case I get run over by a bus I'll burn a
couple
copies to CDs and give them to people who can make it available.

There is a Yahoo group for the YCCC SO2R Box.  There isn't a lot of
activity,
probably because problems are few or are handled by e-mail.

It uses OTRSP to communicate with logging programs - this is an open
protocol
which is available under a creative commons license.  It is used by several
products and projects.

If any club or group wants to make YCCC SO2R Boxes we’ll provide the gerber
files files for the PC board and the box drawings and silkscreen.

I think our support is actually better than microHam which has only one
person
providing support in the US, does not publish schematics on their website,
and
uses a proprietary protocol, parts of which require a non-disclosure
agreement.

The DX Doubler schematic is published on the Top-Ten website.  The LPT port
protocol is well-known and can be discerned from the manual and schematic.
Top-Ten does not provide software because none is needed.  The company does
provide support and their hardware is the simplest of all to troubleshoot.

---
Features
---

All of these controllers share concepts with each other and with other boxes
such as the  WX0B SO2R Master.  An SO2R box switches headphones, keyer,
and microphone.  That’s not exactly rocket science.

The DX Doubler and the YCCC box have a similar approach.  They are SO2R
components.  They take a working station with two radios and add what is
necessary for SO2R. The microHam boxes try to be a station control system,
integrating with other microHam devices and offering features beyond those
necessary for SO2R.

All of the boxes switch headphones.  The DX Doubler and micro2R use a
passive circuit with relays.  The MK2R and YCCC box use an active circuit
with a headphone amplifier and transformers for isolation.  All can listen
to
either radio or stereo and can connect the headphones to the non-sending
radio.  The YCCC box can do reverse stereo and has a spatial mode.  I think
the MK2R can route any audio to either headphone.

The MK2R+ I evaluated had an audible thump when switching radios.  It
sounded
like a DC level shift across a capacitor.  The DX Doubler does not do this. 
I
have not evaluated a micro2R but based on published information I do not
expect a thump.  I know the YCCC box is silent when switching between
radios.

All of the boxes have antenna switching capability.  This goes back to when
CT
put the encoded band outputs on LPT port pins.  Some logging programs put
band
outputs on these pins.  Others allow general antenna selection.  There are
usually
four outputs per radio.  The YCCC box provides sixteen outputs and Win-Test
can take advantage of this.

The YCCC box has a built-in keyer.  Although this isn’t strictly part of an
SO2R
component it was added because it allows the box to handle the interactions
between the keyer and transmit focus switching.

The YCCC box did not originally have RTTY outputs.  This was requested so I
modified the firmware.  Now some of the antenna outputs can be configured to
have RTTY signals.  These are 0/+5 volt outputs so a level converter (which
can
be a transistor and resistor) is needed.  There are some limits to this
capability
and these are described in the documentation.

The microHam boxes have many additional capabilities, including a keyer,
transceiver interfaces, audio level control, and sequencers.  Ed, W0YK
described some of the capabilities of the micro2R.  I would suggest you read
the documentation for more information, especially on the MK2R which has
more features than I could describe in an e-mail message.

---
Which to Buy
---

I don’t care which box is the number one choice and I have no sales figures
to
be able to tell anyhow.  I didn’t buy my K3 because it was the number one
seller.
I bought it because the features and performance were the best match for my
requirements.

The DX Doubler has been around for a long time and is still a viable option. 
It
requires no vendor supplied software.  If you don’t have a parallel port you
can
use a PIEXX SO2Rxlate.  This is what Scott, K0DQ uses.  He wrote an article
about it in a recent NCJ.  He also probably won the US in the recent WPX CW
contest.  Add a USB Winkey for a complete CW solution.

The YCCC box is a bit more modern, and is designed for USB only.  None
of the computers I use for ham radio has an LPT port.  The cost is low
because
it is a club project.  And I think it has the best headphone audio circuit
of any
of the choices.

The microHam devices provide a higher level of integration.  There are
things
they can do that may not be possible any other way.  But the trade-offs are
complexity and flexibility.

For some hams, such as W0YK and N0AZZ, the microHam controllers are the
right choice.

I evaluated the MK2R+ before I designed the YCCC box.  I found it to have
many features I would never use.  More important for me was that I thought
the
router software was very complex (and I did read the manual).  I concluded
that if anything went wrong during a contest when I was sleep deprived I
would
not be able to fix it.

I prefer a component approach.  For me several simple boxes are easier to
configure and troubleshoot than one more complex one.  And if I want I can
replace one of the simple boxes with something better without affecting
other
nominally independent functions.  I also prefer general purpose hardware to
ham station specific hardware.  My home station has a YCCC box, a multiport
serial to USB converter (which also handles the rotor and can download
firmware
to the K3) and a USB sound card. 

As far as making cables with DIN or DB-9 connectors, I find them much
easier if I clamp the connector in a large pair of vice-grips.  That keeps
it
from moving when I solder it.  I would not choose an SO2R controller because
of the cables.

Any of the SO2R controllers mentioned here can do a good job for you.  More
important will be learning how to operate SO2R.  Expect headaches and a
lower
score at first.

My next YCCC project is an antenna switching box, the MOAS II.  It will
follow the philosophy of the SO2R box, and will be less integrated than the
microHam antenna switching solution.  I’m sure some people will prefer the
YCCC solution, some the microHam solution, and will like something else
entirely.

Paul, K1XM





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