KPOD to BT1500A Block Diagram

The KY6R “maker area” in the shack. The radio part of the shack is to the left.

I was able to get a C program that the lead KPOD developer from Elecraft sent me to compile and run on the Raspberry Pi. I learned what a “HID” device is – Human Interface Device, and that the KPOD is not a standard HID (like a Mouse or Keyboard is), but is a HIDRAW device – HID and RAW, the RAW meaning “direct” for Linux. Here is a good explanation:

The compiled program runs as root but while it seems to spit out some identifiers, it can’t find the KPOD. I will consult with the developer, and I am sure there is a simple fix for this. I’ve read the code enough to have a good basic understanding of what it does – and luckily its C – which is something I have coded enough to be very comfortable with.

What I did learn from this is that I will most certainly need Raspberry Pi on the KPOD side, and Arduino on the BT1500A side. The KPOD needs a proper Operating System, the BT1500A is a “slave” and doesn’t need an OS.

So – later today (after a bike ride) I will get the Arduino and stepper motors spinning – most likely following something like this:

And the fellow who posted this has a very nice web site:

I found one other web site that shows how I could emulate having the KPOD working – its almost exactly what I need:

In fact, the only difference is that where he has a joystick, I will have a KPOD which forces me into a client – server architecture. In fact, to get this all set up with just the Arduino part, I’ll just use an Adafruit rotary encoder instead of the joystick he has. In fact, he also has a little control box with buttons so he can switch between motors – so it is exactly what I need.

I’m still highly motivated to use the KPOD because of its expandability beyond what it can control. Maybe eventually, the Function buttons will change bands on a wireless remote antenna switch (?) We shall see. I need to walk before I can run . . .

But as a fall back – I could just run with this design as well. In fact, I could even just use my laptop and the control “unit” could be software with a couple sliders on a screen. The BEST part of this project is that its a journey as I am learning – which is what makes it so much fun. It used to be to avoid becoming a total “DXCC Zombie” I worked on antennas – now that that phase is done – this Maker stuff is rapidly taking over – its highly addictive.

I’m going to come back to the Raspberry Pi and KPOD later (after I get help figuring out why its not being found), and will spend the rest of this 4th of July weekend emulating the BT1500A tuner and Arduino “slave” part of what is essentially a “client server”, or more like a “master – slave” system.


VOACAP Online Now Does P2P Greyline Mapping!

Jari, OH6BG, has been constantly improving VOACAP Online, and it is now my favorite Propagation Prediction Tool. I have noticed that over the past year or so many new features have been added – such as specific station information – which makes it more accurate. I also really love the new ability to get the checkerboard prediction charts by month or year. But he has now added something that really helps me quite a bit, and that is detailed grey line time information as well as a map, as you see above. You know from my propagation studies, I am constantly switching between propagation software (and I use VOACAP Online mostly these days because I love the “data visualization” it offers) and DX Atlas. But that was pretty good, but Jari has upped the ante with this:

This is a very accurate chart of grey line, and includes not only the three types of grey line twilight (civil, nautical and astronomical), but also shows dawn and dusk at each end point in the radio circuit.

This is absolutely critical for Top Band, and is also very important for all low bands. But on Top Band – perhaps the band least understood propagation wise – since VOACAP does not predict it (and is a bit weak on several of the low bands), this new feature fills in the gap very nicely.

When I worked FT5ZM and VK0EK on Top Band, the timing was absolutely critical. You really had to know when to strike – otherwise you might miss a 10 minute or even 5 minute or less opening!

It isn’t quite this tricky on the higher bands, but I very clearly remember VU7RG and ZS8M both being greyline ATNO’s and both on 40M – at dusk – and VU7RG happened during the “set” time, and ZS8M happened on the “dusk” time. Now – here is the real “kicker” – when you look at the difference between pre and set and then set and dusk for mid October 2017, you will see that it lasts 20 minutes. That is EXACTLY how long my VU7RG and ZS8M openings were. These were not the only times I have experienced this, and it happens on all of the low bands.

One of the funny things I always see is a DX Cluster spot where someone is “asking” the DX-pedition to come on a band – like 160, 80 or 40M when its mid day at the DX-pedition location. This new feature would be great as an education tool.

In fact, I like it so much, I will say that once you get really expperienced at DX-ing, this might be THE most important skill. I do not have the best QTH or antennas. They are respectable but I am no big gun. HOWEVER, I beat everyone to several ultra rare DX-peditions because I could really guess what band they would start on based on grey line.

This my favorite data visualization for a year long prediction. It is crisp and very easy to understand. I’m looking at only the last three months of the year since that is the quarter closest to when 3Y0Z will be on the air. I can also look ahead to January, 2018:

No matter how you slice it, conditions for Bouvet look better than I had expected given conditions as they have been the last few months or so. I have a theory that the month leading up to summer solstice and then after is usually crummy – at least on the low bands. This makes a lot of sense – because the grey line and even the night time duration is so much shorter than during the winter.

HOWEVER – you also need to look at what is going on in the DX QTH’s part of the world – be they in the northern, southern or equatorial regions.

The new VOACAP Online gives you EVERYTHING you need now – from 160M all the way up through 10M.

Fantastic job Jari – you just made all of us low banders very happy!



Announcing The Elecraft KPOD Open Source Remote Control for Arduino and Raspberry Pi Project!

After reading the Elecraft Technical Notes on their wonderful KPOD product, I’m so confident that it would be an absolutely awesome controller for my Arduino and Raspberry Pi projects that I just ordered a second one. The first one controls my K3, the second one will be used to develop software that sends input command packets to the Arduino or Raspberry Pi and then, code will send the appropriate control commands to the output.

My first project will be to control this antenna tuner – the Palstar BT1500A. Two stepper motors will turn the L and the C controls. Here’s the script for how it will work:

  1. The rocker switch on the KPOD will select either the L or the C stepper
  2. Turning the rotary encoder will turn the selected component to control
  3. As I am tuning one or the other, I will watch the SWR meter in my Expert 1.3K FA amplifier

This is the exact same way that I would tune an antenna tuner in the shack. But my “Modified Bobtail” with its open feed works very well with this tuner remotely and at the base of the antenna. Because I am transmitting with 1500 watts I am not at all comfortable with trying to use a fully automatic remote tuner – as I have heard too many stories of people blowing up MFJ remote tuners at the base of their verticals. I am sure they were trying to use a shortened vertical on bands that caused excessive voltage at the base of their antenna, and that they never looked into N6BV’s TLW program that comes with the ARRL Antenna Book.

When I was using the Elecraft KPA-500 and KAT-500 in the shack I was basically “lazy” and just let it do its thing. It wasn’t very efficient, but I could be lazy. At 500 watts, you don’t see nearly the issues you do at 1500 watts. This is where QRO teaches lessons that QRP can’t.

I find because of the high voltages that can happen with 1500 watts at the base of a vertical – or vertical array – that I would rather take a few minutes to manually tune and then know there will be no arcing or sparking, and most importantly a nasty amplifier fault.

I have support from Elecraft, and will seek support from Adafruit – run by “Lady Ada” Limor Fried, AC2SN, and will get a proof of concept working and publish this in QST. Then I will open the project as an Open Source project.

If you are interested sooner than when the POC proves success – please let me know – I’d love to have contributors and collaborators!

Using an Elecraft KPOD as a KY6R Mod Bob BT1500A Remote Control

I use an Elecraft KPOD exclusively to tune my K3. I can never go back to the rigs tuning knob.

It has everything I need ergonomically and in the way of connectors and data signals. I’ll double check with Elecraft, but the functions I would use with this would be:

  1. The tuning knob controls the L and C stepper motors
  2. The rocker switch (VFO A and VFO B) switches the L or the C control on
  3. The F switches change bands. I only need 5 bands now (160 – 20M)

The KPOD uses the USB HID protocol, which is what a mouse or keyboard use. That means it’s a common controller, and both the Arduino and Raspberry Pi should support it out if the box 

The only question is what libraries are available, because writing drivers and whatnot from scratch is a bit beyond my level. It almost seems like the Raspberry Pi has this already built in, but the Arduino seems farther along with Stepper driver libraries.

    Anyway, using a KPOD as the controller really steps this project up.

    The Palstar AT-Auto does all of this, but if you bought their remote control, the two parts would be $2000. And it would not be the best tuner for the Mod Bob.

    My project costs $1000 total, and you get the absolute best tuner for the Mod Bob.



    This Weekend: StepperPalooza!

    I’m starting to think that maybe I will just have one really nice control knob and switch between two stepper motors out at the BT1500A. This is because I only ever turn one control at a time when using an antenna tuner.

    Before I purchase an expensive Griffin Powermate Knob, I’ll play with the Adafruit Rotary encoders and try some of the different Stepper libraries – Accell keeps coming up.

    If it turns out that my Arduino Uno is too slow to control the tuner, there is a faster version – the R3 and its only $10

    Saint 03C

    A few years ago I made this silly little art piece (“assemblage”) and I called it “Saint 03C”. I was just going through a big junk box, and the block printing letters at first didn’t seem to spell anything. Then I remember the 2 years I worked at Lockheed in Sunnyvale on Mainframes coding COBOL. I vaguely remember an 03C error, and sure enough:



    The auxiliary storage manager (ASM) found that not enough auxiliary storage space is available for system operation:

    During IPL
    Either the required number of page data sets was not specified, or ASM has detected a problem with a required page data set.
    After IPL
    ASM has run out of usable auxiliary storage for the pageable link pack area (PLPA), common or local page data sets, and any storage-class memory (SCM).

    A reason code identifies the error:

    The cause of the error cannot be determined because of an error in recovery processing.
    Insufficient paging space. All local paging data sets are full, and there is no available SCM.
    The PLPA data set is full, SCM; is full, and the common data set is unavailable.
    The common data set is full, SCM is full, and the PLPA data set is unavailable.
    SCM is full, and the PLPA and common data sets are unavailable.

    System action

    During IPL, the system issues message IEA935W, then enters this wait state. After IPL, the system issues message ILR008W, then enters this wait state, unless all the local page data sets and storage-class memory (SCM) blocks were unusable; in that case, the system does not issue a message before entering this wait state.

    Operator response

    Notify the system programmer. ReIPL the system, specifying larger page data sets or additional page data sets, or additional SCM blocks.

    System programmer response

    Do one of the following:

    • Redefine spaces to conform with the description provided in paging planning specifications. Ask the operator to reIPL with the CLPA option.
    • Provide additional paging spaces and make them available through either the PAGE parameter or the IEASYSxx parmlib member during reIPL.
    • After additional paging spaces are added and the system is re-IPLed, issue the D ASM command to monitor the available paging space to help prevent a reoccurrence of the wait state condition.
    • Provide additional SCM blocks and make them available to the system using the CONFIG SCM ONLINE command.


    Auxiliary storage manager (ASM)

    Serendipity!From the IBM MVS (z/OS) manual.

    So, How Does The Remote Palstar BT1500A Perform With The KY6R Mod Bob?

    I have been told by The Mission Trail Net that my 75M signal has never been better – and quite a few people said “Are you in my driveway, what did you do?” . . 

    I tuned the Mod Bob manually this past weekend on 75M, which is a band that my Elecraft KAT-500 could tune but where the KPA-500 only tolerated about 200 watts before it faulted. That was a clear sign that an L style latching tuner in the shack could not handle the load. I am sure that a Palstar AT2K tuner in the shack would have handled it – but I believe having a 60′ run of coax from the tuner to the antenna with a 1:1 current choke incurred some very serious losses.

    The Palstar BT1500A is absolutely the perfect tuner for the KY6R Mod Bob

    The design of the Palstar BT1500A is very unique, and fits the bill perfectly. Having the 1:1 balun (current choke) at the input where the unbalanced coax is then turned into a balanced input to the tuner is the first big deal. The second big deal is that the Mod Bob feed resembles an open wire feed, and the impedance varies depending on band. The fact that the BT1500A lets me switch the shunt capacitor at the input or output of what is essentially a Pi circuit adds amazing flexibility, but as I mentioned a few posts ago, this is the circuit that I use for 160, 80 and 30M:

    I was lazy before and either used a Palstar AT2K in the shack with my trusty old ACOM 1500, and the KAT-500 with my trusty old KPA-500, but when I stepped my game up to the SPE 1.3K FA, and have found that its not quite as forgiving as the ACOM 1500 was, but the KPA-500 was also not as forgiving as the ACOM. That’s something you will need to understand when you switch from a tube amp to a solid state amp. You can’r be as “lazy” with your antennas because solid state amplifiers with ATU’s should NOT be used with external tuners unless you disengage the internal ATU.

    In fact, my new “mantra” is to make all antennas resonant – they will have less loss and better transfer of signal, but with the caveat that they aren’t rediculously shortened – like trying to use a 41 foot vertical on 160M with a tuner. At least the Cushcraft MA-160V was top loaded, so if you have to go small – do something along those lines.

    I’m enjoying having an antenna that is resonant on 160M but using it on 80 and 30M with the Palstar BT1500A. I feel like I am doing right by my SPE amplifier as well – which is the reason I went to this effort – which on air – is paying off bigly.

    Civil, Nautical and Astronomical Twilight

    While adjusting DX Atlas – which is a “must” tool to have if you are interested in Low Band DX-ing, I actually started wondering about the difference between these twilights. I am sometimes really amazed that even after what seems like sunrise there is that “enhancement” you get for just minutes on 160M, but that on 40M, the long path can stay open for hours after sunrise or before sunset.

    Here is the full story:

    And under “settings” in DX Atlas:

    An easy way to remember which is which:

    Civil – Nautical – Astronomical

    6 – 12 – 18

    This is important not just for DX-ing but when I ride my bike – its always interesting when I need to use my bike light or when I can still see well enough without it.

    Now that’s an interesting analogy!



    DXCC => Carpe Diem

    Lake Pend Oreille, Idaho. Photo by KY6R

    In retrospect, the most important thing to do as a DX-er is to Just Do It. Make Hay While The Sun Shines.

    Its funny how time is marked with another kind of clock – we have calendars, clocks and can count the seconds, minutes, hours, days, weeks, months and years, but some times you get that one chance to work a rare DX and you better be ready. Some of these buggers don’t come around but a couple times in a lifetime. By lifetime I mean the life of your DX-ing – which in many cases is just a subset of a lifetime.

    I’ve learned how important it is to diversify and try new aspects of our hobby. I used to just sit around during the summer pining for the Autumnal Equinox, which happens to be my favorite time of the year, but I can’t remember when, I decided to stop waiting for “DX Season” and try something else.

    Here in the SF Bay Area, June and the beginning of July can have this wonderful mysterious fog. It comes into the Bay and sometimes pops over the East Bay Hills and socks in Orinda. This has happened now after last weeks 100 degree week long heat wave. This weeks and last weekend were perfect days to work on my antenna – rain stopped more or less in May and we don’t get a drop until usually one day on October, but really, it doesn’t start again until November.

    Today is the first day where the days start getting shorter again – by one minute.

    I do wonder about the 3Y0Z Team and wonder about raising $200K that they need. That seems to be an awful lot – but I also know that this team is perhaps the best of the best – or maybe head to head with some of the “5 Star Teams”. The principles of this team have been on 10 DX-peditions of the year, and no other DX-pedition Leaders come close to that.

    My 160M goal this summer is to perhaps work between 1 – 3 new ones. As far as Top of Honor Roll, there is 3Y0Z and Glorioso left. I am convinced that when Glorioso happens next time I will need to use a remote or perhaps satellite. I wonder if DX-peditions might start using satellite more at the bottom of a cycle.

    Speaking of that, an email just popped in my inbox with this very timely video:

    When we get to the bottom of the cycle, I dream of the years where 160M all of a sudden comes to life. Having been through years of getting my Top Band antennas together, I fully understand why DX-peditions usually don’t pay as much attention to Top Band. About 1/2 of the Mega DX-peditions actually do a good job on 160M, the other half have been very disappointing. FT5ZM, K5P, TX5K, K9W and VK0EK all did great jobs on 160M. There were quite a few in OC-Pac in recent years that were just about non existent.

    OK – back to the Maker stuff – DXCC and DX-ing has been really boring lately – the last new one on any band was over 3 months ago – so there has been basically no “DX-Citement” in the KY6R shack. Even the ZS nightly and morning paths have dried up. Luckily, that has been replaced by excitement in the Maker world and by going to Dayton, receiving DX-pedition of the Year and re-tooling the equipment in my shack.

    I will be fully prepared for the Fall and some DX-peditions that I have heard rumors about – where I will need to have my low band antennas together.

    Speaking of that – I am giving the 9 AM presentation at the Pacificon Antenna Forum, and my presentation will be a modified version of one I gave at the East Bay Amateur Radio Club (EBARC) in February.

    The corollary to Carpe Diem is Tempus Fugit – I have been at Credit Karma and so busy at work that I cannot even believe that the second quarter is up – my first three months there have just flown – and in no time flat we will be at the doorstep of the fourth quarter, Pacificon, and like I said a few exciting DX-peditions where I will finally get to add some Top Band New One’s.

    OK – so today will be 1 minute shorter than yesterday. We’ve turned the corner and Top Band lovers get that extra minute of darkness!


    Amazing Maker Tool: Fritzing

    Fritzing is an amazing application that can take a picture of a breadboard that you draw, and with one click:

    Show it as a schematic, and then:

    Show it as a Printed Circuit Board layout (that you can then send to a fabrication shop and order online,

    And show your code that is associated with your project.

    Now think about it – isn’t combining “Making” with Ham Radio pretty cool?