Wideband Transmission #6

Happy New Year 2015!

2014 was a bit of a mixed bag here. It's been a transition year for Etherkit, as I reorganize and reorient the business for a renewed push to get the CC1 and other new products to market. I believe that good things are beginning to happen there.

On a personal level, my two boys have been doing fantastic. Noah started preschool and is really enjoying it. Eli is at a bit of a difficult age (the Terrible Twos) and is between baby and little kid, but he's got an amazing personality and is growing up so quickly. Jennifer and I celebrated five years of marriage and 11 years since our first date! Things haven't been perfect in the extended parts of our families, but at least in our household we've all been pretty healthy and have been able to enjoy many blessings.

Si5351A Breakout Board Campaign

There have been a fair number of neat projects I've seen using the Si5351A Breakout Board that I posted on OSHPark, along with my Si5351 Arduino library, which is absolutely wonderful. However, I realize that it's a pain to order PCBs and all of the parts separately, and that a kit or a finished board would be ideal.

I've decided to try something new in order to bring the Si5351A Breakout Board kit to market: we're going to try crowdfunding the first batch of kits. I'm going to set a modest goal to trigger the funding, but all orders will be welcome over the goal amount. In fact, I intend to set a stretch goal at some higher funding level to devote a certain number of hours to improving the Si5351 Arduino library, including:

  • Add tuning from 8 kHz to 1 MHz
  • Add tuning from 150 MHz to 160 MHz
  • Fix the bug that does not allow output over 125 MHz
  • Implement access to the phase register
  • Implement sub-Hz tuning for modes like WSPR
  • Other bug fixes

I also intend on lowering the BOM cost by removing the broadband output transformers, and offering multiple variants of the kit, including the option to add SMA connectors and a TCXO. I'm composing the campaign on Indiegogo right now, and I'm shooting for a launch in about 10 days. I'm hoping to gain experience with this campaign with the goal of using it to fund CC1 kitting later in the year.

Why am I telling you this now? Because I would like to let those of you are are interested in purchasing one (or otherwise interested in supporing Etherkit) get advance notice so that you can order on the first day that the campaign goes live. This will help to give the campaign more momentum and perhaps help to spread the word further. I will be sure to make a blog post here when the campaign goes live and tweet about it as well, so keep an eye on those channels if this is something that intrigues you.

Simple WSPR Transceiver using Si5351A

I came across this simple WSPR transceiver from KC3XM driven by one of my Si5351A Breakout Boards via @wm6h and Dangerous Prototypes. The WSPR transmitter is simply a BS170 driven by one of the Si5351 outputs, which is buffered by a logic gate and keyed by a standard PNP keying switch. Control of the Si5351 and keying of the transmitter is performed by a plain vanilla Arduino Uno (the code has been posted to GitHub).

This looked so simple to build that I had to give it a try. I quickly built up the transmitter portion, tacked on a 10 meter LPF (the original version is for 30 meters), modified the code for my callsign and grid, and changed the Si5351 output frequency to the 10 meter band. The transmitter put out nearly exactly 1 watt of RF (with only about 1.2 watts of DC input total) into 50 ohms and ran quite cool. Hooked up to my Moxon, it had no problem generating spots when pointed east and started on an even minute so as to properly synchronize. Fun stuff!

Generating PSK with an Arduino

If you haven't been following the blog of KO7M, you should be. Jeff has been doing a lot of experimentation with with NB6M and other home experimenters in Washington state, especially with stuff like the Minima and using microcontrollers in ham radio projects.

Lately, Jeff has been working on getting an Arduino to output PSK audio. He has a series of recent posts about it, but these two are probably the most important. The character timing is not quite right yet, but the basics of how to generate PSK via PWM audio signals are here. Good stuff!

Si5351 and Raspberry Pi

Another really great homebrewer blog is M0XPD's Shack Nasties (oh you Brits and your silly names) blog. Paul has been doing a lot of work with the Si5351 as well, and his latest post about the Si5351 is details of how he interfaced it with the Raspberry Pi. Excellent information to have, as the RPi is of course much more powerful than your garden variety Arduino.

A Bit of Morning DX

Got home from work and had an itch to try a bit of PSK31 this morning. 80 and 40 seemed pretty dead at sunrise, but 20 meters was already hopping with signals. I was wondering if I would ever catch the EU stations from the new and improved QTH, and I finally got my answer this morning. All kinds of different European prefixes were streaming across my PSK monitor window, which was a pleasant surprise. I didn't have much luck trying to work a GM0 or ON8, but did manage to finally snag a quick QSO with Peter, DL3APM. I was running the IC-718 at about 20 watts into the 70-foot random wire. There was a fair bit of QSB, but copy was good enough to allow a good contact on the first try. I know that most of you are probably yawning about a QSO to Germany, but this was kind of exciting to me since I haven't had a EU QSO since I don't know when. WIIGII!

First QSO!

WIIGII! Tonight I had my first QSOs with the new station! I was considering CW but I was feeling a bit sheepish about trying because I'm so out of practice right now. So I dragged out my homebrew sound card interface and homebrew CI-V level converter and hooked them up to the IC-718. A bit of fussing got everything working correctly (why is sound still so hard to get right in Linux?). 80 seemed like my best bet at 0200 local, so I fired up fldigi and double-clicked on the 3580 kHz line in the rig control window. I did a bit of tuning up on 3581, then fired off a PSK31 CQ. Right off the bat I got an answer from N4YZ in North Carolina. Not bad for 20 watts into a 70-foot piece of wire tossed up into the tree! It was especially nice since I can't even remember the last time I had a QSO on 80. The QSB was really bad, so Tommie would be S9 at some intervals and completely gone at others. After a short QSO, I QSYed up to 40 meters and tried again. After a handful of CQs, I got a reply from K5DEY in Bedford, Texas. He had a very strong signal, but there was still some QSB on 40. We still managed to have a nice chat for about 20 minutes before Baxter woke up and started harassing me.

It was a great morning for ham radio and I'm as pleased as punch. Later this weekend I'm going to have to try a few CW QSOs...perhaps I'll try some SKCC contacts since I haven't racked up any of those in quite a while either. Since fldigi has a ton of digimodes built-in, I'm tempted to try some others as well. I guess I should also get my fill of operating and try some SSB as well. What madness!