You may have already seen it, but please allow me to direct your attention to my latest post on the Etherkit blog. For the tl;dr version: sorry to have been quiet on the business front so long, also sorry to have failed to do a good job keeping up on business communications, the OpenBeacon and CRX1 products are being sunsetted (I’ve reduced the price of my limited remaining stock of OpenBeacon to $29), new products and new initiatives are coming in the near future.
I wanted to mention a few more things that I neglected to say in that post. First, I also plan on releasing another revision of the Si5351A Breakout Board for sale as a kit. There are a few bugs to fix on the current version on OSHPark, but it shouldn’t take me too long to get a new revision up there and ready for testing soon. I’ve also reduced the price of EtherProg to only $9, which should make it in line with other similar tools.
To be bluntly honest, it has been a difficult year here on the Etherkit front because of multiple failures, some of which I must keep private for now. However, I have been buoyed by encouragement and help from friends and family, and I plan to redouble my efforts to make Etherkit the company that I envisioned when I founded it.
There will still be quite a bit more to announce in the near future, but now is not quite the time to reveal everything being worked on behind the scenes here. I will have more Etherkit news soon, so as usual, watch this blog for updates.
I ended up having one leftover kit from the CC1 beta test and I thought that an experience builder might like to build it. There are a few minor mods to perform to the PCB, so it’s best suited for someone who feels comfortable with that. The (hopefully) final PCB spin is coming soon and will be slightly different, but this version works well, as AA7EE can attest to. I can offer the kit for a discount over the final CC1 retail price, and it’s currently available for 20 or 40 meters (although the final retail product will be available for more bands). Contact me at milldrum at gmail dot com if you are interested.
SOTA 12 Meter Challenge
I’m not subscribed to the SOTA reflector, but I saw a post on the VK3ZPF blog that there was an announcement on the reflector that there will be a SOTA 12 Meter Challenge. I think this is a great idea and I want to support it if I can. I haven’t made too many 12 meter QSOs, but when I have it seems like the DX has been pretty easy picking. When it’s open, the band seems quiet and the signals sound great. The plus for SOTA activation is that a resonant antenna is small and easy to pack.
My original plans for the CC1 were to only support up to 15 meters, but I think I may add 12 meters in order to support this initiative. The DDS in the CC1 is clocked at 50 MHz, so technically I should be able to output a 24.9 MHz signal, although I don’t know in practice how well this works at a frequency so close 0.5 Fc. If I can get it to work, I will release it as an available band on the CC1.
New PCBs Are Here!
Here is the latest beta PCB from the Etherkit, the CRX1 receiver! It is all-SMT construction, but I spread out the components a bit more than the CC1 and all of the parts are on one side of the PCB only. It’s VXO-tuned for the 40 meter band (a few kilohertz around 7.030 MHz) and is based on the Clackamas transceiver which I entered into the 2010 FDIM Challenge (which means it’s also a cousin of the CC1). This receiver has only discrete components (size 0805 resistors/caps, SOT-23 transistors), so it should be fairly easy to build. In other words, a good warm-up for the CC1. It also has a port for an external VFO, so it will be a platform for experimentation as well.
I’ll build this PCB up today and verify that it works, then get a few beta testers to confirm that all is well. Hopefully I can get this product onto market fairly quickly, with a low price. Stay tuned for more details as work progresses.
More Stuff For Sale!
I’ve added some new gear to my For Sale page that would be a great addition to the bench of any homebrewer. Please stop by and take a look!
This is the first in a series of blog posts covering a wide variety of topics. In the past, I have used Twitter for my microblogging needs. For a variety of reasons, I’m on a Twitter hiatus right now, so I’ll be using this series to convey some of the disconnected (and possibly connected) random thoughts that I feel I need to get out there. I don’t think I’ll be abandoning Twitter completely, but I will be reworking the ways in which I use it once I come back.
I’m also in the process of disconnecting completely from Google, so I wanted to give fair warning to those who correspond with me via my Gmail account that I will be abandoning that service very soon. I’ve already deleted my Google+ profile, and will be deactivating the rest shortly. I’ll probably describe my rationale for this later, but keep in mind that I’ve been a Google customer data mine for nearly a decade, so this is not something that I undertake lightly. I’ll try to get alternate contact information to those of you who regularly correspond with me.
It is an age of new beginnings.
With the introduction out of the way, let’s get down to the good stuff. Above, you can see the latest project on the Etherkit bench. It’s a re-work of the receiver from the Clackamas transceiver (the rig that I submitted to the 2010 FDIM 72-part challenge). I’ve decided to make this receiver into a cheap & cheerful little kit to get people warmed up for building the CC1. It’s currently for 40 meters only, is a superhet, and is VXO tuned (covers 7.030 MHz plus a bit more). It is 100% discrete component (you can see a TDA7052 IC above, but I’ve abandoned it for a different AF amp) and will be SMT construction. The receiver itself is pretty simple, but you can see there’s a fair bit of other circuitry on there. That stuff is mute and sidetone circuits. It’s easy enough to design a standalone receiver, but most of them will probably just gather dust after being built unless they can interface to a transmitter easily. With this extra circuitry, you can just split off your transmitter’s key line and connect it to this receiver to have built-in muting and sidetone. My goal is to make this project cheap and fun to build. I’ll be fast-tracking this one so I can get back to the CC1 soon.
Oddly enough, another project from the FDIM Class of 2010 is also coming out soon. As spotted on The QRPer, the Cyclone 40 transceiver is based on the rig that Dave Cripe, NM0S submitted as his 2010 FDIM 72-part challenge entry. I recall that the rig had a very unique design and that the specs were impressive. Dave’s a great designer, so be sure to buy one to get a rig unlike anything else you’ve seen before and to support 4SQRP.
Choking off the Internet firehose that I had previously directed at me has allowed me to devote a bit more time to enjoyable activities that I’ve neglected, one of those being reading. I’m currently enjoying a book I’ve had on my shelf for a while now called Seeing in the Dark by Timothy Ferris. It’s billed about being about amateur astronomers, but it does get into the professional side quite a bit as well. It’s a good read and very entertaining, and I can’t help but see a lot of parallels between amateur radio and amateur astronomy.
That’s a great segue to the final item, which is a bit of fun from our favorite Canuck astronaut, Cmdr Hadfield. He’s leaving ISS in a few days and just released a surprisingly touching (although obviously light-hearted) rendition of Space Oddity by David Bowie (one of my guilty favorites). Cmdr Hadfield may not be on the level of Neil Armstrong or Yuri Gagarin, but he’s definitely making a play for Coolest Astronaut Ever.
As a mild winter turns into an unusually nice spring here in Beaverton (last week we had multiple days with clear skies and highs in the upper 70s °F), a young ham’s thoughts turn to portable activations, Field Day, SOTA, and the like. I’ve been looking forward to this summer for the opportunity to take the CC1 out in the field, but I may not get to be quite as adventurous as I hoped. Last winter, I slipped in a wet patch on the concrete in the garage and hurt my knee. As a typical guy, I didn’t go to the doctor to have it checked out, I decided to “walk it off”. It did heal, but not completely. So I finally gave in and saw my doctor about it a few weeks ago. She strongly suspects a torn meniscus, and ordered an MRI to confirm it. Unsurprisingly, my insurance company denied coverage on the MRI, instead expecting me to do a bunch of physical therapy based on at best a guess on what the problem is. Coming from a technical background such as mine, this boggles my mind. When you have a problem and you have the tools to make a measurement, you make the measurement to see what’s wrong, not just take a course of action based on a guess! I understand that money is the driving factor behind this decision, but it still seems like a waste of resources for both myself and the insurance company. Not to mention that I don’t have the faith in the efficacy of physical therapy that consensus medicine does.
So now I have to decide whether to shell out beaucoup bucks on physical therapy that probably won’t do anything other than siphon money from our family to their coffers. I’ve looked at many recommended loan options in the meantime and if that fails to miraculously heal the non-specific “knee pain” referred to by the insurance company, then I guess I get the privilege of paying for the MRI that I should have had in the first place.
I’m completely fed up with politics, so I have no desire for a political battle in my comments. I’m quite aware of the history of employer-provided health insurance in the US, and the effect of government distortions in the medical marketplace. There’s plenty of blame to be handed out all around, so let’s just leave it at that.
Anyway, I may not get to do any SOTA summits this year (except for perhaps a super-easy one such as Cooper Mountain right on the outskirts of Beaverton), but hopefully I can at least get out with the CC1 for portable ops to the park or while camping.
Speaking of the CC1, it’s at a bit of a lull in its development right now. I’m waiting for all of the beta builders to complete their construction so I can be sure that I have all of the major hardware bugs worked out (which looks tentatively promising right now). I still have quite a bit of firmware coding to work on, then I’ll be ready for the next (and hopefully last) PCB spin. With any luck, that should come in about 8-10 weeks.
In the meantime, I want to work on some side projects, and perhaps some opportunities to raise more capital to fund CC1 development. In that regard, I’ve been looking at a neat part recently. It’s a MEMS VCXO from SiTime called the SiT3808. What’s cool about this part is that it has linear voltage tuning, so that you don’t have the uneven tuning response like you would from a varactor-tuned VCXO. The phase noise on the spec sheet also looks very good. I ordered some samples for 7.030 MHz and 28.060 MHz and breadboarded them to test the frequency stability. It was nothing short of amazing. The 7.030 MHz part had a long term drift of 5 Hz in 1.5 hours. The 28.060 MHz part drifted only about 20 Hz in 2 hours. That’s pretty spectacular for CW use.
Since the 28 MHz part was so stable, I created a QRP transmitter for it by adding on a keying circuit and a couple of BD139 amplifiers. It outputs a very clean and stable 2 watt signal and has a tuning range of about 20 kHz. I also was fairly easily able to create a TX offset circuit, so that the transmitter can be paired with a direct conversion receiver (which I plan to do soon). Since tuning is linear, the offset is the same anywhere in the tuning range, unlike a typical varactor-tuned crystal oscillator.
I’ve been thinking about a way to introduce these parts to the ham community, since I don’t believe that I’ve seen them mentioned by any homebrewers or used in any kits. Last week on the qrp-tech listserv, K7QO proposed a group build of the venerable NE602/LM386 direct conversion receiver (this one from chapter 1 in Experimental Methods in RF Design). Since this design is so well known, it seems like a “remix” of this design using the SiT3808 as the local oscillator might be a fun way to spread the word about the product. I breadboarded a version with the 7.030 MHz SiT3808 sample, which you can see below (the SiT3808 is in the upper-right corner, and it obscured by the tuning pot wiring).
It works exactly as expected. Wide open band signals directly dumped down to baseband, and a nice, stable LO. This particular SiT3808 part number only tunes about 4 kHz, but I will be able to get parts with a greater tuning range. I’m consulting with SiTime right now about bulk pricing, and hopefully I’ll be able to do a kit run of at least 100 of these bad boys in the near future. Let me know in the comments if this is something that may interest you.
So that’s my big rant for the day. Stay tuned for further updates on all of these projects in the near future.
I imagine that nearly all of my readers are interested in radio in some shape or form, so I thought I would recommend a fun documentary that you can view on Netflix streaming called Resurrect Dead: The Mystery of the Toynbee Tiles. If you enjoy the world of crazy conspiracy theories, pirate radio, and solving a mystery, then you’ll get a kick out of this one.
The subject is the odd “Toynbee tiles” which have mysteriously appeared on urban streets in many of the larger cities of the East Coast of the US since the early 1980s. The documentary follows a trio of gentlemen who are determined to track down the responsible party for these bizarre messages which have been implanted into the asphalt of many city streets. I don’t want to give away much of the story, but there’s a significant and critical bit of the story devoted to SWL and pirate radio, so I think a lot of you will get engrossed in the story based on that, not to mention the general oddness of the topic. As I mentioned, it’s available for free if you have Netflix streaming, so put it in your Instant Queue for a watch soon.
No earth-shattering news to report on the blog, but a few little things to mention (hence the “junkbox” title).
The CC-20 Beta 1 test is proceeding pretty much as planned. As of tonight, AA7EE has his receiver up and running now and a couple of the others are close behind. I’m eagerly awaiting the results of at least a couple of the builds so that I can get moving on the revisions for the Beta 2 circuit (which will hopefully also be the production PCB). I’m anxious to get the business up and running!
I got a very nice mention from Bill Meara on the latest episode of SolderSmoke. He talks up Etherkit and my blog, then mentions that he’s going to try to use the single-ended passive MOSFET mixer from the VRX-1 in his homebrew WSPR transceiver. I hope that the experiment works out well for him.
As we approach the halfway point of the gestation of our new little one, I got to thinking about mortality a bit. I hope to be around for a very, very long time to come and have been taking steps to improve my health to make that more probable. But in the awful case that something were to happen to me in an untimely fashion, it seemed that I’d like my family to have a little bit of my own thoughts with which to remember me. At first, I thought that maybe I should do a private journal, but then it occurred to me that wasn’t necessary. Barring a complete collapse of civilization, all of my descendants will be able to access an archive of all of my Internet activity. Every blog post, tweet, Google+ post, website comment…and perhaps even my email. If you Google my last name, I’m the first result. I’m active enough online that it’s not entirely inconceivable that a reasonable avatar of myself could be created sometime in the distant future (given that Moore’s Law holds up in some fashion for the next 50 years or so). Perhaps this is all pie-in-the-sky speculation and will look as foolish as the “flying car future” does to us now, but I’m pretty sure that I’ll live on in human information space in some fashion long after I’m gone.
I’m getting older. Why do I say that? Because I’ve been feeling a huge wave of nostalgia for hollow-state and other simple radios lately. I think it started out when I stumbled upon a YouTube video from someone who had built a replica of the classic TwinPlex receiver. That reminded me of the Lindsay Publications books that I purchased at Powell’s a little while ago regarding the TwinPlex and other simple tube regens. I also bought a handful of tubes and variable caps from Antique Electronic Supply around the same time, but they’ve just been sitting in my closet. With all of the life changes we’ve been going through in the last year, there just hasn’t been time for this stuff.
That video got me longing for some glow-in-the-dark radio, so I remembered that I had an old National SW-54 receiver that my uncle gave me, somewhere sitting in storage. A bit of digging through the plastic totes got me to my prize, and I was able to fire it up around 1 AM this morning after a long day. The paper caps in the poor radio are probably bone-dry, but it still works (for the most part). The antenna was a hunk of wire about two feet long. I plopped myself down in the recliner, put the radio on the arm of the chair, and gave the dial a whirl.
There’s something to be said for the subjective listening experience of these old radios. Yes, in every quantitative area of measurement, the new stuff made in the last 30 years blows them away. But you can’t discount the intangibles that the vintage radios provide, such as the easy and smooth tuning across a wide portion of the band, the warm audio from the light (or non-existent) IF and AF filtering, and the simple “cool factor”. (By the way, I really like Linux, but this makes me want to cry.)
The audio on the AM broadcast band was a pleasure to listen to, with the exception of some nasty hum that wasn’t masked out by the carrier on weaker stations. I’m one of those people who likes to occasionally listen to sports or evil talk radio on the AM band, so I can see myself setting this radio up for every day use. The SW bands were not as fruitful due to my tiny antenna, but I did come across the usual hellfire-and-brimstone and Spanish language stations that one regularly hears there.
I did come across something kind of neat that I don’t recall encountering before (but you must remember that I don’t do much SWLing). The “CW” mode of the SW-54 is a bit of joke as far as I can tell, as there is no BFO in the radio (it looks like it makes the IF amp oscillate, but I can’t tell for sure). Up around 9 MHz, the radio pulled in a very strong CW signal, something I didn’t expect. After a second, the quieting provided by a carrier told me that it was actually modulated CW. Going back to the shack, I found the signal on 9.110 MHz, and a bit of searching on spynumbers.com showed that this was an M8a, or a Cuban numbers station delivering 5-figure groups in cut numbers. It’s nothing particularly rare, but sitting in the dark, late at night, listening to my 40s vintage radio, I was transported back to the radio days of the past. It reminded me of being a kid and tuning the big, giant, console radio at my grandparents’ house, and discovering this whole new world of the shortwave bands. It reminded me of being a nerdy teen, staying up late on Friday night to try to capture some exotic new signals and rare DX on my Radio Shack DX-440. It has strengthened that link to our history, when there was still magic in our radios.
It’s kinda big with thru-hole components, but the current plan is to use SMT in production. Does that sound like a good idea, or does the mere mention of surface mount turn you off?
Due to “popular demand”, I’ve decided to release a bit of information on this rig. This isn’t a guarantee of final specifications, but the end product should be pretty close to this.
The rig above is a 40 meter CW superhet. Cascode JFET circuitry is used extensively throughout the radio. I’m aiming for this to be a trail-friendly radio. I don’t have any hard specs yet, but here are some general observations:
RX current draw is now around 30 mA, but I’d like to squeeze it down further if I can
TX is Class E, so TX current draw should be pretty good as well
Nominal TX output power is 2 W
MDS should be around -130 dBm (500 Hz BW)
VFO tuning range approximately 40-50 kHz
VFO stability is very good (~2 MHz VFO frequency)
ATmega88 microcontroller for built-in keyer, mute, frequency counter, battery status, etc.
Other planned bands are 80 m, 30 m, and 20 m. Would like to tweak design for upper bands as well for a future date
Hopefully that will whet your appetite a bit. Let me know in the comments any features that you would find useful that would be appropriate for a radio of this class.