As promised a video of Amelia and I building her FM receiver. Funny enough she doesn’t listen to it nearly as much as she listens to her AM radio. AM radio I suppose has lots of drama what with all the politics.
Sidebar/Content
Building the 2P3 AM Radio
In an Episode of Ham Nation or Amateur Logic featuring Joe Eisenberg (K0NEB), I saw him recommend a few radios as good beginner projects. The 2P3 radio looked like an entertaining project and something I could probably tackle with one of the kids. Amelia had recently discovered an old “boombox” from my youth and was playing the radio a lot. We decided it might be fun to listen to a radio that she had built.
I ordered the kit from Amazon. The instructions come on a beautiful HUGE poster. It has an enormous schematic of the radio. I had wanted to build the radio by stage and is recommended when home brewing a radio. We started from the power conditioning part of the circuit. Once we had all the parts of the power we went back and installed the audio amplifier and worked our way backward.
I had intended to test the build frequently as we went along. Initially I couldn’t get any of the measurements to come out according to the schematic. I would go back and study the schematic and I was absolutely certain we had put the parts in the right polarity, etc. and continued forward. On the final day of the build I finally figured out why. . .
The way the circuit is designed there are purposefully installed breaks in the circuit. There is an X to mark the spot in the 3 points. basically they don’t allow power from the power rail to the circuit block you just finished. Being confident I had quintuple checked everything I bridged the circuit breaks and turned on the power the tested all the levels on the schematic. It worked! first try!!
The 2P3 is definitely NOT a beginner kit. But it is a great kit to build with someone who knows just a little and the finished product is a really nice radio.
Ham Gadgets Ultra Pico Keyer
As I mentioned in a previous post, Berkley decided she wanted to learn CW. After having learned a few letters, I was pretty confident it was going to stick, but we needed to have a way for her to practice. I have used the Ham Gadgets Ultra Pico Keyer for a few years on my HomeBrew 630M transmitter. Disconnecting and reconnecting is super annoying, so I opted to get her one of her very own.
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Kids and Amateur Radio
I’ve recently had a break through with the kids.
As a dad, one of the great struggles in life is how to help your kids develop their God-given talents. This must be balanced with not losing yourself at the expense of your children believing the world revolves around them. OK. . . this isn’t a parenting blog. It is possible that we won’t agree on this, but. . . I think we all want to share what we are passionate about with our kids. I enjoy the outdoors, hiking/camping, and amateur radio.
My daughters are forever telling me radio, is for boys.
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My Rig Expert AA-230 Broke!
When I was evaluating who I was going to purchase my Rig Expert from, I spent some time studying up on which vendor I should buy from. You can get them from DX Engineering, PNC Engineering, Amazon, Giga Parts, etc. I chose to order from PNC Engineering because of this statement from their website. (italics added for emphasis)
Why Buy From PNC Engineering?
PNC Engineering covers all RigExpert Analyzers under our United States “in-house” warranty center. Out of warranty repairs may also be contracted through PNC Engineering. RigExpert products purchased from other vendors must be serviced in Canada or in the Ukraine where RigExpert Analyzers are manufactured. This will require the customer to pay the shipping costs of their product to one of those out of country locations. With PNC Engineering your shipping expenses are considerably less, and shipping times much faster due to our ‘local’ U.S. location.
I mentioned in my initial assessment of the analyzer that it had given me infinite readings initially. Being a newb to this tool, I just assumed that I had neglected to fasten the N to SO-239 adapter correctly. I finally got it to give me a flat reading on a dummy load and was happy with the measurements.
My friend Myron WV0H mailed me a few N adapters and 50 ohm loads. No longer would I need to do SO-239 to PL-259 to BNC. The adapter stack was getting out of control. . . So I connected the N to SMA and an SMA 50 ohm load. Infinite SWR. Hmmm. . . Well, the loads are ham fest deals so maybe its a dud. Lets try another.
Infinite.
OK. . . lets do a dummy load I know works. So I do the N to BNC adapter. Then a short coax jump to my dummy load.
Infinite.
OK. . . lets do a known adapter stack that has worked previously.
Your guess is correct. Infinite!
Then I started loosening the threads on the N connector and I got an accurate reading. Hmmm. . . this is not good.
**********Do NOT EVER do what I am about to do***********
I turn off the machine. I take the adapter stack off and look down into the N connector. All looks normal. I then take a screw driver and make contact with the center pin. It moves!! It moves a lot and I am not putting any effort into touching it.
******You CAN DO everything below this line safely************
So I fire off an email to PNC Engineering. They send back a form letter that is intimidating. I kindly respond with the situation and assure them I’m going to mail this thing back for repair under warranty. A few pages of paperwork and $20 in mailing and insurance later, the device is in the mail to California.
A few days go by and I get a confirmation they received it. The next day I get a note that they are going to repair it under warranty and send me a new one. I am looking forward to it arriving!
So. . . I’m hear to tell you that PNC Engineering is good to their word. (Although the shipping time is a week) It’s possible I could have just returned it via Amazon and bought another. Maybe I’m not getting a great deal since I had to pay shipping. I really like the device and have LOTS of plans to measure stuff and report back!
KF5RY
My Rig Expert AA-230 Has Arrived
I cannot express to you how excited I am about this thing. Unfortunately I have a grand total of zero N type connectors or devices that have N type connectors on them. Fortunately Rig Expert provides an N to SO-239 adapter. I can get from SO-239 to pretty much anything else I might need.
An example of what you can see with a Rig Expert.
Strangely upon getting this thing I had a heck of a time getting it to give me a legit measurement. For some reason I kept getting an infinite measurement. The first thing I wanted to test was my dummy load. No luck. Then I decided I wanted to see what the Smith Chart looked like on some conventional Transformers I had built some time ago. I know that the inductance checked out on the windings, but I had never had a measurement device capable of showing me if it actually worked. So I found a 200 Ohm resistor to test my 4:1 conventional transformer. This should give me a reading pretty near 1:1 SWR.
Infinite.
Maybe I got a bad resistor. After wiggling things a bit and trying a new resistor. BAM. . . I have a reading. It checks out. I go on the the 2:1 transformer, etc. All tests come out showing that I did in fact make these things correctly!!
If you can read this, you will now know how bad the match is on my 630M antenna
The next thing I do is put the analyzer into the front end of the receiver I built so that I can peak the input filter to be right at 7 MHz. It turns out I was off by quite a bit! I made some adjustments and will have to get back to you on whether it makes a difference in receiving actual Amateur Radio frequencies.
I go on to measure my 630M antenna. I’ve known for a while that the phase of Voltage and current have not been right in sync so my tuning network was off a little. I had tuned it and thought I had it as close as I could with the scope match. Turns out as I had my rig expert attached I was able to get the waves in phase. YEAH! Unfortunately the magnitudes are not equal, but hey #firstworldproblems.
I plan on working on a better matching network for the 630M set up eventually. I would sure like it to take up a little less space and I would like to put a little more power into it. As it stands now my ERP is in the micro watt power level. It would be great if I could get to milliwatts. 🙂
OK. . . More things to measure. . . I will keep you all posted on what I find!
KF5RY
Connecting the KX3 to a computer for Digital operation. (using Signalink)
Look in any hamshack today and you’re gonna be hard pressed not to find a computer sharing space with the tranceiver. We them for, most importantly, buying equipment, but also for logging QSOs, looking up someone’s details from their callsign, looking for active DX spots…
OR, operating digitally! In this first episode of a series on operating digitally, we’ll begin by hooking up a SignaLink to an Elecraft KX3….
Rig Expert AA-230 Zoom
For sometime I have had a MFJ-259B that I had purchased from an SK estate. I have treasured the device for a number of reasons. I knew what I had paid for the device was helping that ham’s family and I felt like I needed to honor his memory by using the analyzer. Use it I did! KB5NJD even helped me mod it so it would give us readings down to 470 kHz and I could tune my 630M antenna. As my knowledge has improved, I came to find that there are a lot of things this model of antenna analyzer does not do and that made me think about getting a different device.
One: It doesn’t resolve the sign of X. i.e. is my load inductive or capacitive? W2AEW has a great video on how you can actually resolve the sign of X using a smith chart using an MFJ 259B style analyzer.
Two: The oscillator in the machine is not particularly stable in my opinion. i.e. what freq I was measuring was in doubt by up to 20hz. This isn’t a deal killer for measuring impedance in the field, but is frustrating in a lab environment.
Three: The freq. knob is too sensitive in my opinion. I suppose it makes sense given the tuning range within each band the analyzer covers, but I wanted a little more precision.
Four: All it provides is Freq (approximate as noted above), SWR, R and X (unresolved whether it is positive or negative.)
Again — As a new amateur, it is perfectly adequate as an antenna analyzer. But I wanted something a bit more capable. As it turns out a friend has an AA-600. He was showing me his conventional transformers and how he could measure the frequency response with the AA-600. Not only will it define the sign of X, this thing draws a Smith Chart. It will auto sweep over the entire spectrum of the oscillator enabled on your machine. You can do live measurements where it will show you the rectangular format of impedance and the vector form of impedance. This is a genuine scientific instrument.
Now the question is what frequencies should I cover? I genuinely only have an interest in HF, BUT satellite contacts are interesting. . . and I’ve recently started doing some VHF fox hunts with a local club. At some point I’d really like to build some kind of 2M yagi. If I was doing satellite contacts, it would be ideal to have a 440 beam as well, but the cost differential and the likely hood I would ACTUALLY build such a thing. . . I’ll probably just by a satellite antenna, it’ll be close enough. 🙂
If I decide I really want to experiment at 440 MHz I can always up grade later.
KF5RY
Where Does The High Voltage Come From In Mag Loops?
For a long time I have wondered WHY do people always scream a warning at you if you plan on using a small magnetic loop. “Be careful, there is a lot of voltage across the capacitor!” yeah, yeah. . . OK, whatever. . . I’ll be careful.
But Why?!?
I asked a number of friends. I heard a lot of explanations. The one that stood out to me was that a mag loop acts like a auto transformer. uhh. . . I’m sure someone reading this is going, “yeah!” You could have told me that it has to do with a wind storm on Mars and particle entanglement. This seemed just as plausible to me.
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Tuna Tin 2 Finished
As you may remember I left you at a metal can with a hole cut out to an incorrect size and then mashed over. You may also remember that there were a few components that I needed to acquire to complete the kit. While I definitely had a stock of BNC panel mounts, I did not have a supply of SPDT switches. This involved me scouring
the interwebs looking for inexpensive, panel mount, SPDT switches. I ultimately chose to order from danssmallpartsandkits.net. If you are thinking that this guy must be a real niche market seller and cater to his customers. . . You’d be 50% right. . . It’s definitely a niche market! From what I can gather he is a nice guy, but he has rules that must be followed. Read carefully and follow the instructions. I’ve never had a problem. I also always order a bunch of other random parts I don’t “need”, but hey. . . next time when I need an NPO bypass cap, I have a stock of them. This is a practice that was recommended to me by an elmer some years ago. It’s why I have parts on hand. . . not always enough, but sometimes enough and sometimes enough to make it inexpensive to order a couple other parts. Get what you need plus 2-3 items you don’t need, but are generally speaking useful.
So a few weeks pass by and a boring, worn package shows up. In it are my parts. They smell as if they have been living in a smokers attic for at least a decade, but they seem to pass the test of working and that is all I need! The next step is getting the case ready for the board. I installed a coaxial power jack from my stash, 2 BNC panel mounts, and the SPDT switch. I choose to wire up all of the internal components so that when I am ready to connect the board there is little work to be done.
This is where I made my second mistake of the build. If you follow the manual, you will build the transmitter. Then when you are done they will give you some options to improve the performance. I read the manual in advance and had opted to install the circuit for preventing chirp ahead of time. IF one were to build this radio and intend to build it with this mod installed from the beginning, one would not burn themselves with a soldering iron while trying to put an electrolytic capacitor between the coaxial power and a ground lug on a BNC ground lug because that capacitor is NOT necessary assuming the anti-chirp mod is installed. The joys of homebrew!
Anyway. . . I had the can wired up and it was time to start on the board. The manual has great step by step instructions. I won’t belabor them other than to say that in the last step, they have you run a capacitor between two terminals near an inductor on the bottom of the board. If you read the manual in advance you would choose to put the capacitor in before the inductor. I think it looks nicer and is less likely to short out any traces. It also fits through the hole just fine if you put it in ahead of time and just bend it over out-of-the-way.
The last step was to build up the home-brew anti chirp mod. It’s a simple circuit and I had all the parts on hand thanks to some prior orders from kitsandparts.com. See how my advice from earlier has paid off in this build! If I had it to do over again, I would use fewer of the manhattan pads. I laid it out exactly as the schematic showed, but you really only need about 5 islands.
The rest of the build was uneventful. I made a short video to show the first smoke test, but unfortunately I must have hit the slow motion button as the video is completely unwatchable and 20 minutes long for something that took about 2 minutes. You’ll have to just enjoy the pictures. It does work and I hope to make an actual contact at some point when the bands are cooperative!
More projects are in the works. Stay Tuned!
KF5RY