Where ham brains come to fry
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.
I’m a relatively new ham. Got my license, joined a club and I’m having fun! I enjoy CW, pedestrian mobile, backpacking, and I dream of building radios at some point. At present I have a wife and daughters so my building time is limited.
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.
I’m a relatively new ham. Got my license, joined a club and I’m having fun! I enjoy CW, pedestrian mobile, backpacking, and I dream of building radios at some point. At present I have a wife and daughters so my building time is limited.
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
I’m a relatively new ham. Got my license, joined a club and I’m having fun! I enjoy CW, pedestrian mobile, backpacking, and I dream of building radios at some point. At present I have a wife and daughters so my building time is limited.
The FOBB is a contest put on by the Adventure Radio Society. These are the people who also host the spartan sprint once a month. The idea is to get portable and operate your radio. The FOBB and NJQRP Club Skeeter Hunt are the events that I actually learned radio doing!! I’ll never forget the first contest I took part in, I worked Greg Lane N4KGL. How he copied anything I sent and the fact I copied anything back is a miracle! But. . . I still follow Greg on Google+ and we trade emails occasionally. He has been a very helpful elmer over the years. You’ll hear him in my video! (This is actually just a bizarre coincidence! I happened to hit record right before he responded to me.
JD (K5HH) has been showing me up by Vlogging. I doubt I become a Vlogger, BUT. . . I did make a video of the contest and figured I would share with you. Check it out, share with your friends. Tell me what I can do to make it more useful for the upcoming Skeeter Hunt in the comments below!
Tuna Tin finished post coming soon!
KF5RY
I’m a relatively new ham. Got my license, joined a club and I’m having fun! I enjoy CW, pedestrian mobile, backpacking, and I dream of building radios at some point. At present I have a wife and daughters so my building time is limited.
Trying to figure out the center with the intent of cutting out and around
I mentioned previously that I had won a tuna tin 2 at a NORTEX QRP meeting. Well, I’ve finally started building on it. Step 1 is to read the manual. I know. . . shocker. . .
The Manual is pretty straight forward, but I was surprised to learn that it doesn’t actually come with all the parts required to make a working transmitter. You need your own antenna jacks, your own T/R switch, and not surprising. . . Your own tuna can.
For those of you unaware, my wife (KG5WCI) is a vegetarian. Before we got married our prenuptial agreement consisted of this.
Now. . . before we continue I think I need to address the elephant in the room. Many people feel like I made a poor bargain. But lets be real. . . when I got married my diet consisted of frozen Tony’s pizzas, Burger King (nearest fast food), and Jersey Mike’s (around the corner from work). So its not like I was cooking a lot of bacon.
Back to radio!
You can see I left an edge which in retrospect was an error.
As you can see, its not like I can run out to the store and buy a can of tuna. Consuming it at home is not in the cards and consuming it at work, well. . . thats complicated. Primarily because I’ve not made my own lunch in at least a decade and given rule number one exists it’s not like the YL is going to make it.
Luckily. . .
I have friends. A friend at work was listening to my dilemma and rather than running scared, as one should do. . . she mentioned that the next time she makes tuna casserole she will bring me the empty can and even rinse it out. (So as not to even come close to rule number one. #blessed) This actually worked out incredibly conveniently as this friend and her husband are expecting now and canned tuna is expressly not permitted for expecting mothers. Not to mention, she is likely to enact rule number one in her home at least for the next 90 days. 🙂
Chicken of the Sea topless and bent over
A week or two later a chicken of the sea tuna can wonders into my life and the adventure it seems is officially ready to start. The first step was to map out the can and figure out the dimensions and how the top will fit mechanically. The manual gives a couple of options, but I’m enamored with the concept of the full open can. This means the bottom of the can needs to be cut out.
Here my friends is where I exhibit the first word in Amateur Radio. What I should have done was put the PC board on top of the can and got a sense of where the hole in the can needed to be. i.e. how big the finished hole should be.
THE tool for cutting metal
Instead. . . I tried to leave a little bit of the can so I could mount the PC board to the can. Unfortunately after cutting the can out, I discovered that I couldn’t orient the board in a way that did NOT short out a trace. In addition, the edge of the PCB will go right to the edge of the can no matter how big the hole is. There is no need for “structure” to attach it to.
It was time to cut a bigger hole. Unfortunately once I had a hole, it was nearly impossible to cut more metal with a nibbler. It was just too flimsy and wouldn’t “bite” off, which means I just had to bend the metal over. Not an ideal solution, but it worked. We are off to a good start. Hole is cut and its time to mount the hardware.
More to come soon. . .
KF5RY
I’m a relatively new ham. Got my license, joined a club and I’m having fun! I enjoy CW, pedestrian mobile, backpacking, and I dream of building radios at some point. At present I have a wife and daughters so my building time is limited.
Some friends and I decided to go on a camping trip recently. Camping in June, in Texas is generally NOT a great past time. BUT. . . My friend’s dad had passed away recently and we all felt like we should get together and enjoy nature. Much as his father had.
As with all camping trips, on my list of items to pack is a radio and an antenna. For this particular outing we were going to be at Huntsville State Park in Texas. Since I was the only amateur on the trip, I opted for a small footprint antenna and brought my Buddistick to pare with my KX2.
We arrived late in the day and were greeted with some interesting signs. . .
Like all good trips we had a lot of fun. I managed to set up my buddistick and do a lot of CQing. Unfortunately our location was not very favorable. We were in a low spot and the antenna was vertically parallel and near a very tall tree.
I’m confident that some of my radiation went directly into cooking some of the grubs in the tree. I called CQ for about 20-30 minutes the first night and managed to only work one station (XE1XR). While he didn’t answer my CQ, I did work him. I shut down for a couple hours and came back around midnight Central (0500 UTC) and called CQ again for about 1/2 hour on 30M. Not a single spot. Good SWR so I’m not sure what went wrong other than the location. I did enjoy tuning around the band late at night. I don’t do this much, but I heard an “F” Station and some “I” stations. They obviously didn’t hear me, but it was fun to have a chance!
I forgot to take any pictures of my set up. A couple of noteworthy things you would have seen in my picture. . . had I taken one. The picnic tables at Huntsville State Park are extremely thick concrete tables. I couldn’t get my clamp to open up big enough to go around any part of the table in order to mount the antenna. I was also very close to the water and therefore not very high. So I mounted the antenna to a handicap railing at the base (read bottom) of the stairs up to the vehicles. Again. . . not a great location, but it is what I could do with what I had. . . Next time I’ll bring the PPD. There is plenty of room in most campsites to set that up.
Since the bands were not hopping I opted not to do radio and instead went fishing on the 2nd night. Where I ran into this guy. . .
As you can see I made it home to type this, so it all ended OK. I’ve never seen one in the wild and never dreamed I would be so close to one in the wild.
KF5RY
I’m a relatively new ham. Got my license, joined a club and I’m having fun! I enjoy CW, pedestrian mobile, backpacking, and I dream of building radios at some point. At present I have a wife and daughters so my building time is limited.
I have been disappointed to discover that my receiver is easily overloaded. Also tuning the variable capacitor seems to have very little impact on the received frequency where as the adjustment on the front end seems to have a dramatic impact on the received frequency. Why? What measurements can I take and what can I learn? Well I’ll tell you my story. . .
****Warning everything below this line is my best guess, I don’t actually know. If you know I’d love to hear from you in the comments below.***
First of all I don’t have much equipment, but I do have an oscilloscope that Bill Ellis (N5TXN) gave me years ago. It is a 15 Mhz BK Precision 1472C scope. Unfortunately I don’t have any probes. . . Amazon 100Mhz scope probes ordered. While I’m waiting on those, what else can I do? First I used a dummy load to transmit 7.000 from another radio at 5W and used the variable capacitor on the front end to make sure I was peaking the signal in the CW end of the 40M band. I then used the tuning capacitor to try to tune off the signal. No luck. Then I keyed down into the dummy load and started spinning the VFO. I made it to 7.150 before the signal diminished in any way. Hmm. . . that just doesn’t seem right. Could my LO be on the wrong frequency?
How can I measure the frequency of the LO?
Many phone calls and emails to many friends. A couple of notable quotes.
I was advised to use a 1″ form and wind 10 loops of wire around the 1″ form for a receive antenna. I could then use this receive antenna to try to get a frequency count by using my MFJ-259B frequency counter OR use my oscilloscope and the antenna. I was also advised that this was likely a futile effort as the total energy in the LO circuit is unlikely enough to get a good reading. Turns out this was correct. . . The MFJ frequency counter gave me results from 400 Hz to 30Mhz and the oscilloscope could see a signal, but it wasn’t enough that I could actually count the waves.
I took a trip to the local Nortex QRP meeting and brought my little creation. I expressed my frustration that the tuning capacitor seems to have no impact on the tuning. After visiting with Dave Lear (NE5DL) and Joe Spencer (KK5NA) I became convinced that the issue was in my band spread capacitor. It’s not a large enough tuning value. When I arrived home my Oscilloscope probes had arrived!
I hooked up the oscilloscope probe to pin 6 on the NE602. I got nothing. I played with the RF gain pot. Nothing. I put my desk radio on 7.050 Mhz and keyed into a dummy load at 5W. Hello. . . I have signal. I guess that the LO runs at such a low current there is no observable signal until a threshold is met on the RF input. I then spun my tuning cap and the frequency changed as did the amplitude. The amplitude and frequency changed dramatically. I interpret this as confirming my hypothesis. The band spread capacitor needs to be adjusted to tighten up the tuning capacitor. As the tuning capacitor exits the tuned portion of the front end the amplitude drops. In my case, its REALLY fast!!
I think my next update will probably be finishing my final experiments with this receiver and start planning my next project. We are approaching the time of year where operating outdoors is nice so I may take a break from building until it gets to be so hot that operating isn’t fun and field day isn’t far away either!
I’m a relatively new ham. Got my license, joined a club and I’m having fun! I enjoy CW, pedestrian mobile, backpacking, and I dream of building radios at some point. At present I have a wife and daughters so my building time is limited.
A picture of the board with all of its hardware and a 9V battery for a size comparision.
In my last post I had everything wired and simply needed to add power. Why on earth would I leave the devoted readers of this blog hanging on that moment? Well I’ll tell you: It didn’t work!
I said from the beginning I expected to fail, but learn through failure. Mission Accomplished!
If you read my last post you probably caught my mistake. I was mildly distracted while doing the final stages of the build with dad duty. I also did not ever complete an entire circuit in one setting. Even when getting power to the chips I failed to ground the IC ground pins. In retrospect it really was a recipe for disaster!
When I plugged the power in I got a pop. Good news, the LM386 is working correctly! That is the extent of what happened. I attempted to move the RF gain up and down. I tried to “peak” the capacitor in the front end. Nothing happened! I started putting my screwdriver down on different pads on the board. Pin 3 and 4 for the LM386 gave me a noticeable buzz. Seems right. Pins 4 and 5 of the NE602 had the same result. So far no concerns. I put my screwdriver down on the antenna input, no change. Seems strange. I tried adjusting the RF gain, no change. Hmmm. . . Look at the picture, do you see the problem? Well the truth is there were many problems, but the first was that I incorrectly connected the potentiometer for the RF gain. I didn’t realize that a pot is actually a voltage divider network. So your input goes to a resistor on pin 1, your signal feeds through at the voltage divide and you need a lead to ground for the second resistor. You don’t just connect to the next step in the circuit. Speaking of which. . . somehow in wiring all the front end I managed to put all the parts in, but failed to actually connect each of these components to each other to make a circuit. DUH! Even after adding a ground cable for the RF gain control and connecting all the steps for the front end, the receiver was still pretty deaf. Hmmm . . .
I broke out the schematic and started going through each stage and mapping it to my board making sure that I had connected everything correctly. Do you remember my drawing out the schematic. If you look at the original schematic and my sketched schematic your going to see it. Go ahead, compare pictures and tell me. . .
seriously
go
look
Pin 6 on the NE602 is the input of the local oscillator. Pin 7 is the feedback. I have them reversed. Despite having tried to avoid the crossing of wires by sketching it all out, I have to cross pins 6 and 7 because of how I ran the capacitors. The good news is that a hot soldering iron can help get your wires out and repositioned pretty quick. I managed to do it with out permanently harming myself or anyone else. For what its worth, it’s probably a good idea to wear glasses or safety glasses when hot solder and prying wire is involved. Not that I found out first hand. . . but I’m not going to have cat-like reflexes for my whole life. Ha!
OK. . . all pads connected properly. Time to connect an antenna and give it a try. What I experienced was magic. Initially I was receiving local 96 FM station. As I adjusted the input capacitor I lost the FM station and gained radio Havana Cuba. They are very concerned about our President. . . me too I guess. . . prayed for the last one, will keep praying for this one.
Video of initial signals received
As I tweaked the capacitors I realized that I could here RTTY signals and the occasional CW signal. True to the write up, the front end is pretty wide on this thing. I think I sent an email to everyone I know to share with them my accomplishment. It’s a below average receiver, but I did it!
So what now?
Well, I’d like to study what is actually happening in this receiver. Take some measurements and attempt to optimize my LO tuning to be as selective as is possible with the capacitors I have. Then I am likely to start another receiver. Hopefully one that will be made entirely out of discrete components and also hopefully much more selective. Maybe work on a filter of some kind.
More to come!
I’m a relatively new ham. Got my license, joined a club and I’m having fun! I enjoy CW, pedestrian mobile, backpacking, and I dream of building radios at some point. At present I have a wife and daughters so my building time is limited.
initial layout and super glue mess
Now that the board is sized its time to melt some solder. I’m not sure what the real first step is supposed to be. I’ve heard Eric Guth on the QSO Today podcast talk to a number of builders and answers vary from the audio amp to the Local Oscillator. I decided to start with getting power to the chips. Once I had that figured out I’d have a better idea of where the local oscillator would go on the board. I also decided to add a couple of steps to the power input. One is a reverse polarity protecting diode and the second was a 5V regulator. Since I don’t have a real 5V power supply, I am likely to power this with a 9V battery. The NE602 has a max V+ of 8V so I want to make sure that my V+ stays at 5V and not fry anything.
Power stage complete. . . almost
You will see on the board I’ve laid out and superglued the 8 pin DIP sockets as well as the initial pads for the power rail. Lessons learned from this experience. Don’t put superglue on the pad then try to place it on the board. Put the superglue on the board and then set the pad on the glue. If you don’t you will smear superglue on your board as you can see in my picture above. The other lesson I learned was to be a little more thoughtful on where you run the wire from one side of the board to the other. I think I would run it a little closer to the chips so that the Local oscillator could have a little shorter leads over the power wire to the NE602.
If you look closely at my picture and study the schematic from the initial post, you will note that I’ve wired something incorrectly. It can be easily seen in this photo (left). Can you spot it? Leave a comment below when you find it.
The build has begun. . . More to come!
I’m a relatively new ham. Got my license, joined a club and I’m having fun! I enjoy CW, pedestrian mobile, backpacking, and I dream of building radios at some point. At present I have a wife and daughters so my building time is limited.
8 pin DIP socket soldered to the MePads
Now that I know how the layout is going to run its time to start planning how much copper will be needed for the circuit board. This will likely be the post where I get the most wrong! To be clear this is being written as the project is in process, so we will find out together if I set this up wrong. . . but a few weeks from now probably.
The circuit is set up around the two ICs, an NE602 and an LM386. Planning how these devices will sit on the board and creating enough room for the various components supporting the inputs and outputs will determine the size of copper board needed. The full size 4″x6″ copper board seems like major overkill for this circuit.
4″x6″ copper board is probably too big for our project.
I’ve decided to do the K7QO method of using 8 pin DIP sockets. While the socket adds ~$.15 to the build, it guarantees that I won’t smoke the IC with my soldering iron being too hot. I purchased some MePads when building the Regen last year. They went unused as the particular IC I was using was surface mount and didn’t fit. As you can see in the picture above, these fit the sockets just fine. I also intend to use the MeSquares for the other shared connection points. Now that the sockets are on the MePads, its time to lay them on the 4″x6″ sheet and guess how much board I need.
It seems to me that you would probably only need 1/2 of the board. Measuring 3 inches across the top and bottom of the board I drew a straight line with a black sharpie. I carried the line around the back of the board as well.
Copper ready to be drilled for standoff holes
Cutting the board using the AA7EE method resulted in a slightly crooked cut, but ultimately successful separating of the board.
I also wanted to do the K7QO method of adding stand offs to the board to raise the soldering level up off the table a little. To keep the holes semi symmetric I measured 3/10ths of an inch from each edge of the board and drilled a hole where the lines intersected.
MePads and MeSquares together
The last step was to scrub the copper with some steel wool and clean it with alcohol. Then put a couple of coats of matte Krylon on the board. This should help protect the copper a little and allow me to build on it over a period of weeks without the copper oxidizing.
The project is well underway, the next step should be actually super gluing pads and beginning to solder circuit blocks.
I’m a relatively new ham. Got my license, joined a club and I’m having fun! I enjoy CW, pedestrian mobile, backpacking, and I dream of building radios at some point. At present I have a wife and daughters so my building time is limited.
KF5RY (logging) K5JTL (double checking me) and NE5DL (operating)
My favorite radio operating activity is to operate outdoors. Once a month I try to gather a group of hams together here in the Duncanville, Texas area. I really have two objectives. One is to encourage other amateurs to get out and use their gear and the other is to show off our hobby to complete strangers. We were able to accomplish both objectives in February.
In the picture you see Dave Lear (NE5DL) Justin Long (K5JTL) and Steve (not pictured is Steve Edmonds (KZ5MSE) as he is taking the pictures). Steve is visiting Justin and his family and thought it might be fun to see what we consider to be fun.
The forecast was not optimal for radio operation. Lots of rain! BUT. . . it looked like we would have a short window for operating. Justin and I arrived first and set up my buddistick. I was looking to have a quick put up and take down antenna as the rain was an unknown!
When Dave arrived he opted for a much fuller sized vertical. Dave uses a custom mount plate with a Wolf River Coil and a 17′ MFJ Whip. He sets this all on top of an inexpensive tripod mount. He has 4 radials that are precut to the band and hangs them off of plastic electric fence posts.
NE5DL set ups his radial
About 1/2 way through Dave’s set up the skies opened up. I took down all my gear and ran for the car! 3 minutes later the rain stopped and life was normal again. Dave never stopped setting up.
Dave was testing a slight variation on his antenna and we had a little trouble getting everything dialed in correctly. Fortunately between everyone on hand we had enough tools to make it happen. In the middle of all this a man starts shouting at us. I turned around to see a pick up truck parked in the middle of a very narrow road. Outside the truck and approaching us is a very large man in a cowboy hat shouting, “OK. . . You got my attention. What are y’all doing? ? ? Are you talking to aliens?”
Fortunately Justin Long (K5JTL) came to the rescue on PR duty. While that was ongoing Dave and I were able to get the antenna finished up and on the air. We were able to operate for about an hour. Dave made a couple of contacts while I logged. The last contact we made was myself (KF5RY) and Don (VE4ESE).
Overall it was a great day. If you find yourself in Dallas County and are interested in joining us let me know and I’ll get you the date, time, and location information.
I’m a relatively new ham. Got my license, joined a club and I’m having fun! I enjoy CW, pedestrian mobile, backpacking, and I dream of building radios at some point. At present I have a wife and daughters so my building time is limited.
Image from www.qrpme.com
I try to attend the NORTEX QRP meeting each month. One of the fun features of that group is that each person who attends brings some item that is excess from their junk box. At the end of the meeting, they raffle off the items to those in attendance. I was the first person drawn in the January 2018 meeting. There were 2 kits to choose from. The Tuna Tin 2 circa 2004 (link is a more modern version) and the Norcal keyer kit circa 2002. Since I intend to build a 40M direct conversion receiver in the near future, I chose the Tuna Tin 2. So I will hopefully make a QSO on some QRPp homebuilt gear.
Although the ultimate idea is to build and operate a homebrew transceiver while learning about radio. . . this will give me a chance to transmit a little early.
I’m a relatively new ham. Got my license, joined a club and I’m having fun! I enjoy CW, pedestrian mobile, backpacking, and I dream of building radios at some point. At present I have a wife and daughters so my building time is limited.
Something weird about the month of January. I start reflecting on the last year and asking myself, did I accomplished all that I had hoped? Well I didn’t. But the secret to accomplishing a lot is NOT accomplishing everything on your list. Having a list of things you’d like to accomplish. . . Now that is where the magic happens!
…
I’m a relatively new ham. Got my license, joined a club and I’m having fun! I enjoy CW, pedestrian mobile, backpacking, and I dream of building radios at some point. At present I have a wife and daughters so my building time is limited.