Posts Tagged ‘kit’
One for the Boys (or the Girls!)
December 12th, 2018 | 
Author: When I started in this hobby when I was around 7, it was batteries and old car bulbs nicked from my Dad's shed, with wires held on the terminals with sellotape, that was to give me my first taste of electronics, well before I even started making crystal sets. That is all what is needed,just a little encouragement to spark enthusiasm in our hobby, little did I know then I would have held a job in the industry and have an Amateur Radio licence to my name and I would be writing about it today.
So I was in my local discount store the other day, something caught the corner of my eye, an electronic kit. Tronex 50+ Circuit Lab. Made in, you guess right China! But does similar to what I have mentioned above. Yes it resembles the kits that were once produced in late 70's, where wires were held under springs to connect each component into the circuit.
Only having two daughters, one whom is now married, and the other that is now in her latter years of High school, a chance perhaps to encourage her, and get her away from playing with her tablet and computer during the long hours of these dark nights. So I decided to buy one for her Christmas stocking. My wife said you only bought it so you can play with it didn't you? I said no, this is a good educational tool and can be used to encourage, especially with her having to do a science at school.
Not hopeful she will be another Ham in the future, but you never know where it will lead? For overseas readers of my blog I notice there are Tronex kits on ebay of similar content.
I will return to this when she decides to investigate and play, further info here:
https://www.homebargains.co.uk/products/14749-tronex-50-circuit-lab.aspx
So I was in my local discount store the other day, something caught the corner of my eye, an electronic kit. Tronex 50+ Circuit Lab. Made in, you guess right China! But does similar to what I have mentioned above. Yes it resembles the kits that were once produced in late 70's, where wires were held under springs to connect each component into the circuit.
Only having two daughters, one whom is now married, and the other that is now in her latter years of High school, a chance perhaps to encourage her, and get her away from playing with her tablet and computer during the long hours of these dark nights. So I decided to buy one for her Christmas stocking. My wife said you only bought it so you can play with it didn't you? I said no, this is a good educational tool and can be used to encourage, especially with her having to do a science at school.
Not hopeful she will be another Ham in the future, but you never know where it will lead? For overseas readers of my blog I notice there are Tronex kits on ebay of similar content.
I will return to this when she decides to investigate and play, further info here:
https://www.homebargains.co.uk/products/14749-tronex-50-circuit-lab.aspx
It’s ALIVE !
The 1Watter 40m #551 -- Lives
 |
| The 1Watter 40m on it's inaugural QSO |
 |
| Inside the enclosure |
The 1Watter is a kit from kits and parts dot com
The Universal 1Watter (also called the 1H2O) is a full featured little superhet radio transceiver that you can build for about $50. It doesn't come with an enclosure, a tuning pot, speed pot or an on/off switch so that will cost extra unless you already have some in the junk bin.
Some of the features include;
- 1 mighty watt of output
- Good selectivity from the 3 crystal filters
- A VCXO tuned frequency range for the 40m band from approximately 7,020 kHz through 7,039 kHz
- A built-in full functioned keyer with provision for adding a speed pot and messages
- Included command button accesses the functions of the electronic keyer
- Natural sounding sidetone (nicer than my Ten-Tec Century/21)
The Build
The kit is delivered in a box and inside are a couple of brown paper bags stapled together. Inside one of the bags are a couple of plastic bags with the components. The other bag contained the header kit. The ferrite toroid mix types are separated in different unmarked plastic bags so don't mix them up (the instructions tell you which bag has each mix). If anything is missing the kit supplier (Diz, W8DIZ) is very responsive.
The kit includes both SMT caps and through hole caps. I tried to solder one of the SMTs but I didn't have the right kind of tweezers to hold it in position for soldering so I used the through hole caps.
 |
| SMT and through hole caps are supplied |
This is the 3rd revision of the Universal 1Watter board and I was the first to build the 40m version.
While the schematic was correct, some of the instructions weren't sorted out properly for the 40m kit. I related issues as I found them to the designer and he promptly updated the online documentation.
I soldered the components and wound toroids as I had time over a few evenings and the initial voltage tests went well.
 |
| using through hole capacitors rather than the SMTs |
 |
| some of the bits and bobs |
 |
| build is progressing |
 |
| close up |
 |
| XTAL filters give it good selectivity |
 |
| Everything except the final transistor |
 |
| AGC circuit |
Debugging
When the build was completed I connected the rig to an antenna and heard nothing.
The keying circuit and transmitter worked fine and I verified those functions but the receiver was deaf as a stump.
Thus began a number of days of investigation. Diz (the creator of the board) guided me through a number of debugging steps.
The first recommendation was to examine and rewind the binocular toroid balun that transformed the impedance from the xtal filters to the input of the U5 oscillator. He believed that I may had wound it incorrectly. I desoldered it and rewound it but that did not resolve the issue.
He then guided me through determining if one of the filter crystals or filter capacitors was bad. I desoldered a few components as a tests but that did not resolve the issue.
There are 3 identical mixer chips on the board. I swapped them around as there was a suggestion that there were some faulty chips in one of Diz's shipments.
I then took the board to my Elmer Paul Stroud AA4XX. He had a signal generator, Oscilloscope and RF detector. He traced the RF and all looked well but we still were unable to obtain any signal through the U5 mixer. Lastly we tried disconnecting the AGC transistor to see if it was clamping it and that didn't resolve it either.
Diz asked me to return the radio to him so he could take a look. After a couple weeks he emailed me saying he thought the BFO xtal might have a problem. But he later discovered that the oscillator in U5 was not starting up. Apparently the circuit design had a low Q and needed more current to get the oscillator working. He modified the design, adding a 16k resistor to the bottom of the board on U5 to get the oscillator going. After that all was well and he shipped the board back to me.
 |
| The FIX for all those problems required an extra resistor connected across U5 |
Learning from problems
Being the first person to build a particular version of a kit brings its own set of challenges, especially when you're as new to kit building debugging RF problems as I am. However I'm actually glad the kit didn't work right at the initial build.The process of debugging the board, was a great learning process. I studied the schematics and learned, as best I could, the function of each circuit so that I could better understand how to test it. During the debugging process Diz instructed me that although RF signal generators and scopes are useful you can tell a lot by touching a RF component with an inductive metal object and listening for a buzz or hum from the BFO.
So all-in-all, even though the bug in the board was not due to a error on my part, I'm glad it occurred. I understand more about superhet radio design than I did before and more than if the kit had worked right off the bat.
On the air
After receiving the board back, I hooked up the frequency XCO potentiometer, paddle, command button, audio and output potentiometer and an external speaker. I then connected a 12v battery and heard the 1H2O keyer chip announce itself at power up in Morse "1 W".
 |
| Frequency control pot on the left |
 |
| Volume control, output jack, cmd pot and paddle input |
For this first on-air excursion I was using it at the default startup 15wpm keyer speed. You can default the speed higher with a different resistor value.
I have a resistor shrink wrapped and connected in-line to the blue-white wire coiling above the radio connecting to the speed pot terminal. In essence fixing the speed at 15wpm until I add the speed pot.
 |
| Ready to transmit |
 |
| On the air... I was using my paddle out of the photo to the right of the Bug |
First On Air QSO
I tuned around and found a strong station at the end of a QSO near 7030 kHz.
When he sent the final dit-dit I called and WD4AXJ answered my first call. He was in TN near Knoxville, and I received a 559. We chatted for about 10 minutes. Sorry about the blurry video. I thought I'd focused.
After I recorded this video I found an open frequency and sent out my call. Very shortly thereafter KD2FSH answered my call and reported me as 599!
Whoo - hoo. 599 for my little 1Watter 40m.
I was transmitting using my 40m attic antenna. So deed restricted HAMs take note. You can build a one-watt radio and make contacts using your attic antenna. Haha.
You'll hear in the video there is some weirdness going on with the audio derived AGC. It is clamping down sometimes and is worse when I don't have the volume turned up very loud. When I began calling it clamped after every semi-break-in but didn't do it much after that. I'll have to look into that.
The AGC clamping may be a side effect of the increased gain Diz added to the BFO oscillator. I'll ask the forum.
Other than the AGC issue I'm super pleased with the little board. I touched the heat sync a couple of times after transmitting my side of the qso and it was warm but not really hot. It seems as though as long as you have a reasonable match to the antenna the power transistor should be happy.
My next steps are to get it in an enclosure and get it out to the Excalibur antenna site to hook onto that nice 40m doublet we put up a couple weekends ago. I plan to use my efficient little BLT tuner for that purpose. I will do a further review of the feature set on the keyer and record some more qsos for a later review.
Summary
The band was fairly busy and the little 1Watter did a fine job with stations on nearby frequencies. You can hear some getting around the passband but it is not bad at all. I'll do some tests to further define it's selectivity but at first glance it is far better than my old Ten-Tec Century/21.
My calls were answered quickly and I received good signal reports. It didn't sound as though the transmitter was drifting at all during the QSO. That's one advantage of using VCXO in the design. The disadvantage of using a crystal controlled oscillator for the frequency control is limited tuning range. The transmitter only has about a 18 kHz tuning range around 7030 kHz and I don't find many of the SKCC folks around that frequency but it is the QRP watering hole for 40m.
It is possible to shift the frequency with some capacitance changes but I think I'll leave it as is for a time and see how many states I can work.
Just imagine. This little $50 single band kit has good selectivity, a nice built-in keyer with a natural sounding sidetone, and lest we forget... You get a MIGHTY 1 WATT of OUTPUT. What more could a QRP ham need.
That one-watt of output was sufficient for all the QSOs I attempted tonight.
So lower your power and raise your expectations
72/73
Richard, AA4OO
UPDATE: 04/01/2016
I am still having the AGC pumping issue and others on the list have reported similar issues but only on receive. It happens to me when I key unless I turn up the volume very high. I did get it installed in a case but I still need to wire up a real power connector rather than using alligator clips.
 |
| !Watter installed in a case |
UPDATE: 04/05/2016
After doing quite a bit of reading I learned that the LM386 op-amp used in the 1watter is rather notorious for audio oscillations. There are a number of suggested fixes. I went with a 4.7uf cap connecting Pin 7 on U6 (the LM386) to ground. That hasn't totally resolved the issue but it's much less pronounced now.
I have it in the case with all the proper plugs now (see below) so I'm happy. I've been making QSOs every day with it and it continues to amaze me and the stations that work me. It is stable as a rock with regard to frequency and the large knob with the single turn 10k pot seems to work well for tuning. I have enough control to vary the frequency slightly without having to turn it too much. The tuning range is only about 20kHz so just 3 frequency markers are plenty to let me know what frequency I'm near. The selectivity is just fantastic for such a simple little radio. Diz has created an inexpensive winner.
 |
| cap fix for LM386 oscillations |
 |
| 1Watter in enclosure with all the proper connectors for the case |
I will have a BLT please
The BLT-Plus Balanced line QRP tuner
I was looking for a QRP tuner for the 1Watter 40m transceiver I am building that would work with both balanced feedline antennas as well as coax feedline. The traditional Z-Match tuner is quite efficient at tuning balanced line antennas and the built-in SWR bridge gives you an all-in-one tuner and SWR indicator without having to take a separate SWR meter along with its inherent mess of cabling a separate SWR meter. The BLT in the name stands for "Balanced Line Tuner".This tuner kit is available from the fine folks at Pacific Antenna.
 |
| The Kit as it comes out of the bag |
The kit comes with everything you need except for hookup wire and your soldering equipment. Instructions are downloaded from the qrpkits website.
Why use a z-match ?
Here are some advantages that the Z-match design offers:
- Matches balanced loads without the use of lossy baluns.
- Being a parallel resonant circuit, the Z-match can provide some band-pass filtering for your receiver and harmonic attenuation for your transmitter.
- A well-designed Z-match tuner has a high Q and is more efficient (less lossy) than other types of tuners.
- The fixed inductor simplifies construction (no taps or rollers needed).
The secret sauce
Matching balanced line fed antennas is sometimes problematic for a traditional balun and tuner as the antenna can present impedances that are far outside of the balun's design. The Z-Match uses a center tapped coil to keep the complex impedance balanced across the inductor (at least that's how I understand it). I have measured my Elecraft BL2 balun getting appreciably warm at QRP levels when connected to my doublet indicating loss I'd prefer to avoid. The Z-Match design supposedly results in less loss.
Built in SWR indicator
The BLT plus includes a Dan Tayloe N7VE LED SWR indicator which eliminates the need to carry a separate SWR meter. The concept is beautiful. The SWR bridge is switched into "Tune" mode and presents a 50 Ohm impedance to your transmitter while you are tuning so that you don't risk damaging sensitive home-brew finals. The LED lights when the SWR is too high and dims and then goes out as the match is made. It is simple and fast to use. The instructions for the bridge are not with the BLT instructions. Download them from this link.
 |
| SWR bridge with LED indicator |
 |
| Switch to Tune to present a low SWR to the transmitter while matching, switch to Operate when finished |
Building
The kit is relatively easy to build with one tapped toroid to wind for the SWR bridge and one 3 winding toroid for the tuner. I faced a few issues that you might avoid:
- The kit is provided with really nice water slide decals that give it a commercial look (if you don't ruin them like I did). The instructions recommend applying a clear coat to the decals after they are applied. I used a Krylon matte finish clear coat which indicated it was fine for metals and plastics but it partially melted the decals and caused them to bubble. I'd suggest testing whatever you are going to clear coat them with first.
- Don't over tighten the plastic tuner shafts or you won't be able to slide the knobs on (yes I did).
- The binding posts have little plastic spacers that separate and it isn't obvious. If you install them and wonder how they don't ground themselves (like I did) you've done it wrong and will have to go back after it's together and try to remove them with all the wiring in place.
- The bolts for the binding posts are very soft metal and the nuts can strip them if you apply too much force (yep I did that too).
- The main toroid has three sets of windings and they overlap. Pay attention to the instructions about winding them all in the same manner (clockwise or counter clockwise) or you will have to rewind them (yep, I did that too).
- The 3 windings on the main toroid overlap so you won't be able to go back and verify your turns when doing the 2nd and 3rd winding so count carefully (ask me how I know).
- Temporarily attach the SWR bridge to the front panel to get the spacing correct to solder the LED leads.
My tuner toroid ended up being a bit messier than I'd like because I had to rewind it and my resulting leads aren't as short as they could be. I may go back and trim the leads to make it tidier but my least favorite part of winding toroids is heat stripping the insulated magnet wire so I'll probably leave it as is. Initial tests indicate it's working great.
 |
| My messy toroid winding... but it's working fine |
Operation
- Connect your transmitter and antenna.
- Choose the appropriate switch in the back for coax or balanced line antenna (Up for coax, Down for balanced line).
- Start with the inductance switch on the back set to low-impedance (Low-Z) because it is the most efficient. It uses the 6 turn secondary rather than the 12.
- Switch the front switch to "Tune"
- Key the transmitter and be sure you are using 5 watts or less
- Turn the "Load" knob first until you see a dimming of the LED then the "Tune" knob to make it go out completely
- The knobs interact so you'll need to go back and forth between them to achieve best match
- If you can't get a good match switch the inductance switch on the back to "High Z" and try again
- Don't apply power too long at a time during tune because the 50 Ohm resistors are heating up in there during the Tune process
- When the LED goes out or gets very dim you have a very good match. Switch to "Operate" and enjoy a well matched antenna
Photos
 |
| Result of having to rewind the secondaries made it messier than I'd like |
Dimensions
Remarks
Qrpkits offers a great little kit that results in a commercial looking product. You end up with a small portable tuner plus SWR indicator that reduces the complexity of your portable operation. Pacific Antenna is very responsive to questions. I sent a question concerning the incorrect instructions I'd downloaded for the antenna bridge and James answered me the same day with a different link (included above).
So if you have a QRP radio that needs an antenna tuner I recommend this kit. It's well thought out and works well.
That's all for now
So lower your power and raise your expectations
72/73
Richard, AA4OO
Low cost oscilloscope kit (Bangood)
Steve G1KQH has tracked down yet another bargain. I think my SMA assembly skills are probably still not up to the task, but you can hardly go wrong at the price which includes free air-mail shipping. Another absolute bargain. I think Steve must have shares in Bangood!! If not, they ought to make him their UK agent, HI.
Here’s another one (kit), we could get our teeth into:
I have that many kits at the moment, I don’t know where to start next? If I come back in another life can we have a 48hour clock pse!73 Steve
http://www.g1kqh.talktalk.net/
First 40m Pixie QSO
At 1000z this morning I exchanged RST 579 reports with G6ALB who is 3km from me on my 40m Pixie on 7.023MHz CW. This was my first on-air QSO. Netting was perfect and I used the rig directly into my low Par triband antenna. An ATU might have helped. Andrew G6ALB said the channel was pretty busy but that I was a good RST579 with no hint of chirp. This afternoon we’ll put the rig on his spectrum analyser. I gave Andrew 579 probably reflecting the poorer MDS of the Pixie. I have no idea of his power or antenna.
My initial goals have been met: I built the kit and have managed a QSO on the air with it. With the fatigue associated with my brain bleed still very apparent (I am well and truly shattered currently), I was well pleased. A few more QSOs with the 40m Pixie would be good, HI.
$10 well spent. Excellent little kit. FB little transceiver. Works surprisingly well.
Genesis Q5 1W QRP kit from Australia
 |
| http://genesisradio.com.au/Q5/q5_1.jpg |
A trawl of the internet earlier found this kit, a 1W QRP transmitter for any band from 3.5MHz to 14MHz. It is available for S19.95 (US Dollars) + S9 (US Dollars) shipped anywhere worldwide. That seems pretty good value. Also on the website are SDR transceivers.
I last showed this particular kit on my blog 5 years ago.
See http://www.genesisradio.com.au/Q5/ for more details including how to order the various kits. Details on the page include parts lists, schematics and building details.
The are some pretty good SDR transceivers on this site.
So you want to play with a Pixie?
 |
| My own surface mount version of the Pixie2 |
This page provides a guide to Pixie and related kits in a table format. These are simplistic single-band transceivers which are fun to build, yet they perform well enough to be used, although with some effort, for real contacts.
The idea of using the power amplifier transistor as a mixer seems to come from George Burt – GM3OXX – whose five transistor FOXX was described in 1983 in SPRAT. The basic design of the oscillator, PA/mixer and the simple keying has been more or less unchanged since RV3GM – Oleg Borodin – described the four transistor Micro-80 in 1992 in SPRAT. Later the Pixie 2 by WA6BOY replaced two of those transistors with the LM386 audio amplifier (QRPp 1995). Most later versions are variants of these designs.
Foxx | |
 Foxx-3 kit from Kanga, £29.95 | Incorporates a sidetone oscillator, changeover relay and low-pass filter. Different versions for the 80, 40, 30 or 20 m bands |
Micro-80 | |
 Kit from QRPme, $35.00 | Micro80D. Updated version with choice of high or low impedance headphone, polyvaricon tuning cap and board mounted connectors, 80 m. |
Pixie2 | |
 Kit from HSC Electronic Supply, $14.95 | For 80 and 40 m. Eham review |
 Kit from Kenneke, $29.95 | Includes 80 m crystal |
 Kit from QRPme, $40.00 | Lil Squall Transceiver ][. Several components and the output low pass filter are on sockets. Comes with a crystal for 40 m. |
 Ali Express Ham QRP DIY Kit Shack 40 m, $15.07 | 40 m version. Tuning pot for VXO. |
 Radi0kit, £22.00 | Enhanced Pixie2 which comes in 80, 40 and 20 m versions. Judging from the PCB layout it has an improved pin 7 muting circuit. |
What can we say to characterize these designs? One the one hand they are very simple to build and get to work. One the other hand they are also simple in the sense that they do not always perform very well. Therefore I don’t think I would recommend them to any novice ham. It takes some understanding of frequency offsets and sidebands in order to make real contacts. But many have had great fun with this minimalist transceiver which in its basic version puts out some 2-300 mW. And it encourages experimentation and modifications. Also, it should be remembered that it isn’t really necessary to get a kit, as the Pixie 2 is quite simple to build from scratch also. I did that myself.
The original designs and many variants and modifications are documented in the Pixie file document of SPRAT. There are many, many more clever modifications out there and I have my share on this blog also. To sort out and link to all the other pages is too daunting a task, so therefore I have focused on kits here. Finally I wouldn’t be surprised if the table is incomplete so I would appreciate comments if you think that something is missing.
