Tecsun 2P3 AM Radio Receiver Kit - DIY for Enthusiasts, Built it into a Radio case !

The Tecsun 2P3 Radio Kit is Amazing. I have been scanning Amazon for months, looking for a follow-up to the Elenco AR Radio Kit for my 6YO daughter. Here I have finally found it. Let me start off by saying, I am officially a "radio guy". As a life-long semi-pro musician and an Amateur Radio Extra Class license holder, I have been building tube amps, antennas and radio circuits for well over 35 years. My tube radio collection numbers over 100 pieces. My workbench is full of the nicer Heathkit last-generation test gear, HP and Agilent equipment, and I have prototyped all sorts of SMD RF electronics in the OEM Automotive industry for over 24 years. I have an eye for quality and I'm known for fussiness on detail. OK, credentials established. This kit exceeded all expectations, starting with the documentation. The neatly and securely packed kit comes with a large-format poster. Heavy-gauge paper with a brilliant 4-color 2-sided print job, registered as well as any I have ever seen. The detail includes a large traditional schematic, but enhanced with actual pictures of each component so everything is really easy to identify. The draftsmanship is open and very good, making it easy to read. You can follow it well while reading the included theory of operation. Voltages at key points are given and the whole diagram is split into the traditional AM groupings - input/oscillator/mixer/IF amps/detector/audio output. Really nice and really clear. The rest of the (LARGE) 2-sided poster has all the goodies: exploded views, component placements, bill of material, parts ID, how to solder well, etc., etc. All in fine detail and high-resolution color. This document was clearly someone's labor of love. Best of all, the translations are excellent and only a tiny bit stilted here and there (charming), but written with a clear reverence of the task and a nice sense of history. The parts quality, (it's not built yet), appears fine. The PCB is 2-sided FR-4, (the good stuff) and seems very stable. The housing is a nice throwback to the 1960's, a simple clear design that fits well in the hand. Everything about it says professional and not "toy". I'm really loving this, can you tell? You betcha. I would have given up my Schwinn banana-seat bike for a month to get one of these as a kid! The design is discrete - meaning it has individual transistors and components, all through-hole and no surface-mount items. There is one IC - but it is just the output amplifier, a simple little SIP CD7368, that looks easy to install and will assure clean output, with minimal fuss. The alignment instructions are pretty clear, and don't require fancy test gear, although the novice may have to read through them a couple of times before the idea gets completely clear - this is radio after all and some sense of theory is needed before you can align the 3 stages to receive as well as a factory unit would. All in all I am amazed at the care and trouble someone has taken to put this all together - the documentation poster is truly amazing and makes the project very approachable for young and old radio fans. Did I mention they also include a gift/storage box just the right size for the finished radio, denoting it's "Homebrew" status? Way cool. Schools, ham radio clubs, Scouts, churches - take note: under some friendly direction this is THE kit to get for a group project, and it's not expensive, so everyone can get one. In my opinion this is the deal of the decade and I hope they made a lot of them... because once word gets out on the street, they are going to go fast. I bought 2, because my other daughter, at 3YO, will be wanting one too...even if she has to practice a bit more will the soldering iron before I'll let her tackle it. And there is a good point to make. This kit comes with everything you will need EXCEPT solder. You have to make a choice. If you use lead-free solder (which I recommend, even though it is a touch trickier to handle) make sure you are using a hot enough iron, around 800F. Invest in a decent imported adjustable pencil iron for this kit. The old standard of ~700F works for leaded solder, (cheaper) but there is the cleanup and obvious health concerns to think about. I've been using lead free solder with the kids, and so far so good. 5 Stars, Tecsun, many thanks to you!!! Someone is finally doing it right again! - Dan N8ZJV UPDATE 2015: My daughter did build this kit (with help of course, she's only 6!) and aside from the missing 10k resistors others have mentioned (which, BTW were shipped to me without me asking) it went really well. The coils were pre-tuned almost spot-on, to my surprise, as alignment using an HP digital RF signal generator soon made clear. (I think you can get decent performance without a fancy generator - but if you have one...it's good to know you have it peaked) We were not disappointed. It worked fine after one small issue - the amplifier SIP went in backwards despite being aware of the possibility. My solution was to use a hot-air gun to carefully reflow the back side of the PCB at the SIP leads, while applying gentle pulling pressure from the component side. Despite already having had power applied, the amp chip was not DOA once installed correctly. Nice. My daughter is SO proud of it - and we made pix and video so she can prove that she really did it! She is already asking about the next project! Kudos again to Tecsun for a wonderful kit - much more kit than the price would imply! Slick!

This is the best AM radio kit available today. Packaging, component quality, PCB quality, and final performance of the radio are all excellent. The radio is of moderate to moderate-high difficulty and is best performed by a builder with good soldering skills. A teen with prior experience assembling an electronic kit is ideal. Younger ages can assemble this kit with some adult assistance. Radio reception is very good for all local stations during the day and distant stations at night. Tuning is crowded due to the small size of the tuning knob and the density of stations on the AM band but that is typical of most small AM receivers. The assembly instructions are the most important part of any electronics kit and my personal opinion is the instructions rate 3 out of 5. The instructions are excellent in comparison to other kits available but room for improvement exists. Below is the criterion I used to rate the assembly document: Clarity - 3 out of 5, The information in the assembly instructions could have been better organized. Technical - 3 out of 5, The circuit technical description contains an average quality description of a superheterodyne AM radio. Some minor English language translation issues exist, Step-By-Step Assembly - 0 out of 5. The greatest weakness of the assembly document is the lack of clear step-by-step instructions. Print Quality - 5 out of 5. The print quality of the instructions is excellent. Drawings and schematic diagrams are excellent. Testing and Troubleshooting - 2 out of 5. The documentation contains minimal testing and troubleshooting instructions. One oddity with the assembly is the process for checking the idle current in three places on the PCB, and then using larger or smaller value resistors to bring the idle current within the desired range. When the current is within the desired range, the builder must solder closed some very small jumper pads. The currents to be measured were in the micro-amp range which is very difficult for the typical low-cost DVM to measure. Instead of measuring current, I recommend the manufacturer switch to measuring the voltage on the collector or emitter resistors. That is much easier to do with a low cost DVM and does not require the use of jumper pads. I used the voltage measurement process with good results. The assembly instructions recommend building each radio function block and then testing each one when completed. However the instructions do not indicate which component should be installed. Below is the order I installed the radio components in order to accomplish the goals of the manufacturer: Audio Amplifier EJ1 - Earphone Jack IC1 - Audio Amplifier IC C8 - Electrolytic Capacitor C9 - Polyester Capacitor C10 - Electrolytic Capacitor C11 - Electrolytic Capacitor C12 - Electrolytic Capacitor C13 - Electrolytic Capacitor R14 - Resistor R13 - Resistor R12 - Resistor VR - Variable Resistor (Follow instructions on soldering VR to small PCB, the solder small PCB to large PCB) Battery Holder Test Audio Amplifier Insert batteries. Plug dynamic headphones into EJ1. Touch soldered terminals of VR with your finger and listen for hum and noise. Remove batteries. If you heard noise, proceed to the Detector section below. If you did not hear noise while touching VR, double-check that all components above were installed correctly and all solder joints are good, then repeat the audio test. Detector C14 - Electrolytic Capacitor C15 - Ceramic Capacitor C6 - Ceramic Capacitor C7 - Ceramic Capacitor D1 - Detector Diode R11 - Resistor Shield Cover Test Detector No tests. Proceed to the 2nd IF Amplifier section below. 2nd IF Amplifier T3 - Transformer Q3 - Transistor R10 - Resistor R8 - Resistor R3 - Resistor D4 - Diode D2 - Diode D3 - Diode Test 2nd IF Perform current check indicated in instructions or the alternative test procedure I recommend below: A. Solder the terminals of Jumper Pad C together (Jumper Pad C is indicated in the top PCB layout of Figure 6 in the instruction document). B. Install the batteries and measure the voltage across R10 with a volt meter. C. If the voltage is between 50mV (0.05V) and 100mV (0.1V), remove the batteries and proceed to the 1st IF Amplifier section below. D. If the voltage at R10 is lower than 50mV, remove the batteries then remove R8 from the PCB and replace with a lower value (120K) from the extra resistors supplied in the kit. E. If the voltage at R10 is higher than 100mV, remove the batteries then remove R8 from the PCB and replace with a higher value (220K) from the extra resistors supplied in the kit. F. Repeat B and C. 1st IF Amplifier SFU - Ceramic Filter C5 - Ceramic Capacitor C4 - Electrolytic Capacitor Q2 - Transistor R7 - Resistor R6 - Resistor R5 - Resistor R9 - Resistor T2 - Transformer Test 1st IF Perform current check indicated in instructions or the alternative test procedure I recommend below: A. Solder the terminals of Jumper Pad B together (Jumper Pad B is indicated in the top PCB layout of Figure 6 in the instruction document). B. Install the batteries and measure the voltage across R6 with a volt meter. C. If the voltage is between 0.6V and 1.2V, remove the batteries and proceed to the Local Oscillator/Tuning section below. D. If the voltage at R6 is lower than 0.6V, remove the batteries then remove R5 from the PCB and replace with a lower value (10K) from the extra resistors supplied in the kit. E. If the voltage at R6 is higher than 1.2V, remove the batteries then remove R5 from the PCB and replace with a higher value (22K) from the extra resistors supplied in the kit. F. Repeat B and C. Local Oscillator/Tuning C1 - Ceramic Capacitor C2 - Polyester Capacitor C3 - Ceramic Capacitor C16 - Electrolytic Capacitor T1 - Transformer R4 - Resistor R1 - Resistor R2 - Resistor Q1 - Transistor VC3/VC4 - Variable Capacitor L1/L2 - Antenna Test Local Oscillator/Tuning Perform current check indicated in instructions or the alternative test procedure I recommend below: A. Solder the terminals of Jumper Pad A together (Jumper Pad A is indicated in the top PCB layout of Figure 6 in the instruction document). B. Install the batteries and measure the voltage across R2 with a volt meter. C. If the voltage is between 0.5V and 1.0V, remove the batteries and proceed to the Local Oscillator/Tuning section below. D. If the voltage at R2 is lower than 0.5V, remove the batteries then remove R1 from the PCB and replace with a lower value (100K) from the extra resistors supplied in the kit. E. If the voltage at R2 is higher than 1.0V, remove the batteries then remove R1 from the PCB and replace with a higher value (150K) from the extra resistors supplied in the kit. F. Repeat B and C. Refer to the Figure 7 of the instructions for the following: Install the knobs, L1/L2 antenna mount, and back cover hex standoff. Secure the L1/L2 antenna with two wire ties supplied in the kit. Install the grill cloth and speaker in the speaker grill. Screw the speaker grill to the front case half. Solder the speaker to the PCB. Insert the PCB into the front case half and secure with screws. Insert the front knob faceplate onto the front case half. Insert batteries and power on the radio. You should be able to receive stations and hear them on the speaker and headphones. Install the back cover. Overall this is an excellent AM radio kit. The assembly instructions and testing sections could be better, but they are actually better than most other kits available today.

This radio is a kit so, if course, you must put it together. This means soldering all the components to the board, which requires some soldering skills. The directions are adequate but could certainly be better. They do Not give you a blow by blow step quide for each component as you would see in a Heathkit or Elenco. However, if you have even basic common sense and a bit of electronics knowledge, you really shouldn't have that much trouble building it. There are a couple quarks with it though. One is there are 3 test points that have a cut in a trace so after it's assembled, you are to test current at these points. If they are in range, in theory, you should be able to bridge the gap to close it. I found it was necessary to add a tiny bit of a discarded lead to bridge these points. One of them is in a pretty tight spot. The other thing is that the volume control works backwards. By this I mean when you first turn it on, what would normally be the lowest volume is the highest! That's pretty annoying. It was easily fixed, but it required a modification. I desoldered the 2 points for either side of the volume pot, and swapped the leads. It now works as expected. The circuit is a unique design in that with only 3 transistors, it's able to achieve quite a sensitive and selective radio! All of the actual receiver section is done with those 3 transistors! Yet it does have 2 IF stages. The audio amp is done with a single IC. The volume is quite good, and everything matches up well. The alignment is quite simple. It helps to have another radio to compare with so you know what station you are actually listening to. The finished radio is quite small and very usable. If course not many people are into a radio that is only AM now a days but I found it to be a fun experience and I do still listen to AM. Part of the reason it's as selective as it is, is due to the fact it uses a ceramic filter between the 2 IF stages. It has quite a large farrite bar antenna for such a small radio. Don't let the minor issues deter you from building this kit. I had a lot of fun doing it and got a good radio to boot so it was well worth the cost. I just wish they had designed it so the volume worked as normal. That is the reason I gave it 4 instead of 5 stars.

SEE ATTACHED PICTURES. GRIPES, PROBLEMS, ETC. COMPLETED BUILDING TODAY. I HAVE BUILT HUNDREDS OF KITS (IN FACT I JUST FINISHED 2 OTHER ELENCO KITS THIS LAST MONTH, NO PROBLEMS) AND THIS TECSUN 2P3 KIT IS PRETTY AWFUL AS FAR AS INSTRUCTIONS, FIT FINISH, TEST AND ALIGNMENT. ITS AWFUL. THE FIT AND FINISH IS THE WORST, QUALITY. PWB ASSEMBLY GRIPES: 1. THIS KIT WAS NEVER “PROOF OF ASSEMBLY FOR HOME ASSEMBLERS” BY A LAYMAN DO IT YOURSELF KIT BUILDER. YOU APPEAR TO NEVER HAVE DONE ANY TRIAL ASSEMBLY WITH A HOME DIY KIT BUILDER GUYS TO GET BUGS OUT. I THINK I’M FIRST BECAUSE YOU HAVE SERIOUS MISTAKES, OMISSIONS, MISSING PARTS ETC., ESPECIALLY SEE #3, #11! REQUIRED FILING TO FIT! THAT’S JUST POOR QUALITY ! 2. ARE THE BLUE TRACES SHOWN ON THE ASSEMBLY DRAWING JUMPER WIRES? IF SO YOU SAY NOTHING ABOUT THEM. WHAT DO I DO? FOR NOW I’LL ASSUME THEY ARE NOT JUMPER WIRES AND NOT ADD THEM. I DOUBLE CHECKED WITH MAGNIFYING GLASS AND THEY ARE TRACES. 3. MISSING PARTS FROM THE KIT. R13, R14 10K RESISTORS. YOU OBVIOUSLY HAVE NO QUALITY CONTROL ON BAGGING / KITTING THE PROPER PARTS, ALL THE CORRECT PARTS. YOU SHIPPED PARTS MISSING, SHORT! 4. POOR QUALITY RESISTOR, COLOR CHIPPING OFF, COLOR WASHED OUT, HARD TO READ. HAD TO VERIFY MANY WITH OHM METER. 5. MISSING MANY ASSEMBLY DETAILS. IE HOW MOUNT BATTERY HOLDER, HOW MOUNT ANTENNA. ANTENNA WIRE CONNECTIONS UNCLEAR. OTHER KITS I’VE DONE SHOW LOOP STICK WIRES IN GREAT DETAILS, YOU DO NOT. ALSO “PLASTIC RIBBON” MISSING FROM ANTENNA MOUNT. SHOWN IN DRAWING,BUT ITS NOT IN THE KIT. MORE MISSING PARTS. 6. NO CHECK OFF FOR EACH COMPONENT AS INSTALLED. 7. POLARITY MARKING OF CAPACITOR HORRIBLY CONFUSING, INDUSTRY STANDARD IS TO LABEL A + SIGN ON PWA SILKSCREEN, YOUR HASH MARKS, WHAT THE HELL DO THEY MEAN? C13, WHAT IS POLARITY? THE PWB HAS HASH MARKS, NO PLUS SIGN. I ASSUME BY CAREFULLY CHECKING YOU MEAN HASH MARKS ON PWA IS +?????. CONFUSING! 8. NO LOGIC TO ASSEMBLY. SAYS, BUILD STAGES AND TEST, BUT HOW? START WITH WHICH? YOU SAY TEST COMPONENTS BUT GIVE NO WAY TO TEST THEM. DO YOU NEED TO BE COMPONENT TEST ENGINEER TO TEST THESE? YOU ARE SUPPOSED TO GIVE GOOD PARTS, I SHOULDN’T HAVE TO TEST THEM AGAIN. 9. MISSING GLUE. CHASSIS BOX WHITE PLATE FALLS OFF. NO GLUE IN KIT. 10. VOLUME CONTROL BOARD REQUIRED FILING WITH FILE TO GET THE PWA TO SNAP IN PLACE. IF YOU HAD EVER PROOFED ASSEMBLED THIS KIT, YOU WOULD HAVE CAUGHT THAT AND YOU DID NOT. POOR QUALITY! 11. IS THERE A SHIELD OVER C6, C7,R11? YOU SHOW A SHIELD CAN IN THE ASSEMBLY DRAWING, BUT NONE IN THE KIT. WHICH IS CORRECT, NO SHIELD, OR SHIELD CAN? THIS IS ONE OF THE MOST HORRIBLE KITS I EVER PUT TOGETHER. ITS JUST AWFUL! I COMPARE YOU TO TEN TEC, EXCELLENT KITS, XTAL SET SOCIETY, EXCELLENT KITS, BORDEN RADIO KITS EXCELLENT; THOSE KIT COMPANIES ARE EXCELLENT, YOU ARE NOT. FINAL ASSEMBLY GRIPES: 12. THE EARPHONE HOLE IS TOO SMALL AND NEEDS TO BE FILED BIGGER. MAJOR MISTAKE IN THE MECHANICAL DESIGN. SEE PICTURE. YOU NEVER PROOFED THIS KIT OR YOU WOULD HAVE CAUGHT THIS MAJOR MISTAKE! 13. THE FINISHED PRINTED WIRING BOARD PWA DOESN’T FIT PROPERLY IN THE CASE. 14. THE THREE MOUNTING SCREWS ATTACHING THE PWA TO CASE ARE VERY DIFFICULT TO LINE UP. THERE IS A BIG BULGE IN THE PWA AND THE BOTTOM PLASTIC CASE DOESN’T FIT PROPERLY, SEE PICTURES. WHAT’S CAUSING THIS I DON’T KNOW AS IT A BLIND FIT AND I CAN’T SEE. SO THE CASE BULGES. SEE PICTURE. 15. KIT MISSING GLUE. 16. BOTH CONTROLS, VOLUME, AND TUNING CHAFE, RUB AND ARE VERY DIFFICULT TO TURN BECAUSE OF THE MECHANICAL FIT PROBLEMS. THE RADIO IS BARELY USEABLE THIS WAY. MECHANICAL IS AWFUL! TEST/ ALIGNMENT GRIPES: 17. NO TEST EQUIPMENT LIST. 18. NO CLEAR CONCISE ALIGNMENT PROCEDURES WITH TEST EQUIPMENT, OR EVEN WITHOUT TEST EQUIPMENT. 19. NO ALIGNMENT SPECIFICATIONS, SETUP CONDITIONS, OR PROCEDURES. 20. CUT JUMPER AT GAPS A, B, C: VERY CONFUSING. WITH THEM OPEN THE KIT DOES NOT WORK. JUMPER GAP CURRENTS: I’VE NEVER SEEN SUCH A THING! YOU NEVER EVER ASK CONNECTIONS TO BE DONE WITH SOLDER BLOBS ONLY, EVER!!!!!! SOLDER HAS NO STRENGTH!. 21. I CHECKED CURRENTS AT A, B, C ANYWAY, ALL THREE AT A, B, C IN SPECIFICATION. WHY YOU HAVE THE TESTER KIT BUILDER DO THIS IS BEYOND ME. IT ADDS NOTHING TO TELL YOU THE KIT IS WORKING. THEN YOU ARE UNCLEAR AS TO WHEN TO APPLY SOLDER BLOB JUMPER BRIDGE. WHICH? 22. TEST SELECT AND CHANGE RESISTORS R1, R5, R6? I’VE NEVER EVER SEEN THIS DONE IN ANY KITS. YOUR DESIGN SHOULD HAVE NO TEST SELECTS. BESIDES, CHANGING THESE LIKELY DOES NOT AFFECT READING MUCH. THIS IS JUST AWFUL AND WILL RESULT IN MORE DAMAGE TO THE PWB TRACES. 23. VOLTAGE TEST POINTS USELESS. ALSO REFERENCE TO GROUND? 24. NO 455 KHZ IF ALIGNMENT. I ENDED UP PEAKING FOR MAXIMUM MEASURING MVPP WITH MY OSCILLOSCOPE ACROSS THE SPEAKER TERMINALS AND A LOW LEVER RF GENERATOR OR SET TO 455 KHZ MODULATED 1 KHZ. PEAKED T2, T3. BOTTOM LINE: 25. THE RADIO DOES WORK, BUT YOUR ASSEMBLY INSTRUCTIONS, TESTING , MECHANICAL DESIGN AND QUALITY, MISSING PARTS, NO ADEQUATE TESTING PROCEDURE NEEDS TO BE FIXED.

I technically should knock of one star because, as other reviewers have mentioned, the kit IS missing two 10K-ohm resistors; and also because the documentation shows an empty IF transformer shield can soldered to the circuit board (covering the detector diode and a couple of other small parts) and that shield can is missing. I'm sure the radio will work fine without the shield can, but you MUST replace the two missing resistors or it won't work. BUT . . . the rest of the kit in it's implementation, documentation, and design is so outstanding that I'm still giving it 5 stars. It's just that good, and we haven't seen anything this good in America since Heath-Kit lamentably went out of business. Other reviewer stated that he had to cut holes in the plastic case in order to get a good fit, that is just plain false. Folks, this is a kit, you have to expect to do some work here! It's not going to just snap together like some Lego blocks. Doing the work, taking your time and doing it right with some finesse, and winding up with a nice thing you can have some pride of accomplishment in, that's all part of the kit building experience. I found that if you position the volume control and headphone jack on the PCB and hold it there with a little piece of blue painter's masking tape (do one of them first, then the other) in their positions and DON'T solder yet, then place the PCB in the case and test for fit with the holes in the case . . . if the fit is not good, reposition the part and secure again with the tape. Once the fit is perfect, carefully remove the PCB without disturbing the position of the part being held by the tape, and then with the tape holding the part in it's perfect location, you solder it down to the PCB. That's what I mean by taking your time and doing the job with some finesse. Again to the reviewer who complained he had to file the little volume control daughter board after breaking it off the main PCB, it's to be expected, it's a kit, not a pile of Lego blocks. Another totally invalid complaint IMHO. The 4-color poster is fantastic, there are NO errors on it. The reviewer who complained about the electrolytic capacitor markings was just nit-picking, Thee negative side of the capacitors is marked plainly on both the pictorial chart AND on the PCB itself. I have been working as a professional in Avionics for over 38 years, and most ALL capacitors of that type I've seen have the NEGATIVE side marked. In the kit, the parts themselves, the pictorial, and the PCB all are plainly marked as to which side is the negative side, so no problem there at all IMHO. I have an extensive "junk box" full of electronic parts at home, so I had no problem replacing the two missing resistors. Still, no excuse for that, they need to fix that issue so that people don't have to go to Radio Shack and get something that is supposed to be included in the kit. I also had plenty of "junk" miniature IF transformers, so I gutted one of them and installed the can on the PCB over the detector components as shown by the outline on the PCB and in the documentation. Missing parts issue solved. I turned on the radio and it worked right away. Then I aligned it via the simple method in the documentation and it was working just fine, with the stations 560 and 1450 showing up on the station dial in their proper relative positions. Maybe the reviewer who complained about the stations not being in the right place was in too big of a hurry to read the documentation about the part that says it NEEDS to be aligned. Again, it's a kit radio, NOT a snap-together pile of Lego blocks. I then did what I consider to be a "proper" alignment using a voltmeter to monitor the AVC voltage at the points marked "TP1 and TP2" in the documentation, and using an RF signal generator set to 455khz to align the IF, and then set to 540KHz and 1650Khz to alternately align the inductor and trimmer capacitors to get the stations to appear almost perfectly with the tuning dial markings. I then had a remarkably sensitive and selective little receiver; that tells me they used good parts for the tuned circuits in the radio considering there are just a couple of transistors in there doing all the "work". It even received my talk radio station inside a metal aircraft hangar, better than any radio anyone else has in the shop (but still it wasn't as loud as it can get outside the building). I then noticed it I place my hand, or a small metal plate near the back of the radio inside the metal hangar, it picked up as good as it could outside. So an idea came to mind - I took the back of the radio off again, and I covered the whole inside surface of it with "1000 mile per hour tape" AKA aircraft battle damage tape, it's metal (aluminum) tape and you can get a roll of it at any of the big box home improvement stores, usually in the section that has the duct work for heating and air conditioning (or sometimes it's in the paint department with the masking tape). I carefully cut around all of the ventilation holes in the radio's back (even though it doesn't get hot and doesn't need ventilation) mostly because the sound from the speaker can get out through those slots and makes the radio's sound fuller. VOILA, not the radio pick up just as good in metal or rebar reinforced concrete structures as it does outside in open air. Then I went on a camping trip way out in the desert 155 miles as the crow flies from my home town's low-power talk radio station. The little radio picked up that station with plenty of volume and no static - unlike all 4 of the car radios of the folks who were at camp with me, none of the car radios (two stock ones and two after-market ones) could even pick it up. So I'm very impressed with the engineering, sensitivity and selectivity of this little radio. Overall, despite the missing parts, it was a pleasure to build and a pleasure to listen to. Oh, and the batteries last a long time I'm sure, because I've been listening to it almost everyday for 5-7 hours each day at work, plus on Saturdays in the house (talk radio junky here) for almost 2 months now, and there is no sign of the radio's volume being any lower than the first time I used it. A well deserved 5-Stars, and that's not even taking into account it's educational value to kids who are just learning radio electronics. But I sure wish Tecsun would hurry and get the missing parts issue solved for those kids big and small that don't have a huge collection of electronic parts laying about the house as I do.

Others have said that their kit had missing resistors. Mine has extra resistors but is missing three diodes. I also found solder mask covering some of the pads. I don't have the diodes in my inventory so now I get to wait after spending way too much for replacements from Amazon (Seven bucks for a pack of ten. Reminds me of Radio Shack!) On the plus side, I love the case! It brings back great memories from my youth. While this radio does have transistors it's actually powered by an integrated audio output chip. The data sheet for the audio output chip (CD7368CS) says that it outputs 35 watts at 4 ohms. That's pretty darn loud for a pocket radio! The radio itself is powered by two double A batteries. It will be interesting to see how efficiently it runs on just three volts. Despite the minor setback I am still excited about the kit. If the radio works as well as I hope I will undoubtedly buy a few more of them to give as gifts.

This radio is incredible! I am listening to it even as I write my review. I am playing 830am, WEEU, on it. It’s about 90 miles from me, and a fringe station under good conditions, yet I am hearing it loud and clear with good quality sound and this little radio is filling the room with it. I will caution you that this does require soldering skills, and will require some understanding of how to align a radio to achieve peak performance. Practice on old radios first and learn how they work before you try building this kit. That way you will have less frustration and more enjoyment from it. Plusses: quality parts, nothing missing. The circuit is well laid out and designed. With a couple days of work to assemble it, plus another hour to align, you are rewarded with a really good radio. I have a 1971 Zenith RE-10, which is the best pocket radio I have seen. The performance of this kit comes very close to that Zenith. That says a lot. Minuses: the layout and content of the instructions could be better. I had a few missteps putting it together where a few more words or pictures would have kept me from my mistakes and rework. The instructions are a giant fold out piece of paper. It felt like working with an old school paper map. The other minor annoyance is the faceplate that goes over the volume and tuner display has no way to attach it. You’re expected to glue it on, I guess. The instructions are mute on that—I ended up gluing it on. That’s about it. I am loving this little thing. Oh, by the way, I almost forgot. They even include a fold out cardboard box to store your completed radio in. It’s a nice touch!

I've been aware of the 2P3 kit for some time and finally decided to purchase and build one. As a radio amateur & MW DX enthusiast for nearly 50 years, I've built most of the commercially available ham radio kits. The 2P3, although fairly simple in concept, is an exceptionally well designed & executed kit with all high quality parts and materials. The result of the builder's effort is an attractive and very functional traditional pocket radio that I expect will provide years of dependable use & enjoyment. This is not the average beginners/educational/amusement kit. I consider it a serious kit requiring some requisite basic skills and experience to ensure an enjoyable and successful completion without struggle, troubleshooting, and rework. The poster-sized assembly guide although generally well-written, is a little fragmented in content and does not guide the builder with step by step guidance. I suggest careful study before building is undertaken. I found some differences from western circuit board marking conventions such as hash marks to indicate negative lead polarity of electrolytic capacitors. I had to hunt the assembly instruction for bias current values at 3 test points as well as color code guidance for the ferrite bar antenna wires. Assembly is otherwise conventional and as an experienced builder, posed no uncertainty or difficulty. My first task beyond study of the manual was to take inventory of the parts against the bill of materials. All parts were present in my kit. Upon completion of circuit board assembly, bias current readings were within spec without the need for resistor value changes (as described in the manual). Extra resistors of various values are provided to accommodate if needed. The radio immediately functioned quite well from initial power up. The alignment process was simple but I spent considerable time peaking for maximum performance before I was satisfied....just my nature! Build time from unpacking to completion of alignment to my satisfaction was in excess of 6 hours! This included cleaning of flux and careful inspection. There was no rework involved. Final mechanical assembly was intuitive and all parts aligned perfectly. Performance wise, I found sensitivity is quite good. Selectivity is average and as expected for its design but readily aided by the radio's excellent directional nulling ability. Audio quality is excellent, particularly with headphones, and has plenty of power. Consistent with the 2P3's conventional superhet design, the noise floor is nearly non-existent in an RFI-quiet environment. As a result, signal-to-noise ratio is excellent. This combined with full, crystal clear audio may be an eye-opener for those of us used to DSP-based radios that prevail today. As expected, tuning requires some finesse. One caution - AGC action is minimal and the headphone jack receives full speaker drive without any safety attenuation, so caution is advised when listening with headphones. I truly hope Tecsun will keep this great kit available so all can enjoy it. I'm not aware of any serious competing kit radios currently available. Personally, I'd like to build another one. Availability of different colors or cabinet styles would serve as an excellent excuse! Here's hoping for future availability.

This was a very enjoyable kit to make and the completed unit works well. For those that have a transistor beta (hFE) tester, a voltmeter, some spare resistors, and a breadboard, you might want to make the following changes to the build procedures: Measure hFE of each S9018 transistor and order them from highest to lowest and then assign them to the circuit as follows (my hFE examples in brackets). Q1 - highest hFE (104) Q2 - mid-level hFE (102) Q3 - lowest hFE (97) Note that the provided kit bias resistors seem to assume hFE 100 so you will know to modify the resistors if you measure far off that nominal value (100). Build and test each section as you go - starting from the audio amplifier, then second IF amp./detector (Q3), then first IF amp. (Q2) then the Mixing circuit (Q1). Calculating modified bias resistors: ----------------------------------------- A. Calculate R2 Ve = 0.68 (given on schematic) hFE Q1 measured (e.g. 104) Ic = (0.6 + 0.3)/2 = 0.45 mA desired collector current. then R2 = (hFE1 * Ve) / (1 + hFE1) / Ic e.g. R2 = 104 * 0.68 / 105 / 0.45 = 1.50k ohms B. Calculate R10 Ve = 0.07 volts (given on schematic) hFE Q3 = 97 (measured) Ic = (1.0 + 0.5)/2 = 0.75 mA desired collector current. then R10 = (hFE3 * Ve) / (1 + hFE3) / Ic e.g. R10 = 97 * 0.07 / 98 / 0.75 * 1000 (mA/A) = 92.4 ohms C. Calculate R8 Vc16 = 1.853 volts (build and measure the diode voltage source from your kit) hFE Q3 = 97 measured Ic = 0.75 mA (same as step B.) then R8 = hFE3 * (Vc16 - 0.8) / Ic R8 = 97 * (1.853 - 0.8) / 0.75 = 136k ohms D. Calculate R6 Vc15 = 2.78 volts (capacitor voltage given on schematic) Vc2 = 1.6 volts (collector voltage given on schematic) Ic = (0.6+0.3)/2 = 0.45 mA (range given on schematic) then R6 = (Vc15 - Vc2) / Ic R6 = (2.78 - 1.6) / 0.45 = 2.6k ohms E. Calculate R1 Vc16 = 1.853 volts (build and measure the diode voltage source from your kit) hFE Q1 = 104 measured Ic = 0.45 mA (same as step A.) Vb = 1.3 volts (given on schematic) then R1 = hFE1 * (Vc16 - 1.3) / Ic R1 = 104 * (1.853 - 1.3) / 0.45 = 128k ohms The values of R5 and R7 were used unchanged (as they came in the kit) because their calculation is made more difficult by the circuit feedback. My circuit worked well even with hFE of Q2 (102) being slightly off the nominal value of 100.

マニュアルは、分かりやすく、完成して性能が良かったが、半年で選局ができなくなった。部品の品質に問題あり。

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A qualidade do produto é conforme as minhas expectativas.

Well thought out assembly instructions, require good soldering skills for small components