This class AB RF amplifier is sold widely on Chinese Webs. It really works perfectly, but it is not suitable for beginners. First: It is not accompanied by a scheme. Second, the SMD components are not identifiable with the naked eye, so you have to use measuring devices, in the case of capacitors, of those used in a laboratory. There is a lack of instructions such as that parts of the printed circuit must be cut to make the support of the ferrite transformers. Fortunately, on the Internet it is easy to find blogs and videos that describe the problems to build this Kit, a symptom that is very popular and sold. The most important: It can not be used without a low pass filter attached to the emission band. That detail is very important and is omitted by the sellers. In my case, it worked perfectly, although it does not really reach 70 W of antenna power. For the price of the Kit, which does not exceed the price of the components, I am very satisfied. EA8ARX, Álvaro Felipe Hernández.Vollständige Rezension lesen
Bestätigter Kauf: Ja | Artikelzustand: Neu
Works ok with Transistor given irf530's. Bout 65w bird peak with tone and 14v., Still needed fine tuning for the HF frequency I use, Really a Nice project kit. If you have a Antenna analyser you can tweak input and output (no power on board) to the HF frequency you'll be using it for. I Will be trying a pair of ERF9030 transistors with next purchase of boards. Fun Stuff! I was able to convert one of two of my boards that I ordered to the mrf186 mosfet with little work and personal knowledge of amps... 140w 28v CW bird. I used the other board in the rear of super star 121 radio, using a old Magnum radio heatsink and cut out chassis for transistors to heatsink, mounted board to inside chassis with nylon standoffs, power wires from inside power connector, used a 10amp 12v relay and keying circuit to complete it. Used one of the front panel switch hi/lo to turn amp off/on, (sort of like an XRF75/150) and using the irf530 transistors supplied in kit. Good luck with your project amp! 73'sVollständige Rezension lesen
Bestätigter Kauf: Ja | Artikelzustand: Neu
This kit is only for experienced builders with proper soldering equipment and an understanding of FET amplifier construction. You will get a bag of very small surface mount parts. The value s an excellent printed circuit board. No schematic or instructions are included but can be found on-line.
Bestätigter Kauf: Ja | Artikelzustand: Neu
This kit has good design and parts. What it is lacking is assembly information, a parts list, diagrams showing what parts go where, etc. Heck, there isn't even a schematic! Yes there are some youtube videos on this item, showing some flashes of a schematic, but that is NOT enough. These items MUST come with each kit! Or else the seller is just relying on others, and not providing added value. Given how hard it is to find the information, and nothing that traces the design to its original source that I have found, I'd skip this kit.
Bestätigter Kauf: Ja | Artikelzustand: Neu
The kit was sent to me with a hole in the bag missing one part and one part fell out in the mailed envelope. MOST IMPORTANT THERE ARE NO DIRECTIONS. THERE ARE NO SCHEMATICS. THERE ARE NO INSTRUCTIONS OR DIRECTIONS TELLING ME HOW MANY TURNS FOR THE TRANSFORMERS. THERE WAS NOT ONE PIECE OF PAPER SENT WITH THE KIT EXPLAINING WHERE THE PARTS GO WHAT THE VALUES ARE, THERE ARE NO PART INDICATORS ON THE BOARD SUCH AS R-1 OR C-13, AS AN EXAMPLE. I BELIEVE I SHOULD BE COMPENSATED FOR THIS ITEM BY SENDING ME EITHER THE INSTRUCTIONS OR DIRECTIONS ON HOW TO PUT IT TOGETHER, WHAT PART GOES WHERE, HOW MANY TURNS ON THE TRANSFORMERS, OR JUST ANOTHER LEGITIMATE KIT, RATHER THAN JUST A BUNCH OF PARTS THROWN IN A BAG AND SENT TO ME, WITH ONE RESISTOR MISSING.
Bestätigter Kauf: Ja | Artikelzustand: Neu
First, this is a kit. All the SMDs were already soldered in. Otherwise, a bag full of parts. The MOSFETs are not packed in static proof bags so who knows their condition. Second, the instructions are minimal. You better know what you are doing. IIRC, no winding turn info. Not even a circuit diagram. Third, putting the input and output transformers together is a pain. You need five fireproof hands. Fourth, there is an option to connect to an outside low pass filter. This kit has it jumpered. Although it has a relay to switch it in and out, is NOT RF activated. It is PPT activated. You'd have to build another circuit on your own to do RF activated switching. Uses SMA connectors rather than anything else. You have to provide your own heat sink and fan(s) if you want better cooling. Still building it so I can't describe it's performance. In my application (mobile), I don't need all the power but need the small size so I'm added a 3 db pad in the input to lower the output, reduce the input SWR and not stress out the transistors.Vollständige Rezension lesen
Bestätigter Kauf: Ja | Artikelzustand: Neu
it should have a schematic and some step by step directions. YOu have to google and watch videos and you are still in doubt. I found a german write up but google translate would not translate because it was too long. Finally, i broke it into pieces and got it translated. I also got a bunch of surface mount parts that are apparently extras. builder beware.
Bestätigter Kauf: Ja | Artikelzustand: Neu
I found a few components defective out of the package, so I ordered them through my normal sources. Device works now.
Bestätigter Kauf: Ja | Artikelzustand: Neu
This amplifier is a good value for what you get. However, there are several caveats: 1. It has no instructions on how to assemble and test the unit. 2. You need a massive heat sink to keep the FETs from self destructing 3. You need to add low pass filters to use it legally 4. It produces at best 50W output with a 13.6 volt supply, both measured and in simulation You should be technically skilled and have good test equipment to build this. A signal generator, osciloscope are minimum, and a spectrum analyzer is recommeded.
Bestätigter Kauf: Ja | Artikelzustand: Neu
For the ham on HF this is fantastic value. Blown you PA and not worth the repair well this is the item for you. Dead easy to make works first off find room to fit it bypass the original circuit and you are off with 70 Watt 1 to 30 megs easy.
Bestätigter Kauf: Ja | Artikelzustand: Neu