NXP Homebrew RF Design Challenge

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NXP Homebrew RF Design Challenge

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Jacques Depijpere

5 жыл бұрын

Jacques Depijpere ON7NP entry to NXP Homebrew RF Design Challenge

Пікірлер: 32

@kevinscheveneels1596 5 жыл бұрын

great experiment, simple but effective design, and nice to hear about the alternative way of cooling. sure a thing to remember in next builds with power devices. best 73, Kevin ON5DRE.

@jacquesdepijpere5750 5 жыл бұрын

Thanks Kevin, 73 Jacques

@aga5897 7 ай бұрын

The schematic looks silly - Bias going to the centre tap of the Primary winding of the input transformer and the Gate of the lower transistor grounded ... The copper plate between both Source connections is a great idea ! Not just mechanically - it improves the Ground plane which will help at 15m to 10m. Superb heat solution !

@peterderidder6549 5 жыл бұрын

Prachtig Jacques. Proficiat van Peter, ON4AGP

@jacquesdepijpere5750 5 жыл бұрын

Dank u, Peter

@AmateurRadioAwesome 4 жыл бұрын

Nice! Well explained.

@AmateurRadioAwesome 4 жыл бұрын

I think the bias wire is connected to the wrong side of the input transformer. Tell me if I'm wrong.

@uwepolifka4583 3 жыл бұрын

The BIAS comes over R4 to T1 and goes than direct to ground. There is no connection dot but if it is connected the gate of a MRF300 is also on ground. This gives absolute no sense for me.

@workout74 4 жыл бұрын

thank you for this video best 73 de NQ2L

@juststeve7665 2 жыл бұрын

heat sink works much better if the fins are longways not crossways

@jacquesdepijpere5750 2 жыл бұрын

I agree you have to put it longways. It depends on the airflow. I didn't intend to put it crossways. The little blowers however create a shirl which improves the cooling tremendously as measured with a IR image temp meter. So far I have found no one who can calculate what actually happens in the swirl. But it works exrtremely well.

@bigliftm 3 жыл бұрын

Jac hoe heb jij die mrf 300 samples voor elkaar gekregen ? 73s van PD0ROH

@jacquesdepijpere5750 3 жыл бұрын

Destijds gekregen bij deelname aan de challenge. Waren overigens niet echt gratis, heb invoertaksen moeten betalen, 73 on7NP

@richsjt4021 3 жыл бұрын

Very interesting project. It's been about a year, have you made progress? I would like to build one, your design appears to be truly minimalistic. I have given thought to using heat pipes from cpu coolers. Your publications are about a year old, updates? Rich N5TBT

@jacquesdepijpere5750 3 жыл бұрын

Sorry, no updates, Jacques ON7NP

@RickGreenPhoto 4 жыл бұрын

I would like to build one can I get more information such as a bill of materials and source?? In fact I would buy one from you if you put the kit together.

@jacquesdepijpere5750 4 жыл бұрын

Hi Rick, There is a full article about the amplifier in RadCom 12/2019 and 1/2020. Succes.

@alteriaautomation6867 3 ай бұрын

Wrong schematic. transistor working in class C as no bias is provided to the base. Bias goes directly to ground via primary input transformer. Heat system no sense as cutting fins to a shallower dimension will produce high turbulence and back pressure. I don't understand the designs. Where is the decoupling in the center tap of the output primary transformer. This will never work!

@antronx7 4 жыл бұрын

hello. what are the values of 2 to 5th harmonics in relation to carrier frequency at full power and above 70% efficiency.

@jacquesdepijpere5750 4 жыл бұрын

I have not measured that. You would have to use a 5th of 7th order lowpass filter at the output to filter out harmonics. I have not used this amplifier on the air jet.

@jacquesdepijpere5750 4 жыл бұрын

I have not measured the harmonics. But you would use a low pass filter to attenuate harmonics. Best regards, Jacques