Wanted: a simple 10 w 10MHz rf source

[harry weston]

In a couple of months I will be giving a talk to my amateur radio club about how an SWR meter works, so I would like to take along a simple demonstration. For that I need about 10 of RF power at about 10MHz into a 50 Ω load. As it will be on for only a brief period, no antenna, and in a large hall, there is no need for finesse. The design criteria are: cheap and dirty, easily found components. Can anybody help with a simple design for such an RF source ?

 

[kspalla]

pls check these links
https://www.electroschematics.com/893/70mhz-rf-power-amplifier/
https://www.electroschematics.com/24/rf-15w-30w-power-amplifier-kt922-kt930-kt934/
hope this meets your requirement.

Regards.

 

[jiripolivka]

In a couple of months I will be giving a talk to my amateur radio club about how an SWR meter works, so I would like to take along a simple demonstration. For that I need about 10 of RF power at about 10MHz into a 50 Ω load. As it will be on for only a brief period, no antenna, and in a large hall, there is no need for finesse. The design criteria are: cheap and dirty, easily found components. Can anybody help with a simple design for such an RF source ?

As you plan to make a demonstration for the radio amateurs, almost any of them has a transceiver and a SWR meter you can use. It is therefore not making much sense to procure or make your own instrument.
By the way, the radio amateurs should inform you that only a licensed amateur is allowed to generate 10 W at 10 MHz (the 10 MHz amateur band is precisely specified) for such demonstration. Cheap and dirty emission of 10 W at 10 MHz can be legally prosecuted.

 

[harry weston]

Thank you for your reply. Yes a transceiver could give me 10W but the permissible SWR is limited to 1.5, so it would not do for a reasonable demo, I want an SWR of 3 or more. As to 10w, that is the permitted radiated power, so my "transmission" into a dummy load is no problem, and the interference, too, will really be minimal. If they prosecute me, I hope they will apply the same criteria to all the rest who mess up the bands continuously.

 

[jiripolivka]

Thank you for your reply. Yes a transceiver could give me 10W but the permissible SWR is limited to 1.5, so it would not do for a reasonable demo, I want an SWR of 3 or more. As to 10w, that is the permitted radiated power, so my "transmission" into a dummy load is no problem, and the interference, too, will really be minimal. If they prosecute me, I hope they will apply the same criteria to all the rest who mess up the bands continuously.

First, I received your reply in spam, so please make sure you PC does not send a virus.

Second, most good amateur transceivers can output up to 100 W, then you can insert an attenuator to protect the final stage. Then you can twist your load to a SWR >10 if you wish.

Maybe it is true that there are lot of bad guys interfering.But your statement sounds like : "streets are full of thugs, so I want to be one of them". Please don't!

 

[harry weston]

I don't want to get into a slanging match, the answer to all your points is "yes, but ...".