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QRP Guys Trap Antenna


K2DB Paul Mackanos
 

It says it’s rated for 20 W. I’m just wondering if it will take the 50 W output of the QCX Amp. If not what is the best for beefing up the parts to handle it. 😎
I plan on using it only in the CW mode, normally 25 to 35 words per minute.


Dave N3AC
 

Paul K2DB,

I didn't analyze the circuit, but since it's a tank circuit, I'd think your capacitor voltage rating or wire diameter will limit your power level... unless you want to conduct a "smoke test" and tell us! Good luck!

Dave N3AC

On Fri, Sep 4, 2020 at 11:35 AM K2DB Paul Mackanos <paul.mackanos@...> wrote:
It says it’s rated for 20 W. I’m just wondering if it will take the 50 W output of the QCX Amp. If not what is the best for beefing up the parts to handle it. 😎
I plan on using it only in the CW mode, normally 25 to 35 words per minute.


Klaus Beckers
 

Don't forget a bigger toroid core size that will not be so quickly saturated than the small cores of the original circuitry. Your traps would no longer work properly with saturated cores and shorted capacitors.


@CurtisM
 

Paul

Honestly, only the board might be useful at those levels, 25 or 50 watts. Any antenna with tiny coils is suspect there. What band do you wish to radiate with? Bending ends of wires can be an option for fit. For low bands, consider something like small garden vertical. 

Curt


ajparent1/KB1GMX
 

For higher power I use those 7.5KV door knob caps and the coils
are air wound with 1 wire width air spacing between turns.

I tried toroids but at 100W I had a few T80-2 arc between turns.
The voltages and RF currents are higher than you would expect.

Pushing the QRPguys product a little might fly but 50W is more than
twice and has very high risk of failure.  If it fails it will during transmitting
the SWR will go very high for the now mismatched antenna.  That's not
a good thing for any transmitter or amp.

For 50 W I'd suggest a more robust trap.

Allison
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tk5ep
 

Why the heck do you want to apply more than twice the power they are rated for ?

Would you use a 1A fuse for a 2.5 A equiment ?

Patrick