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IRF-510 in QDX

 

The IRF510 has virtue but not for this.

THe inpput (gate) capacitance is about 150PF about 3x the BS170s!
The gate threshold voltage is 2-4V (most about 2.7V) and the ACT08 peak is 5V
except for the higher input C of the IRF510 will likely depress that (and make it run hot).
That means the actual mode is likely closer to class B (more current, heat, less efficient).

That it works at all is pretty amazing.? Its still a bad solution.

Allison
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Post online only, please no email.
 

The driver will most likely not have enough power to drive the IRF510 FETs hard enough. Especially on higher bands the gates of the IRF510 FETS have too high capacity to open to saturation quickly or at all.

Vojtech OK1IAK
 

Take a reading at this article!




and watch for the page stating:?¡°Bigger is not Better¡±

Have fun, de dl2arl
 

There are many posts here about problems with the BS-170. , such a misfortune happened to my QDX. Everything was in order, the antenna is good tuned, the reasons are not clear.
There was no BS-170, I didn¡¯t want to wait for delivery, so I put the IR-510. The transceiver is working. The current consumption during transmission increased to 2 Amps, I lowered the supply voltage to 8 Volts. Now the current during transmission is 1.8 A. I also had to adjust the band-pass filter. Reduced the number of turns by two turns of the inductor. While everything is OK. On load from QRP-LAB about 20 Volts. There is no way to accurately measure power. More than 300 contacts were made on 20 meters. 52 countries including PY and VK. The antenna is a dipole at a height of 3 meters. On other bands so far QRT. There are no antennas.
On IRF - 510 I installed small aluminum radiators from a beer can :-)
Perhaps my solution is not beautiful, but allowed me to restore the transceiver
--
73, Oleh, I2/UY2ZA

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