OM's in need of a doc. copy please send me a mail , i'm happy to help. E-mail adress at QRZ.com
It seems that the seller often forgets to add the doc. ....
My first impression : High quality PCB , all parts in the kit including 2 power FET's type IRF530N.
However i had doubts about the claimed 70 Watts output at 13.8V for these fets are normally fed with 24 - 36V to get a good modulation. The 0.5 turns windings are on the PCB by means of the tubes inside the toroids. Construction is easy but a lowpass filter for each band is mandatory. I used the low pass data from WA2EBY's broadband HF amplifier. WA2EBY amplifier part 2
The first test was in the original configuration at 13.8V and 5Watt input from my FT-817. Max. power 80 Watt but the input swr on tx was 1:2.2 much to high. At 4 Watt input the swr drops to 1:1.5
Output was about 65W at 20m.but the modulation was as expected distorded at 2.7V bias voltage.
At 3.7V bias the modulation is verry acceptable.
5 Watt transceivers need a 1 dB attenuator to work with this Amplifier.
Conclusion : This is a nice kit with acceptable results for a low price.
|PA 70 with 20m LPF on T68-6 toroids|