Tuesday, 19 November 2013

New ATV 5 Watt Class-A amplifier

Last week Erwin, PE2ER, informed me that he had an assembly kit of a 23 cm amplifier. Since I am involved with some ATV activities these days, he asked me if I could use this kit. I struggled with some PA designs last weeks ( with power modules or CLY15) and therefore I was very glad with this offer. 
Last sunday I assembled the 1.2 GHz amplifier which is a design of PA0VRE from 2002.
It contains two SHF transistors: A BFQ68 and a BFQ136. The amplifier is able to generate 5 Watts RF power at 1.2 GHz with 200 mW input.
Assembling the kit was a delicate job. Some very small SMDs (2p2) had to find their way to the pcb and the whole circuit is mounted on a heatsink. 
All details are here: http://www.van-rees.nl/23pa/versieNL.PDF

Anyway, after building the first test on the bench were promising.

                                             The 23 cm amplifier finished

This morning I connected the amplifier to the ATV baseband circuit, connected the biquad antenna to the amp and pointed the antenna to the local ATV repeater and switched the power on.
A nice steady ATV signal at 10 GHz from PI6ZTM came back for me:

    My 1255 MHz ATV signal (LH upper corner) arrived at the PI6ZTM repeater

 LNB for 10 GHz reception and dual quad antenna for 23 cm transmissions. With this    antenna setup a distance of 4.2 km between my QTH (JO22gb) and the repeater on "De Blankaard" (JO22fb) is bridged.

Steady ATV FM signal

I am curious what is possible with the 1.2 GHz Watts available now. Maybe, now it is also time to give my ATV antenna a permanent place on the roof.
Thanks Erwin !


  1. Dank darragh! Das ist genau das, was ich brauche, um mich im Blog kommentieren vertraut zu machen. Wir freuen uns auf viele interessante und hilfreiche Artikel von Ihnen......

    pa verstärker

    pa endstufe