Stefan,

Thanks for the info and advice.  Yes,  ferrite beads sound like a
good idea.  The resistors and caps (1M 100k 68pF 680pF etc) between the
FET's are for lowpass or something else?

73
Joe VO1NA

On Sat, 9 May 2015, DK7FC wrote:

Hi Joe,

That choke was just intended to improve the supply voltage stability (low pass filtering). It's value is not critical. Meanwhile i've learned that it can be helpful to spend a ferrite bead in front of the jFETs gate, to prevent VHF oscillations... I am one of those who prefer to spend one more component here and there, just to prevent eventual unintended behaviour...

73, Stefan

Am 09.05.2015 02:44, schrieb [email protected]:

Hi Stefan and group,

I am building a probe using your design. Could you
explain the interstage network and the 470 uH choke?

I hope to use this to detect some 36 km photons. So far,
using the PA0RDT miniwhip (without the VLF refit)
and Spectrum Lab has resulted in reception only of
near field electrostatic and induced artefacts
ie: my best DX is only 5.2 km.

Best 73 & TNX
Joe VO1NA