[hpsdr] MRFE6VP61K25

[Tim O'Rourke]

This was posted on Juma forum recently.
Tim W4YN

Hi

Congratulations on your fine work so far with the PA1000. I am interested to understand your experience with harmonic energy levels from the MRFE6VP61K25. I have been experimenting with one of these devices for use in a low weight "airline friendly" travel amplifier for DX-pedition use. Initial encouragement by Freescale in the choice of the device was strong but experience has revealed problematic levels of harmonic energy at the output. Freescale now acknowledge this problem to be significant when using these devices at HF. They have quoted H3 at -7dBc and H5 at -13dBc being their experience. These figures are bad enough to require use of a power dumping diplexer at the output or development of some frequency adaptive class F filtering which seems rather impractical in a broadband amplifier. My own experience with the particular device I have on hand is H3 at 0dBc +/- 2dB and H5 at -2dB +/- 2dB throughout the frequency range where H3,5 are within the passband of T1/T2. Harmonic attenuation obviously increases outside the passband.

Extensive discussion with Freescale resulted in them saying, "Development of a wholly acceptable amplifier for this frequency range (1.8 - 54MHz) will be very difficult to achieve."

I am wondering whether you have had better experience with harmonic levels or found a way to address the issue satisfactorily?



Tim O'Rourke 
W4YN at ARRL.Net
Low Power Amateur Radio Rocks 
Member of Flying Pigs,ARCI,GQRP,RSGB,ARRL Life Member
NHRA Life Member