RE: H mode mixers at 144 MHz

["Leif Åsbrink" <SMTP:LEIF.ASBRINK@xxxxxxxxxxxxxxxx>]

Hi All,

> Giancarlo did some tests with his H-Mode HF mixer at 144
> MHz. 
>
> These tests demonstrate the H-Mode Mixer could be used 
> at 144-148 MHz. Need to do some studies on 
> transformers cores (suggested #61 = mu 125) and 
> numbers of turns to improve mixer attenuation. 
> 
> I hope there are some friends of the Linrad list that 
> will tackle trial test at 144 MHz. 
> ----end of Giancarlo's message
> 
> And now to try and find some time to play with these new
> mixers ;)

I made some experiments with the NC7SB3157, another member of
the Fairchild CMOS switch family. I tried to use it to convert
from 70MHz to 10.7MHz but the results were not too encouraging.
I do not remember the details any more, but performance was similar
to what I could get with the J310. Since the microscopic devices 
are awkward to work with I decided to use the J310......

Some day the modern switches will be superiour for use at VHF. 
I do not know if the day has already arrived, my tests did not 
give good enough IM3 performance but I did not study very carefully 
since I do not have the tools to work with these very small components.

Maybe someone will make a PCB with just the mixer on it?

73

Leif / SM5BSZ

LINRADDARNIL