Amplifier advice for 2M

Digital ATV - The latest generation, cutting edge ATV - Please discuss it all here.
Forum rules
This forum is run by the BATC (British Amateur Television Club), it is service made freely available to all interested parties, please do not abuse this privilege.

Thank you
Post Reply
radiogareth
Posts: 1232
Joined: Wed Jan 06, 2016 9:46 am

Re: Amplifier advice for 2M

Post by radiogareth » Tue Dec 18, 2018 4:53 pm

This is my cheap eBay MRF186 based amp. 100mA bias per side, no attenuation, 12 watts out for 54 watts in.... -40dB shoulders though.....
Attachments
MRF186.PNG
MRF186.PNG (23.17 KiB) Viewed 2046 times
Top
g0mjw
Posts: 2346
Joined: Sat Sep 20, 2014 9:15 am

Re: Amplifier advice for 2M

Post by g0mjw » Tue Dec 18, 2018 5:01 pm

Getting better. I think higher voltage would help with the linearity. The aim is -50dB shoulders - quite hard to achieve.

Mike
Top
radiogareth
Posts: 1232
Joined: Wed Jan 06, 2016 9:46 am

Re: Amplifier advice for 2M

Post by radiogareth » Tue Dec 18, 2018 5:11 pm

This is what's coming out the back of my Portsdown. Can't make -50 if its not there to begin with ;-)
146raw.PNG
146raw.PNG (29.43 KiB) Viewed 2043 times
Top
G8GKQ
Site Admin
Posts: 2810
Joined: Sun Mar 22, 2009 1:21 pm

Re: Amplifier advice for 2M

Post by G8GKQ » Tue Dec 18, 2018 6:56 pm

Hi Gareth

I think that is pretty good. What really matters is the out-of-band transmissions, and you are well over -50 dB below the in-band power density.

Time to stop playing and put it on the air!

Dave
G8GKQ
Top
radiogareth
Posts: 1232
Joined: Wed Jan 06, 2016 9:46 am

Re: Amplifier advice for 2M

Post by radiogareth » Tue Dec 18, 2018 7:19 pm

I'll have a good scout round the spectrum tomorrow Dave, once I find a fan for the heatsink :-)

Gareth
Top
Post Reply

Return to “DATV - Digital ATV”