EMRFD Message Archive 6091
Message Date From Subject 6091 2011-04-11 16:38:36 ka3j12 5 Watt Amp Opttions Hi - I'm attempting to design a rig that will put out 5 watts SSB/CW through 21 MHz running on 10 volts. Available drive will be about 300 mW or less. Is there any chance that an IRF510/512 would work as a final or would I be better off going with a real RF Mosfet like an RD06HHF1? Other suggestions and specific designs also would be appreciated.
Ron (KA3J)6092 2011-04-11 18:31:43 kb1gmx Re: 5 Watt Amp Opttions 6093 2011-04-11 19:44:07 Adi AM Bls: [emrfd] Re: 5 Watt Amp Opttions that is right allison.
the irf 510 below of 12v very low output.
in indonesia can not get the type of RD.........
with the 2sc19696095 2011-04-12 08:43:03 Tim Re: 5 Watt Amp Opttions IRF510 will be running out of oomph at low voltages and 21 MHz.
At low voltages like 10V and 5 watts - perhaps some "stacked and combined" or "paralleled" 2N7000's/BS170's would work nicely.
By "stacked and combined" I mean several parallel final stages each with output transformer, and the secondary winding snakes between them.
e.g. KD1JV's Simple PSK rig gets 3.5 watts from 3 BS170's in parallel but that's class C. http://kd1jv.qrpradio.com/PSKTX/SIMPLEPSKTX.HTM
I've made class AB 2N7000 push-pull stages that I've been quite happy with at the 1W level. Combine 5 of them?
I still feel slightly guilty if I fry an IRF510 on the workbench (not that I haven't fried a lot.). I have no guilt at all frying a little 2N7000 or even a stack of them :-)
Other designers go as far as designing SWR protection for 2N7000 class finals. Probably makes sense for field use where no soldering ir6096 2011-04-12 08:49:58 n7ve Re: 5 Watt Amp Opttions I used to like 2N7000s before I found out about the BS170. 300 mW for a 2N7000 vs. 800 mW for a BS170.
- Dan, N7VE
6097 2011-04-12 08:52:19 Tim Re: 5 Watt Amp Opttions Thinking from a different direction:
I am not in the public service mobile radio repair business. But it seems to me that 10V and HF use, ought to be able to use whatever part is comm6098 2011-04-12 14:46:35 kb1gmx Re: 5 Watt Amp Opttions 6099 2011-04-12 14:54:23 kb1gmx Re: 5 Watt Amp Opttions 6100 2011-04-12 22:27:44 victor Re: 5 Watt Amp Opttions The IRF510 can be used at low voltage PA when it is used as a single band tuned matched PA.
I built and used a 10m PA with single IRF510 at 13V giving close to 10W6121 2011-04-14 01:50:00 Ashhar Farhan Re: 5 Watt Amp Opttions have you considered jbot?
http://phonestack.com/farhan/jbot.html
it is a pretty stable amp. i am quite happy with it. though, i haven't
performed any IMD measurements on it.
- farhan VU2ESE