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Class E 10m

PostPosted: Tue Jul 30, 2013 5:44 am
by GW8LJJ
Gentlemen:

Any ideas for Class E on 10m.

Eric GW8LJJ

Re: Class E 10m

PostPosted: Tue Jul 30, 2013 9:21 am
by kf1z
Good question....

Whenever I ask it, what I get is "... it should be possible...",. or " I have done it..."
but that's as far as it goes.
No offers of schematics, drawings or pics, etc from those who have done it.


I picked up a pair of devices that I hope will help.
They are drivers/mosfets all in one package.
they are a bit pricey, at $50 + each, but should eliminate some of the
problems ( parasitics, etc) at the higher frequencies.

Have been hoping to get them in a circuit, and see what smokes for a while,
but recently moved across the country, and the dust is still settling from that.


A couple years ago, I may have had a successfull go at it.
At the time, I thought it was a failure ( very very low efficiency.. like <50%)
However, I was using a lowpass filter that I ASSUMED was right... it cam from communications concepts as a 10m LPF
but.... long after I had given up on my little 10m class e try, I tried to used the filter for another project, that ALSO
failed due to the filter.
I found that the filter cutoff was much too low!!
So, maybe my little experiment worked better than I had thought. But, still have not gone back to try it again.


So much trial and error ( lots of the last part)
But, since I am far from being an engineer, that's the only way I can figure this stuff out.

Fun to learn, when there is time... but I would MUCH rather be handed a set of schematics. :lol:

Re: Class E 10m

PostPosted: Sat Aug 03, 2013 11:28 am
by GW8LJJ
Hi kflz,
Thanks for the reply. Yes seems to be a black art! No problems with getting it all working on 160m,80m, 60m and 40m which seems to be the limit. We in UK are limited to 400W pep and this easily achieved using TC4422 drivers along with IRF640 FETs.

The main problem in getting higher frequencies may very well be the drivers as FETs will switch faster although I have not tried others because the drivers are not fast enough. At least i don't know of any that are.

I also prefer to throw a handful of components in the air and build something when they land on the bench. can't be bothered with design by software methods.

anyway, be interested if anything turns up.

Regards,

Eric GW8LJJ

Re: Class E 10m

PostPosted: Sat Aug 03, 2013 2:53 pm
by kf1z
The drivers that ARE fast enough ( as far as I know...) are expensive...

The DEIC420, DEIC515 etc

The device I mentioned has the DEIC515 as the internal driver.

See:

http://www.ixysrf.com/index.php?page=sh ... &Itemid=36

Re: Class E 10m

PostPosted: Mon Aug 05, 2013 9:21 am
by GW8LJJ
Hi,
yes as you say, expensive. Especially for experimenting with. You wouldn't want to blow up many of those!

Interesting though. Will keep an eye open for them to see if any traders will have them cheaper at some time.

Thanks,

73,

Eric GW8LJJ

Re: Class E 10m

PostPosted: Thu Aug 15, 2013 10:05 am
by Diego-CX4DI
Hi,

I do a quick test with the ARF460A/B of Microsemi in 29Mhz and work good. I driver it with my FT-950 with 6W and the appropriate rf gate transformer.(efficiency 89%)

best 73's
Diego
CX4DI

Re: Class E 10m

PostPosted: Mon Aug 19, 2013 10:16 am
by kf1z
Diego-CX4DI wrote:Hi,

I do a quick test with the ARF460A/B of Microsemi in 29Mhz and work good. I driver it with my FT-950 with 6W and the appropriate rf gate transformer.(efficiency 89%)

best 73's
Diego
CX4DI



Would you be willing to make at least a sketch diagram of exactly what you did and post it?

Bruce
kf1z

Re: Class E 10m

PostPosted: Tue Aug 20, 2013 8:11 am
by Diego-CX4DI
I cannot post because I've not web address, sorry!
but I can do a draw and send you via e-mail.

best 73's
CX4di
cx4di@adinet.com.uy

Re: Class E 10m

PostPosted: Wed Aug 21, 2013 12:13 am
by kf1z
That would be kind of you.

If you do, I will, with your permission, repost it here from one of my webservers so everyone can see it.. ok?

Thanks
bruce

email address is

kf1z@hughes.net

Re: Class E 10m

PostPosted: Wed Aug 21, 2013 9:24 am
by Diego-CX4DI
Hi Bruce,

All the information just was send you.
Please do not re-post yet.
The circuit that I sent you was not sufficiently tested, you do testing first and then depending on the results we see if re-post or not.
we are in contact via e-mail.

best 73's
Diego
cx4di

Re: Class E 10m

PostPosted: Sun Aug 25, 2013 5:14 pm
by GW8LJJ
Hi Diego and Bruce ,
Can I also have a look at the tests? Perhaps I can play here as well.
thanks,
73,
Eric GW8LJJ... eric@ericedwards.co.uk

www.GW8LJJ.com

Re: Class E 10m

PostPosted: Fri Aug 30, 2013 7:09 am
by Diego-CX4DI
the ARF460AG and ARF460BG are availables from DIGIKEY.

http://www.digikey.com/product-search/e ... &x=11&y=14

73's
diego
cx4di
cx4di@adinet.com.uy

Re: Class E 10m

PostPosted: Fri Jan 10, 2014 9:45 am
by steve_qix
KC2UDZ has built a 15 meter class E transmitter, and it actually should be able to work on 10 meters.

Analog drive, which might make sense up at those frequencies.

I forget the MOSFET that was used. Definitely a metal gate MOSFET from APT, I believe.

IXYS and some other manufacturers produce metal gate MOSFETs. Without the metalized gate, the gate resistance is too high to allow the MOSFET to be driven at high frequencies.

Re: Class E 10m

PostPosted: Sat Jan 11, 2014 5:21 pm
by w5hro
What would you guys suggest for 6-meters?

The class E project I started back around 2008 could be converted for 10-meters, but what about also including 6-meters?

I work for Linear Technology in California and we have MOSFETS, but I have not even thought about class E since 2008 so my memory is really bad :cry:

I think for low band work my tube stuff will always rule, but I do like the idea of using MOSFETS on the higher bands like 10 and 6-meters because it solves problems.

Re: Class E 10m

PostPosted: Sat Jan 11, 2014 10:33 pm
by steve_qix
I've seen some app notes someplace that documented a 6 M class E RF amplifier - I think it was from IXYS.

It would be quite the layout challenge! IXYS has drivers that will work up into the VHF range, but like all of that sort of technology - it's expensive :shock:

Regards, Steve