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RD15HV change to MRF136 #v6 #ubitxv6

 

Hi all,
I would like to replace RD15HV MOSFET to MRF136 given in the uBitx v6 schematic. What would be your comment on such a change? 

--
TB3EN From Turkey. Electronic Communication Technician, Member YM3KM.

MadRadioModder
 

Good luck?

 

Need more drive…

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Bora Gürbüz
Sent: Friday, April 24, 2020 6:11 AM
To: BITX20@groups.io
Subject: [BITX20] RD15HV change to MRF136 #v6 #ubitxv6

 

Hi all,
I would like to replace RD15HV MOSFET to MRF136 given in the uBitx v6 schematic. What would be your comment on such a change? 

--
TB3EN From Turkey. Electronic Communication Technician, Member YM3KM.


Virus-free. www.avg.com

--

…_. _._

ajparent1/kb1gmx <kb1gmx@...>
 

Good luck mechanically incompatible in a big way. 
MRF136 is SO211 flange mount.
It will want a substantial heatsink.
To get full power you need about twice the drive the ubitx drivers
can do.

Getting them to work in the uBitx RF is very hard as mechanicallly its incompatable
and it expects a stripline mounting and the final amp is not laid out that way.
Additionally its a 28V device and at 12V it will perform poorly with maybe 5W
out.  At 28V its a 15W device or use the MRF137Y (dual device) that will do
30W at 28V.

I've used that part (actually the base 136 and the -Y diual) and they are fine
devices but only if you serious about 28V power and doing the electrically
correct PCB layout as its a very good 150mhz VHF device and not at all
tolerant of bad layout or poor design.

Allison
---------------------------------
No direct email, it goes to bit bucket due address harvesting in groups.IO

 

Thanks, Allison,
I search for some transistor and NXP AFT05MS031N MOSFET cheap and possible than MRF136. What do you think about it?

--
TB3EN From Turkey. Electronic Communication Technician, Member YM3KM.

ajparent1/kb1gmx <kb1gmx@...>
 

On Fri, Apr 24, 2020 at 08:14 AM, Bora Gürbüz wrote:
AFT05MS031N
Possibly good save for it has to be soldered down to a copper plinth.
It was designed for mobile use so 12V is a good voltage.
 
All the same issues of mechanical and electrical fit.  That and its good to 520mhz
and much better oscillator in a poor circuit.

Allison
--
---------------------------------
No direct email, it goes to bit bucket due address harvesting in groups.IO

 

Thanks for your time and information. I will consider. 

Have a nice day.
--
TB3EN From Turkey. Electronic Communication Technician, Member YM3KM.

 

Hi Bora,

If the schematic is just viewed quickly, it's hard to see that the normal transistor used there is the IRF510 not the RD15HV part.  The IRF510 does its job pretty well there and it's low cost.

73,


Mark