[hpsdr] New Munin2 Schematic for 24V-DC Operation

[Dick Faust]

Rod [Jim - FYI]
I will answer in line.  Further questions should go to Kjell as I have 
no experience at the higher voltages.
Dick K9IVB
On 12/5/2013 2:38 PM, Rod Brink wrote:
> Hi Dick -
>
> I have a few questions regarding the 24v Munin version.  I probably 
> should be asking Kjell directly, but no longer have his email address.
See cc's
> 1)  About the IMD measurements shown in your posting: 
> http://k9ivb.net/munin2/Munin%20Tests.zip   Do you know if these are 
> from the 13.8v version or the 24v version?  They appear to be from the 
> 13.8v version.  I would expect significant improvement with the output 
> MOSFETs running at the higher voltage.
Posting is for 13.8V version
>
> 2)  And speaking of the higher voltage, I'd be worried about operating 
> the RD100HHF1 at 24v.  At a minimum the drains will see twice the 
> supply voltage owing to push-pull transformer operation - higher 
> voltages with SWR>1.0. The max. Vdss rating for that transistor is 
> 50v.  Seems to me there is virtually no operating margin.
True, you could back down to 20V or so for more margin.
>
> Your use of RG8X braid as the L4 primary seems like a much easier way 
> than what I struggled with when I built one of Kjell's very first 
> prototypes.  I made mine with 25-ohm coax and had trouble splitting 
> out the secondary turns from the braid.  At the time that was the 
> method favored by Kjell.  I can't tell for certain but it looks like 
> Kjell is now making his the same way as you.  So here are my questions:
>
> 3)  Is your L4 secondary just plain wire threaded through the braid?
No it is the 18ga Teflon wire provided in the kit.  I could not find my 
supply of RG303 and I had a bunch of the 8X which was far more flexible 
than the coax in the kit - would have preferred the Silver plated 
variety, but think this will be just as effective.
> 4)  Are you getting good response at 50mHz?
Have not finished the cables and housing as yet so no tests.
>
> 73 de Rod KQ6F
>
> ----- Original Message ----- From: "Dick Faust" <k9ivb at cox.net>
> To: "HPSDR" <hpsdr at lists.openhpsdr.org>
> Sent: Thursday, December 05, 2013 11:56 AM
> Subject: [hpsdr] New Munin2 Schematic for 24V-DC Operation
>
>
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> The Munin2 Page has been updated with new information for 24V-DC 
>> operation.
>> There are four new components for Bias stabilization.  Details at:
>>
>> http://k9ivb.net/munin2/
>>
>> Dick K9IVB
>> _______________________________________________
>> HPSDR Discussion List
>> To post msg: hpsdr at openhpsdr.org
>> Subscription help: 
>> http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org
>> HPSDR web page: http://openhpsdr.org
>> Archives: http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/ 
>
>


 1386446660.0