[hpsdr] Fwd: Re: MUNIN low output

[Ken Shutt]

Hi Kjell,

My Munin2 has been completed and tested.  When driving with Penelope (ca .5 
watt) I only get 10 to 40 watts out (depending on band).  I suspect that L4 
may be the problem.  I had a lot of problems getting 4 turns into the coax 
braid.  I may try to rewind as soon as I can locate some more teflon 
insulated wire.

How much drive should be required to get 100 watts out?  Should I consider 
adding the T5 stage?

73 de Ken W5KQ


-----Original Message----- 
From: Kjell Karlsen
Sent: Friday, October 11, 2013 1:23 PM
To: hpsdr at lists.openhpsdr.org
Subject: [hpsdr] Fwd: Re: MUNIN low output

***** High Performance Software Defined Radio Discussion List *****


Hi All.

I have tried to find what the problems with low power on on the higher
frequencies from Munin might come from but I have not been able to
reproduce it on the two samples I have tested lately.

The problem can be the voltage ratings on C25, C26 and C27. 200V might be
too low when high SWR is present. I see that all capacitors I have tested
with has a voltage rating of 500V or higher.

One of my Munin PA´s has been run on 24V for about one year. I do not take
more than 100-120W out. I am not using an Antenna tuner and the SWR on my
80 meter long loop antenna can be >3:1 on some bands but Munin has not had
any problems.

DigiKey have 470pF/500V in stock. PN:709-1024-2-ND (Man. Pn:501R18N471JV4E)

200pF/500V seems to be difficult to find. Instead of using 1pc. 470 pF and
2pc. 200 pF, they can be replaced by 4 pc. 220pF. Replace C27 with 2 pc.
220 pF, one on top of the other.

DigiKey PN:709-1023-1-ND (Man. Pn:501R18N221JV4E)

I am sorry for all the trouble this might have lead to!

73, Kjell




På Fri, 11 Oct 2013 17:52:22 +0200, skrev Giovanni Santin
<gsantin at mclink.it>:

> ***** High Performance Software Defined Radio Discussion List *****
>
> Just thinking, a dummy load that is not perfectly resistive, will show a 
> higher and higher reactance ( capacive or inductive ) as the frequency 
> increases. This reactive load may explain why the active power is less 
> and less at higher frequencies and also why C27 burns.
> I still have to build my Munin kit, so this is just a thought.
>
> Giovanni, IZ0SQZ
>
> -----Original Message-----
> From: Byron Engler <12byron34 at gmail.com>
> Sender: hpsdr-bounces at lists.openhpsdr.orgDate: Fri, 11 Oct 2013 22:00:59
> To: dlwaddel at netzero.net<dlwaddel at netzero.net>
> Cc: <hpsdr at lists.openhpsdr.org>
> Subject: Re: [hpsdr] MUNIN low output
>
> ***** High Performance Software Defined Radio Discussion List *****
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