LF: Re: Re: M0BMU mods to the G0MRF PA

["mal hamilton" <g3kevmal@talktalk.net>]

Gary

I see you only wind on half the ferrite core whereas I spread the turns symetrically around the whole circumference.

In my case I need 8 turns on Prim es 24 on Sec.

I first wind the 24 turns around the circumference evenly then the 8 tunrns on top also evenly. This works for me.

I wonder if there is any real difference in efficiency

 

73 mal/g3kev

 

----- Original Message -----

From: Gary - G4WGT

To: rsgb_lf_group@blacksheep.org

Sent: Saturday, December 15, 2012 8:01 PM

Subject: LF: Re: M0BMU mods to the G0MRF PA

Hi Warren,

 

I have carried out the M0BMU mods to my G0MRF amp. The improvement is extremely good. Not only does the PA run cool the output is greatly increased. I have run mine at 600 watts into dummy load during the initial testing after the mod & up to 400 watts into antenna during normal Tx.

 

See my web page at :-

 

http://myweb.tiscali.co.uk/wgtaylor/LF%20&%20MF%20Experiments%203.html

 

I hope this will help.

 

73,

 

Gary - G4WGT.

 

----- Original Message -----

From: Warren Ziegler

To: rsgb_lf_group

Sent: Saturday, December 15, 2012 4:17 PM

Subject: LF: M0BMU mods to the G0MRF PA

Hello the list...

       Since my G0MRF is experiencing intermittent short circuit in the final amp, I plan on re-doing the output circuit per the M0BMU modification:

http://www.g0mrf.com/images/300w/PA_schematic.jpg

       The M0BMU mod changes the circuit to a current fed design which improves the efficiency. The mod calls for a transformer primary winding using 12 strands of 0.3mm e.c.w. (enamel covered wire). 

I assume that the 12 strands are used to improve the Q similar to the way Litz wire works? 

        Has anyone done this mod? Has anyone tried alternatives to the 12 strands of enamel wire?

   73 & tnx Warren K2ORS

--
73 Warren K2ORS
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