Topband: DHDL matching Transformer

[jeremy maris]

Hi Trevor,

Luis IV3PRK has good info on DHDL, based on the original by George Wallner, AA7JV
See http://www.iv3prk.it/TX3A-DHDL.htm

I use a 1200 ohm terminating resistor;  source resistance is about 900 ohms.  
900/75 = 12 so turns ratio to match is 3.5:1    I use a 2 turn primary and 7 turn secondary on a BN73-202 core.

Make sure that you have a feedline choke near the feed to the DHDL so you don’t get common mode noise.

They work well!


> On 28 Nov 2017, at 15:07, MR TREVOR DUNNE <ei2glb at eircom.net> wrote:
> 
> Hi All
> 
> My quest to better my station continues I want to try a DHDL can someone recommend a matching Transformer and what size termination resistor should I use,
> 
> I have some bn73-202 cores and I wish to use 75ohm feed line,
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband

—
Jeremy Maris G3XDK / G4AQG