Topband: FT-140-43 transformer measurements for 50 to 900-950 Ohm transformer.

[Sergio Cartoceti]

Bologna - Italy, Sept 12 -2002


To N6WG, Bob and all TOPBAND List

Object: 50 Ohm to 900 Ohm transformer with Amidon Ferrite Toroidal Core FT140-43 for Flag, pennant, delta-ewe, as pointed out from
              Earl K6SE.

Primary  50 Ohm low impedence side is 8 turns and secondary is 34 turns with about 990 microH to 1 milliH with a 20 AWG enamelled wire

on an Amidon FT-140-43 imported from Amidon.    

Ros check with a new MFJ269B Analyser showed better ROS match a bit lower in frequency than 1.8 Mhz.

Insertion loss test  I performed a while ago so I do not remember but maybe close to around 2 dB. 

Measurements of two of them back to back  to get 50 Ohm to 50 Ohm is better performed with same lot ferrite selection.

FT-140-43 mechanical data can be found at Amidon Web site:

http://www.amidon-inductive.com/associates_prod_toroidal.htm

Best greatings.                                              73 de Sergio, IK4AUY 

Also IR4B in contest
Also AC7PC
One of official op. at IY4FGM, Marconi Memorial Station   

My personal WEB Site: http://www.qsl.net/ik4auy/
e-mail: ik4auy@arrl.net