[AMRadio] AM Audio


Geoff w5omr at satx.rr.com
Sat Aug 20 10:30:15 EDT 2005


Well, I completed the task yesterday of installing a Reactor for the 
250TH rig.
(Push-pull Class C 250TH link-coupled final, modulated by push-pull 
Class B 250TH modulator)
http://w5omr.shacknet.nu:81/~w5omr/hamstuff/AM-Stuff/Titanic/modulator/new_titanic.jpg

Six inductors in series, 5 of which are known values
10Hy @ 500mA
10Hy @ 500mA
9.9Hy @ 500mA
12Hy @ 400mA
16Hy @ 450mA
(unknown)

The unknown choke is 1/3 larger than the 16Hy @ 450mA choke and the 
unknown choke is the largest in the chain, physically.  I'm going to 
'assume' it's a minimum of 10Hy.  Eventually, I will take it out of the 
lineup, feed about 10vAC through it, and a 1k potentiometer, and adjust 
the pot until the voltage across it, matches the voltage dropped across 
the choke.    Thanks to John/WA5BXO for help in that area:

__________________

by equalizing the voltage across the resistor and choke results in the creation of a resistance that is equal to XL of the choke at 60 CPS.

Measure the resistance of the variable resistor after equalizing the voltage drops and you have the XL of the choke at 60 cps. 

L = XL / 2 * pi * F

L = XL / 6.28 * 60

L = XL / 376.8

Divide the resistance by 376.8 and you have the inductance.
___________________


I will do that, soon.

Still using 9uF of coupling capacitance @ 4kVDC (because those two caps 
were still paralelled together and it was easier) and this morning, was 
able to work (among several other stations) John/W5GI, on Lake Travis 
near Austin, TX.

John is working with the guys who are continuing development on the 
'Flex Radio' software-based, computer-controlled radio transciever system.
(http://www.flex-radio.com/)

He sent me a screen-shot of how my audio currently appears on the air.  
A Lot of information is on this screen.
http://w5omr.shacknet.nu:81/~w5omr/pictures/w5omr_frm_w5gi.jpg

Would appreciate your comments.

---
73 = Best Regards,
-Geoff/W5OMR





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