[AMRadio] Broadcast transmitter


Rick Brashear rickbras at airmail.net
Sat Apr 22 10:30:33 EDT 2006


Roger,

Thank you so much for the information.  I only hope my conversion will 
go as well as yours.  I don't know why, but I don't seem to have Orr's 
book, but will get it.  According to the dimensions you gave it will be 
a tight squeeze and likely some of the facings will have to be removed, 
but I think she'll go.  I'm sure I'll have many questions when the 
actual conversion begins.  I certainly agree with your idea to get it up 
and running the way it was originally intended before making any changes.

Thanks again... 73,
Rick/K5IZ


KC8OPP Roger S. wrote:

>Rick,
>
>Here is what I did to bring the RCA to 160/80/40M.
>
>First thing is get a copy of the "Radio Handbook" by
>William Orr, W6SAI.  This book has all the answers.
>
>I started by bringing the transmitter up on the freq
>the radio station used.  I cleaned and repaired as
>required.  I checked all voltages against the book,
>swept the audio section and made more repairs.  When
>it works as advertised by RCA, then you can start to
>have fun.
>
>I removed the master osc board and built a box for the
>grid input circuit.  I used link coupled coils that
>are switched in for each band and drive the grids with
>a Kenwood TS-520.  The same band switch is used to
>changed the taps on the final tank coil.  The winding
>data for the grid coils was borrowed from the 16th
>edition of the Radio Handbook.  I did install a grid
>coil for 20M, but have never tried the transmitter on
>20M, wishful thing I guess.
>
>The final tank that RCA installed was completely
>removed and I used the "L" coil for my tank.  Vac
>variable caps were used for Tune and Load.  I put the
>circuit together on the bench to find the right taps
>on the coil.  Use a non inductive resistor in place of
>the tube that is equal to the calculated plate load
>and then a antenna analyzer connected to the output. 
>This put me in the ball park and just some minor
>changes were needed when the tank circuit was
>installed in the cabinet.
>
>The cabinet measured 32 inches deep and 34.5 inches
>wide when I removed the meters and switches, just
>enough room to fit through the doors.  I would guess
>that in the stripped down mode the cabinet still came
>in around 300 pounds or so.
>
>Hope this helps a bit, I will look forward to hearing
>your RCA on the air.
>
>
>Good Luck and 73's
>Roger
>KC8OPP
>
>  
>
>  
>





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