Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: AM Transmitter, Plate Modulated  (Read 1936 times)
AJ4CU
Member

Posts: 75




Ignore
« on: August 25, 2008, 04:30:07 AM »

Hi,
Can anyone suggest a nice homebrew AM plate modulated transmitter? I am really wanting to build one.

Thanks in advance.




AJ4CU
Logged
WB2WIK
Member

Posts: 20574




Ignore
« Reply #1 on: August 25, 2008, 08:06:59 AM »

My 1966 ARRL Handbook is loaded with such designs.  Best recommendation is pick up any Handbook from about 1955 through 1968 -- they are all full of plate modulated AM transmitter designs, from low power (40W) to high power (kilowatt) levels.

WB2WIK/6
Logged
W7ETA
Member

Posts: 2528




Ignore
« Reply #2 on: August 25, 2008, 12:40:02 PM »

What parts do you have now?
Bob
Logged
W7ETA
Member

Posts: 2528




Ignore
« Reply #3 on: August 25, 2008, 12:41:39 PM »

What power supplies and or transmitters have you already built?
Bob
Logged
W6GF
Member

Posts: 161




Ignore
« Reply #4 on: August 27, 2008, 10:53:58 PM »

First of all today...full legal AM is 375 watts output carrier at 100% modulation

stick to triodes...much easier power supply

4 572b's moded by 2 572b's could make a low cost near full power AM TX

George, W6GF
Logged
KB1LKR
Member

Posts: 1899




Ignore
« Reply #5 on: August 28, 2008, 12:39:27 PM »

"...from low power (40W) to high power (kilowatt) levels"

In 1966 these would be input power not output, and 1kW (right?) input limit would have applied then, though good point on 375W (RMS) max out for AM now.

I have a 1947 ARRL handbook if you'd like copies of some older designs.
Logged
N2DTS
Member

Posts: 102




Ignore
« Reply #6 on: August 30, 2008, 08:05:34 PM »

You can do a pair of 812a's or 811a's modulated by a pair of 811a's, will do 340 watts carrier out and 100% modulation at 1500 volts.

I built one of those, push pull link output, it worked very well.
i also built a rig using three 4d32 tubes pie net running 1200 volts, modulated by a pair of 811a's, it also works very well.
The big rig is a pair of 813 tubes running at 2000 volts, can do 700 watts of carrier, and modulate well over 100%. The modulators are a pair of 4cx250b tubes, 600 watts of audio in class AB1.

Dont let screens scare you, just variac a light supply and use a dropping resistor for screen protection.

The old Bill Orr handbooks have loads of great designs.

Brett
N2DTS
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!