Warning: Creating default object from empty value in /homepages/11/d132647312/htdocs/Amfone/mkportal/include/SMF/smf_out.php on line 47
Recent Posts

The AM Forum
December 09, 2018, 09:50:17 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: 1 ... 9 [10]
 on: December 05, 2018, 07:42:07 PM 
Started by k7mdo - Last post by K4RT
Tom and Nico,

What did you use for the top of your respective operating desks, and about how many inches is the desk above the floor?  I'm currently building a new shack and will need to build a bench.

My Novice shack had one dual outlet but that was enough.

Brad K4RT

 on: December 05, 2018, 07:27:17 PM 
Started by W4RFM - Last post by DMOD
I did some more FIG-ER-IN' and here is what the power supply should look like to develop 315V at 55 mA for the Speech Amplifier and Driver:

Current for Speech Amplifier/Driver = 48.7 mA
Current for 50k Bleeder = 6.3 mA
Transformer Secondary = 470VAC@100 mA with CT to ground (235 VAC each to ground)

R1 = 200 ohms 2W
R2 = 50k 5W

C1, C2 should be modern 10 uF @ 450V.

The values in brackets are for a 500VAC CT transformer  (250 VAC each to ground).


 on: December 05, 2018, 06:23:22 PM 
Started by k7mdo - Last post by KK4YY
I bet we can each remember having a shack where one duplex outlet was enough.

 on: December 05, 2018, 06:03:33 PM 
Started by W4RFM - Last post by KK4YY

A 700 vct transformer, wow. I'd think it should be about half of that. 350 vct maybe. I'm at a loss. I can't figure out how you end up with 305V without using a choke input filter if the transformer is 700 vct. A bad filter cap maybe?

Try making more measurements. I like to check the values of components before I use them. Not just my junk-box stuff, but new parts as well. I've had NOS power resistors, right out of the original box, be open circuit. Check voltages, voltage drops, run the calculations. As a newly built piece, don't overlook the posability of a miswire. We've all done it!


 on: December 05, 2018, 05:32:35 PM 
Started by K8CA - Last post by KK4YY
It's not a good idea to use the CW-PLATE switch while the PLATE switch is on. The contacts may arc and fail if done too many times.

Is the audio gain pot at "0" when you turn the PLATE switch on (in PHONE)?


 on: December 05, 2018, 05:22:35 PM 
Started by PA0NVD - Last post by PA0NVD
and more

 on: December 05, 2018, 05:21:47 PM 
Started by PA0NVD - Last post by PA0NVD
and more

 on: December 05, 2018, 05:10:57 PM 
Started by PA0NVD - Last post by PA0NVD
and more..

 on: December 05, 2018, 05:09:56 PM 
Started by PA0NVD - Last post by PA0NVD
The shack is starting to fill up. Here some pics. But there comes more........

 on: December 05, 2018, 05:02:05 PM 
Started by k7mdo - Last post by PA0NVD
Nice to have photo's of the first shack Tom Must be pleasant memories to look back. I only can remember, but unfortunately I don't have pictures. That was in the years 60, I am licenced in 1963 in the Netherlands and had homebrew VHF stuff at two meters and 23 cM and a set WS19. I wish to have pics of that time.... Undecided

Pages: 1 ... 9 [10]
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.044 seconds with 14 queries.