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Re: [TenTec] Argonaut 505

To: tentec@contesting.com
Subject: Re: [TenTec] Argonaut 505
From: Bill Fuqua <wlfuqu00@uky.edu>
Reply-to: tentec@contesting.com
Date: Wed, 17 Dec 2003 16:19:37 -0500
List-post: <mailto:tentec@contesting.com>


At 01:16 PM 12/17/2003 -0700, you wrote:
Bill,

Thanks for the input. I am monitoring with another receiver in the shack and with the Argonaut driving a Heathkit Cantenna. I can hear an obvious difference when I change the power supplies, the 210 and another regulated AC supply produce a hummy cw note while my battery supply is clean.

Jim


What had me thinking about this possibility was that you said you could not see any envelop on the O'scope. Is your scope sync-ed off the power line and horizontal set for about 5mS per division? Having FM is usual from a power supply if there is no AM as well.
Can you see ripple on the power supply?


73
Bill wa4lav


  ----- Original Message -----
  From: Bill Fuqua
  To: tentec@contesting.com
  Sent: Wednesday, December 17, 2003 12:20 PM
  Subject: Re: [TenTec] Argonaut 505


How are you monitoring the hum when you transmit? Possibly another receiver
in the hamshack?
If you are using another receiver near by it may not be real. Some times RF
gets into the
power supply and the rectifier diodes that are switching on and off at 120
Hz rate amplitude
modulate it and it is re-radiated by the power cords. If this happens the
solution is to ignore it or
put RF bypass capacitors across the rectifiers.


  Usually Magnetic field coupling into the transmitter is only noticed when
  transmitting phone due to the fact that the microphone preamplifier is
  sensitive enough to amplify the small millivolt signal produced by the
  magnetic field from the transformer.

  73
  Bill wa4lav


At 09:49 AM 12/17/2003 -0700, you wrote: >Y'all, > >I just became a new owner of an Argonaut 505, the very first Argonaut and >my first Ten Tec rig. It came with the model 210 power supply. I am >noticing a 120 Hz hum on the transmitter note on CW and a corresponding >hum on the SSB signal when I run the rig from the 210. When I power it >from a battery there is no hum. It is most noticable on 40 meters which >is where the local oscillator is tripling, and I don't see a hum on the >wave-envelope with my HP1740A 100 mHz oscilloscope. So it may be FM on >the local oscillator. > >I would appreciate first of all a circuit diagram for the 210 power >supply, and then of course any suggestions about what to do. It is a >really fun little rig when I run it from the battery. > >Thanks, > >Jim Hanlon, W8KGI >_______________________________________________ >TenTec mailing list >TenTec@contesting.com >http://lists.contesting.com/mailman/listinfo/tentec

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