[Amps] Re Direct rectification of AC mains to derive the amp, VDD, supply

[Roger (K8RI)]

On 9/18/2013 9:43 AM, Manfred Mornhinweg wrote:

>
> I think that the reluctance of some people to accept line-connected
> electronics stems only from gut feeling, and not from a cool-headed
> analysis of the advantages and disadvantages.

My reluctance comes from finding I couldn't let go of a radial wire tied 
to a ground rod.  If it's strong enough that you can't let go..IT HURTS!

The culprit? A Yaesu FT101B that had an extra generous solder joint on 
the (2 wire)  connection to the mains.  The rig ground was some ground 
rods outside the basement wall and the ground at the antenna that were 
about 130 to 150 feet apart.

Normally the chassis was not hot, but you could push the power connector 
to one side with very little pressure from one finger.  Actually, 
setting the rig on its side was enough to make the connection.

That was in the late 60s or when ever the 101B came out.

Yes, today we'd make sure that the earth ground for the station  is also 
tied into the house electrical ground, or most of us would, but not all. 
You'd be surprised (or maybe you wouldn't) at some of the station 
electrical hookups and set-ups to service high powered amps I've seen by 
old timers.  It scares me that many of the new comers see these setups.


So my reluctance is not from a gut feeling, but a lot of pain from 
nearly being electrocuted and with the direct hookup it is very easy for 
a small mistake, or bad connection to create the same situation.

BTW I put one lead from me Simpson 250 on the ground rod at the antenna 
and the other as far out into the yard as the two leads would allow and 
measured over 90 volts.  The house electrical ground was mid way between 
the antenna ground and station ground.

73

Roger  (K8RI)