[TenTec] Station power supply??

[Bob McGraw - K4TAX]

I've found more brands of power supplies, both linear and switchers, other 
than Astron have painted surfaces that prevent good electrical connections. 
In these instances, removing the attempted connection and then using a 
scraping method or better yet, a bit of sandpaper to remove the paint to 
expose the bare metal and then re-attaching the green ground is preferable. 
The same could be true within the radio.  There is no debate on the topic, 
the GREEN wire must be electrically and with a low resistance point, 
connected to the power supply chassis.

I've also found the covers, top and bottom where attached with screws, may 
not provide a good electrical connection between the pieces.  Here again, 
cleaning the paint away and I prefer to use internal tooth lock washers, 
re-assemble the covers and attachment methods.

I've always found the station power supply should be the zero reference 
voltage point for the station.  Hence the reason the negative should be 
connected at the power supply common ground point.  As you will read, Jim - 
K9YC and I typically disagree on this point.  When we operated equipment 
with internal power supplies this became a mute point as the chassis, 
equipment ground, and power supply negative were always the same.

With external power supplies there is resistance between the power supply 
negative and the radio negative due to wire resistance, connectors in line 
and such.  During transmit a noticeable voltage drop occurs across the 
negative lead, just as Jim points out.  This floating up and down of the 
negative point within the radio can cause issues sounding much like RF 
artifacts.  Jim points this out in one of his posts.

As stated earlier, connection of the transceiver to the external power 
supply should employ 3 wires being;  Positive, Negative and Ground.  On this 
point I've found that crimp style terminals should be soldered as the 
crimping provides the mechanical connection and soldering provides the 
lowest resistance for electrical connections.

73
Bob, K4TAX

----- Original Message ----- 
From: "Mike Hyder -N4NT-" <Mike_N4NT at charter.net>
To: <k9yc at arrl.net>; "Discussion of Ten-Tec Equipment" 
<tentec at contesting.com>
Sent: Tuesday, September 04, 2012 9:42 PM
Subject: Re: [TenTec] Station power supply??


> The  way I grounded the negative lead was to remove the insulators from 
> the contact bolt and clean the paint from around the hole INSIDE the 
> chassis, then added a star lockwasher inside the chassis and threw the 
> insulators away. I never experienced any more trouble.
>
> 73, Mike N4NT
>