[Elecraft] Astron VS-35M Powwer Supply V-
Victor Rosenthal 4X6GP
k2vco.vic at gmail.com
Wed Apr 11 02:27:17 EDT 2018
But since there may be multiple devices connected to the power supply,
and most of them have the V- connected to the case, then in effect there
is a path to the radio through all of these connections.
How can you "Keep all of the transmitter power supply return current
confined to the power cable between the rig and the power supply" when
there is a path from the PS to the V- input of an accessory, through the
case of the accessory, back to the ground bus, to the case of the radio,
and from there to the V- input of the radio?
Wouldn't it REDUCE the change in the ground reference to bond the V- to
the bus?
73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
http://www.qsl.net/k2vco/
On 11 Apr 2018 00:04, Joe Subich, W4TV wrote:
>
> On 4/10/2018 3:21 PM, Jim Brown wrote:
> >
>> I'm probably the source of this, although W8JI and W4TV have also
>> raised this issue. See comments below.
>
> >> Does that negative rail need to be bonded to the chassis?
> >
> > No, and in general, it should NOT be bonded.
>
> You *DO NOT WANT* the station bonding ("ground") and the V- rail to
> be interconnected. If you allow that to happen, particularly at
> the transceiver and power supply, the station ground becomes an
> alternate return for the high current pulses during transmit.
>
> When the station bonding is allowed to "float" with the high current
> pulses any other accessory connected to the bonding (particularly
> "linear" bonding) sees a varying ground reference level which
> contributes to "RF feedback" as that varying reference "pumps"
> (excites) any pin 1 problem in the device.
>
> Keep all of the transmitter power supply return current confined to
> the power cable between the rig and the power supply. Make sure all
> power supply connections are tight and all power cords as short as
> possible. Always use the largest practical wire for all power cords.
> If possible, use twisted pair cables, *bolted* connections (like
> on the Astron RS/VS series power supplies) and multiple, parallel
> pin connections in any power connectors.
>
> 73,
>
> ... Joe, W4TV
>
>
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