[ARC5] R-392 power connector question

[Meir WF2U]

The R-392 is a component of the AN/GRC-19 radio together with the T-195
transmitter, the primary voltage specified for the system is 28VDC. The
T-195 transmitter doesn't work well with voltages under 28V, the autotune
becomes unreliable, and the older units with the dynamotors would draw much
higher current (current=heat!) at 24 VDC than at the normal 28VDC (the newer
production run T-195's use solid-state inverters, but these also draw more
with lower voltage). Not only my experience, but others' too! Manuals were
written to read them and to comply with the specifications...

73, Meir WF2U
Landrum, SC


-----Original Message-----
From: arc5-bounces at mailman.qth.net [mailto:arc5-bounces at mailman.qth.net] On
Behalf Of Roy Morgan
Sent: Friday, March 14, 2014 6:12 PM
To: Dave Merrill
Cc: ARC-5 List
Subject: Re: [ARC5] R-392 power connector question


On Mar 14, 2014, at 1:19 PM, Dave Merrill <r390a.urr at gmail.com> wrote:

> Pins A (Plates) and D (Filaments) should both be connected to +28 Volts.
> Pin E is Ground.

HOWever,

I've seen reports that though the filaments work fine on 24 to 28 volts, the
radio works much better if the B+ voltage is 28.

Roy

Roy Morgan
RoyMorgan at alum.mit.edu
K1LKY Since 1958

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