While admiring my newly received divider board from David Partridge and
thinking about a suitable enclosure for its use on my bench, I happened to
look  at an Extron ADA3 80 video distribution amplifier that I acquired after
suggestions from KO4BB.  These enclosures are mechanically sturdy and quite
empty on the inside.  There is plenty of room to mount the divider board
if existing (unused) threaded standoffs are relocated to match the  divider
board mounting holes.  As the distribution amplifier's circuit  board and
connections are all on the back panel, the front panel is completely  free and
clear for mounting the division ratio switch and output  connectors.

The analog performance of the distribution amplifier seems very good;
however, the BNC output connectors are grounded to the case and there is only
one active output device for each of the R, G, & B outputs.  The  three
output connectors provided for each are simply isolated through resistors,  thus
isolation is limited.  Nevertheless, for a single bench setup  like mine,
the distribution amplifier will probably serve adequately well to  distribute
10 MHz from a T-bolt to the counters, divider board, and a  signal generator
-- all on the same bench.  As the R, G, & B DA  inputs can be looped, the
ADA3 80 can provide up to nine 10 MHz outputs  via BNC connectors.

The ADA3 80 is powered from an external 9-volt, 500 ma wall wart.
According to KO4BB:  http://www.ko4bb.com/Timing/Distribution_Amp/
(http://www.ko4bb.com/Timing/Distribution_Amp/) ,  the DA has an onboard switching
converter and + and -5 volt regulators to power  the distribution amplifiers.  It
is possible there is sufficient +5 volt  current capacity to power the
divider board too.  I have not investigated  this yet as I am not certain about
the maximum current requirement for the  divider board.  Assuming it can be
powered from the existing supply, one  could wind up with a very nice and
compact bench frequency reference and  distribution system.

Extron rates the power consumption of the ADA3 80 at 2-watts.  However, it
appears Extron uses the same PC board and power unit for the ADA3  180 for
which the power consumption is 3-watts.
Thus there may be adequate capacity to safely power the divider  board.

If power supply noise is a problem, there is plenty of room in the case for
additional filtering.

Bruce Hunter, KG6OJI

Peak worst case (all outputs shorted) current draw for the divider board is 400mA, 320mA on average.

HTH,
David Partridge

-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On Behalf Of Brucekareen@aol.com
Sent: 28 February 2011 01:36
To: time-nuts@febo.com
Subject: [time-nuts] Partridge Divider Board and 10 MHz DistributionAmplifier Enclosure -- an Idea

While admiring my newly received divider board from David Partridge and thinking about a suitable enclosure for its use on my bench, I happened to look  at an Extron ADA3 80 video distribution amplifier that I acquired after suggestions from KO4BB.  These enclosures are mechanically sturdy and quite empty on the inside.  There is plenty of room to mount the divider board if existing (unused) threaded standoffs are relocated to match the  divider board mounting holes.  As the distribution amplifier's circuit  board and connections are all on the back panel, the front panel is completely  free and clear for mounting the division ratio switch and output  connectors.

The analog performance of the distribution amplifier seems very good; however, the BNC output connectors are grounded to the case and there is only one active output device for each of the R, G, & B outputs.  The  three output connectors provided for each are simply isolated through resistors,  thus isolation is limited.  Nevertheless, for a single bench setup  like mine, the distribution amplifier will probably serve adequately well to  distribute 10 MHz from a T-bolt to the counters, divider board, and a  signal generator
-- all on the same bench.  As the R, G, & B DA  inputs can be looped, the
ADA3 80 can provide up to nine 10 MHz outputs  via BNC connectors.

The ADA3 80 is powered from an external 9-volt, 500 ma wall wart.
According to KO4BB:  http://www.ko4bb.com/Timing/Distribution_Amp/
(http://www.ko4bb.com/Timing/Distribution_Amp/) ,  the DA has an onboard switching converter and + and -5 volt regulators to power  the distribution amplifiers.  It is possible there is sufficient +5 volt  current capacity to power the divider board too.  I have not investigated  this yet as I am not certain about the maximum current requirement for the  divider board.  Assuming it can be powered from the existing supply, one  could wind up with a very nice and compact bench frequency reference and  distribution system.

Extron rates the power consumption of the ADA3 80 at 2-watts.  However, it
appears Extron uses the same PC board and power unit for the ADA3  180 for which the power consumption is 3-watts.
Thus there may be adequate capacity to safely power the divider  board.

If power supply noise is a problem, there is plenty of room in the case for  additional filtering.

Bruce Hunter, KG6OJI

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