[time-nuts] Partridge Divider Board and 10 MHz DistributionAmplifier Enclosure -- an Idea
David C. Partridge
david.partridge at perdrix.co.uk
Mon Feb 28 09:31:52 UTC 2011
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 at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Brucekareen at aol.com
Sent: 28 February 2011 01:36
To: time-nuts at 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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