In a message dated 16/06/2009 09:04:25 GMT Daylight Time, did...@cox.net writes:
> -----Original Message----- > From: microwave-boun...@lists.valinet.com > [mailto:microwave-boun...@lists.valinet.com] On Behalf Of Randy Bynum > Sent: Monday, June 15, 2009 9:03 PM > To: microw...@echo.valinet.com > Subject: [Mw] Efratom 10MHZ Rubidium FREQUENCY Standard FRS-C > > Does anyone have the pin connections for this frequency > standard? There is a male DB-25 connector on it and the box > has the 3 TNC female RF connectors. > All in a box about 4X4X3. ------------- I didn't see this message until Didier posted his reply but this sounds like it could be the Lucent module containing the FRS itself plus two interface boards. If it is then I asked a similar question recently and Bill Ezell was kind enough to provide the connection information for the DB25 which I'll forward to the list again after sending this to save you having to look for it in the archives. Note that Bill's list describes pin 20 as ground but on my unit it links to an internal resister, purpose unknown, and not ground. The only connections I've used are the +24 power connections on pins 1 and 2, and ground on pins 3 and 4. The only advantage I found in using the complete module, or the PCBs in my case as I don't have the box, was havng the RF output provided on one of the TNC connectors rather than having to rely on a take off point from the interface PCB that connects directly to the FRS. The interface board with the DB25 and TNCs serves no other obvious useful purpose if only wanting to use the FRS and it adds 200 to 300 mA to the supply current. In the longer term, if this is the same unit, I would recommend not using either of the PCBs but removing the FRS mating connector from the otherwise unpopulated "bridge" PCB and using that to make direct connections to the FRS itself. Didier's manual will have all the necessary information for that. As per the assorted and very wide ranging recent discussions, the FRS should be mounted on some form of heatsink:-) This applies even if kept in that outer box, Viewing the unit on the connectors with the DB25 at the top, as marked on the PCB the DB25 is J1, the bottom left hand TNC is J2, the middle TNC is J4, and the right hand TNC, slightly above the others, is J3. TNC connections are.... J2 -- 15MHz output when used in original Lucent kit. J3 -- Direct connection to FRS 10MHz output. J4 -- Also 10 MHz output. Bill describes it as buffered, I metered 50 ohms between this and J3 when unpoweredso not sure if it's actively buffered or just padded. The 25 pin details to follow, and if this isn't the same module then humble apologies in advance for the wasted bandwidth:-) regards Nigel GM8PZR _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.