Hi I'm sitting here looking at the spec sheet for the splitter:
A normal four way splitter should have a loss of a bit over 6 db. The reason that's bad is that it may degrade the noise figure at your otherwise perfect receiver (and sub 1 db noise figure antenna) by 6 db. (it may also do absolutely nothing bad at all) The splitter has a rated noise figure of 7 db max / 5 db typical. It has a gain that may be a loss of 3 db or a gain of 3 db. Worst case, it's got a -3db gain and a 7 db noise figure. It may degrade the noise figure at the receiver by 10 db. Best case it's got 3 db of gain and a 5 db noise figure. That's still a noise figure hit of 5 db. All of that is pretty easy to blow holes in as far as a real / normally operating system is concerned. I *think* it's pretty close in the limit case though. If it is close, then the part (yes I bought one to) might improve things by 1 db. It also might degrade things by 4 db under the worst case conditions where it likely matters. Am I missing something here? Obviously it does more than split. It may have better isolation than a conventional splitter. It also has the cute little DC loads in it. Seems like a little bit more RF gain might have been a good idea. Bob -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Wednesday, January 27, 2010 9:41 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 58516A GPS distribution amplifier information Hi, Another option is to remove the DC-block cap on port 1. Then let your primary GPS power the splitter and upstream antenna. http://www.to-way.com/tf/hp58516a.pdf -- Björn > Hi > > I found a SMC-BNC adapter of the correct orientation in the bottom of my > junk box. Somehow I doubt I'll ever use it for anything else. BNC cables > and jacks are something I can find easily. > > The top of the unit is held on with screws so getting inside it should not > be very hard. You could swap the SMC out to something that's more common > for power distribution. Maybe an APC-7 ... > > My guess is they used the SMC because it's unusual. That way you don't get > a cable with 30 VDC on it hooked where it shouldn't go. If you did run a > 30 volt supply the dc could do some damage. Of course 30 volts on that > unit connected to a "normal" antenna would do some damage as well. > > Bob > > > On Jan 27, 2010, at 1:14 AM, [email protected] wrote: > >> I recommend un-screwing that SMC since it is almost impossible to find >> the >> mate, and feeding two wires from a 5V supply into the unit through the >> hole, and soldering the wires to the PCB. Works well for me. >> >> bye, >> Said >> >> >> In a message dated 1/26/2010 18:36:18 Pacific Standard Time, >> [email protected] writes: >> >>> I'm using an HP 58516A GPS distribution amplifier to share my GPS >>> antenna between my receivers. >>> >>> What is the proper part number or connector "name" for the power >>> supply connector ? >>> >>> Thanks for your help ! >>> >>> Claude >>> >>> >> According to the datasheet option 05 uses an SMC connector for the >> power. >> >> Bruce >> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
