Hi, I have a pair of these units, that is an RFTG-m-X0 (10 MHz disciplined crystal oscillator with a GPS receiver) and an RFTG-m-RB (10 MHZ disciplined rubidium oscillator). I have the two J2's and the two J5's interconnected. These are very nice units and appear to function very well, despite what you and others may have heard. I also know three other Time-Nuts with properly functioning pairs (one since damaged by a lightning strike). As far as I've been able to determine no info is available to us Time-Nuts (manuals, specs, schematics etc). The 15 MHz main outputs are derived from the 10 MHz oscillators. I understand its possible to bypass (or replace) the 15 MHz filter to obtain a 10 MHz main output. I have not done this as of yet. The 10 MHz test Output (J1) on the RB gives a good strong 10 MHz source. It's also quite easy to tap the 10 MHz signal directly off the crystal or rubidium oscillators internally. I think an isolation amplifier might be a good idea however.
I have no exact way of measuring the output impedances, however I made the following 3 measurements on each output port with an HP436A power meter, an 8481A (50 ohm) head, and precision coaxial terminations of 50 or 75 ohms. The measurements below are in the order of power meter alone, with an additional 50 ohm load (using a BNC "T"), and finally with an additional 75 ohm load (using a BNC "T"). XO 15 MHz Out (J4) 17.71, 13.80, 14.93 dBm RB 10 MHz Test Out (J1) 7.24, 12.80, 12.33 dBm RB 10 MHz Ref Out (J2) 13.03, 9.54, 10.52 dBm RB 15 MHz Out (J4) 17.45, 13.03, 14.28 dBm If the output impedances were exactly 50 Ohms, the values with a second 50 ohm termination would be 3 dB less then the power meter alone readings. Therefore I surmise the output impedances are around the 50-75 Ohms range. The readings of the Test Out (RB J1) are rather strange, but that's what it repeatably measures. 73, Bob Martinson, N1VQR -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Stuart Sent: Wednesday, December 19, 2007 5:41 PM To: [email protected] Subject: [time-nuts] Lucent RFTG-m-RB unit output level Has anyone measured the 10Mhz output level of these units. How about the output impedance? Has anyone tried to tap off the 10Mhz from the OCXO on the XO unit? if so what output level did you get. I am looking for a GPSDO with an output level of at least 0dbm into 50 ohms. Stuart --------------------------------------------------------------------- Outgoing mail is certified Virus Free Checked by McAFEE on-Line subscription Anti-Virus. Only two defining forces have ever offered to die for you, Jesus Christ and the American G.I. One died for you soul; ~ the other for your freedom. _______________________________________________ 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.
