Re: [time-nuts] 2201A GPS

2011-04-10 Thread Rob Kimberley
What I meant was - 10 MHz going up the cable, and 75 MHz coming down. Rob K -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of paul swed Sent: 08 April 2011 6:35 PM To: Discussion of precise time and frequency measurement Subject: Re:

Re: [time-nuts] 2201A GPS

2011-04-10 Thread Rob Kimberley
Another thought - I know it was 75 MHz coming down, as they had some problems from interference from a VHF transmitter on one installation which was in that band. Rob K -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of paul swed Sent: 08

Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

2011-04-10 Thread Magnus Danielson
On 04/09/2011 11:57 PM, Chuck Harris wrote: Hi Brooke, My recollection of first seeing the 4K7 style of marking was around about the time computers started being used for inventory control... 1970's. It was only the European companies that were doing it. It eliminated the confusion caused by

Re: [time-nuts] BNC question

2011-04-10 Thread Magnus Danielson
On 04/10/2011 01:51 AM, Mike S wrote: At 06:53 PM 4/9/2011, Joseph Gray wrote... I have an old Arcnet hub that I want to salvage the isolated BNC connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm and 75 Ohm versions of BNC connectors, but the ones from the hub look like a

Re: [time-nuts] BNC question

2011-04-10 Thread Bruce Griffiths
Magnus Danielson wrote: On 04/10/2011 01:51 AM, Mike S wrote: At 06:53 PM 4/9/2011, Joseph Gray wrote... I have an old Arcnet hub that I want to salvage the isolated BNC connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm and 75 Ohm versions of BNC connectors, but the ones

Re: [time-nuts] BNC question

2011-04-10 Thread Magnus Danielson
On 04/10/2011 01:44 PM, Bruce Griffiths wrote: Magnus Danielson wrote: On 04/10/2011 01:51 AM, Mike S wrote: At 06:53 PM 4/9/2011, Joseph Gray wrote... I have an old Arcnet hub that I want to salvage the isolated BNC connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm and

Re: [time-nuts] 2201A GPS

2011-04-10 Thread paul swed
Rob understood what you meant. My comment was that the 1st mixer and local oscillator is at 1500 Mhz. So the system has to multiply 10 MHz to 1500 and mix it to produce the 75.42 MHZ IF. Luciano was saying it was a multiplier chain and I was thinking out loud about the numbers that could have been

Re: [time-nuts] BNC question

2011-04-10 Thread Greg Broburg
From what I recall from our candle lit lab, the 75 ohm BNCs had a slightly larger pin and would open up the 50 ohm females just a skoosh so when you put a 50 ohm, into a 50 ohm that had been tweaked by a 75 ohm, they were noisy or intermittent. Greg On 4/10/2011 5:30 AM, Magnus Danielson wrote:

Re: [time-nuts] BNC question

2011-04-10 Thread Greg Broburg
Types BNC connectors exist in 50 and 75ohm http://en.wikipedia.org/wiki/Ohmversions, matched for use with cables of the samecharacteristic impedance http://en.wikipedia.org/wiki/Characteristic_impedance. The 75 ohm types can sometimes be recognized by the reduced or absentdielectric

Re: [time-nuts] BNC question

2011-04-10 Thread David J Taylor
I had remembered that it was a 75 ohm that would damage a 50 ohm socket. This article states that a 50 ohm would damage a 75 ohm socket. Greg Indeed, the 75-ohm will have the smaller inner, and hence may be damaged by the larger pin on the 50-ohm connector. David GM8ARV -- SatSignal

Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

2011-04-10 Thread Chuck Harris
Magnus Danielson wrote: On 04/09/2011 11:57 PM, Chuck Harris wrote: Hi Brooke, My recollection of first seeing the 4K7 style of marking was around about the time computers started being used for inventory control... 1970's. It was only the European companies that were doing it. It eliminated

Re: [time-nuts] BNC question

2011-04-10 Thread Chuck Harris
Greg Broburg wrote: receivers used 75 ohmantenna http://en.wikipedia.org/wiki/Antenna_%28radio%29inputs, so they often used 75 ohm BNC connectors. I had remembered that it was a 75 ohm that would damage a 50 ohm socket. This article states that a 50 ohm would damage a 75 ohm socket. Greg

Re: [time-nuts] BNC question

2011-04-10 Thread Bruce Griffiths
Chuck Harris wrote: Greg Broburg wrote: receivers used 75 ohmantenna http://en.wikipedia.org/wiki/Antenna_%28radio%29inputs, so they often used 75 ohm BNC connectors. I had remembered that it was a 75 ohm that would damage a 50 ohm socket. This article states that a 50 ohm would damage a 75

Re: [time-nuts] BNC question

2011-04-10 Thread Joseph Gray
Thanks for all the input. I looked closely at the connectors and they seem to match some 50 Ohm connectors that I have. I have removed them from the board and now have eight isolated BNC connectors for my project. Joe Gray W5JG ___ time-nuts mailing

Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

2011-04-10 Thread Bruce Griffiths
Bruce Griffiths wrote: Hal Murray wrote: bruce.griffi...@xtra.co.nz said: The 16MHz is necessary for the loop to function: The mixer mixes down the 26MHz to a pair of conjugate frequencies, 10MHz and 16MHz. Thermal and device noise is sufficient to start the process. 10MHz = 26MHz - 16MHz

Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

2011-04-10 Thread Bruce Griffiths
Bruce Griffiths wrote: Bruce Griffiths wrote: Hal Murray wrote: bruce.griffi...@xtra.co.nz said: The 16MHz is necessary for the loop to function: The mixer mixes down the 26MHz to a pair of conjugate frequencies, 10MHz and 16MHz. Thermal and device noise is sufficient to start the process.