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WA5JAT 1

Microwave Frequency Standard

Jim Hudson

WA5JAT

HamComJune 2010

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WA5JAT 2

Microwave Frequency Standard

• Why Do we Need a Frequency Standard?•Remember the 100 KHz Calibrators on HF?•The Same Issues Exist on the Microwave Bands

•Uncertainty in Frequency (+/-100 KHz at 24 GHz)•High Gain Antennas for Microwave Bands

•<3 Degree Beam Width•Uncertain Rover Station Locations

•Too Many Things to Monitor:•Antenna Elevation/Azimuth•Frequency Dial + Readout•“Hopefully”, Copy a CW Signal “In The Noise”

Doing All These at Once is “Not Fun”Having a Precision Frequency Standard andEliminating the Frequency Uncertainty is a BIG Help

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WA5JAT 3

Microwave Frequency Standard

Rubidium StdRFG-M-RB

Crystal OscillatorRFG-M-XO

Rubidium Std (RB) outputs to XO which locks to the RB

RFG-M-RB & RFG-M-XO(EFRATOM Labels on PCBs / LUCENT on Panel)

Surplus Equipment is Available!!!

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WA5JAT 4

These Screws Release the Rb unit from the tray

P1 = DB9 Male Power ConnectorPin 1 = +24 VDCPin 2 = Common

10 MHz Output15 MHz Output

RFG-M-RB

Microwave Frequency Standard

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WA5JAT 5

Rear Panel Removed

Rubidium Std House Keeping Sub-Unit

RFG-M-RB

Microwave Frequency Standard

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WA5JAT 6

These Screws Release the RB Sub-unit afterRear panel removal

The RB Sub-Unit Slides Sidewise and Unplugs

RFG-M-RB

Microwave Frequency Standard

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WA5JAT 7

LPRO-101

10 MHz Sine Output

Microwave Frequency Standard

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WA5JAT 8

Supplier Specification Sheet

Source: http://www.datasheetarchive.com/

Microwave Frequency Standard

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WA5JAT 9

Comparison of Several Frequency Sources

Source: http://www.leapsecond.com/museum/manyadev.gif

Microwave Frequency Standard

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WA5JAT 10

Comparison of Several Rubidium Sources

Source: http://www.leapsecond.com/museum/lpro/

Microwave Frequency Standard

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WA5JAT 11

Microwave Frequency Standard

How Do You Use 10 MHz for a Microwave Frequency Standard?

•Direct Digital Synthesis (DDS)

•Phase Locked Loop

Followed by Multipliers to the Band of Interest

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WA5JAT 12

Microwave Frequency Standard

Direct Digital Synthesis (DDS) 10 MHz In – 96 MHz Output

Source: NTMS FEEDPOINT Vol. 21, Issue 2 / WW2R

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WA5JAT 13

Microwave Frequency Standard

Phase Lock Loop (N5AC/Down East Microwave) 10 MHz in - 1152 MHz Output (And 49 Others Available)

Source: http://www.downeastmicrowave.com/PDF/A32_pd.pdfAlso See: http://www.n5ac.com/apolLO-32Operation.pdf

FrequencySelectionJumpers

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WA5JAT 14

Microwave Frequency Standard

Source: http://www.w1ghz.org/MBT/multiband.htm

Example of a Frequency Multiplier

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WA5JAT 15

Microwave Frequency Standard

Questions?

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WA5JAT 16

RFG-M-XO

Front View

Back View (Rear Panel Removed)

Microwave Frequency Standard

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WA5JAT 17

Top View

RFG-M-XO

Microwave Frequency Standard

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WA5JAT 18

Bottom View

RFG-M-XO

Microwave Frequency Standard

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WA5JAT 19

Internet Search Came Up with:

]> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.cSent: Friday, December 29, 2006 6:44 AM Subject: Re: [time-nuts] Lucent RFG-M-RG and XO > Back when these Lucent units were first appearing GPS had not yet been > implemented at the cell sites here in Alaska. The rubidium was too noisy > for direct frequency synthesis, so the XO unit was phase locked to the rubidium > to provide the long-term stability needed, and the XO output was > up-converted for the system clock. By using the XO to smooth the rubidium > output the phase noise in the system clock was reduced due to better > short-term stability in the XO. As I remember it (It's been a while) the > 10M Rb disciplined the 10M XO, which was divided by 2, multiplied by 3, > filtered, and supplied as the 15M system clock. The XO was always > supplying the 15M system clock, and "standby" just meant the XO was locked to the > rubidium, which was acting as the primary frequency reference. When the > rubidium failed the system alarm output went high, XO PLL went into hold, > the standby light on the XO extinguished, and the undisciplined XO became > the source until the rubidium could be replaced. The GPS connection didn't > appear until later units and disciplined the XO during normal operation, > with failover on extended GPS loss to disciplining the XO from the > rubidium.

Microwave Frequency Standard

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WA5JAT 20

Internet Search Also Came Up with:

Sent: Monday, October 31, 2005 4:56 PM Subject: Re: [time-nuts] Unknown Efratom 10MHz Assy, information asked > The board you are describing is used in the Lucent RFG-M-XO reference > frequency generator. It takes in 10 MHz on J2 from a Rubidium oscillator and > disciplines the Efratom SC cut OCXO on the main board from the 10 MHz input. > The output from the OCXO is converted to 15 MHz and supplied as the reference output on J4. > The RFG-M-RB and RFG-M-XO normally mount together in a chassis (which I didn’t > get) and the modules are connected to the chassis by a harness with a > DB15 on the chassis end. The pin out for the harness is as follows: > DB15M TO/Pin# Description > Pin # > 1 RFG0 - P1-1 +24v 1.3A/0.6A > 2 RFG0 - P1-2 Common > 3 RFG1 - P1-1 +24v 0.6A/0.4A > 4 RFG1 - P1-2 Common > 10 RFG0 - J3-1 Alarm > 11 RFG0 - J3-2 Alarm > 12 RFG1 - J3-1 Alarm > 13 RFG1 - J3-2 Alarm > > A second interface cable ties the RB to the XO as follows: > RBJ5 XOJ5 > Pin # Pin# > 1 5 > 3 3 > > The male DB9 is P1 and pin 1 = +24v @ 400ma, Pin 2 = Common. This will power > up the board so you can verify operation of the OCXO. Unfortunately that is > all the information I have on the unit.

Microwave Frequency Standard

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WA5JAT 21

Internet Search Also Came Up with:

Author, G Molenkamp, ( vk3fgjm@commtelns.com)

Repair of Rubidium Source

Microwave Frequency Standard

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WA5JAT 22

Microwave Frequency Standard

Repair of Rubidium Source-Cont’d

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WA5JAT 23

Repair of Rubidium Source-Cont’d

Microwave Frequency Standard