Best AM FM Stereo RF Generator for a Newbie

George S. said:
Made a very low ball offer on this unit from a Riverside CA electronics recycler. They accepted. Former Pan Am Satellite unit. If it works or is repairable it'll be a kick ass GPSDO (GPS Disciplined Oscillator) for a 10 MHz reference standard. Looks to be highly optioned. Only downside is a lack of documentation for these units, but we'll get it figured out. Here's the listing.
https://www.ebay.com/itm/1656998469...NB_S8D7Qg2&var=&widget_ver=artemis&media=COPY
Click to expand...
Nice that it appears to be all aluminum.
 
Yes, as do I. Looked at the HP units prior. Very, very, nice stuff. Settled for a project. Almost went with one of the slightly newer Microsemi XLi SAAS (ex DOD?) boxes. They bought out Symmetricom True Time.
Actually the best solution for me is one of these.
https://www.ebay.com/itm/2830646388...NB_S8D7Qg2&var=&widget_ver=artemis&media=COPY
But, I just couldn't pull the trigger even after all the excellent reviews and YouTube videos. Just wouldn't learn much using that unit.
 
After listening to Dave on the EEVBlog, I am leaning towards the Siglent SSA3021X. He is very animated.
 
Well, the Siglent SVA1015X is a 9 kHz to 1.5 GHz Spectrum Analyzer (do I need more than 1.5 Ghz?) and a Vector Network Analyzer. The VNA is good for HAM antenna SWR measurements...
And the price is only $40 more than the Siglent SSA3021X (which goes up to 2.1GHz).
The new Rabbit Hole...
 
I'm very happy with the $125 SDRplay RSP1A and free spectrum analyzer software, for now. It exceeds my present knowledge level and need. Very easy to use.
 
Got the True Time XL DC on the bench. A very clean well optioned unit with the low phase error frequency standard output cards.
Unfortunately the unit came configured for long cable runs with the GPS radio built with the integral up converter which runs at 12 VDC and LO at 16.368 KHz. The matching 12 VDC antenna with the built in down converter is rare because most were left on rooftops when these units were retired.
Going to button her up and set it aside until I find the antenna. Just a very nice and clean, lab grade piece.
 

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Found the info for bypassing the receivers up converter and changing the antenna voltage from 12 VDC to 5 VDC so I can use a Trimble Bullet 3 antenna.
Also did a lot of digging on The Wayback Machine and found Symmetricoms govt support files including manuals and firm ware downloads.
Need to order a few SMD pieces to make the modifications, so going to recap the power supply while I'm at it.
 

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The low phase noise sine wave and PPM output boards. Some of the BNC connectors have been hit and need remade round.
These oscillators are reported to have a appx 10 year constant use service life before they drift so far out of spec that the DAC is unable to trim them to spec.
It's a gamble if they're still good. We'll find out. No dust in the unit, and it's a late model, so perhaps they're still good.
 

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Using Chipquik to remove a SMD 0 ohm resistor and a .1 uF ceramic. Also moved another 0 ohm resistor from one pad to another to convert from 12 volts to 5 volts for the Trimble antenna.
That little Chipquik kit is worth every cent when working on densely populated boards with a iron.
 

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Here's a nice HP, a complete setup. They show some of the software available for these old GPS receivers. Most communicate with a PC through a RS-232 serial port.
Interestingly, the software shows the HP as a Symmetricom product, and the photo shows what appears to be a Trimble bullet antenna.
Check out the photo of the HP counter displaying the receivers output of the 10 MHz frequency standard.
A option for the Symmetricom TrueTime receivers was a HP Cesium oscillator, and most TrueTime use Trimble GPS boards and antennas.
It appears that HP, Symmetricom TrueTime, and Trimble were sharing technology and development.
https://www.ebay.com/itm/2749210386...NB_S8D7Qg2&var=&widget_ver=artemis&media=COPY
 
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