Best AM FM Stereo RF Generator for a Newbie

[George S.]

Recapping the power supply after finding my cheap used Trimble antenna is no good. The LNA (low noise amplifier) in it is "open".
Ordered a NOS Symmetricom antenna.

 

[George S.]

Done. Was able to replace that short Jamicon 400V 100 uF cap with a full size Nichicon because the supply is going into a 2RU rack. It was originally sized to also fit the low profile 1RU rack.

 

[laatsch55]

Nice George...

 

[VSAT88]

The Sound Tech 1000A was the standard for audio manufaturers. Current used pricing is $500. It really shines if you are working on older tuneable IF stages (ala Marantz 10B and vinyage tube McIntosh). The 1000A had an option (003 IIRC) which lowered THD to 0.05%. Option 001 was a switchable internal 400/1000 Hz oscillator. I would have no concerns about the age of a 1000A. Note that it should have an external 50 to 300 ohm matching transformer if you plan to make accurate sensitivity measurements.
The Sencore SG165 is a cheap and dirty AM+FM signal generator with stereo and built in loads. THD was about 0.25%

Just like I like em.

 

[George S.]

Well, the NOS antenna arrived and the receiver still reports the antenna as open, and no satellites found.
The 10 MHz oscillators are working, but won't get precision trimmed until multiple satellites are locked in.
Going to try different coax to the antenna next. Not a whole lot of info available on these units.
This may become a very long term project.

 

[George S.]

Got Budwig feet installed and the face plate cleaned up. Read and learned more about the GPS receiver. I'm on the hunt for the non "up converter" receiver assembly so I can get this operational and locked onto the satellites.

 

[George S.]

Just scored another parts unit with the correct receiver I need to get up and running. Was I bidding against anyone here?

 

[WOPL Sniffer]

Just scored another parts unit with the correct receiver I need to get up and running. Was I bidding against anyone here?

Yes, I was needing a new anchor for my row boat.... I forgive you though

 

[George S.]

Got the second XL-DC receiver up and running. It immediately locked onto 6 satellites and calculated my position and elevation.
This one is a 1RU unit, only option is the back lit left side display, and a N8 Synthesizer card that I can find no info on.
No optional OCXO precision oscillator cards in this unit, but the receivers main on board oscillator self reports as healthy. Same power supply as the one I just recapped.
I'll strip it down and install the good parts in the larger 2RU chassis, get the optional oscillator cards running, and see how they look on the spectrum analyzer.

 

[George S.]

The optional back lit LCD was intermittent. Traced it to a open connection on a pin header. The pins they used were too long, so they shortened them with dykes leaving a burr that collapsed the header contacts.
Fortunately I have just enough parts from a previous project to fix this. And, the sockets are far better quality.

 

[George S.]

Hope this solves the issue.

 

[George S.]

Success.
Been learning about using a RS232 terminal in Windows to communicate with this receiver and use some other software. Both of my RS232 cables are straight through wired, and I've been unsuccessful.
Ordered a Null Modem cable. Will give that a try.

 

[George S.]

Looks good in low light. Locked onto to six satellites here, it has only a six channel receiver.
The rear shows six 10 MHz OCXO low phase noise outputs in the center, and five as yet unidentified outputs on the far right above the antenna jack, Irig-B and 1 PPS outputs.
Going to hook up the DSO tomorrow and see what's on those unidentified jacks.
Time for a Rolling Rock and a LP.

 

[George S.]

I'll let this cook and stabilize until this evening, then align the OCXO in the counter to the GPSDO in the receiver. The counter is definitely slightly off. Probably has never been adjusted due to lack of a Stratum 1 frequency standard.
Then I can use the HP counter to accurately align the Panasonic FM Stereo Signal Generator.
It's been a long circuitous route to getting the Panasonic aligned. And as Joe has pointed out, modern PLL receivers don't need this precision. But, what the hell, it's what we do here.
Nice clean wave form on the old HP 1742A, and most importantly on the Spectrum Analyzer.

 

[George S.]

The HP counter has a apparently seized frequency adjustment on the OCXO. Going to sit it aside and do some reading this evening.
The null modem cable arrived, so going to see if I can access the receiver via Windows.

 

[George S.]

Screwdriver pointing to the seized trimmer on the HP 10811-60111. Fook!
Going to heat the brass barrel and see if I can work it loose.

 

[George S.]

Got it loose. Heat gun for stripping paint, then a tiny drop of oil. Now to get this reassembled. This little box has a 111 page manual.

 

[George S.]

The 3 wires to the crystal are degraded and need replaced. My understanding is they're spot welded to the studs because the studs are nichrome and won't accept solder.
Going to cut them off leaving the welded on copper stub. Then wrap new copper around the stud, and solder to the welded copper.
Nothing to loose trying to fix this.

 

[mlucitt]

You are officially the Mad Scientist of RF Generators.

 

[George S.]

Making progress. Cut the barrels off some small crimp ons to crimp the new wires to the studs, then soldered.
Using 22 AWG silver plated Teflon wire. Better than originally used.