GDO for acurizing tranceiver timebase / freq. std.

[Opcom]

A really nice Trak Systems (Trak Microwave) GPS Disciplined Oscillator has come my way.

It's a series 8900 with one GPS RX, two digital modules (for decoding?) and two oscillators (and two power supplies, for redundancy). One of the oscillators is bad, the other one is running at 10MHz and seems to be precise. No manuals, unfortunately.

So, the question- several AM/SSB rigs around here as well as numerous test equipments have an input for an external standard. What real benefits can I realize by synchronizing the radio's standards? What are the applications where an operator would prefer to use a standard with the radio?

[WD5JKO]

Patrick,

   Getting all your radio's running from the same timebase has advantages. First they will track better, and any error will be equal between several boxes. I presume the 10Mhz standard suits your boxes?

   I don't have much here, but I bought a TCXO 10 Mhz oscillator which I put in my Fluke counter. Now instead of being up to 100 hz or more off, I might be a few hertz off, right from a cold start. Big, and welcome change.

Jim
WD5JKO

[Opcom]

10MHz is not exactly right for everything. Inputs vary between 1Hz, 1MHz, 5MHz, and 10MHz. But I can divide these without any problem and distribute the signals with a bunch of analog video distribution amplifiers lying around here. I agree it will make a big difference with the test equipment.

[WB6NVH]

Do share your results regarding the divider.  The typical IC-based divider winds up making square waves out of a sine wave input, which some equipment doesn't care about, while other gear does, such as timebase reference inputs on communications receivers.  I'm pondering a way around that to run a bunch of R-1051B receivers ( 5 MHz) so that I don't need to wait an hour or more for their internal ovens to stabilize.

[Opcom]

I think the R-1051 shares this issue with the GRC-106. I have to build the divider and when that is done I'll share the results. It might be some time before that is done. I was considering if the square wave could be softened a bit, that would be good. Some study needs to be done on that. A tuned circuit might help, and there is also the question of the signal level needed by any particular equipment.

[Mike/W8BAC]

Patrick,

Am I reading your post right? Is that a Grid Dip Oscillator? I picture a GPS disciplined GDO  with plug in coils for testing resonate circuits. If so, that alone is a great find. Anyone that has owned the ham bone stuff can tell you how unstable GDO's are.

I use a GPS disciplined oscillators 10 MHz output for the master oscillator for my Flex SDR 1000. I route the output through a multicoupler and use it as the standard for three other pieces of test gear.

I picked it on eBay. It was an orphan because the owner didn't know anything about it. No manual, antenna or power supply. Fortunately the company is still in business. The unit was sold as a master for cell phone sites. I built a power supply and learned what kind of LNB antenna was intended. I found a used antenna on eBay as well.

A few things to know. The antenna is active. DC is duplexed on the feed line to power the low noise block converter so you'll have to match the antenna to the DC output of the receiver. Use a good feed line (coax) with lots of shield and ground the receiver well. My (GPS) receiver was getting hosed by my transmitter and reverting to the slave 10 MHz secondary when I keyed up. Not a big deal but some extra work fixed that.

I hope you find a manual. Have fun with it.

Mike

[Opcom]

It's a disciplined oscillator. The mention of tuned circuits was regarding the sine-izing of any frequencies divided from the 10MHz signal. I have not had time to go back to it yet or look for an antenna. By active, then it is a preamp in the antenna assy? OK, I can see about that.