[time-nuts] New NTBW50AA

[Bob Camp]

Hi

With a Trimble TBolt, when you do an auto-cal it comes up with a sensitivity of the OCXO, and modifies the filter (as in the PID control loop filter) coefficients. You can then save them to the eeprom / flash in the TBolt. The settings persist across multiple reboots. The settings do impact the way the TBolt functions. This allows you to use OCXO's with different sensitivities (and even control polarity) in the TBolt.

In the Trimble NTBW50 (and Trimble made clones) you can run the auto cal via LH. The sensitivity is calculated and may appear to change. The settings can not be saved in flash / eeprom. They do not persist across multiple reboots. There is no evidence that the NTBW50 actually uses the changed settings. 

Switching elevation masks, changing AMU limits, works with both units. These changes do save to flash / eeprom on both units. They persist across multiple reboots on both. The do impact the way both units function. 

-----------------

My guess is that the antenna you have is virtually identical to the Lucent 26 db gain device. I doubt that the cost of getting one is worth the money. If you want a better antenna, go for one of the $300 - $500 choke ring antennas. You will also need a bias Tee (they mostly run on 12 volts), but it's often included. 

Enjoy!

Bob



On Sep 19, 2013, at 9:40 AM, "quartz55" <quartz55 at hughes.net> wrote:

> Thanks Bob, Charles,
> 
> Well, here's my plan.  Get a single piece of RG-11 direct burial.  Get a more stable post for the antenna and perhaps a bit taller. Keep my eye out for a different antenna, right now they seem to be going for $50 and up for the 26 dB versions, I could contact RDR, but I didn't see anything on his site about other antennas.  Yes, this is no high RF area except when maybe I turn on the 170 W 2M brick and that's nothing, I saw that thread about filters in the antenna.  Finish this 48 hour survey and get these other things done and then do a 72 hour survey.  Let it run for months and see where we are.  Get a smaller switching type power supply.
> 
> I figured nothing was broken or not working right.
> 
> Bob, are you saying playing with the masks TC, gain and other stuff in LH does nothing to the NTBW50AA? It just affects how LH looks on my computer screen and I'm really not changing anything of how the Nortel works?
> 
> Thanks,
> Dave
>  ----- Original Message ----- 
>  From: Bob Camp 
>  To: Discussion of precise time and frequency measurement 
>  Sent: Thursday, September 19, 2013 7:23 AM
>  Subject: Re: [time-nuts] New NTBW50AA
> 
> 
>  HI
> 
>  What can be said with reasonable confidence:
> 
>  1) The unit isn't broken and it does not need to go back to RDR under their 30 day return policy.
>  2) The OCXO isn't broken and it does not need to be replaced.
>  3) The unit is functioning ok, but probably not as good as it could.
>  4) Without comparison to an independent standard, there's no way to know how well it is or isn't doing.
> 
>  Bob
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