[time-nuts] uBlox F9P versus F9T

[Bob kb8tq]

Hi

The price of a bare module is still a bit steep. The price of the uBlox board for the F9P still looks 
like a steal though …..

At this point you still don’t seem to be able to buy F9T modules through distribution at all. Both are 
priced just below $200 on the uBlox site. The F9P is priced identicallyat Digikey as at uBlox. I have 
not seen either one pop up at any other distributors yet. My guess is that once more of these get out 
in the wild, other distributors will come in and the price will drop a bit.

Right now the M8N is at $25 and the M8T is at $89 at Digikey. I doubt the F9P or F9T will get to 
the M8N price. Getting a lot closer to the M8T price seems pretty likely. However if your system is 
being designed today, the M8T is  < 1/2  the price. 

For a “Time Nut” sort of project where best performance is the goal, the F9P / F9T seem like the 
best way to go. It’s a basement build and you aren’t going to market it to Lucent or Nokia. The 
performance plus the features ( and yes … the cool factor …) make it the one to go with. Being able
to do data reduction via the various free services is a *big* plus. 

Bob

> On Jul 18, 2019, at 1:23 AM, Glen English VK1XX <glenlist at pacificmedia.com.au> wrote:
> 
> fine business.
> 
> thanks for the insight.
> 
> The dual band L1, L2 is a certain plus. At a price Hard to ignore the benefits certainly for apps that can afford it.
> 
> I'll report back...
> 
> cheers
> 
> 
> On 18/07/2019 7:37 AM, Bob kb8tq wrote:
>> Hi
>> 
>> Having played with both, there are differences in how the P and the T do things. Both do a better job on
>> timing than single band modules do. The T has multiple pps outputs and *should* handle logging (at a
>> fairly coarse resolution) an input pps on two inputs.
>> 
>> Both will handle external correction inputs via a serial port. The P does not do SBAS, but the T does.
>> They now say that SBAS degrades timing on the T (as it does on all other receivers) so that may not be a plus.
>> 
>> I have not checked the latest firmware on the T, but with the last version, the P actually delivered better
>> timing performance. Indeed it was running defaults so SBAS likely running at the time.
>> 
>> If you are trying to do some sort of master / slave setup, it’s best to dive into just what is involved with
>> that task. For a system where both master and slave are mobile, the P is likely the better choice.
>> 
>> Bob
>> 
>>> On Jul 17, 2019, at 4:57 PM, Glen English VK1XX <glenlist at pacificmedia.com.au> wrote:
>>> 
>>> The F9T and F9P - are these interchangeable for stationary timing use and stationary high performance position ?
>>> 
>>> From how I read the datasheets, :
>>> 
>>>>> the F9P has an internal RTK engine, and the F9T outputs the info RTCM etc and that data can be run on a external RTK engine on a micro.
>>> The P provides 1.5m standalone positional accuracy compared to the T standalone positional accuracy of 2.0m. Not much difference there..
>>> 
>>>>> the F9P and F9T have their timing pulse performance shown using different description.
>>> The P  has this as "RMS and 99%", while the T has this as '5nS','2.5ns diff'
>>> 
>>>>>> Both can operate with companion receivers to enhance performance but I interpret this as only the P can do a (internal, companion mode) differential position fix and only the T can do a (internal companion mode) differential time fix. That is , internally without using an external engine.
>>> ***
>>> 
>>> So it seems, if using an external RTL etc engines, the devices can do roughly the same thing.
>>> 
>>> How do others interpret this ? I want to do projects using positional for one app, and timing for another, and would like to be able to acheive the deep quantity discounts...
>>> 
>>> glen
>>> 
>>> 
>>> 
>>> 
>>> 
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> 
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