[time-nuts] Re: Measuring oscillators against GPS

[Bob kb8tq]

Hi

New flash card on the NetRS:

1) Pop off the front cover, flip the latch on the flash holder and pull the 
old card. Carefully put it somewhere safe :)

2) If you can find a 512 Mb flash card, good for you. At least around 
here 1 GB is an easier thing to dig up. Download the image that will
fit in the card you have found. 

3) Fire up your Linux box and use the normal tools ( dd?) to copy the
image file to the card. It’s no different than copying a fresh image to
any “empty” hard drive. Other tools on other operating systems may
(or may not) do a fine job. You want something that just does a copy.

4) Put the card back in the NetRS and watch the serial port. You will see
a long spew of some very alarming looking messages. It will do this / reboot /
do that / reboot again …. 

5) Eventually (if the card is one the device is happy with) it will settle down. 
It will boot one last time and you will see the normal flow of messages. 

6) The device now needs the normal setup stuff that you would do on
any NetRS. 

Indeed, you can pull the 512MB card out of the typical NetRS and put 
a 1GB card in. Assuming the card is big enough, you will have the 1GB 
model as a result. ( big enough = is at least as big as the original Trimble
card, there are a surprising number of “close to 1GB” versions out there).

I seem to recall that you can indeed “go big” and put in a 2GB card. The
result is still a 1GB device. It’s been long enough that I’m not 100% sure
I went that way on one of the devices. 

Fun !!

Bob

> On Mar 13, 2022, at 12:07 PM, Skip Withrow <skip.withrow at gmail.com> wrote:
> 
> Hello Time-Nut,
> 
> Just would like to comment on Bob's recent post regarding the Trimble NetRS.
> 
> 1. Antenna voltage - I measured the antenna voltage put out at the
> antenna connector of my NetRS and it was 7.23 volts (open circuit).
> Yes, some of the 3.3V antennas might not like that, however, 5V
> antennas (what I use) should be perfectly happy.
> 
> As for the issue of gain adequacy, the best bet is to just look at the
> received signal strengths (on the Sattellites/Tracking page of the
> GUI).  It gives you SNR for both L1 and L2.
> 
> 2. Flash Card - From looking at the Unavco site regarding the NetRS,
> it appears that there is a significant build process to prepare a card
> for insertion into the receiver.  I don't think you can take a random
> flash card and just insert it into the receiver and expect it to work.
> Would love to hear from someone that has gone through the process with
> this receiver.
> 
> BTW, there are two part numbers for the NetRS, 45905 and 75905.  My
> thinking is that this may indicate the size of the flash card in the
> unit (500MB vs 1GB).  If anyone could confirm this it would be
> appreciated.
> 
> Regards,
> Skip Withrow
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com -- To unsubscribe send an email to time-nuts-leave at lists.febo.com
> To unsubscribe, go to and follow the instructions there.