Anyone have a Motorola Part Number for the GPS Antenna that ships with the CMM Micro?
I am in need of only the antenna but there is no visible P/N that I can find.
Also, anyone out there have any knowledge of what frequencies or band GPS uses on both the old CMM, and the new CMM Micro? I am wondering if the GPS cable that BestTronics recommends for use with GPS is ample in terms of loss over GigaHertz frequencies. I feel that after powering up a CMM Micro that waiting in excess of 13+ minutes until the GPS is fully synced and set on a 3D Fix is unacceptable.
Is anyone using LMR-400 or any other cable besides what BestTronics provides?
Any help is highly appreciated.
We use LMR400 for all our CMM’s. One CMM-2 and two CMM-micros.
Works just fine. And all are fairly good at picking up satellites.
I just did a calculation.
At 75’ using LMR-195 (which is what Best-Tronics ships) at 1575.MHz the loss is around 10 dB not including connectors or lightning arrestors, etc.
Belden 9913 (almost equivalent to LMR-400) @ 75’ at 1575.42 MHz has a loss of 4.521 dB. The LMR-400 with the same specs has 4.091 dB of loss.
Quite a significant difference and also interesting.
FYI as an addition to this post, there are some interesting FAQ’s at www.synergy-gps.com regarding the difference between “Satellites Tracked” and “Satellites Visible”.
Satellites Visible is actually a derived value as a function of the number of satellites tracked. Intuitively I would think this would be the other way around. In the explanation it also describes how it takes approximately 15 minutes for the number of Satellites Visible to become an accurate value. This would explain my previous post expressing my concern why it was taking around 13 minutes for me to receive accurate information on the GPS Status page of the Micro.
i had my gps cable hand made, and it gets a 3d fix in under a minute. There are no cable shops here to make them.
Are you using a CMM Micro or a CMM Gen II? What type of cable are you using? How may satellites tracked and how many satellites visible?
I am using a 15-20’ RG6 coax cable with N male connectors on it and it works great. have this on about 5 sites and it works great… traking 9 of 10 on most and 8 of 10 on another.
I’m surprised that 75ohm TV cable works but your short lengths are probably saving you from the impedance mis-match (translate that as high VSWR)