Thanks everyone. In addition to the blown transistor that feeds 5V down the coax, the one week out of box Motorola hockey puck antenna was blown too. I bought it in 2006 as a spare and I broke the shrink wrap two weeks ago.
So I will order another spare but see if I can fix this spare. It's definitely worth it to have a few extras!!! Chris — Sent from Mailbox On Thu, Aug 13, 2015 at 8:01 PM, Magnus Danielson <[email protected]> wrote: > Hi, > On 08/08/2015 07:05 PM, Bob Camp wrote: >> Hi >> >> A factory reset will not brick the unit. >> >> Either: >> >> 1) Your TBolt is blown >> 2) The cable has an issue >> 3) The antenna has an issue. > I've seen them all over the years, so neither is necessarily the most > likely. I'd also add: > 4) Power-issue > 5) Serial cable problem > For this case 1-3 should be your culprit. > Oh, do remember that engineers invent the most complex scenarios of what > the failure mode is, but fail to identify the simple ones such as power, > cables and connectors failing. >> For troubleshooting this sort of thing, multiples of each are a >> handy thing to have. Baring that: >> >> 0) Put a DVM on the coax and see if you have bias to the antenna >> 1) Hook up a TDR to the cable and ring it out both with a load and a short >> on the end. >> 2) Put the antenna on a *very good* spectrum analyzer and look at what is >> coming out. >> 3) Grab a signal generator that will simulate a GPS constellation and drive >> the TBolt with that. >> >> Since nobody (other than Magnus) ever has the sort of gear for 1-3, and it’s >> all pricey stuff > TDR is a nifty tool for this sort of thing so 1) is nice, but it won't > really help you and you will have to know what to expect from a > unpowered LNA. Spectrum analyzer will not directly help you since the > satellite signal spectrum is below the noise-floor, but you *might* see > the amplified noise as shaped by the LNA pre-filtering, which is > hopefully SAW filtered, so 2 is doable but tricky to interpret for the > novice. If you have a constellation simulator lying around, it will help > you to see if the receiver is working at all, but even I don't have that... > Having a VNA helps, and the nifty TinyVNA for instance will be quite > useful. Similar to the TDR, it sends a signal up the wire and analyze > the response, but in frequency plane rather than time-plane. Again, some > experience is required but this is a good time to learn. >> the simple answer is: >> >> 1) The antenna is probably the cheapest part of the setup. I’d swap it out >> first. >> 2) The cable is cheap but a pain to run, is it #2 or #3. >> 3) Hook up another timing receiver to the cable. There are lots of them out >> there in the $100 to $150 range. >> >> TBolts do die. My experience is that roughly 1 or 2 in 50 show up with a >> fatal issue. Another 1 or 2 show up >> with a (correctable) minor problem. I have had one drop dead after running >> for a while. > I would grab an antenna, toss it out a window and see if I get anything. > It is always handy to have additional antennas and cables around, and > for checking things to be operational, only modest requirements in type > and position is needed. > Similarly, having another GPS receiver to see if I get any form of > signal is a great tool. > Just taking the time to do quick and dirty tests helps. I've found that > I made stupid mistakes, so just doing a round of quick reality checks > have been important hints to find errors. > Cheers, > Magnus > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
