One of my 4000SSi receivers has stopped picking up more than 4 SVs. I've swapped antenna and antenna cable with known good ones, but it didn't help. Anyone have a clue what might be going on?
> One of my 4000SSi receivers has stopped picking up more than 4 SVs. I've swapped antenna and antenna cable with known good ones, but it didn't help. Anyone have a clue what might be going on?
Does it appear that the receiver is simply only logging four channels? They aren't the same four SV's all the time, are they? Do you have the means to reload the receiver firmware?
elevation mask too high ?, ..in case someone was playing with it and you did not know about it 🙂
> elevation mask too high ?
Good thought, but I checked and it's set at 10°.
I'll have to do some experimenting to see if it's always just 4 SVs and whether or not the SV numbers change. I'll try reloading firmware, but my hunch is a hardware failure of some sort.
http://trl.trimble.com/docushare/dsweb/Get/Document-2344/hardres.pdf
Perhaps this may help to resume normal operation.
Phil
San Leandro, Ca.
Is the signal strength normal on the four it is tracking?
If not, that points to a RF problem of some sort which could be antenna and antenna cable which you said you checked, or an RF frontend board problem.
I second on trying the hard reset.
> One of my 4000SSi receivers has stopped picking up more than 4 SVs. I've swapped antenna and antenna cable with known good ones, but it didn't help. Anyone have a clue what might be going on?
Success!
> I second on trying the hard reset.
The hard reset appears to have worked. I set up an antenna in my backyard -- which has pretty marginal sky visibility -- and hooked up a known good receiver, which saw 6 SVs. I then swapped in the dodgy unit, and it only saw 4. I did the reset, and as soon as it got an almanac it was looking at 8. I logged a short (4-minute) data file that I'll check later against a CGPS station a km or so away. Just for grins I converted it to RINEX and took a quick look; it picked up 9 SVs for the whole session.
Based on this experience, I think I'll reset all my 4000-series receivers when I get time.
Thanks to both of you for suggesting an easy and effective solution to the problem!
Success!
I recently picked up an old 4000 SSI for grins. It seems to get significantly worse signal to noise than other receivers, even for satellites at high elevations. The 4000 SSI went totally "wacko" for no apparent reason the other day at 3:05 UT for about 30 minutes with all DOPs going through the roof (25+) during that time, then returning to normal. Very strange. I'm hoping it's just a bum antenna cable. Rather than purchase a new known good antenna cable, I have decided to make a LEMO to N jumper using a short length of LMR-195 cable. All my other coax cables are LMR-400 Ultra Flex with more "normal" N and TNC connectors. Those LEMOs are hard to find and man are they ever expensive. I have a LEMO FFA.1E.250 connector on order from Mouser and I was lucky to find it there. Digikey was out of stock and wanted me to buy a minimum order quantity of 25 (at about $45 each that would be insane). Mouser actually had them in stock.
Success!
> Mouser actually had them in stock.
Mouser is my supplier of choice for Lemo connectors. Their prices are good, and small quantities aren't a problem.
Success!
I am glad that it worked.
I used those units for many hours at Caltrans D04 and once in a while they just had trouble. Most often it was antenna cables, but every so often the hard boot was necessary.
Phil
San Leandro
