Vantage Vue ISS and Console losing connection - RESOLVED

I am running a Davis Vantage Vue on a control tower at a grass airfield here in the UK. It’s not our main weather kit, that is Vaisala and it is situated out on the airfield and cabled back to the tower. The Vantage Vue is just so we can put the weather on the internet.

Most of the time the Vantage Vue works fine. The tower is only manned when we have an event, usually every two weeks or so. However, whenever the tower is manned the ISS and the Vanatage Vue console lose contact; not straight away, usually after a few hours. If left to its own devices, it restores itself, usually the next day when we are not there (I can log into the PC remotely).

It happened yesterday afternoon, after we had been manning the tower since morning, and has restored itself at lunchtime today when it’s on its lonesome.

Can anyone suggest why?

The ISS is on a pole fairly near our radio antennas. We transmit on the VHF airband (130.7MHz) and also a UHF frequency (450MHz or there abouts). There are also a lot of mobile telephones nearby when we are operating. Or perhaps it doesn’t like the size 15s clomping up and down the tower steps.

It’s got me beat.

Does it ever lose contact when nobody is there? If not then I would suspect RF and move the ISS farther way from the antenna’s.

Hi Dan

No, it does not appear to lose contact when we are not there but what I don’t understand is it does not lose contact as soon as we start using the radios, it is always after a few hours. Then it takes more hours to regain contact again.

I have been in contact with Davis Instruments and they tell me this is not normal behaviour! Yep, I’d go with that. They have drawn my attention to the diagnostics in the Vantage Vue manual so I will try that next time I am on site.

It is not really practical to move the ISS to a different location although I think that is what we might have to do in the future.

It would be helpful to get some more information on reception quality, signal strength (RSSI) etc to see if this gives any clues.

One possibility (but only a possibility) is that your reception is marginal. Under these circumstances the console will potentially lose synchronisation with the transmitter signal at random intervals and will need to lock on to the signal again, ie to resynchronise. This resync process will happen automatically, but may be a lot more difficult and delayed if background interference, eg from other UHF transmitters, is increased or even if there are human bodies in the direct signal path or in the immediate vicinity of the console antenna.

It’s worth taking a look at the wireless diagnostics section towards the back of the Vue console manual and/or for further info on interpreting the RSSI values see the relevant topic on our Davis knowledgebase at:

http://www.manula.com/manuals/pws/davis-kb/1/en/topic/wireless-reception-monitoring

eg see the section on ‘Interpreting the RSSI value’

Thanks John, most useful.

I have been communicating with Davis and they directed me to the Diagnostics screens but I wasn’t sure what I was seeing. I’ll study your pages and try again.

i was back on site yesterday after a gap of a couple of weeks operating the radios and sure enough, after five hours, the console and ISS lost contact. I left it all running and checked remotely this morning and it was back on line again!

We are going to try and relocate the ISS so it is not close to our VHF and UHF antennas but there is not a great deal of scope.

Thanks again.

If you do decide that weak signal strength is a real possibility (and at this stage it’s obviously only a hypothesis) then another potential fix is to look at introducing a wireless repeater into the system. You’d need to work out the repeater siting, but if it could be located roughly midway between ISS and console then you could get higher RSSI at the repeater antenna and similarly higher RSSI from the repeated signal at the console.

We were on site again today and sure enough, after five hours of pretty intensive RF, the ISS and Console lost contact.

Here are the two diagnostic screens first thing this morning

Here are the two diagnostic screens after the loss of contact

Not sure what this all means!

There is no point in installing a repeater as the ISS and Console are only about 4m apart.

Does any of this help?

OK, the signal strength looks excellent, as you might expect from such a short range.

That certainly makes it rather a puzzle. All I can quickly guess is that the resync process is being interfered with by interference from the other nearby transmitters.

AIUI even with a strong signal, the receiver will very gradually drift out of lock with the transmitter and will need to resync at infrequent intervals. I’m just speculating that for as long as the receiver is correctly locked on to the data packets then reception is good, but when that lock is lost and a resync needed then that resync process struggles to re-establish data lock if there is significant background interference. I’m no radio engineer and can’t be sure that this is the explanation but it sounds plausible to me.

Unfortunately this explanation doesn’t suggest any fix beyond trying to move the relative positions of console, ISS and potentially competing transmitters/receivers (which I appreciate may be tricky). It’s possibly the case that you would have been better off with a cabled VP2 station rather than a Vue, though of course even cabled stations are not immune from RFI pickup on the cable.

You could try switching to a different wireless channel of course, but I doubt that this will make any difference - these are channels in the time domain, not different frequencies. The only other option I can think of is to buy/borrow a second console and see whether this behaves in the same way. With a second console running on battery power you might be able to try locating it well away from the primary console (eg up to 50-100m away) just as a troubleshooting exercise. This won’t provide a cure but it might give a clue as to whether it’s the proximity of the ISS to nearby transmitters or that of the console to nearby transmitters and receivers (ie the interference might be IF radiated from a receiver) that is causing the worst of the problem.

Thanks John

That certainly sound plausible. We have a spare ISS which is unserviceable at the moment so we’ll get that fixed and then try and work out a new location for the kit. I think we may have bought the original kit from your company.

We have moved the pole, not far, just a few metres. It’ll be a week and a half before we have an event there to see if it has made any difference.

We appear to have resolve the problem we were having with the ISS and console losing connection by moving the ISS to other side of the control tower away from the transmitting antennas. Just three metes but it seems to have made the difference

Good news.