Topic: Old Vantage Pro with Reception Issue

[wxnerd]

Kind of a long shot, but maybe someone can give some pointers.

I've got a very old original (version 1) Vantage Pro that's nearing 20 years old. Other than the common supercap issue needing replacing years back, the station has performed flawlessly (and surprisingly, even the temp/humidity sensor is still quite accurate)...For the past 10 years or so, the receiver has been sitting on my desk next to a desktop computer.

A few weeks ago, I noticed a lost connection. First step was to check the CR123A battery. While taking out the battery, one of the joints of the battery compartment came loose (desoldered) from the circuit board. Thinking it may have come loose on it's own and causing the problem, I soldered it back on, checked all the connections with a multimeter to confirm proper continuity, then replaced with a new battery. Station then started working again as normal.

A day or two later, I noticed a lost connection again. Rechecked the battery (still had full voltage and battery compartment still connected to the board well).. I checked the supercap and it had the proper voltage on it, though from some angles it appeared as though it may be a bit swollen in the middle. Having an extra supercap on hand (bought 2 when doing the repair years ago), I decided to swap it out with a new one. Hooked everything back up and everything worked normally for a few hours, then lost connection. Went back in and removed the new supercap and tried it out with no supercap (just solar and battery) to rule out any supercap issue...Same result; Worked for a few hours then lost connection for a few hours. Connection comes back on it's own for a few hours, then loses connection again for a few hours. Timing of lost connections seemed random (ie. sometimes at night, sometimes during the day, sometimes during full sun, sometimes when cloudy)...

I did some other tests while the connection was out. Checked solar panel for correct voltage, turned on the 4th dip switch on ISS board and it showed the LED flashing every 2.5 seconds indicating that it was transmitting. Checked continuity on antenna. Though not the proper way to tell much, I checked voltage between the switch and antenna and it would spike up to 3 volts every 2.5 seconds.

Then an interesting discovery by accident. 2 nights ago, while the weather station was in a non-working phase, I shut down the desktop computer next to the receiver to get ready for bed. Happened to be looking at the Davis console at the time. Soon as the computer shut off, weather station started receiving a signal. Turned computer back on, weather station stopped. Turned computer off, weather station works again. Tried this same test several more times yesterday with the same result.

Obviously, the computer (when powered on) is causing interference  and making me lose signal....But keep in mind, the Davis receiver has been right next to this computer for about a decade with no issues...This narrows me down to 2 possible conclusions...

Possibility 1: Something has gone wrong inside this computer that has suddenly started causing interference in the area at times.

Possibility 2: Something has weakened the transmission signal of the Davis; The computer has created interference all along, but my Davis signal was strong enough to not be affected by it until now...

Unfortunately, I'm not really sure how to go forward with narrowing down which is correct and what to do about it. For right now, moving the Davis receiver to the other side of the room while the computer is running seems to be working as a work-around, but an inconvenience. Has anyone else had reception issues related to a desktop computer? Any way to tell if the computer is somehow causing an abnormal amount of interference? Any way to determine if the Davis is pumping out a below-average signal strength? (Remember, this is version 1 so the receiver does not have the reception diagnostics than VP2 stations have)... I realize it's probably beyond time to just break down and buy a new VP2, but there's too much that is working on this station to convince me to give up on it just yet.

[wxnerd]

Oh and one other note I forgot to mention. After putting in the new supercap then putting in the CR123A battery,this battery almost instantly charged the supercap up to 3 volts. I know the charge came from the CR123A battery as the solar panel was not even reconnected yet. Is that normal? I was always under the impression that the solar panel charged the supercap and then the battery took over after the supercap drains. It seems odd to me that the supercap is even able to receive a charge from the battery as that would defeat the purpose. Wondering if there's a diode between the battery and supercap that has gone bad and causing improper power management.

[miraculon]

The original VP did not have frequency-hopping-spread-spectrum technology. Your experience may have been one of the reasons Davis implemented it in the VP2. Frequency hopping increases the probability of receiving packets by randomly avoiding interference frequencies.

There could be components in the computer that have changed value or failed, such as capacitors. Or grounding connections may have deteriorated inside the computer.
I think that you are on the right track with the computer being an EMI culprit. You might look into adding clamp-on EMI ferrite filters to the power and signal lines connected to the computer. It also might we worthwhile tightening case and motherboard screws in the computer.

I don't know if Davis had implemented the signal diagnostics screen in the old VP1 units, but if it is there, it might help understand what is going on. A RF Signal Anaylzer like the RF Explorer might be useful. You can see noise emanating from the computer with it, and also confirm that the ISS is transmitting. The basic model would work for this purpose.

Greg H.

[wxnerd]

Unfortunately, the VP1 only has the first diagnostic screen and not the second reception screen.

Spending hundreds for an RF detector is a bit out of budget for me. I'm curious if a cheap EMI meter, like this $15 one at Amazon ( https://www.amazon.com/dp/B09GKWY41X ) could somehow be of any value in determining if the computer is giving off anything unusually strong?

But the biggest issue with any kind of tester, as I see it, is I don't have values from the past (when all was working well) to compare to. I don't know what kind of radiation the computer may have been giving off in the past or just how strong the Davis station's signal used to be. The fact that the Davis stops working immediately when the computer power button is turned on and immediately returns to working the second the computer shuts off all but confirms that the Davis is transmitting (at some signal strength) and that the computer is causing interference (at least to some degree). Just not sure how I would know which unit (Davis or computer) has gone bad without any prior statistics to compare with...Unless there's some unusually extreme values measured around the computer or if there's a known, expected signal strength at the Davis transmitter.

Meantime, I'll try tightening the computer screws and looking over the motherboard for any visual clues of damaged/defective components.

[miraculon]

The Amazon meter you found could be useful as a "sniffer" to isolate the source at the computer. Be sure to check the cables, since the could be conducting then radiating RF from them.

Palomar Engineering is one source of EMI ferrite clamps (there are others such as DX Engineering, or Fair-Rite). DX is a Ham radio equipment supplier. Fair-Rite is a good outfit, but is oriented towards engineering applications and not the general public.

If you order clamps, make sure that they are the proper material with suppression in the frequency range of the Davis. (VP2 is ISM 900MHz, but I don't recall what the original "VP1" was, since I got my Davis in the VP2 era).

Greg H.

[wxnerd]

If you order clamps, make sure that they are the proper material with suppression in the frequency range of the Davis. (VP2 is ISM 900MHz, but I don't recall what the original "VP1" was, since I got my Davis in the VP2 era).

Original VP1 is 916MHz, so the VP2 just created a larger range around the original frequency to allow room for the frequency hopping.

While researching this issue, I noticed that the 61xx series VP2 has been discontinued and replaced with the 62xx series with the newer, more expensive weatherlink console adding a few hundred to the price...Since I know it's only a matter of time before my original 20 year old VP1 has to be replaced (maybe sooner rather than later) and I don't need the Weatherlink console, I went ahead and grabbed a 6152 on a closeout special while I can still get it. Hopefully, whenever the time comes to send the VP1 to the grave, I'll have saved myself a few hundred bucks on it's replacement. When it arrives, I'll at least try it out a few days. If it doesn't have reception issues with the computer, I'll just mount it permanently and replace the VP1 now. Save the VP1 as an emergency backup. If the new one also has the reception issue, then I'll know for sure that the computer needs further attention.

Will update in the coming days....And big thanks Greg (@miraculon) for your assistance! You're the only one that's stepped up to offer any help and advice on this, so I really appreciate it! 

[johnd]

VP2 generally has better VP2 performance than VP1 though of course every configuration has its limits. But if your VP1 was previously OK but becoming marginal then I would expect VP2 to perform OK. But it will depend on the level of background interference, both through-air RFI and, potentially, mains-borne.

[wxnerd]

For what it's worth, I tightened all the screws inside and outside of the computer case and doesn't seem to have made any noticeable difference. No components on the board looked bad to the naked eye, though I realize visual clues don't always show. Oh well, it gave me the opportunity to remove a layer of dust and replace a failing CMOS battery that's been screwing up my computer clock, so I still made the effort worth while....Lemons to lemonade, if you will!

New VP2 has arrived. Now time to unbox and see what happens.

Edit to add: Looks like the CR123A battery is charging the supercap in the new VP2, so I guess this is just normal behavior. Does seem counterproductive, though. I like the fact that the SIM is side mounted rather than bottom mounted like the VP1. Working upside down to get to it was a bit of a task on the VP1. Only thing I'm not really crazy about on the VP2 so far is the solar panel connection. Very loose and wobbly. And when you take off the SIM cover, it dangles by the solar panel cables. Seems like a broken wire waiting to happen if you're not careful. Also noticed on the radiation shield, there's 2 solid bottom plates. Not sure what that's about as the second bottom plate seems completely useless?

[wxnerd]

Well here's a plot twist. I decided to start setting up the new VP2 console first before hooking up sensors and out of nowhere I started receiving weather data on it...After a bit of confusion and research, it turns out that a neighbor 2 houses behind me has a Vantage Vue sending data to Wx Underground...And broadcasting on "station 1", which is the same station as my VP1. When I put the new VP2 console near my running computer, this neighbor's station starts coming in good. So it seems my computer is somehow acting as an antenna and amplifying my reception of my neighbor's Vantage Vue while interfering with my own VP1. 

I went out and switched my VP1 over to channel 8 thinking maybe that will solve the issue...Unfortunately, I'm getting an even poorer reception on channel 8!  Guess it's back to the yard to test all the other channels to see if any solve the issue. Looks like that neighbor has actually had his station online for a long time, so I still get the feeling that something has recently degraded my VP1 transmitter. If no other channel solves it, then hopefully the new VP2 is strong enough to overcome the interference.

[92merc]

Try channel 2 or 3 instead of 8.  I don't recall the reasons, but the lower the number the better for reception.

[wxnerd]

Try channel 2 or 3 instead of 8.  I don't recall the reasons, but the lower the number the better for reception.

Since my last post, I've tried all channels and none of them made any real difference. I put the new VP2 ISS next to the old one and it comes in great. Even with the VP2 console sitting on top of the computer and even using the same channel 1 that the neighbor is using. So looks like I might as well replace VP1 with VP2. Kind of hate to do it with everything else working perfectly on the VP1, but I need a reliable signal and not have to worry about every piece of electronics possibly interfering...I'm still curious to figure out what has degraded the VP1 signal. I'm assuming it's somehow power related (ie. Transmitter not getting the proper voltage or current it needs to pump out the full signal)...Just can't seem to figure out exactly why.

[92merc]

I had a similar issue with my old VP1.  It ran for 4 years without issue at my old home.   Moved to the new one, started dropping quite often.  I fought it for close to a year.  Changed out to the now new VP2.  No issues since.  And I live out in the country, large lots, too far for neighbors to interfere.

[wxnerd]

Just looking at the SIM board, there's lots of components that could go bad. Many small capacitors (in addition to the supercap), diodes, resistors, transistors, at least one transformer, etc...Any of which could be having issues. No easy way to test all of these things,  but something seems to be mishandling the power, taking too much power or not transferring enough power.

For what it's worth, even my solar panel seems to be having issues. Thought it was working because even on a cloudy day when I recently tested, it was putting out 1.5 volts. But I checked yesterday in full, direct sun and it was only up to 1.9v (used to be 5.5v in full sun)....Even so, I should still be transmitting the full signal because the battery is good.

There comes a time when all electronics have to be replaced. And I guess my unit has just reached that time, if I expect to have a reliable signal.