Temporary decrease in range

[Bethsalem]

I'm not sure exactly where the correct place is to post this as it's a problem I've never encountered before.

On Friday afternoon (4th July) my range very noticeably decreased. Previously I was getting 250nm every day out to the east of the Balearic Islands. On Friday afternoon I was only getting 130nm. I checked the Beast, changed cables, made sure there was no electrical interference from something in the house, then went on the roof to check the antenna, its connections and cables.

Nothing was different or damaged. The neighbours around me, bar one, are on holiday and there are no new antennas or satellite dishes on the roof either, so no new sources of electrical noise were apparent.

Saturday and Sunday the same. 130nm maximum distance. Could see Reus airport traffic only above 2000ft (prior to Friday afternoon 200ft), Palma traffic above 10000ft, (previously 4000ft) and Barcelona traffic above 8000ft (previously 1200ft).

The last night about 11pm local time, everything back to normal!  I've changed nothing, neighbours still not back from holiday. So the question I have to ask is -

Does anyone have any idea what happened for about 55 hours to my setup???

[Anmer]

Moisture in the coax connections?

[Bethsalem]

Nothing obvious, but it has been more humid of late so condensation is a possibility.

[Bethsalem]

For arguments sake, if it is condensation that's causing the decrease in range (it happened again for a few hours this afternoon) is it better to leave the antenna alone until it dries naturally, or is it better to go to the hassle (and it would be a hassle    ) of stripping it down, drying it and applying some silicon grease where appropriate?

[Anmer]

Depends on ease of access, but I would check the connections and dry them out (assuming no lasting damage) and then use self-amalgamating tape to keep the moisture out.

[Bethsalem]

I'm wondering if it's one of the neighbours, the only one not away on holiday, who has bought a new wifi system and has been trying different locations to get the best coverage. He's not at home today and my coverage is back to normal. I haven't changed my setup in any way. As you can see from the screenshot, 280+ nm range.

Could my intermittent loss of range be down to electrical interference?

[Attachment deleted by Admin to save file space]

[Anmer]

Over the years we've seen reports of range reduction due to interference from local transmission towers, CCTV and even halogen lights being turned on.

I haven't seen anyone report this from a neighbour's WiFi setup.  I have been using WiFi with receivers for many years and used to have nearby neighbours' secured networks showing up in the available list.  Now I only have sheep and they're not into WiFi networking, yet!

[viking9]

I haven't changed my setup in any way. As you can see from the screenshot, 280+ nm range.

I've never seen anyone claim 280+ nm range before. Are you recalibrating by clicking on your home location before moving the cursor onto the furthest aircraft?

[Bethsalem]

Yes. Also the antenna is on the top of an apartment block, which is on the side of a hill, so the antenna is probably 800ft above sea-level, and out to that area of the sea where I picked up the aircraft at 283nm there are no obstacles at all.

This is an unusually far away contact. I would see 240 - 250nm on a daily basis, but 280nm plus is pretty rare.

However, from Friday afternoon to Sunday evening I saw nothing beyond 130nm, and 110nm was more the norm.

All day today everything is back to normal, so with any luck the problem's gone.

[viking9]

Sorry, I thought you were suggesting you got that range on a daily basis. I too get 240/250nm max range on a daily basis and I'm only 300' above sea level.

I do sometimes get up to 275nm when tropospheric ducting is strong, which I assume is what is happening in your case.

[Bethsalem]

Tropospheric ducting can be significant over the Balearic Sea occasionally, and as you say, explains yesterdays 284nm.  http://www.dxinfocentre.com/tropo_eur.html

The temporarily decreased range problem hasn't so far returned. I think it'll remain a mystery as to why, I'm just glad it's gone and I hope it doesn't come back.

[birdie]

WiFi doesn't interfere with ADSB.

My WiFi setup is only 1.5 metres from my ADSB antenna and I have about 250 - 275 nm range.

Most likely, its moisture in your Antenna / Coaxial Cable.