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Lowest WSPR Signal

Posted: Mon Mar 21, 2016 9:46 pm
by VK2XTC
What is the limit for a WSPR decode ?

This is the lowest signal strength I have seen.

Tonight on 30M. (-30dB) Amazing !!

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1032 -30 -0.5 10.140207 0 JQ2WDO PM95 37

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Brian

VK2XTC

Re: Lowest WSPR Signal

Posted: Tue Mar 22, 2016 5:01 am
by VK3KCX
You can sort the entire database by SNR, plenty of -33 decodes.

Database

Specify query parameters

50 spots:
Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az
2016-03-20 19:04 GM1MSS 7.040137 -33 1 IO85 0.2 DL0HT JO43jb 813 104
2016-03-20 19:04 K4EH 14.097108 -33 0 EM73qk 5 KE7BJB FN42iu 1564 44
2016-03-20 19:04 G3YFG 7.040093 -33 0 IO83tu 0.2 PE2HD JO21rl 590 113
2016-03-20 19:10 G7EOB 10.140178 -33 1 IO91tr 1 EA8BVP IL28fd 2910 212
2016-03-20 19:16 DF8AV 14.097154 -33 0 JO51am 0.2 EB5DQ IM99tp 1546 215
2016-03-20 19:16 W3SMK 14.097143 -33 0 CM87xq 5 AB8EF EN63vb 3069 67
2016-03-20 19:18 LZ0DLS 10.140286 -33 0 KN12 0.2 EA8BVP IL28fd 3798 258
2016-03-20 19:18 XP1FNV 14.097188 -33 0 LB12 5 N5CEY EL16gq 14007 225

Re: Lowest WSPR Signal

Posted: Tue Mar 22, 2016 12:40 pm
by VK2EFM
I suspect the SNR is averaged over the whole transmission period.
So if the received signal is strong enough for long enough to be decoded and then reduces in strength for the rest of the transmission, you can get SNRs below -28dB.
Allan

Re: Lowest WSPR Signal

Posted: Wed Dec 19, 2018 1:17 pm
by VK7HH
WSJT-X v2.0 has an extra 1dB of sensitivity now on WSPR.

I've seen a handful of -33 decodes.

Re: Lowest WSPR Signal

Posted: Wed Dec 19, 2018 5:51 pm
by ZL2IT
I have at least one at -34 in last week and have had them previously on WSjt-x V1.9 (630 m)

2018-12-18 12:30 K9FD 0.475617 -34 0 BL11je 1 ZL2IT RF80km 7264 202
Cheers
E
ZL2IT

Re: Lowest WSPR Signal

Posted: Wed Dec 19, 2018 9:30 pm
by VK3ZAZ
Best I have seen on 6m is -31
Seen VK7HH at -29 on two.
if you check my 2m wspr logs using just a simple 5 el yagi on a hockey stick at 15 feet I monitor vk5gf and others daily from turn on it tells me what the band is doing.
as for comparisons each band is different.
I dont think you can make an emphatic statement to emcompass all bands too many variables.
I use wspr to test as to my stations capability.
you have no doubt seen my results including zl2 on 2m wspr
but as I say there is oils and oils mate
or oils aint oils.
station noise level line noise, etc etc
wspr is not a qso its an alert.
and I wonder when some guys who wspr will ever make a 6m qso?
maybe thats not their aim?

:om:

Re: Lowest WSPR Signal

Posted: Thu Dec 20, 2018 7:17 am
by VK7HH
VK3ZAZ wrote: wspr is not a qso its an alert.
and I wonder when some guys who wspr will ever make a 6m qso?
:om:
G’Day Steve,
Correct. I use WSPR on 6m to indicate when the band is open on 6 metres, and potentially 2 metres if it shorterns on 6. Also yesterday when signals got into the +dB range I called CQ on 50.110 (should be 50.200 but that’s a different story) and spoke to several VK2’s and a 4. WSPR is an ideal mode to determine when the band is opening, or indeed opened. Or good if you’re at work all day usually as I am.