QO100 beacon signal level

Also known as ADALM-PLUTO.
M0TGC
Posts: 96
Joined: Wed Aug 19, 2020 7:49 pm
Location: East Devon

QO100 beacon signal level

#1

Unread post by M0TGC »

Can anyone tell me what signal level to expect from the PSK beacon on QO100 via Pluto and SDRC?

At the moment mine seems quite low at -112dBm or S2 but listening via the batc Goonhilly sdr it is about s9+10db. I am using a 90cm dish and 0.1 lnb.

Thanks
David M0TGC

G4ZFQ
Posts: 58
Joined: Wed Aug 19, 2020 10:26 am
Location: Cowes Isle of Wight

Re: QO100 beacon signal level

#2

Unread post by G4ZFQ »

David,
Signal strength readings mean nothing.
Compare the Signal to Noise Ratio, then decide if anything is wrong.
73 Alan G4ZFQ

M0TGC
Posts: 96
Joined: Wed Aug 19, 2020 7:49 pm
Location: East Devon

Re: QO100 beacon signal level

#3

Unread post by M0TGC »

Alan

Fair comment. The Goonhilly snr is about 18dB and my Pluto is about 10dB.

What do others get?
David M0TGC

4X1RV
Posts: 22
Joined: Sat Aug 08, 2020 6:39 am

Re: QO100 beacon signal level

#4

Unread post by 4X1RV »

Hi
1 meter dish, lnb,Limesdr
abt 30-35 db 'eyeball' on the signal history display
SNR by Simon's compute: 30-40 db


de Joe 4X1RV.

G4ZFQ
Posts: 58
Joined: Wed Aug 19, 2020 10:26 am
Location: Cowes Isle of Wight

Re: QO100 beacon signal level

#5

Unread post by G4ZFQ »

I should have thought, even that is not so simple.
You have to know what bandwidth the SNR is being measured in to be able to compare.
An interesting point. I've no figure for when I tried, must get it going again.
The SNR however you measure it should be set by the time the signal leaves the LNB. Dish size/aim/efficiency/LNB noise. Anything following it must not increase the noise level. I'd expect every receiver to be much the same on any one system.
As David says "What do others get?" Maybe better answered in a dedicated QO100 group?
73 Alan

M0TGC
Posts: 96
Joined: Wed Aug 19, 2020 7:49 pm
Location: East Devon

Re: QO100 beacon signal level

#6

Unread post by M0TGC »

I re-aligned the dish and lnb and tried other lnb's and now have a snr of 20-23dB. This is better than it was but I can't get any where near the 30dB others have mentioned.

Thanks to all.
David M0TGC

User avatar
Simon G4ELI
Posts: 2134
Joined: Thu Aug 06, 2020 7:27 am
Location: Mawnan Smith
Contact:

Re: QO100 beacon signal level

#7

Unread post by Simon G4ELI »

M0TGC wrote: Sat Jan 23, 2021 1:02 pm I re-aligned the dish and lnb and tried other lnb's and now have a snr of 20-23dB. This is better than it was but I can't get any where near the 30dB others have mentioned.

Thanks to all.
I would like to see screenshots of SNRs of 30dB on the beacon - despite a 1.4m dish I can't achieve this.
Simon Brown :shock:
www.sdr-radio.com

Do not send me direct e-mail, thank-you!

4X1RV
Posts: 22
Joined: Sat Aug 08, 2020 6:39 am

Re: QO100 beacon signal level

#8

Unread post by 4X1RV »

Hi Simon.

Attached a screenshot shoing S/N of 38 (get 32-40 depending of the data on the beacon)
Screenshot-2021-01-23-171716.jpeg
.

User avatar
DK8KW
Posts: 42
Joined: Sun Aug 09, 2020 1:21 pm

Re: QO100 beacon signal level

#9

Unread post by DK8KW »

Hi Simon,

1.8m offset dish with LNB "looking" through the feed helical antenna, getting an SNR of around 39dB for the CW beacon and around 28dB for the data beacon @ 1.2MHz bandwidth


Vy 73

Geri, DK8KW
Screenshot-2021-01-23-164738.jpeg
Screenshot-2021-01-23-163244.jpeg
Last edited by DK8KW on Sat Jan 23, 2021 3:49 pm, edited 3 times in total.

4X1RV
Posts: 22
Joined: Sat Aug 08, 2020 6:39 am

Re: QO100 beacon signal level

#10

Unread post by 4X1RV »

Hi
To add: Just noise is S6 S5 on signal history

So levels are similar to the display of the Goonhilly site...
Screenshot-2021-01-23-173339.jpeg

Post Reply