locked FT8 Low Signal Reports #FT8


John VK6FD
 

I consistently get low signal reports for FT8 contacts, typically 15db less than what I send as a received signal. I am using Windows 10 with WSJT-X v2.5.3 with a USB connection to an iCom 7610 transceiver running 100w. Is there a setting that I am missing somewhere to fix this problem. I can see on an external SWR meter that I am sending 100w. I would think that is more than enough to get a decent signal report. Any suggestions on what the problem might be?


Alan G4ZFQ
 

I am sending 100w. I would think that is more than enough to get a decent signal report. Any suggestions on what the problem might be?
John,

Two things come to mind.
1) You have a good RX setup.
2) Your TX antenna system is not very good. Low SWR can mean high losses.

Or, maybe a combination of both?

73 Alan G4ZFQ


Pietro Molina
 

Or you have a very quit location! Remember this is a S/N report,not a power level report.
If the average recipient has a lot more noise than you, you will get a worse report on average.

Pietro I2OIM


Roger
 

On 04/01/2022 10:32, John wrote:
I consistently get low signal reports for FT8 contacts, typically 15db less than what I send as a received signal. I am using Windows 10 with WSJT-X v2.5.3 with a USB connection to an iCom 7610 transceiver running 100w. Is there a setting that I am missing somewhere to fix this problem. I can see on an external SWR meter that I am sending 100w. I would think that is more than enough to get a decent signal report. Any suggestions on what the problem might be?
Good morning John

Can you confirm if this is an FT8 only problem or other WSJTX modes as well?

73
Roger
G4HZA
moderator


neil_zampella <neilz@...>
 

As others have said, the signal reports are based on the signal-to-noise
ratio of the receiving station.     Has nothing to do with your Tx
power, or the noise level at your location. You may have a very quiet
location, thus capable of sending plus reports (+5), however, others may
not.    Others may use full legal power, and the reports they get are in
the low minus numbers, it all depends on local noise, propagation, local
antennas, etc.

Neil, KN3ILZ

On 1/4/2022 4:32 AM, John wrote:
I consistently get low signal reports for FT8 contacts, typically 15db less than what I send as a received signal. I am using Windows 10 with WSJT-X v2.5.3 with a USB connection to an iCom 7610 transceiver running 100w. Is there a setting that I am missing somewhere to fix this problem. I can see on an external SWR meter that I am sending 100w. I would think that is more than enough to get a decent signal report. Any suggestions on what the problem might be?




Tony Collett
 

Most likely your noise level is much lower than the station(s) you are working but I have also noticed a difference in the reports I give out depending which radio/AGC setting I am using.

Normally I use a K3 with a very high AGC threshold setting and find that is capable of giving out very high reports, reducing that threshold to default settings also reduce the maximum report that I give out. Noticeable on FT8 but even more so on MSK144.

By its side an IC9700 running with AGC off gives similar reports but can't cope with strong signals so have to run with fast AGC and the reports it then produces are way lower on the same signals. I would guess same would happen on HF with IC7300 etc??

73
Tony G4NBS


John VK6FD
 

No, I have just as much noise here as most others living in suburbia. Typically S7 to S9+ on HF.


John VK6FD
 

No, I can't confirm that, I only use FT8.


Michael Black
 

What's your antenna setup?
Mike W9MDB

On Tuesday, January 4, 2022, 07:13:50 AM CST, John <jcg2412@...> wrote:

No, I have just as much noise here as most others living in suburbia. Typically S7 to S9+ on HF.


John VK6FD
 

On Tue, Jan 4, 2022 at 09:15 PM, Michael Black wrote:


What's your antenna setup?
Mike W9MDB
Simple dipole, 10m above ground.


Arnold Lausevich <nk9o@...>
 

Suggest running at 50% duty cycle on the IC7610 for data.

On Tuesday, January 4, 2022, 04:32:27 AM CST, John <jcg2412@...> wrote:

I consistently get low signal reports for FT8 contacts, typically 15db less than what I send as a received signal. I am using Windows 10 with WSJT-X v2.5.3 with a USB connection to an iCom 7610 transceiver running 100w. Is there a setting that I am missing somewhere to fix this problem. I can see on an external SWR meter that I am sending 100w. I would think that is more than enough to get a decent signal report. Any suggestions on what the problem might be?


John VK6FD
 

On Tue, Jan 4, 2022 at 10:15 PM, Arnold Lausevich wrote:


Suggest running at 50% duty cycle on the IC7610 for data.
Not sure what you mean Arnold. Where do I set that up?


Chris VE3NRT
 

Do you mean 50% power? FT8 is by nature < 50% duty cycle.

One question I have on this topic is whether the RF power output has actually been measured or is the stated 100W going by the setting on the radio?

73,
Chris


Pietro Molina
 

If this is the case, then you probably have signal distortion in audio output. Try lowering the AGC, if any, and/or the output audio level. Be sure your audio chain does not introduce any distortion.

Pietro I2OIM


John VK6FD
 

On Tue, Jan 4, 2022 at 07:19 PM, neil_zampella wrote:


As others have said, the signal reports are based on the signal-to-noise
ratio of the receiving station.     Has nothing to do with your Tx
power, or the noise level at your location. You may have a very quiet
location, thus capable of sending plus reports (+5), however, others may
not.    Others may use full legal power, and the reports they get are in
the low minus numbers, it all depends on local noise, propagation, local
antennas, etc.

Neil, KN3ILZ
Neil, I have just as much noise as everyone else, S7 - S9+. That can't be the problem. I just feel that it is more likely to be a threshold setting somewhere. We are talking about 15dB difference, that is an awful lot of difference in signal to noise.


Arnold Lausevich <nk9o@...>
 

its key down on the carrier how is that 50%?

On Tuesday, January 4, 2022, 08:25:36 AM CST, Chris VE3NRT <dx@...> wrote:

Do you mean 50% power? FT8 is by nature < 50% duty cycle.

One question I have on this topic is whether the RF power output has actually been measured or is the stated 100W going by the setting on the radio?

73,
Chris


Chris VE3NRT
 

"The cycle of operation of a machine or other device which operates intermittently rather than continuously.
the time occupied by the cycle of operation of a machine or other device, especially as a percentage of available time."

FT8 is key down on the carrier for 13 seconds out of 30, so about 43% duty cycle. If you just measure it over the period in which it is transmitting it is 100%, of course, but there's no way to set it to 50% during that that period. You can set the power to 50%, and many transmitters are limited to 40% or 50%, but specifying "50% duty cycle" for FT8 is meaningless if you're only referring to the period in which the transmitter is actually transmitting.

73,
Chris


John
 

What sort of AGC are you using? Could a strong signal lower the gain so much that the weaker signal no longer decodes?

You could try turning off the AGC and setting the RF gain for about 30 dB when no signals are present. You may have to reduce the RF gain further if very strong signals are present.

John, W0GN

On 2022-01-04 8:34 am, John wrote:
On Tue, Jan 4, 2022 at 07:19 PM, neil_zampella wrote:

As others have said, the signal reports are based on the signal-to-noise
ratio of the receiving station.     Has nothing to do with your Tx
power, or the noise level at your location. You may have a very quiet
location, thus capable of sending plus reports (+5), however, others may
not.    Others may use full legal power, and the reports they get are in
the low minus numbers, it all depends on local noise, propagation, local
antennas, etc.
Neil, KN3ILZ
Neil, I have just as much noise as everyone else, S7 - S9+. That can't
be the problem. I just feel that it is more likely to be a threshold
setting somewhere. We are talking about 15dB difference, that is an
awful lot of difference in signal to noise.


neil_zampella <neilz@...>
 

Not at all ..... I've seen variations of that kind coming from the same
state.    Take a look at PSK Reporter and see what you are being
received at, you'll see.

Neil, KN3ILZ

On 1/4/2022 8:34 AM, John wrote:
On Tue, Jan 4, 2022 at 07:19 PM, neil_zampella wrote:

As others have said, the signal reports are based on the signal-to-noise
ratio of the receiving station.     Has nothing to do with your Tx
power, or the noise level at your location. You may have a very quiet
location, thus capable of sending plus reports (+5), however, others may
not.    Others may use full legal power, and the reports they get are in
the low minus numbers, it all depends on local noise, propagation, local
antennas, etc.

Neil, KN3ILZ
Neil, I have just as much noise as everyone else, S7 - S9+. That can't be the problem. I just feel that it is more likely to be a threshold setting somewhere. We are talking about 15dB difference, that is an awful lot of difference in signal to noise.




dennis v
 

???

On Tue, Jan 4, 2022 at 7:15 AM John <jcg2412@...> wrote:

No, I can't confirm that, I only use FT8.