Date
1 - 11 of 11
Locked Curved Line in Waterfall
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Brian Wilkins <bwilkins@...>
I was listening on 17m today. What causes this curved line in the waterfall? Link to picture Brian Wilkins KO4AQF |
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K8BL BOB LIDDY <k8bl@...>
Brian, That was from a Space-X launch today. Actually, it's a drifting carrier detected on the WSJTX Waterfall. You'll see that often on various Bands. Also, you can often see a straight vertical line from a solid carrier or an interrupted one from CW. 73, Bob K8BL
On Sunday, May 10, 2020, 12:17:53 PM EDT, Brian Wilkins <bwilkins@...> wrote:
I was listening on 17m today. What causes this curved line in the waterfall? Link to picture Brian Wilkins KO4AQF |
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Birdie drifting. On May 10, 2020, at 12:17, Brian Wilkins <bwilkins@...> wrote:
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Brian Wilkins <bwilkins@...>
Bob You had me at first. I live on the Space Coast and thought I missed one! Thanks for the info On Sun, May 10, 2020 at 12:29 PM K8BL BOB LIDDY <k8bl@...> wrote:
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Brian Wilkins KO4AQF |
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Dave (NK7Z)
Hi,
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It looks like a carrier started at the bottom of your screen, (or you came upon it at that point), at around 1230 Hz, higher than your dial frequency, and over the period of one minute moved upwards in frequency. This assumes the graticule marks are 100 Hz apart, and 15 seconds apart on the vertical. This could be pretty much anything, heater, thermostat, controller for stoves, etc... All you really know is some signal moved up in frequency across a one minute period. 73, and thanks, Dave (NK7Z) https://www.nk7z.net ARRL Volunteer Examiner ARRL Technical Specialist ARRL Asst. Director, NW Division, Technical Resources On 5/10/20 9:17 AM, Brian Wilkins wrote:
I was listening on 17m today. What causes this curved line in the waterfall? |
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Samuel W7STF
Has anyone else noticed some slight variation in received messages in WSJT-X well after warmup? I'm noting a little tilting, and I wonder if the radio is experiencing a little thermal drift. Is there a PC program to measure drift using WWV as a calibrated source?Thx. Sam KJ4VPI
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On 11/05/2020 12:58, Samuel KJ4VPI wrote:
Has anyone else noticed some slight variation in received messages in WSJT-X well after warmup? I'm noting a little tilting, and I wonder if the radio is experiencing a little thermal drift. Is there a PC program to measure drift using WWV as a calibrated source?Thx. Sam KJ4VPIHi Sam, you can use WSJT-X Frequency Calibration mode to measure your rig's frequency accuracy over time. 73 Bill G4WJS. |
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Gary - AG0N
On May 11, 2020, at 05:58, Samuel KJ4VPI <sernstfortin@...> wrote:There’ll be those who say to use the Freq Cal mode, but you don’t even need that if you’re just looking for large drift. Take the VFO and shove it to your nearest friendly neighborhood WWV/CHU frequency, tune off center by 1000 or 1500 (whatever you want), and just leave it. If the radio is drifting, you should be able to see it right away. If it is a long term deal, park it for an hour, or hours, and see what it does over time. If you use the Freq Cal mode, it will read out the tone frequency in decimals of cycles so you can see precisely what it is doing. Gary - AG0N |
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Gary - AG0N
On May 11, 2020, at 09:27, Gary - AG0N <mcduffie@...> wrote:On May 11, 2020, at 05:58, Samuel KJ4VPI <sernstfortin@...> wrote:There’ll be those who say to use the Freq Cal mode, but you don’t even need that if you’re just looking for large drift. Take the VFO and shove it to your nearest friendly neighborhood WWV/CHU frequency, tune off center by 1000 or 1500 (whatever you want), and just leave it. If the radio is drifting, you should be able to see it right away. If it is a long term deal, park it for an hour, or hours, and see what it does over time. If you use the Freq Cal mode, it will read out the tone frequency in decimals of cycles so you can see precisely what it is doing. By the way, drifting should not change anything WSJT-X presents to you in the form of a message. The only thing you should see WSJT-X do is show you a different DF each receive cycle for a given signal that is not really moving. Gary |
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Dave (NK7Z)
Pretty much, if all the traces are tilted in the same direction, it is probably your radio drifting. If you have a few straight traces, and a pile of tilted traces, the radio is probably not drifting, but still a bit suspect...
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Just watch things for a bit, if in the whole you are seeing all traces tilt, the radio is drifting. I was seeing that now and then, I changed to a TXCO, and have not seen it again. 73, and thanks, Dave (NK7Z) https://www.nk7z.net ARRL Volunteer Examiner ARRL Technical Specialist ARRL Asst. Director, NW Division, Technical Resources On 5/11/20 8:27 AM, Gary - AG0N wrote:
On May 11, 2020, at 05:58, Samuel KJ4VPI <sernstfortin@...> wrote:There’ll be those who say to use the Freq Cal mode, but you don’t even need that if you’re just looking for large drift. Take the VFO and shove it to your nearest friendly neighborhood WWV/CHU frequency, tune off center by 1000 or 1500 (whatever you want), and just leave it. If the radio is drifting, you should be able to see it right away. If it is a long term deal, park it for an hour, or hours, and see what it does over time. If you use the Freq Cal mode, it will read out the tone frequency in decimals of cycles so you can see precisely what it is doing. |
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Dave_G0WBX
Re:-
Is there a PC program to measure drift using WWV as a calibrated source? Though WSJTx has some functionality, I've not seen anything in it to calibrate for any sound card sample rate discrepancy. (Unless I've just not found it yet.) However. Fldigi has a frequency measuring and recording function. It also does allow you to correct for the sound card's "Actual" sample rate against any of the usual broadcast Standard Frequency and Time stations. 73. Dave G0WBX. -- Created on and sent from a Unix like PC running and using free and open source software: |
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