I heard APRS on the 144 MHz band. But I did not hear any PSK31 on the downlink. I did not try to transmit.
1. What's the secret to receiving PSK31 on FM? I never tried that before. 2. Transmit says 28.120 kHz +2 kHz SSB uplink. Can someone please translate that into USB DIAL and software tone? If it is 28120 USB and 2 kHz tone, most SSB rigs attenuate the audio at that level.
Mark Lunday, WD4ELG Greensboro, NC FM06be wd4elg@arrl.net http://wd4elg.blogspot.com
Mark,
The FM transmitter does not turn on unless the SSB receiver hears a PSK-31 signal.
Once you start transmitting on 28.120 USB, never stop for the duration of the pass. Keep the transmitter turned on. Just change the Macro Text as needed for the contact. If you see the FM transmitter turning off and on, increase your power. I usually need 40-80 watts. As with anything on HF, band conditions are important.
The reference to 28.120 +2kHz means set the radio dial on 28.120 USB and transmit at 2KHz on the waterfall. (This is +/- for other station signals as you would expect.)
If your signal is too high on the waterfall to copy well, just turn the VFO to bring it down where you can copy yourself. For the decoder, I suggest using anything that displays two or more signals. For the transmitter, use DopplerPSK_ V:0.2.
Hope this helped.
KO6TZ Bob
-------------------------------- I heard APRS on the 144 MHz band. But I did not hear any PSK31 on the downlink. I did not try to transmit.
1. What's the secret to receiving PSK31 on FM? I never tried that before. 2. Transmit says 28.120 kHz +2 kHz SSB uplink. Can someone please translate that into USB DIAL and software tone? If it is 28120 USB and 2 kHz tone, most SSB rigs attenuate the audio at that level.
Mark Lunday, WD4ELG Greensboro, NC FM06be wd4elg at arrl.net http://wd4elg.blogspot.com
Mark,
I might add that most of the psk31 decoderS seem to work. I have been using DigiPan, Fldigi and my lash up of some of the WinPSK technology. If you use DopplerPSK you don't have to worry about a full duplex psk program - one app is your receiver and one app is your transmitter.
Most days I find I am the only one on the bird while it is visible here in VA. But I have been able to make 4 unique contacts so far. KC4LE and I have several repeat contacts in the past week.
What Bob says about transmitting continuously is so true - your transmitter has to be able to stand the 10 minutes or so. But it is bothersome to see a signal, click on it to start decode (which is not instantaneous) and the station stops transmitting.
You can tell the stations that are using doppler control on the uplink as their psk31 traces are more or less a vertical line as apposed to the traces that move rapidly down in frequency (high tone to low tone). There is a lot of 10m ground activity as well as some robot that tells me I am being received at some ground station, hi
The 70cm signal seems to be hard to decode with a lot of errors from noise or whatever so you want to put a lot of redundancy in your messages and keep the message short but repeat them often so other stations might decode the pieces eventually.
I am finding a protocol similar to JT65 etc where you call cq, you acknowledge a station answering your cq with your grid, they acknowledge your grid and send their grid, when you decode their grid you can send 73s. So the 5 messages like DppplerPSK has works very well and that is all the time there is on a pass.
Give it a try. Remember the downlink doppler on 70cm is going to shift the signal up by 10 KHz at AOS, to zero at TCA and down 10 KHz by the end. Your can program 5 memories in your radio, hand tune the downlink or use one of the doppler control programs for the downlink.
I have found that the idea of shifting the audio tone instead of the RF carrier (that is keep the USB transmitter right on 28.120) works much better for decoding the signal.
Probably too much info at the moment, but come back to it after getting your feet wet.
73 and see you on NO-84 psk31
Jerry, W6IHG
On 12/7/2015 3:09 AM, KO6TZ Bob wrote:
Mark,
The FM transmitter does not turn on unless the SSB receiver hears a PSK-31 signal.
Once you start transmitting on 28.120 USB, never stop for the duration of the pass. Keep the transmitter turned on. Just change the Macro Text as needed for the contact. If you see the FM transmitter turning off and on, increase your power. I usually need 40-80 watts. As with anything on HF, band conditions are important.
The reference to 28.120 +2kHz means set the radio dial on 28.120 USB and transmit at 2KHz on the waterfall. (This is +/- for other station signals as you would expect.)
If your signal is too high on the waterfall to copy well, just turn the VFO to bring it down where you can copy yourself. For the decoder, I suggest using anything that displays two or more signals. For the transmitter, use DopplerPSK_ V:0.2.
Hope this helped.
KO6TZ Bob
I heard APRS on the 144 MHz band. But I did not hear any PSK31 on the downlink. I did not try to transmit.
- What's the secret to receiving PSK31 on FM? I never tried that
before. 2. Transmit says 28.120 kHz +2 kHz SSB uplink. Can someone please translate that into USB DIAL and software tone? If it is 28120 USB and 2 kHz tone, most SSB rigs attenuate the audio at that level.
Mark Lunday, WD4ELG Greensboro, NC FM06be wd4elg at arrl.net http://wd4elg.blogspot.com
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NO-84 listeners want-a-bees,
Mark asked a good question for beginners (aren't we are all beginners with a new mode?):
On 12/6/2015 11:43 PM, Mark Lunday wrote:
- What's the secret to receiving PSK31 on FM? I never tried that
before.
Given your 70cm FM radio, you will want to get an audio output that you can connect to a sound card in your computer. You are looking for the type of low level audio output that maybe you would feed to a rtty modem, etc while is a SSB mode. Some radios might have special audio connections for 1200 or 9600 baud FM packet - this is not what you want. The audio connection you are looking for might be called AFSK or maybe DATA - one that gives you the full 3KHz of bandwidth. Worse case, you can use high level Speaker audio through an attenuator so as to not overdrive your sound card.
Once you get the audio connected to your sound card, then probably the easiest PSK31 program to start listening with is DigiPan. I find the waterfall view very helpful to find signals to work. There is a good picture of what to expect on the apps.org/psat.html web page. The signals you will be able to decode are those vertical lines. In the web picture you see the signal of DK3WN at about 1000 Hz. And you see the beacon at 314 Hz. The slanted signal is a signal that is not being doppler corrected - either ground based or trying to call thru NO-84. These are much harder to decode.
So with your radio in FM, keep it tuned to the NO-84 downlink frequency of nominally 435.350 MHz, remembering that at the beginning of a pass the UHF signal is going to appear closer to 435.360 MHz, move through 435.350 at closest approach and leave you around 435.340 MHz all due to the doppler shift. If the radio has a Narrow FM mode, that might help to recover a stronger audio signal.
Once you can comfortable see some signals and decode them, you can then move on to the transmit side. Probably DopplerPSK, by K0SM, is the easiest way to start. Here you are using a USB HF signal which may be more familiar to most hams as the standard setup for working PSK31 on the HF bands.
Give it a try. NO-84 PSK31 is a challenge but doable.
73, Jerry, W6IHG
participants (3)
-
Jerry Pixton -
KO6TZ Bob -
Mark Lunday