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eHam Forums => Digital => Topic started by: KC9RCG on November 20, 2011, 09:38:43 PM



Title: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: KC9RCG on November 20, 2011, 09:38:43 PM
First off, I am shocked at how easy it was for me to receive psk31. I know transmit is a different baby.

I am using digipan for now. I have typed a few lines in the program and pressed transmit and get the audible signal. If I keyed the mike, would it transmit that information?

Again, I know this is primitive but wonder if it would work?

thanks so much


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: VA7CPC on November 20, 2011, 10:41:37 PM
Yes, it would work.  Try Googling "PSK31 air interface" -- you will find some posts I wrote.  I started using PSK31 like that.

HOWEVER:

It is not a _good_ way to operate.  The computer's loudspeakers, and the rig's mic, introduce harmonic distortion (and maybe IM distortion as well).  Controlling levels is tricky, since neither the loudspeaker nor the mic has a flat frequency response.  And you'll be sending shack background noise, as well as PSK31, when you transmit.

Once you've convinced yourself that PSK31 really works, it's time to buy (or build) a soundcard interface or a SignaLink

Take a look at recent posts -- the subject just came up a few days ago.
 
             Charles


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: W8BRI on November 22, 2011, 06:48:28 PM
as stated earlier it will work. If you are going to use the 857d for psk, rtty etc. you don't need a interface, just a cable from the soundcard in/out to the data port on the 857 and use the rig in digimode and you are good to go. these cables are all over ebay and I think west mountain radio sells them if you don't want to make your own.

Brian W8BRI


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: AA4PB on November 23, 2011, 06:12:06 AM
"And you'll be sending shack background noise, as well as PSK31, when you transmit."

Which is actually illegal - to transmit voice shack background noises using SSB in the CW bands.



Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: KC9RCG on November 26, 2011, 06:09:56 PM
Where is that found in the FCC regs? I have looked incessantly and I cannot find where it states that one is not supposed to have background noises in the shack when transmitting.


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: KG6AF on November 26, 2011, 09:22:50 PM
Where is that found in the FCC regs? I have looked incessantly and I cannot find where it states that one is not supposed to have background noises in the shack when transmitting.

If you're transmitting PSK31 and picking up background shack noises with an air interface, you're transmitting SSB in a portion of the band where it's not permitted (as AA4PB already pointed out).  Not to mention that you're potentially interfering with other nearby PSK31 signals.

The air interface seems to come up every few weeks in this forum.  Bottom line: use it for receiving, if you want, but it's bad practice to use it for transmitting.


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: AA4PB on November 27, 2011, 10:51:53 AM
Where is that found in the FCC regs? I have looked incessantly and I cannot find where it states that one is not supposed to have background noises in the shack when transmitting.

You won't find anything about transmitting background noises. However, background noises would be considered SSB "phone" which is not permitted in the CW bands. In addition, there will likely be room acoustics (reflections off the walls) that will cause the PSK31 signal to be transmitted two or more times with a small delay.

Using an "air interface" for tranmitting is not good amateur practice - which is also specified in the regulations.


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: NA4IT on November 29, 2011, 05:43:59 AM
So I guess the fact most rigs are in USB mode when TXing on PSK31 on 14.070 isn't SSB?

You guys are nit picking a guy who is exploring the fun of ham radio. Sure, your signal would be better not having the noise in the background, but as long as the shack is quiet, go for it.

As one poster mention, it is pretty simple to set up an interface for the 857 using the internal digital VOX. Also, the Signalink USB is one of the best interfaces to use for digital modes. Runs around $120 most dealer, and includes everything you need.

de NA4IT


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: KG6AF on November 29, 2011, 09:12:35 AM
So I guess the fact most rigs are in USB mode when TXing on PSK31 on 14.070 isn't SSB?

Putting a clean PSK31 audio signal through a properly-adjusted SSB rig produces a signal that's all-but indistinguishable from "pure" PSK31, in either the time or frequency domain, just as putting a CW audio signal through such a rig produces a signal that's indistinguishable from a CW signal produced by keying a carrier on and off.  (If the carrier weren't properly nulled out, you'd see a difference, but any halfway decent rig will be fine on that score.)  So if you want to call it SSB, go ahead, but it's not the 2.5kHz-wide SSB that you get when transmitting voice.  If you use the air interface, it potentially is 2.5kHz wide.

You guys are nit picking a guy who is exploring the fun of ham radio. Sure, your signal would be better not having the noise in the background, but as long as the shack is quiet, go for it.

It's not a nit-pick; the air interface is a bad way to transmit PSK31, for the reasons stated here and in a half-dozen other threads.  Even hooking up a straight-through audio cable between the sound card output and the rig's transmit audio input is better, and costs next to nothing.  A transformer-isolated interface costs just a bit more.  Why the resistance to avoiding something that's patently bad, when doing it the right way is so inexpensive?


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: VA7CPC on November 29, 2011, 06:46:31 PM
Quote
  Why the resistance to avoiding something that's patently bad, when doing it the right way is so inexpensive?

I can tell you my own experience, circa 2003, shortly after I was licensed . . .

I had read about PSK31, but didn't know anybody who was using it.  I could set up an "air interface" with _no_ investment, and _no_ commitment at all.  I didn't even need a soldering iron.  So as a "proof of concept" for PSK31, it was easy, and instant.

. . . What do you know -- the mode worked, and worked well!

I ordered a soundcard within a week of that first test, and haven't looked back. 

"Doing it the right way" is better.  But there has to be _motivation_ to do it at all.

              Charles


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: KG6AF on November 30, 2011, 07:04:27 AM
["Doing it the right way" is better.  But there has to be _motivation_ to do it at all.

Doing it the right way is legal; doing it the wrong way is sketchy at best, illegal at worst. 

And doing it the right way  is easy.  How much motivation does a person need to wire up a cable?


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: VE3FMC on November 30, 2011, 08:21:34 AM
["Doing it the right way" is better.  But there has to be _motivation_ to do it at all.

Doing it the right way is legal; doing it the wrong way is sketchy at best, illegal at worst. 

And doing it the right way  is easy.  How much motivation does a person need to wire up a cable?

I agree, do it right the first time or don't do it at all.

It is one thing to receive digital signals by simply hooking an audio line from the rig to sound card in the computer.

It is another thing if you key a mic and hold it to the computer speakers to transmit that digital signal.

Buy or make an interface so you have a good clean digital signal.


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: AA4PB on November 30, 2011, 08:34:37 AM
I heard some DX stations operating SSB down in our CW band. Do you suppose it would be okay if I tuned to that freq and gave them a call on SSB? After all, I'd just be testing the waters to see if I had any interest in working DX. That's so much easier than learning to set my transceiver up to operate split and I don't want to invest the effort until I find out if I have any real interest in DX.  Same type of reasoning.

And no... just because the transceiver is set to USB mode does not necessarily mean that the output of your transmitter is SSB.


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: VE3FMC on December 03, 2011, 11:40:08 AM
I heard some DX stations operating SSB down in our CW band. Do you suppose it would be okay if I tuned to that freq and gave them a call on SSB? After all, I'd just be testing the waters to see if I had any interest in working DX. That's so much easier than learning to set my transceiver up to operate split and I don't want to invest the effort until I find out if I have any real interest in DX.  Same type of reasoning.

And no... just because the transceiver is set to USB mode does not necessarily mean that the output of your transmitter is SSB.


When I first read this I thought "You can't be serious?"  :o Then I read it again and had a good laugh! ;)


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: KC3JV on December 08, 2011, 11:00:44 PM
I tried PSK31 using an "Earbud" taped to the desk microphone to try out PSK31.   It worked and I had a PSK31 QSO then switched to a real interface.   It works and there is no noise in my shack.    I found it a good way to start.

Mark KC3JV


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: K7RBW on December 09, 2011, 06:21:29 AM
And no... just because the transceiver is set to USB mode does not necessarily mean that the output of your transmitter is SSB.

Good point. I use my radio in SSB to send CW using HRD and my Signalink USB adapter. Works great and no one is the wiser :) (OK, except maybe the CW pros who can tell I'm sending by computer and not using a key)


Title: RE: I know this may sound primitive but here goes....psk31 with ft-857d.....
Post by: AD6KA on December 18, 2011, 08:05:49 PM
Quote
Doing it the right way is legal; doing it the wrong way is sketchy at best, illegal at worst.
Three words come to mind:
Bad Amateur Practice