Re: [digitalradio] VFO Dial Frequency, Audio Frequency, Centre Frequency
Thanks for all the info Bob. But I'll still call the dial frequency for RTTY. Been doing it that was for over 30 years. And still using the same equipment - model 28ASR KSR with a pair of Hal ST-6. Kenwood 520 ( no S or anything) At 08:11 PM 5/17/2007, you wrote: Hello John, Technology is changing this concept. I was recently re-educated on this topic after returning from a ham radio hiatus. Like you, I grew up on the principle you mentioned in your message, the transmit dial frequency is the Mark frequency. This statement is no longer true or false! The answer to what your dial is displaying is... it depends! In the old days, you would log and spot a RTTY station using the dial frequency. This was because FSK was generated by switching a small capacitance in and out of parallel with the main VFO capacitor. The Drake equipment (T4X, TR4, and RV4) had a solder tab sticking out the side of the VFO can for this connection. Your dial frequency WAS your Mark frequency and you shifted 850 Hz or 170 Hz lower when the external capacitance was switched into the circuit. Today, the modern transceiver dial frequency may indicate the suppressed carrier frequency, the Space frequency, the Mark frequency, or whatever you want (in some cases). There doesn't seem to be any consistency among the manufacturers, and in some cases within the same manufacturer. For a particular transceiver, you may be able to determine what the dial frequency is from reading the operations manual, but sometimes not! You can determine what a transceiver is doing by dialing in 28.100 MHz and transmit in RTTY. Using an external frequency counter or receiver, you can then find your FSK Mark carrier. It may be the same as the dial or not. It's a crap-shoot! Here are some examples why the newer technology has become a quagmire... My Kenwood TS-450 transceiver dial frequency IS the Mark frequency. This is described on Page 38 in the operations manual. The dial displays the Mark frequency, independent of the shift width or polarity. Likewise, the Ten Tec Orion II displays the Mark frequency when operating in FSK mode. But there are a variety of other systems... My Kenwood TS-950S (and TS-950SDX) transceiver dial frequency displays the SPACE frequency. This is described on Page 32 (Page 36) in the operations manual. It shows the Space frequency independent of the shift width or polarity. The dial frequency will be off by 170 Hz, hardly noticeable by most operators. I also have an Icom 756 Pro III. The operations manual is vague regarding the relationship between dial frequency and Mark frequency in this transceiver. I can't find a specific statement in the book, but from experience it appears the dial frequency is the suppressed carrier frequency. The Yaesu FT-920 throws yet another layer of configuration possibilities. This transceiver allows you to program the dial frequency to display Mark, Space, or the Center frequency! See Page 56 in the FT-920 manual which describes Menu Item U-45. Likewise, the FT-1000MP provides menu 6-3 which allows the user to set the transceiver displayed frequency to their choice. The default setting is to display the Mark frequency. See Page 54 of the operations manual. With the introduction of computer soundcards being used to generate RTTY tones, transceivers without FSK capabilities can now be used for digital communications. In this case, the dial frequency is the suppressed carrier frequency. The transceiver has no clue what tones are being broadcast through its audio chain! The contesting (N1MM) and logging (DXKeeper) software I use in my station have provisions to adjust to any method of FSK or AFSK frequency logging. Once you know what your specific transceiver dial is telling you, you can adjust these software so it logs and spots the exact Mark frequency. Welcome to the digital revolution! 73 de Bob - KØRC in MN
Re: [digitalradio] VFO Dial Frequency, Audio Frequency, Centre Frequency
Usually, the Winlink bulletins specify the frequency as the average of the channel for P1 or P2, and 1500 Hz above the dial frequency for P3. It has been long usual to define the frequency of an RTTY signal as the RF frequency of the mark tone. And so on. If you want to define univocally something on the air, you refer to some distinctive feature of its RF spectrum. How you achieve it does not matter, as long as you get the same frequency of that distinctive feature on the air. Otherwise, you must specify TWO things, dial frequency, +/- audio frequency. Why state two numbers if one is enough to define it ? 73, Jose, CO2JA --- expeditionradio wrote: --- In digitalradio, W4LDE Ron wrote: I recommend that we all start using the VFO plus the audio frequency or waterfall frequency. Ron W4LDE Hi Ron, I agree. Some modes are appropriately defined by RF centre frequency, Some modes are appropriately defined by VFO dial frequency. There certainly are many operators using digital soundcard modes who do not have CAT control on their rigs, so their display does not show the mode's RF center frequency. Probably the majority of hams on PSK31 don't use CAT control... they simply set their VFO dial frequency to 14070 USB. To know their RF frequency, they must calculate it by adding the audio frequency to the dial frequency. Many of us understand this mainstream fact, and define our sked frequency by VFO dial frequency + audio centre frequency. There is a trend to simply use the USB VFO dial frequency as the reference point for MFSK modes, with about ~1500Hz audio center for the signal. This rule of thumb enables a sked QSO to switch any mode or flavor that is desired by the operators at the time, and appropriate for conditions. The digital protocols that use fixed frequency audio signals are almost always defined by VFO dial frequency. Especially when there is a mix of voice, images, and data, it is by far more convenient and appropriate to simply call out the VFO dial frequency. Bonnie KQ6XA __ V Conferencia Internacional de Energía Renovable, Ahorro de Energía y Educación Energética. 22 al 25 de mayo de 2007 Palacio de las Convenciones, Ciudad de la Habana, Cuba http://www.cujae.edu.cu/eventos/cier Participe en Universidad 2008. 11 al 15 de febrero del 2008. Palacio de las Convenciones, Ciudad de la Habana, Cuba http://www.universidad2008.cu
Re: [digitalradio] VFO Dial Frequency, Audio Frequency, Centre Frequency
At 01:36 AM 5/17/2007, you wrote: It has been long usual to define the frequency of an RTTY signal as the RF frequency of the mark tone. And so on. Really ? In my 37 years I have always seen it given as dial frequency. Reason: RTTY has fixed tones - never changes. Therefore if you give the dial frequency there is no math to be done just tune and go. You will be right on.
Re: [digitalradio] VFO Dial Frequency, Audio Frequency, Centre Frequency
Hello John, Technology is changing this concept. I was recently re-educated on this topic after returning from a ham radio hiatus. Like you, I grew up on the principle you mentioned in your message, the transmit dial frequency is the Mark frequency. This statement is no longer true or false! The answer to what your dial is displaying is... it depends! In the old days, you would log and spot a RTTY station using the dial frequency. This was because FSK was generated by switching a small capacitance in and out of parallel with the main VFO capacitor. The Drake equipment (T4X, TR4, and RV4) had a solder tab sticking out the side of the VFO can for this connection. Your dial frequency WAS your Mark frequency and you shifted 850 Hz or 170 Hz lower when the external capacitance was switched into the circuit. Today, the modern transceiver dial frequency may indicate the suppressed carrier frequency, the Space frequency, the Mark frequency, or whatever you want (in some cases). There doesn't seem to be any consistency among the manufacturers, and in some cases within the same manufacturer. For a particular transceiver, you may be able to determine what the dial frequency is from reading the operations manual, but sometimes not! You can determine what a transceiver is doing by dialing in 28.100 MHz and transmit in RTTY. Using an external frequency counter or receiver, you can then find your FSK Mark carrier. It may be the same as the dial or not. It's a crap-shoot! Here are some examples why the newer technology has become a quagmire... My Kenwood TS-450 transceiver dial frequency IS the Mark frequency. This is described on Page 38 in the operations manual. The dial displays the Mark frequency, independent of the shift width or polarity. Likewise, the Ten Tec Orion II displays the Mark frequency when operating in FSK mode. But there are a variety of other systems... My Kenwood TS-950S (and TS-950SDX) transceiver dial frequency displays the SPACE frequency. This is described on Page 32 (Page 36) in the operations manual. It shows the Space frequency independent of the shift width or polarity. The dial frequency will be off by 170 Hz, hardly noticeable by most operators. I also have an Icom 756 Pro III. The operations manual is vague regarding the relationship between dial frequency and Mark frequency in this transceiver. I can't find a specific statement in the book, but from experience it appears the dial frequency is the suppressed carrier frequency. The Yaesu FT-920 throws yet another layer of configuration possibilities. This transceiver allows you to program the dial frequency to display Mark, Space, or the Center frequency! See Page 56 in the FT-920 manual which describes Menu Item U-45. Likewise, the FT-1000MP provides menu 6-3 which allows the user to set the transceiver displayed frequency to their choice. The default setting is to display the Mark frequency. See Page 54 of the operations manual. With the introduction of computer soundcards being used to generate RTTY tones, transceivers without FSK capabilities can now be used for digital communications. In this case, the dial frequency is the suppressed carrier frequency. The transceiver has no clue what tones are being broadcast through its audio chain! The contesting (N1MM) and logging (DXKeeper) software I use in my station have provisions to adjust to any method of FSK or AFSK frequency logging. Once you know what your specific transceiver dial is telling you, you can adjust these software so it logs and spots the exact Mark frequency. Welcome to the digital revolution! 73 de Bob - KØRC in MN - Original Message - From: John Becker To: digitalradio@yahoogroups.com Sent: Thursday, May 17, 2007 8:14 AM Subject: Re: [digitalradio] VFO Dial Frequency, Audio Frequency, Centre Frequency At 01:36 AM 5/17/2007, you wrote: It has been long usual to define the frequency of an RTTY signal as the RF frequency of the mark tone. And so on. Really ? In my 37 years I have always seen it given as dial frequency. Reason: RTTY has fixed tones - never changes. Therefore if you give the dial frequency there is no math to be done just tune and go. You will be right on.
[digitalradio] VFO Dial Frequency, Audio Frequency, Centre Frequency
--- In digitalradio, W4LDE Ron wrote: I recommend that we all start using the VFO plus the audio frequency or waterfall frequency. Ron W4LDE Hi Ron, I agree. Some modes are appropriately defined by RF centre frequency, Some modes are appropriately defined by VFO dial frequency. There certainly are many operators using digital soundcard modes who do not have CAT control on their rigs, so their display does not show the mode's RF center frequency. Probably the majority of hams on PSK31 don't use CAT control... they simply set their VFO dial frequency to 14070 USB. To know their RF frequency, they must calculate it by adding the audio frequency to the dial frequency. Many of us understand this mainstream fact, and define our sked frequency by VFO dial frequency + audio centre frequency. There is a trend to simply use the USB VFO dial frequency as the reference point for MFSK modes, with about ~1500Hz audio center for the signal. This rule of thumb enables a sked QSO to switch any mode or flavor that is desired by the operators at the time, and appropriate for conditions. The digital protocols that use fixed frequency audio signals are almost always defined by VFO dial frequency. Especially when there is a mix of voice, images, and data, it is by far more convenient and appropriate to simply call out the VFO dial frequency. Bonnie KQ6XA
Re: [digitalradio] VFO Dial Frequency, Audio Frequency, Centre Frequency
It may be simple for YOU Bonnie, but those of us with good software which does all the figuring for you, do NOT find it simple when someone spots a station on 14071. I click on that, and my rig goes to 14070, and hopes the signal is at 14071 on the waterfall, and quite often is NOT there, because someone else uses a different offset. I too started out with spotting the rigs freq, and quickly understood that is NOT where the signal is in the waterfall, and that my spot was rather useless to those who had software that did if for them. Those of you that jiggle the main tuning knob around to do their tuning, can still do so. You have to know what YOUR offset is anyway, so go ahead and tune it where you know it will set the waterfall tracer up where YOU want it. I dont care at all what YOUR offset is. Just giving me the correct spot, allows instant tuning and I dont have to search around amongst 30 or so digital signals to find the station you just told me was there. Contraywise, if I tell you the signal is on 14,17205, you just have to subtract(or add) your offset from that and you know where to set your tranceivers knob. On top of all that, when I spot a station, my software automatically sends it out with the ofset figured in, so if you go to the frequency in the waterfall, you will find the signal I spotted. The four software packages I have used do this automatically. They also give me the whole freq readeout right above, or below, the signals on the waterfall. (Which is what they spot). As to the percentages of those who use CAT or not, I have no idea. But, it would supprise me if their isnt a larger percentage that do - than dont. Certainly with all new tranceivers being built to allow CAT control, I cannot imagine that most hams in the future will be using CAT. After all, we most all have a computer already - and are using that to send/receive digital modes - so the equpment is there to run CAT control. It is far more convenient to use CAT control, and the automatic offset - than to fiddle with knobs. \ Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalk - Original Message - From: expeditionradio [EMAIL PROTECTED]
