PSK on 50MHZ?

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PSK on 50MHZ?

Postby VK4WDM » Mon Jan 19, 2009 5:21 pm

I just noticed the following post on the logger: "Calling CQ in BPSK31 on 50.231". Is that mode legal on 50MHZ?

73

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Re: PSK on 50MHZ?

Postby VK2OMD » Mon Jan 19, 2009 5:49 pm

VK4WDM wrote:I just noticed the following post on the logger: "Calling CQ in BPSK31 on 50.231". Is that mode legal on 50MHZ?

73

Wayne VK4WDM


Wayne,

It is my view that PSK31 does not fit within any of the permitted modes on that part of 6m (in the Ch0 restricted areas of VK). I have set out elsewhere that PSK31 is a complex modulation that includes both amplitude and phase modulation, and for that reason does not comply with the permitted modes. I recall the WIA suggesting some years ago that the AM in PSK is incidental. That is not true, it is intentional, it is higher average modulation index than most pure AM signals, it carries the bit timing reference, and the decoding requires the AM as well as the PM.

There are many in the hobby that reason that because it goes in the mic jack, it is SSB, and therefore is permitted. Similar has been argued for SSTV for instance. I see the band plan being called up as a reference from time to time, but it is the LCD that is definitive. It all has appeal to a dumbed down view of emissions. The "digital modes" grouping is part of that dumbing down.

Emission types (as used by ITU) are not designators of method of generation, but characteristics of the emission (ie the transmitted signal). For instance, there are many methods of generation of AM, and the emission designator for AM does not indicate which is used, just the necessary bandwidth, sideband structure, type of information carried etc.

Someone recently referred SSTV on low end 6m to the ACMA, and the advice was that it didn't comply with any of the permitted modes. The same could be done in the case of PSK31, but it may just confirm to the ACMA that we really don't know what we are doing.

It is probably fair to say that the restrictions on low end of 6m are more honored in the breach than in the observance! Some stations in Canberra shouldn't even be on low end of 6m being within 120km of ABMN0, much less on PSK31.

Owen
Last edited by VK2OMD on Thu Jan 13, 2011 7:18 am, edited 2 times in total.
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Re: PSK on 50MHZ?

Postby VK4GHZ » Mon Jan 19, 2009 6:34 pm

VK1OD wrote:...but it may just confirm to the ACMA that we really don't know what we are doing.

OR
The WIA is spreading misinformation, that confuses the issue.
OR
The LCD is too difficult for the layperson to interpret.
OR
Both?

:wink:
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Re: PSK on 50MHZ?

Postby VK4WDM » Mon Jan 19, 2009 9:51 pm

I am not an expert in emmission types but I believe that PSK and similar modes are definitely illegal on 50MHZ.

I think we have to be VERY careful with our use of 50MHZ. Our original plea to have use of the segment was based upon the need for VK hams to have access for INTERNATIONAL communication and take part in INTERNATIONAL experiments designed to enhance the knowledge of propagation in the lower VHF spectrum. All other traffic was supposed to remain on 52MHZ.

Sooner or later, we are going to have to undergo an audit of our use of this segment, how well we are adhering to our reasons for asking for access to it, and how good we are at ahering to the rules. There are other players eying this spectrum. Defence is badly in need of extra room and we have had ADF fixed point stations operating for weeks at a time on the lower half of 6M.

It was a very hard fight to get the 50MHZ - a fact not well understood by newer ops on the band. Let's not risk losing it by not observing the regs.

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Re: PSK on 50MHZ?

Postby VK7XX » Tue Jan 20, 2009 7:29 am

This is an interesting topic for sure. And, I would like to ask a question. I have been asked this question myself a few times and I admit, I do not know the answer. The question stems from many people generating these 'modes' by using similar methods to my own although, not too many are as crude as my current setup.

Currently, the radio I use for PSK, SSTV, WSJT and several other "digital" modes has no direct way of generating these modes. I have no modems / interface box's or other generating devices connected to the radio. To generate the signals for these modes I use the sound card of my computer. Further to this, my radio stays on SSB mode, (usually usb) and I put my radio on to VOX. I put the microphone near the computer speaker and the audio from the speaker triggers the VOX, keying the transmitter.

My radio is on SSB, the microphone is being used, all that I have done is stop talking and place the microphone in front of a speaker so, it is still transmitting audio. I am not a guru on this subject and I am sure that others would be interested too so, please tell me how my SSB transmission type suddenly becomes one that is different, and possibly illegal, than my talking in to my microphone.
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Re: PSK on 50MHZ?

Postby VK2OMD » Tue Jan 20, 2009 7:44 am

VK7XX wrote:This is an interesting topic for sure. And, I would like to ask a question. I have been asked this question myself a few times and I admit, I do not know the answer. The question stems from many people generating these 'modes' by using similar methods to my own although, not too many are as crude as my current setup.

Currently, the radio I use for PSK, SSTV, WSJT and several other "digital" modes has no direct way of generating these modes. I have no modems / interface box's or other generating devices connected to the radio. To generate the signals for these modes I use the sound card of my computer. Further to this, my radio stays on SSB mode, (usually usb) and I put my radio on to VOX. I put the microphone near the computer speaker and the audio from the speaker triggers the VOX, keying the transmitter.

My radio is on SSB, the microphone is being used, all that I have done is stop talking and place the microphone in front of a speaker so, it is still transmitting audio. I am not a guru on this subject and I am sure that others would be interested too so, please tell me how my SSB transmission type suddenly becomes one that is different, and possibly illegal, than my talking in to my microphone.


John, the answer is in my earlier post...

VK1OD wrote:Emission types (as used by ITU) are not designators of method of generation, but characteristics of the emission (ie the transmitted signal). For instance, there are many methods of generation of AM, and the emission designator for AM does not indicate which is used, just the necessary bandwidth, sideband structure, type of information carried etc.


The matter of whether an emission type is permitted is entirely in the current LCD.

For an Advanced Licence, there are very few restrictions on emission type, but the low end of 6m is one and they are the outcome of a negotiation where hams begged for even restricted access to that band segment. Now it seems, some people think it is too hard to understand, too complicated for the modern world.

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Re: PSK on 50MHZ?

Postby VK7XX » Tue Jan 20, 2009 10:16 am

Hello Owen and thank you for your time and reply.

What I have difficulty understanding is how my "emmission type" can change from one thing to something else with just the movement of my microphone. I know, I might be slow on the uptake, but for the life of me, I cannot see how moving my microphone from my mouth to my speaker can change my "emmission type". Surley if my radio is on the SSB mode my emmission type is Single Sideband suppressed carrier. and if my radio is on FM my 'emmission type" is Frequency Modulation" etc etc.. Is this where I am getting confused ?????

It is sometimes nice to get other ideas but my original question, from my point of view, has not been clarified so, with a minor alteration to that question I now ask..... "please tell me how my SSB transmission "emmission type" suddenly becomes one that is different, simply by moving my microphone from my mouth generating audio across to my speaker which is generating audio"



In addition, I would like to add....... It really is no wonder there is confusion because, according to Page 26 of the ACMA document entitled "Radiocommunications Licence Conditions (Amateur Licence) Determination No.1 of 1997" (which I just a moment ago downloaded after searching for the ACMA site for the word "emmission"), under item 3 on that page it states that, for some licence classes the band portion 50.000 MHz - 54.000 MHz the permitted emission modes are "Any emmission mode with a necessary bandwidth not exceeding 100 KHz" to me, this means that, as I am transmitting an SSB signal that has a bandwitth of far less that 100 KHz I should be able to put any sort of audio I want in to my microphone because, I wont be sending out anything that will approach the 100 KHz bandwith limitations. I also thought that I better add (by way of edit) and before someone jumps down my neck, that I am aware of various amendments to the LCD that alter the blanket "Any emmission mode with a necessary bandwidth not exceeding 100 KHz" I have used above.....
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Re: PSK on 50MHZ?

Postby VK4ABW » Tue Jan 20, 2009 11:13 pm

I recently heard packet frames being sent on 50.110 which were eminating from the 'south'. I didn't chase up who it was but was appalled by the operating practice of that station. If we are to keep 50mhz allocated then the band should be used 'wisely'. I have no hassles with stations operating digital modes on the lower end of 6 metres provided they stay well away from the International calling frequency. Heck, even i operate WSJT below 50.3 but i stay well away from 110.

An International frequency for digital modes should be allocated as this would provide the opportunity for more activity and possibly move a few stations off 50.110 that insist on staying there. Technology has changed and will continue to change and if we don't cater for these new modes then who is being left behind? Digital modes open up a whole new world of possible contacts. How many times have we sat there and listened to 'white noise' when there could potentially be a marginal opening which digital modes excel in! That is the reason i went to great lengths for a permit to experiment with terrestrial and EME digital modes below 50.300.

The smallest station i have worked (wsjt) was a 5 element single yagi station in the Carribean (ZF2)! This is pushing the boundaries of digital communications which is why i am experimenting with it.

Give digital modes a go on 6mtrs. Just my 2c worth

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Re: PSK on 50MHZ?

Postby VK2OMD » Wed Jan 21, 2009 5:51 am

vk4abw wrote:I recently heard packet frames being sent on 50.110 which were eminating from the 'south'.


Was it 1200Bd AFSK as is commonly used on 2m?

If so, it is not a permitted mode in QLD, VIC, ACT, NSW.

Lower baud rate FSK that has a necessary bandwidth of less than 1.12kHz is permitted under 1K12F1D at 30W pY max, which includes 300Bd 200Hz shift (Bell 103) HF style RTTY / packet, and JT65A, JT65B, and JT65C. FSK441 is NOT included.

Another example of why the 'digital modes' umbrella is just plain dumb.

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Re: PSK on 50MHZ?

Postby VK7XX » Wed Jan 21, 2009 7:03 am

VK1OD wrote:

vk4abw wrote:
I recently heard packet frames being sent on 50.110 which were eminating from the 'south'.


Was it 1200Bd AFSK as is commonly used on 2m?

If so, it is not a permitted mode in QLD, VIC, ACT, NSW.

Lower baud rate FSK that has a necessary bandwidth of less than 1.12kHz is permitted under 1K12F1D at 30W pY max, which includes 300Bd 200Hz shift (Bell 103) HF style RTTY / packet, and JT65A, JT65B, and JT65C. FSK441 is NOT included.



Thanks for this Owen. It clears up a lot of questions I had rolling around in my empty head. And, depending on which VK call area the signals originated from, also answers the original question by VK4ABW.

Another example of why the 'digital modes' umbrella is just plain dumb.


I agree.

And for what its worth, I also heard these packet signals and made comment on the vklogger at the time. (Someone else thought they were PSK signals but the ones I heard were 'packet') I was able to determine that the signals came from the 'north' in an area somewhere between Zero and 30 degrees from my location.
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Re: PSK on 50MHZ?

Postby VK4WDM » Wed Jan 21, 2009 5:43 pm

Hey guys, I did not set up this topic to dob in anyone or complain about PSK on 50MHZ. I was confused myself. I use PSK on other bands, and if it is legal on 50MHZ I will use it too.

I agree with Gary VK4ABW. 6M is a band where we defintely do need to have all the technology available to us, and perhaps somebody who has the technical know how should present a case for the use of digital modes to the ACMA.

However, until PSK and other digital modes ARE legal, we should not use them. I love 6m - not just Dxing - domestic, around town, over the back fence (all in the right part of the spectrum though) and I would hate to see misuse or stupidity cause us to lose the lower end.

I believe (and with some evidence) that there ARE some envious eyes looking at that slice of spectrum, they ARE taking note of what the hams are doing, and it is more than likely that they are taking notes of any breaches for future reference.

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Re: PSK on 50MHZ?

Postby VK2OMD » Wed Jan 21, 2009 9:34 pm

VK4WDM wrote:Hey guys, I did not set up this topic to dob in anyone or complain about PSK on 50MHZ. I was confused myself. I use PSK on other bands, and if it is legal on 50MHZ I will use it too....


Wayne,

The following assumes that you are talking about a mode known as PSK31 and described by By Peter Martinez, G3PLX, in the document entitled PSK31: A New Radio-Teletype Mode.

The reference above describes the characteristics of the mode, including the modulation type.

Screenshot - 21_01_2009 , 22_04_31.png


Above is a figure from that document. Click on the pic for a full size view.

It shows the waveform for transmission of the space character, note the amplitude modulation of the waveform, and the inset shows the phase modulation.

To my mind, this does not comply with any of the permitted emission types specified in the LCD for restricted use of low end 6m because its content is data or telegraphy for automatic reception, and modulation of the main carrier involves both amplitude modulation and phase modulation.

However, if you can get the ACMA to advise you in writing that PSK31 is permitted, then well and good, because it may be a reasonable defence that their advice should be competent and dependable.

If you think you have a case for reconsideration of the permitted emission types (bearing in mind that it is just a couple of years before channel 0 is planned for turn down), then put the case.

Someone recently reported the ACMA's opinion on SSTV which is narrow band frequency modulation carrying facsimile content, and the advice was that it was not permitted. You might ask the question why is arbitrary n level FSK with maximum necessary bandwidth of 1.12kHz acceptable, but FM with a maximum necessary bandwidth of about 2.5kHz is not. I cannot see that there is a lot of difference from an interference risk point of view, but it is different, and their decision might just indicate that they are not prepared to revisit the matter.

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Re: PSK on 50MHZ?

Postby VK3BPN » Thu Jan 22, 2009 11:04 am

I have just been reading the Radiocommunications Act 1992 and find it allows Advanced Licensees to use "50.000 MHz–54.000 MHz: Any emission mode with a necessary bandwidth not exceeding 100 kHz"

In the 2008 call book the band plan for 6m under Note 1: Narrow Band Modes, states: "The following spot frequencies are recommended for digital DX operation using SSB-based modes: 50.220 Weak signal modes with bandwidth below 100 Hz, e.g. PSK and slow CW"

My comments here are NOT whether PSK is a SSB mode or not but refer to the original question by VK4WDM “Is that mode legal on 50MHZ?”

As far as my interpretation the regulations are concerned PSK is a legal mode for Advanced Licensees on any 6m frequency, dare I say even 50.11 or am I missing something here?

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Re: PSK on 50MHZ?

Postby VK2OMD » Thu Jan 22, 2009 11:47 am

vk3bpn wrote:I have just been reading the Radiocommunications Act 1992 and find it allows Advanced Licensees to use "50.000 MHz–54.000 MHz: Any emission mode with a necessary bandwidth not exceeding 100 kHz"

In the 2008 call book the band plan for 6m under Note 1: Narrow Band Modes, states: "The following spot frequencies are recommended for digital DX operation using SSB-based modes: 50.220 Weak signal modes with bandwidth below 100 Hz, e.g. PSK and slow CW"

My comments here are NOT whether PSK is a SSB mode or not but refer to the original question by VK4WDM “Is that mode legal on 50MHZ?”

As far as my interpretation the regulations are concerned PSK is a legal mode for Advanced Licensees on any 6m frequency, dare I say even 50.11 or am I missing something here?

Peter
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Peter,

I don't think you are reading the "Radiocommunications Act 1992", I don't think it contains that level of detail.

The Radiocommunications Licence Conditions (Amateur Licence) Determination No. 1 of 1997 as amended (LCD) contains relevant information.

In particular, clause 15: Operating an amateur advanced station in the frequency band 50 MHz to 52 MHz which sets out further conditions that apply in some states and locations.

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Re: PSK on 50MHZ?

Postby VK6ADF » Thu Jan 22, 2009 7:52 pm

Also if you look at page 25 onwards in the LCD mentioned above it goes through the various emision designators. PSK31 I read on one site I visited was designated as xxxxG1D and so because of the special conditions mentioned on page 16 falls into the non allowed category. I hope I got it right...its confused me as well. :wink:

73 Phil...
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Re: PSK on 50MHZ?

Postby VK2OMD » Fri Jan 23, 2009 6:23 am

VK6ADF wrote:Also if you look at page 25 onwards in the LCD mentioned above it goes through the various emision designators. PSK31 I read on one site I visited was designated as xxxxG1D and so because of the special conditions mentioned on page 16 falls into the non allowed category. I hope I got it right...its confused me as well. :wink:

73 Phil...


Phil,

If you read the earlier posts, the modulation is simultaneously amplitude and phase, so G (for phase modulation alone) is not an accurate modulation type designator. It probably should be D (Emission in which the main carrier is amplitude- and angle-modulated either simultaneously or in a pre-established sequence). (Note: phase modulation is a form of angle modulation.)

I am not sure of the exact necessary bandwidth, it is probably around 50Hz. If that is so, the emission designator would be something like 50H0D1B.

(It is a pity that the inventor does not define the emission type in terms of the ITU designation, and publish that as part of his description.)

Again, I am not in favour of rigid emission type specification for the amateur service, it is after all, or we pretend it still is an experimental service. Notwithstanding that, there is regulation in place that was the outcome of a negotiation where hams sought access to the low end of 6m and we should respect that.

Dumbed down responses like "the LCD is too hard to understand" just support the argument that we shouldn't be on that sub-band, or should be using type approved equipment to simplify life for ourselves and give the regulator more confidence of observance.

Owen

PS: There are signs that the ITU's modulation type for an emission in which the main carrier is amplitude- and angle-modulated either simultaneously or in a pre-established sequence may have changed recently to I (why would they do that?). ITU charges fees for access to most of their recommendations, but they still publish documents showing D, the FCC still shows D, ACMA RIB8 shows D.
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Re: PSK on 50MHZ?

Postby VK3TOM » Thu Mar 19, 2009 9:03 am

Looking at the Callbook it is

recommened spot frequencies
50.220 weak signal 100 HZ bandwith e.g. PSK, Slow CW
50.225 weak signal 500 HZ Bandwith e.g. MFSK, JT44 and simular
50.230 High speed meteor scatter bandwith 3 KHZ e.g FSK 441

I am guessing these should be treated as call channels only but if you look at WSJT modes if all goes well the call is fairly quick, have not operated them so some one might be able to add some light to the subject.

Just for intrest 2M is marked the same but also has dupicate frequencies 320 / 325 / 330

The way I see it the only modes that can't be used in this section is MT63 cause of its width but maybe it can be used in the normal SSB section.

Would like to try digital ine day, Wisper should be ok as well as its based I think on the WSJT modes. There is now so many modes to try, all different and good for different conditions

Must try and but those digital books from the WIA.

Just another opion

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Re: PSK on 50MHZ?

Postby VK4ABW » Fri Mar 20, 2009 11:19 am

In reference to my original post of 20 Jan 09, I am permitted to run digital from 50.000 to 50.300mhz. My application to the ACMA was to run cw, ssb and JT65 into a high gain array and it went straight through!

You just need to ask the ACMA and be clear, concise and smart about your applications.

So stop ya whinging about limitations and do something about it.

Total cost was 43 bucks.

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Re: PSK on 50MHZ?

Postby VK3TOM » Sun Mar 29, 2009 3:31 pm

Now your getting me confused !

Been thinking it about it more and checked the WIA getting a amature radio licence....

It states :

<Quote>
6 Metres 50.000 - 54.000 MHz
2 Metres 144 - 148 MHz

Any emission mode with a necessary bandwidth not exceeding 100 kHz
<\End Quote>

This means to me modes that can operate on 50.220 marked as 6M NB 100KHZ IE PSK, CW, wide should be legal but you would special permission to use the other modes on 50.225 and 50.230 Ie MFSK, JT44, FSK441

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Re: PSK on 50MHZ?

Postby VK4TU » Mon Mar 30, 2009 1:49 pm

Here are your licence terms as a radio ham. Download, read and digest.
http://www.comlaw.gov.au/ComLaw/Legisla ... icence.pdf
For advanced licencees - Part3 section 15 states;
Operating an amateur advanced station in the frequency band
50 MHz to 52 MHz

(1) Subsections (2) and (3) apply if the licensee operates an amateur advanced
station in the frequency band 50.000 MHz to 52.000 MHz.
(2) The licensee must not operate the station if it causes interference to the
reception of the transmissions of television channel 0.
(3) If the licensee operates the station in New South Wales, Victoria,
Queensland or the Australian Capital Territory, the licensee must operate
the station:
(a) in the frequency band 50.000 MHz to 50.300 MHz only, using:
(i) emission mode 200HA1A and a maximum transmitter power of
100 watts pY; or
16 Radiocommunications Licence Conditions (Amateur
Licence) Determination No. 1 of 1997
Federal Register of Legislative Instruments F2008C00085
Conditions for amateur licence (amateur advanced station) Part 3
Section 16
(ii) emission mode 1K12F1D and a maximum transmitter power of
30 watts pY; or
(iii) emission mode 4K00J3E and a maximum transmitter power of
100 watts pX; and
(b) at a place that is:
(i) at least 120 kilometres from a television channel 0 main station;
and
(ii) at least 60 kilometres from a television channel 0 translator
station; and
(iii) at least 60 kilometres from a television translator station that has
inputs on television channel 0.
Note For details of VHF television channel 0 stations, see Schedule 7.

That's 100W of keyed carrier (Max 200Hz BW) , 30 Watts of FM Data (Max 1120Hz BW) or 100W of SSB (Max 4KHz BW)
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