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A plea to 60m CW activators (plus comments on 60m in general WRC <> UK comms)


#61

US amateurs “must assure that their signal is transmitted on the channel-center frequency.” In order to center a USB signal in the channel, we use a suppressed carrier frequency 1.5 kHz lower than the channel center. For the channel centered on 5405, we set the transmitter to 5403.5.

The channels are 2.8 kHz wide.

wunder


#62

Your two statements are contradictory. If the center frequency is 5405 and the dial frequency is 5403.5, the channel must be 3.0 kHz wide.

Also, 5405.0 kHz has been used for DX working on CW by European stations for as long as I can remember.

73,
Walt (G3NYY)


#63

You would be in danger of infringing your licence regulations if you transmitted CW on 5403.5 kHz, which is specified as the USB carrier frequency to be used in this bandlet. A steady carrier, in theory, has zero bandwidth, so you would be OK to transmit an unkeyed carrier on 5403.5. However, as soon as you start keying the carrier, it does have some bandwidth … admittedly very small, but the actual bandwidth is dependent upon the speed of keying, the hardness of the make and break, and a variety of other factors. To be safe, it is recommended in practice that you should not transmit CW closer than 50 Hz relative to the band edge.

73,
Walt (G3NYY)


#64

Unfortunately the pdf for operating procedures during the 5 MHz experiment does not seem to be available on line any more, and my memory may well be at fault since it was over ten years ago, yet I seem to remember that the recommended procedure was to keep CW at the lower limit of the channel with the intention of making each channel available for simultaneous use on CW and USB. I do not disagree with your technical point, mind you, but perhaps this usage was part of the NoV. I think that a 50 Hz deviation from the carrier frequency would make the simultaneous use difficult but not being a CW man I never tried it.


#65

Hi Walt,

To be fair to wunder he’s only quoting the ARRL guidance:

http://www.arrl.org/60m-channel-allocation

Does seem a bit odd though - no channel edges are stated, but you’d think the bottom edge of a 2.8kHz channel centered on 5405 kHz would be at 5403.6 kHz… guess they’re relying on good carrier suppression, poor low frequency response in their speech amplifiers and steep-skirted filters :wink:

73 de Paul G4MD


#66

No, because real-world SSB signals don’t transmit audio down to DC (carrier). To stay legal, US amateurs need to limit audio to above 100 Hz and below 2900 Hz (5403.6 to 5406.4).

wunder


#67

This differs from the RSGB’s guidance on the use of SSB in the 5 MHz band, which is as follows:

“Ensure that the transmitted spectrum is completely within the allocated frequencies. The transmitted spectrum of an upper sideband signal extends from the suppressed carrier frequency, usually also the indicated or dial frequency, to 3kHz higher.”

Source: http://rsgb.org/main/operating/band-plans/hf/5mhz/
Note #4

73,
Walt (G3NYY)


#68

This guidance is simplistic and the actual transmitted spectrum will be dependant on such factors as audio filtering, the shape factor of the crystal or ceramic filter and the carrier insertion point…not to mention opposite sideband suppression. To take one real case, the specifications for my FT857D give a frequency response of 400 Hz - 2600 Hz at -6 dB though I have tightened that up using the filtering menu.


#69

Good point, Andy. Sometimes we forget that there are different 60M allocations in various countries. Maybe there are 1 or 2 common frequencies which all operators with a 60M allocation may use and we make it a point to activate n those (that) frequency.


#70

There is a good listing on http://hflink.com/60meters/ which shows a lack of universally available common frequencies.


#71

If only there was a way to transmit on frequencies in our own allocations and listen on frequencies in other’s allocations. If only… :wink:


#72

Still Promoting Limited Implemented Techniques Andy?


#73

ROTFL! It’s part of my campaign to dispel the rumours that such activity is in some way hard or rocket-science like!

Been back home for 30mins and was in the pickup with the heater on full for 1hr10mins and I am still perishingly cold after the wind, mist, snow and hail on Windlestraw Law. I hope to be warm before tomorrow!


#74

Split isn’t difficult; it just requires a bit of RTFM or judicious use of RIT or memories.
Working out which frequencies to use on 60m however is enough to make me turn to drink (as I pour the 2nd glass of wine tonight). Maybe a hot toddy is called for in your case?

PS not being a child of the facetwit generation- ROTFL?


#75

Two things.

  1. RSGB guidance doesn’t apply to US amateurs.
  2. The 2.8 kHz channel is a US rule, not guidance. It is from the National Telecommunications and Information Administration (NTIA).

https://www.ntia.doc.gov/home

Because it is a rule, we must follow it. That means using a suppressed carrier frequency of 5403.5 and limiting our USB emissions to fit within the 2.8 kHz channel.

Which reminds me, I need to set the TX EQ on my KX3 to cut the top audio band -16 dB instead of leaving it flat whenever I use 60 meters. I think I can do that with a macro.

wunder


#76

I have a diabetes MOT coming up soon so I have to be strict to ensure my HB1 numbers are good so I always have a dry January (after a very wet Christmas). 13 days without a drop so far.

Rolling on the floor laughing.


#77

Oh the agony!


#78

By the same token, NTIA, FCC and ARRL rules do not apply to amateurs outside the USA.

:wink:

73,
Walt (G3NYY)


#79

Which is why my original post started with the words “US amateurs”.

This diagram shows how common SSB bandwidth fits in the US allocations.

2_8kHzChannelVoiceB

http://hflink.com/60meters/#SSBsignal

wunder


#80

Reasons not to seek WRC-15 allocation in the UK.

"The Iceland Radio Amateurs (IRA) site says the regulator PFS has updated the Amateur Radio regulations

It would appear that Icelandic amateurs have gained the new WRC-15 60m 15 kHz wide allocation (5351.5-5366.5 kHz) limited to 15 watts but lost the 150 kHz wide allocation (5260-5410 kHz) which permitted 100 watts EIRP and had been available by special permit. "