Well I, for one, would welcome the chance to experiment on the 73kHz band. I can, I believe, legally (even without a licence) do so with earth-mode but I'd like to see how effective earth-electrode antennas work as radiating structures on this band. With modem digital techniques there are so many experiments to do.
Sadly, like much of our spectrum, this is now managed by "the military" in the UK so it is very unlikely we'll get access to this band again. When originally available in the UK, I was not active on LF.
Showing posts with label 73khz. Show all posts
Showing posts with label 73khz. Show all posts
16 Nov 2014
19 Feb 2014
OFCOM - sub-8.3kHz and around 73kHz in the UK
You may recall that several weeks ago I contacted OFCOM to clarify (1) the legality of no-licence operation in the UK below 8.3kHz (band is unallocated) and (2) operation around 73kHz with limited ERP (licence exempt). 3 emails later, I have STILL to receive a response. I wrote again today hoping for a reply this time.
The same issues are to be raised by the RSGB on March 13th at their OFCOM liaison meeting.
It now looks like the address I was given was a DEAD email address Today I contacted Spectrum.Licensing@ofcom.org.uk and hope, this time, to get an answer.
The same issues are to be raised by the RSGB on March 13th at their OFCOM liaison meeting.
It now looks like the address I was given was a DEAD email address Today I contacted Spectrum.Licensing@ofcom.org.uk and hope, this time, to get an answer.
30 Jan 2014
73kHz band in the USA
In recent days and nights European LF enthusiasts have been looking, with some success, for the transatlantic transmissions in the 73kHz band from W4DEX and others who have been granted special permits QRSS60 transmissions have been copied well in Germany by Marcus Vester DF6NM and others. See http://dl.dropboxusercontent.
With the right kit (and stability) almost anything appears to be possible.
With the right kit (and stability) almost anything appears to be possible.
28 Jan 2014
73kHz UK access?
According to my interpretation of the latest UK frequency allocation table, one can use the old 73kHz band without a license as long as the output is less than 72dBuA/m at 10m under inductive devices rules. Perhaps someone can tell me if I am wrong. A very low ERP is not a handicap as amateur antennas tend to be VERY inefficient.
See http://stakeholders.ofcom.org.uk/binaries/spectrum/spectrum-information/UKFAT_2013.pdf
See http://stakeholders.ofcom.org.uk/binaries/spectrum/spectrum-information/UKFAT_2013.pdf
4 Aug 2013
68-76kHz LF band allocated in the USA
Just in from WG2XRS/4.....
"You might have heard a group of us have received a license covering 68 to 76 kHz with 10 W ERP for most all modes including SSB! Authorization came yesterday and already have W4DEX on QRSS and into W1VD and others with very solid sigs on 72.4 kHz. Am gearing up for that operation as we speak.Bob, WG2XRS/4."
This is fascinating news. Although getting anything like 10W ERP is a major challenge at 73kHz, much weaker amateur signals have spanned the Atlantic in the early 2000s when the 73kHz band was available by NoV here in the UK. See
http://homepage.ntlworld.com/m
There is no doubt that some of the US stations will be copied in Europe this coming DX season. Since the first few years of this century a number of new weak signal modes have appeared such as WSPR2 and WSPR15 and OPERA. Also, with GPS locked systems and superb frequency accuracy, it is possible to run very slow CW and DFCW modes knowing that the TX frequency can be very accurately set, so the RX can look for the signal in uHz bandwidths to dig it out of the noise over a period of hours. All we now need is for a limited number of 73kHz permits to be again allocated in the UK.
Please note this is NOT a general allocation in the USA: it is a special research permit to a limited number of stations in much the same way as some access to 500kHz and 136kHz has been granted over there. Their FCC does seem to be incredibly slow at getting new bands like 472kHz allocated. I don't know why this is such a problem: perhaps they fear allocating these LF bands will be a threat to homeland security?
There is no doubt that some of the US stations will be copied in Europe this coming DX season. Since the first few years of this century a number of new weak signal modes have appeared such as WSPR2 and WSPR15 and OPERA. Also, with GPS locked systems and superb frequency accuracy, it is possible to run very slow CW and DFCW modes knowing that the TX frequency can be very accurately set, so the RX can look for the signal in uHz bandwidths to dig it out of the noise over a period of hours. All we now need is for a limited number of 73kHz permits to be again allocated in the UK.
Please note this is NOT a general allocation in the USA: it is a special research permit to a limited number of stations in much the same way as some access to 500kHz and 136kHz has been granted over there. Their FCC does seem to be incredibly slow at getting new bands like 472kHz allocated. I don't know why this is such a problem: perhaps they fear allocating these LF bands will be a threat to homeland security?
15 May 2013
37 and 73kHz tests through the ground?
Further to my comment on VLF WSPR, I am still thinking about doing some earth-mode (through the ground) transmission tests at a couple of frequencies between the 8kHz dreamer's band and 136kHz. I'd like to test in the old 73kHz band (legal with earth mode and minimal radiation) and possibly around 37kHz too. A radiated test in the old 73kHz band would not be legal despite low uWs ERP unless I applied for the modern equivalent of a testing and development licence and paid £50 a year, stupid for a couple of tests taking a few hours. Getting MoD approval for that would likely take months and months too.
As my FT817 does not cover this frequency range, and the frequencies will be too high for direct sound card reception, I shall have to build an up-converter for the FT817 with a couple of front-end filters to pre-select the desired LF frequencies or a down converter to feed a sound card directly. A loop, E-field probe or earth electrodes would be used on RX ahead of the converter with the eventual output feeding a PC running appropriate weak signal software (Spectrum Lab, Spectran, WSPR etc).
I made a request to OFCOM very many months ago to permit me to do some low ERP radiated tests in the band between 9 and 136kHz on the basis that the potential for interference with very low ERP (uWs) and transmissions lasting no more that a few hours at a time would be extremely low. Such a request required lateral thinking and empowered decisions. Many, but not all, people at OFCOM seem incapable of making common sense decisions any more. They are also hindered by stupid bureaucracy. Ho hum.
As my FT817 does not cover this frequency range, and the frequencies will be too high for direct sound card reception, I shall have to build an up-converter for the FT817 with a couple of front-end filters to pre-select the desired LF frequencies or a down converter to feed a sound card directly. A loop, E-field probe or earth electrodes would be used on RX ahead of the converter with the eventual output feeding a PC running appropriate weak signal software (Spectrum Lab, Spectran, WSPR etc).
I made a request to OFCOM very many months ago to permit me to do some low ERP radiated tests in the band between 9 and 136kHz on the basis that the potential for interference with very low ERP (uWs) and transmissions lasting no more that a few hours at a time would be extremely low. Such a request required lateral thinking and empowered decisions. Many, but not all, people at OFCOM seem incapable of making common sense decisions any more. They are also hindered by stupid bureaucracy. Ho hum.
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