New 630m amateur band from 1 Jan 2013

[VK3YE]

(Don't think this has been reported here before)

http://www.comlaw.gov.au/Details/F2012L02574

472 - 479 kHz / 5w EIRP / restrictions in north and west

Transverters for 630m are very simple to build (eg http://g3xbm-qrp.blogspot.com.au/2012/1 ... dated.html ) so the main challenge will be the antenna.

Also note the deletion of 420 - 430 MHz

[VK2GOM]

Does this look like we've also got the full 6m allocation?

73 - Rob VK2GOM / GW0MOH

[VK4WDM]

Note that 50-54MHZ is listed!

73

Wayne VK4WDM

[VK2AAH]

Yep, the 50MHz restrictions are gone (oh no they aren't).
Richard
VK2AAH

[VK2GOM]

It would appear they're not. See viewtopic.php?f=2&t=9089&p=30054#p30054

This is a problem; different regulations spread over different documents.

I wouldn't be surprised to hear VK2's above 50.3MHz from 1st Jan though!

73 - Rob VK2GOM / GW0MOH

[VK2AAH]

Thanks Rob, you are dead right...

Cheers

Richard
VK2AAH

[VK4WDM]

I wouldn't be surprised to hear VK2's above 50.3MHz from 1st Jan though!

What! Away from 50.110!

73

Wayne VK4WDM

[VK4WDM]

Getting back to the main topic, which is rather exciting

With regard to equipment for 630m. Most ham receivers already cover the band. Transmitters should be quite easy. There is a lot of ex aircraft gear that can operate at those frequencies that could be converted to ham use. I have a couple of candidates under my bench now and could probably get a CW signal out of them today if I had a play. This equipment also has good receive capability and is likely to be much better than current ham gear.

There is also maritime gear for 500KC. Doc VK5BUG is the expert in that area. I will email him and see if he is willing to contribute to this discussion

The transverter that Peter VK3YE suggested is another way to go.

Antennas? More difficult to get an efficient antenna, especially if you want to work DX (define DX on this band), but I have seen portable aircraft beacons setup using a loaded whip that worked OK, and something like that could be used for local contacts at least.

This is a band that I am definitely interested in (I like ODD bands!) so listen out for VK4WDM - especially if you only live a street or so away!

My suggestion is to form an active group (maybe a new forum topic?) to exchange ideas and source equipment.

(Now where in this mess is that radio DF gear?)

73

Wayne VK4WDM

[VK4WDM]

Already commercial gear: http://www.nikkemedia.fi/juma-tx136

73

Wayne VK4WDM

[VK4WDM]

Wrong one! Try this: http://www.nikkemedia.fi/juma-tx500/

[VK4WDM]

Good info here: http://www.vk2xv.net/mf_630m.htm

[VK3HJ]

I collected parts for a 2200m transmitter of Drew Diamond's design.
This was published in AR a couple of years ago.
But I quickly lost interest, mainly due to the antenna demands.
So I should build up a transmitter for 600m instead. With my 160m vertical, I have calculated about -10dBi gain, so a 50W transmitter should do the job.
Receivers are no problem, just about anything tunes 475 kHz.
I'm not interested in contacts with stations only "a few streets away". There are no Amateurs within 10km of here anyway, so I'd want at least interstate contacts to make it worth the effort!
73,
Luke VK3HJ

[VK2AAH]

Hi all,

Can someone clear up my confusion? In the Determination it states:

"This item inserts a new section 15D which limits a licensee operating amateur advanced station in the frequency band 472 kHz to 479 kHz to a radiated power of not more than 5 Watts pX EIRP. "

So which is it? pX or EIRP?

pX is defined as the average power supplied to the antenna transmission line by a transmitter during one radiofrequency cycle.

So are you limited to 5W pX and the antenna gain (read: loss) or is it 5W EIRP?

The way I look at this is if you comply with the 5W pX limit there is little chance of achieving 5W EIRP.

Cheers


Richard
VK2AAH

[VK2GOM]

WSJT-X looks like it might be the go for some inter-VK experimentation on 472kHz.

http://physics.princeton.edu/pulsar/K1JT/wsjt.html

It will be a challenge, given antenna inefficiency, but it looks interesting.

73 - Rob VK2GOM / GW0MOH

[VK2AVR]

Can someone clear up my confusion? In the Determination it states:

"This item inserts a new section 15D which limits a licensee operating amateur advanced station in the frequency band 472 kHz to 479 kHz to a radiated power of not more than 5 Watts pX EIRP. "

So which is it? pX or EIRP?

pX is defined as the average power supplied to the antenna transmission line by a transmitter during one radiofrequency cycle.

The LCD defines pX simply as "peak envelope power". Therefore stating the radiated power as 5W pX EIRP makes sense - 5 watts of peak isotropic radiated power.

Whenever the LCD refers to the transmitter it always says "transmitter power of X watts [pX/pY]".

[VK2AAH]

Hi Geoff,

Unfortunately I can't agree with you on that. "pX" is measurable- the definition says that it is the average power in watts measured at the input to the antenna. That antenna could be a dummy load or a parabolic dish and make no difference to that result. However the addition of the term EIRP indicates that it is the radiated power relative to the isotropic reference that is the limiting factor. Well... it can't be both. The way I read it the absolute maximum "average" power is 5W... so no-one can argue that since the antenna is exceptionally lossy (in EIRP terms) that a 50W (for example) transmitter is permitted.

I've had a long battle with ACMA on the "loose" or illogical use of these terms, this is just another example of ITU abbreviations being used in a very ambiguous way. It should be either pX or EIRP- not both.

Cheers

Richard
VK2AAH

[VK5ZD]

Hi

The ITU definition actually says it's the power delivered to the antenna transmission line. Be that as it may, whoever wrote the Amateur LCD has chosen to define it as "pX means peak envelope power." so, in that context, pX EIRP does make sense. Maybe they should have said that maximum permitted PX is 37dbm less the antenna gain (i.e. plus the loss for any practical antenna).

73
Iain

[VK2AAH]

Hi Iain,

Yes the way you expressed it makes sense. I can see the current wording causing some debates in the future.

Cheers


Richard
VK2AAH

[VK4DU]

The average MF amateur antenna will be so inefficient, you could put a kW into it....the worms will thank you on those winter nights...

[VK2AAH]

That is very true, but hopefully those worms can snuggle up because a 5W transmitter isn't going to do much worm warming...

Cheers

Richard
VK2AAH