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Author Topic: New Band, 630m  (Read 7500 times)
KC2VDM
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« on: March 18, 2012, 11:03:22 AM »

From page 9 in QST "In Feb. 2012, at the World Radio Conference of the ITU, a new worldwide frequency band for the amateur service was born: 472 to 479 kHz, destined to be known as the 630 meter band."

Just wondering what some of you think of it.

To me it sounds interesting, But Imagine the antenna length for a half wave dipole. About 500 ft. per leg! And what radio will work on that band? Unless you still have your 1905 spark gap transmitter in service.  Grin
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KD8DEY
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« Reply #1 on: March 19, 2012, 04:23:54 AM »

With just 7KHz of bandwidth who really cares?
Barely enough space for 2 CW QSO's.
BUT I doubt if it will get crowded.

Modified BCB receiver with a home brew CW transmitter,.......
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WX7G
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« Reply #2 on: March 19, 2012, 05:50:35 AM »

The IERP will be 1 watt and 5 watts depending on the QTH. A base loaded vertical having a radiation efficiency of 1% is about 35' tall and so it won't be difficult to build a useable antenna. Drive that with 100 or 500 watts (I did not correct for IERP vs ERP), depending on your QTH, and you are at the legal limit.

Some think 7 kHz isn't much of a band. Much of the 40meter US-to-US CW activity occurs in about 7 kHz. That's enough for 10-15 CW stations.

I read that Elecraft is coming up with a software mod to allow the K3 transverter output and the receiver to work on 630 meters. I have worked from coast-to-coast running an ERP of 1.25 watts on 160 meter CW so I expect to work 1000 miles on 630 meters.
« Last Edit: March 19, 2012, 06:06:27 AM by WX7G » Logged
AD4U
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« Reply #3 on: March 19, 2012, 05:54:39 AM »

I imagine that some of the abandoned AM broadcast towers at stations that have closed down will find some use.

Dick  AD4U
« Last Edit: March 20, 2012, 05:39:27 AM by AD4U » Logged
K0OD
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Posts: 2559




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« Reply #4 on: March 19, 2012, 08:54:13 AM »

I listen below the AM BCB occasionally with my TS-850 or TS430. My Flex is useless there, by the way.

Anyone try an active antenna for really low frequencies? The DXE active antenna is rated down to 100 KHz. Some others are rated down to about 10 KHz.
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KG4NEL
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« Reply #5 on: March 19, 2012, 09:00:11 AM »

I'm still trying to put a halfway decent signal on 160  Tongue

Very cool to have more room to experiment with, though.
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KB2FCV
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« Reply #6 on: March 19, 2012, 09:02:11 AM »

im curious to try out this new band. An antenna will be difficult but I have a couple of ideas. I wonder if there will be any 1/2 wave dipoles out there?  Roll Eyes
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WD9FYF
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« Reply #7 on: May 27, 2012, 12:59:19 PM »

Gentlemen (and Ladies) participating in this discussion:

After reading all the most interesting comments, I recognized a common theme:  everyone needs to read more on LF radio.  I recommend a very good book from RSGB (Radio Society of Great Britain), titled "LF Today".  It is an excellent book on the subject of radio communications on both 136 kHz and 500 kHz.  Our brethren in the UK have had a few years experience on us in this part of the radio spectrum and for that, we thank them.  There are a few typo errors, but the treatment is great.  There are answers to most questions in addition to those questions we never considered.  Like the majority of you, I am wanting to "test the waters".  When I read the follow up article after the WARC proceedings, I was more than a bit dismayed with the prediction of 5 years before it will happen for us in the USA.  Perhaps it will give us the time to check out our equipment for receiving and perhaps a bit of dummy load transmitter testing.

As for reception, the Icom IC-706 family has had LF receive since the straight IC-706.  Yaesu likewise made similar enhancements to their HF lines.

One clever approach is a transverter, generally to use the 30m band as home and "transvert" down to 630.

Harry. WD9FYF
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K0OD
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« Reply #8 on: May 27, 2012, 04:38:18 PM »

Quote
destined to be known as the 630 meter band.
Who says 630 meters?  From what I see most hams refer to it as 600 meters, not 630 meters. Admittedly there may be some confusion with 6 and 60 meters.

Note that DXSummit already carries spots for 137 KHz.
http://www.dxsummit.fi/CustomFilter.aspx?customCount=50&customRange=137

Recently DX Sherlock enabled spots for 600 meters (that's what they call it):
http://www.vhfdx.info/spots/map.php?Lan=E&Frec=06&ML=M&Map=W2L&DXC=N&HF=S&GL=N
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KE4YOG
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« Reply #9 on: May 27, 2012, 05:55:11 PM »

I have 42 acres. I was wondering if I could  make a 2 element yagi for that band. I hope it would fit. Wink
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W4OP
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« Reply #10 on: May 27, 2012, 06:48:57 PM »

I have been listening to the current 600M band for several years. With ARGO software monitoring the QRSS gang, you can fit a different station every few Hertz. But I also hear  a lot of beacons and 2 way QSO's. No one is going to use half wave dipoles. Even if you got it up 600' or so, it's still a cloud burner. Loaded Inverted L's seem to dominate for TX while active whips, loops, K9AY's and Beverages are used on RX. Even my 550' long Beverages perform very well down there.

You can buy a transverter from Juma, or Elecraft looks to make the K3 work down there. There are other synthesized TX designs out there also.

It's a fun band full of surprises.

Dale W4OP
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STAYVERTICAL
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« Reply #11 on: May 28, 2012, 02:00:01 AM »

This frequency range is part of the old 500Khz based maritime frequency segment.
It had been used by shipboard and coast stations as the primary working frequencies for many years.
The international calling and distress frequency was 500Khz, and working frequencies were between 400 and 512Khz.
From memory 476 used to be a working frequency, as was 425Khz.

If any of you guys can get hold of some old shipboard radio's (outside a museum), they are set up for transmit,
with tuners (and ATU's), and ready to go on CW (and MCW). No voice on those frequencies.
If you look up typical shipboard antennas, frequently multi-wire, single wire fed jobs - like a windom - you will see these were not elaborate.
Cloud warmers don't matter as much at these lower frequencies, as the ground wave is more predominant.

Many modern wide range receivers will tune down to 100Khz and up to 1 or 2 Ghz, so receiving should be ok.
Since these frequencies are so low that effective filters are easy to make, I will probably use the transverter idea with my FT817ND.
If I set it to 160m, the image will be easy to remove, and then its just making a power amplifier with garden variety power transistors.
I am not sure if there are any mode restrictions, but PSK31 could fit a few dozen stations in 3Khz, and still leave plenty left over.

It will be good to be back on 600m again - with the simplicity of LF/MF building, it should spur on some great home brew gear.

73 - Rob

« Last Edit: May 28, 2012, 02:58:24 AM by STAYVERTICAL » Logged
G3RZP
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« Reply #12 on: May 28, 2012, 04:25:36 AM »

If using old marine gear, make sure you transmit CW and not modulated CW, which was common on those rigs - and always used on 500 kHz.

A lot of the ship stations used around 100 watts into an antenna that looked around  5 ohms in series with about 500pF: a LOT of inefficency in both matching, antenna and loss in the trunking through which the feeder passed. But because of the conductivity of sea water, they got a long way. One older ship with masts giving a flat top some 150 feet long 80 foot above the water could regularly send telegrams to Lagos Radio (Nigeria) when off Liverpool (UK) in the early evening  with 400 watts.
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K0OD
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« Reply #13 on: May 28, 2012, 08:44:08 AM »

What can low power and a tiny antenna do at 600 meters? 

Highway department traffic advisory stations that broadcast AM on 530 KHz are limited to ten watts and antennas of 15 meters size. I was monitoring one about 40 miles away on my car radio. 530 is packed with hundreds of low power stations, and a few high power broadcasters in the Caribbean. Hams running digital or cw on clearer frequencies could do far better.

Anyone know how to convert the radiation of those 10 w traffic stations into EIRP? 
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W4OP
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« Reply #14 on: May 28, 2012, 07:01:03 PM »

Hi Jeff,
I regularly copy New England, Louisiana  and the west coast from North Carolina on the current 600M band, very easily.
Of course, like 160M, it's a winter band for anything serious.
Here's a good link to get interested amateurs started:
http://www.500kc.com/
Dale W4OP
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