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Author Topic: Does this forum include LONG wave listening (LOL)  (Read 19751 times)
K0OD
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Posts: 2578




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« on: November 19, 2011, 12:27:08 PM »

How about the new Lowfer bands? What do you find works well around 500 kHz? My Flex 5000 is beneath worthless even on the AM broadcast band. I think my old Kenwood TS-850 is good. Has anyone published a Lowfer ham receiver comparison?

 CQD! ... I need help with the new old tech?
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WB6BYU
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Posts: 13479




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« Reply #1 on: November 20, 2011, 09:08:49 AM »

Shouldn't the title read "LWL" instead of "LOL" in that case?


Most rigs have reduced sensitivity on the AM BC band.  One simple solution is to
build a converter - for example, using a 4 MHz canned oscillator driving a DBM
you can use the 4.0 - 4.5 MHz range on your radio to tune 0 - 500kHz.  Then
it is just a matter of designing preselectors for each frequency range you want
to listen to.

Total parts count of the circuit can be less than 10 (including switch and connectors)
plus whatever front-end filtering you need to keep out the local AM BC stations.
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N5RWJ
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Posts: 461




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« Reply #2 on: November 20, 2011, 03:35:33 PM »

Rumors has it that a new allocation on 200m for cw could be coming.
« Last Edit: November 21, 2011, 11:35:01 AM by N5RWJ » Logged
WB6BYU
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Posts: 13479




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« Reply #3 on: November 20, 2011, 06:54:34 PM »

I thought that was 600m (500kHz.)

200m puts it at 1500kHz, and I don't think that would go over very well.
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N5RWJ
Member

Posts: 461




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« Reply #4 on: November 21, 2011, 11:38:28 AM »

I thought that was 600m (500kHz.)

200m puts it at 1500kHz, and I don't think that would go over very well.
Think your right, around 400 to 500 KHz.
« Last Edit: November 25, 2011, 09:50:20 AM by N5RWJ » Logged
KD6KWZ
Member

Posts: 276




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« Reply #5 on: November 24, 2011, 01:07:27 AM »

Quote
Think your right, around 400 to 500 Hz

Oops, typo there,  600 meters, or 500 KHz, an Amateur band used in some countries.

400 to 500Hz would need a MAMMOTH antenna!  Grin
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WB6BYU
Member

Posts: 13479




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« Reply #6 on: November 24, 2011, 08:01:49 AM »

500kHz is the old maritime CW distress and calling frequency.  The proposal is
for a narrow ham band in that range somewhere - perhaps just a bit higher.

Some countries also have a ham allocation around 170 - 175kHz.

Antennas are a real challenge to get any sort of efficiency, but contacts have
been made from New Zealand to Canada.
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AC5UP
Member

Posts: 3927




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« Reply #7 on: November 24, 2011, 04:37:29 PM »

200m puts it at 1500kHz, and I don't think that would go over very well.

There are one gallon AM stations in my part of the world that have been through every format imaginable trying to find their groove... For all we know, just because C&W didn't catch on doesn't mean CW won't.

All Morse, All The Time.
1500, KQRS..........
   Roll Eyes
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Never change a password on a Friday                
KD6KWZ
Member

Posts: 276




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« Reply #8 on: November 25, 2011, 12:15:21 AM »

Quote
Some countries also have a ham allocation around 170 - 175kHz.

Antennas are a real challenge to get any sort of efficiency, but contacts have
been made from New Zealand to Canada.

There's been a no license, 1 watt, 50 foot antenna & feedline maximum length, band 160 to 180 KHz for years. Yet, some manage to work that band, with all the restrictions.

From the NIST page on WWVB's history:

http://tf.nist.gov/stations/wwvbhistory.htm

Quote
The station known today as WWVB began life as radio station KK2XEI in July 1956. The transmitter was located at Boulder, Colorado and the radiated power was less than 2 watts. Even so, the signal was monitored at Harvard University in Massachusetts.

They also have some serious antenna issues, due to being on 60 KHz.
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KE5JPP
Member

Posts: 0




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« Reply #9 on: November 25, 2011, 06:58:10 AM »

Shouldn't the title read "LWL" instead of "LOL" in that case?


Most rigs have reduced sensitivity on the AM BC band.  One simple solution is to
build a converter - for example, using a 4 MHz canned oscillator driving a DBM
you can use the 4.0 - 4.5 MHz range on your radio to tune 0 - 500kHz.  Then
it is just a matter of designing preselectors for each frequency range you want
to listen to.

Total parts count of the circuit can be less than 10 (including switch and connectors)
plus whatever front-end filtering you need to keep out the local AM BC stations.

Most SDR receivers like the QS1R and the Perseus cover down to 10 kHz without degradation of sensitivity. 

Gene
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KH2BR
Member

Posts: 103




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« Reply #10 on: November 25, 2011, 07:46:44 AM »

There are 2 kits that will get you on the air down there. Surface mounted parts, If you have not tried surface mount kits, and really tried, you don't know what a enjoyable project you are missing. The link is here. http://www.nikkemedia.fi/juma-tx500/
I have built there qrp rigs and it is nothing but pure enjoyment.  Here is there main page
http://www.nikkemedia.fi/juma/

Robert  KH2BR
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KE5JPP
Member

Posts: 0




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« Reply #11 on: November 25, 2011, 01:41:02 PM »

There are 2 kits that will get you on the air down there. Surface mounted parts, If you have not tried surface mount kits, and really tried, you don't know what a enjoyable project you are missing. The link is here. http://www.nikkemedia.fi/juma-tx500/
I have built there qrp rigs and it is nothing but pure enjoyment.  Here is there main page
http://www.nikkemedia.fi/juma/

Robert  KH2BR

Isn't this a SWL forum?  The first link is to a transmitter.

Gene
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KH2BR
Member

Posts: 103




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« Reply #12 on: November 25, 2011, 04:12:48 PM »

It sure the heck is a swl forum, and it also pertains to hams! (EHAM.NET). Read further into the link and it tells you what features the tx500 has that will enable you to receive on the gear that you already have. If a 500 kHz receiver is not available, you can switch ON the built-in high dynamic RX up-converter and listen to the 500 kHz band with a 3.5 MHz receiver.
If you don't like to buy a kit, then use the schematics and build your own up converter and band pass filters. With the kit, all of the math has been figured out for you so you dont have to brew your own.

Robert KH2BR
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OH6I
Member

Posts: 26




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« Reply #13 on: November 26, 2011, 08:23:51 AM »

K0OD, you very lucky because you own TS-850.
It is very popular with hams who work in 136 kHz and 500 kHz bands. It have good sensitive under 500 kHz because it not have attenuator like TS-870, TS-950 etc radios.

Only receiver comparison for LF bands I have seen RSGB book: "LF Today, a guide to success on 136 and 500 kHz" and TS-850 got high praise. Hope this have any help...

Jari
OH6I
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K0OD
Member

Posts: 2578




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« Reply #14 on: November 27, 2011, 06:21:12 AM »

Great info Jari.  "LF Today" is available from the ARRL and other sources. There have been two editions:
http://www.arrl.org/shop/LF-Today

Here's a Russian site that has a full chapter from that book that answers my original question. From the age of the equipment listed, I gather the chapter is from the first edition of "LF Today."  http://relax-sdr.3dn.ru/_ld/0/82_10-136kHz.pdf

TS-850 is said to be the "most popular amateur bands transceiver used to receive on 136 kHz." Only thing I can offer is that I have picked up some 500 kHZ ham beacons with it and a hunk of wire for an antenna.

BTW, I happen to own a '77 vintage portable SWL receiver that's a cult item among BCB SWLs, the Panasonic RF2200. I ran a comparison between it and my TS-850 and thought the 850 performed far better and even had better AM fidelity with its built in speaker. Of course the 850 is from the early 90s and is hardly portable.

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