Operating on the 630 Meter Band by John Langridge KB5NJD

Nice to see this chunk of the Medium Wave band being made available to Amateur Radio users.
472 - 479 Khz. Until very recently, 1999 - 2000, these frequencies were being used by Coast Stations
around the world to transmit CW traffic to ships at sea, mainly in coastal waters up to a few hundred
miles away. For example, 472 Khz was allocated to Kuwait Radio 9KK and 476 Khz to Aden Radio 7OA.
Any ships communicating with these stations would probably use 468 Khz or 480 Khz, which were
two of the frequencies allocated to shipping.

Dave SV1RUX

 

Im not sure I understand. Does the 735 transverter output provide full transceive on 630 even if the TX power is in the milliwatt range? There is no filtering at those levels for any band if it follows the Kenwood version.

If the power is via the power amp section what is the actual input power? Id hate to be running ~ 170w INPUT to the finals to get 5W out
Disabling the 160M filter section should then maybe provide an unfiltered 100W on 630. A suitable filter could be fitted internally if there is room or externally; I have never been inside a 735 nor studied the manual.....yet.

Carl

 

No. That's the transverter's job.

 

That's really cool about 630m. I'd love to get something working.

I'm still working on trying to get something setup on 160. I was thinking stealth weather balloon or a WW1 style kite at night. I really like your loop. Nice work!

 

I'm surprised at what I can hear down there with my 50 foot wire and a 9:1 balun. I have heard quite a few on WSPR, including stations in Tennessee and Texas. If we can do it on WSPR, FT8 or JT9 should work fine, too.

 

It is quite possible to operate on 630m from an average suburban lot. I have had spots with Hawaii, which is over 7000km from here on a regular basis.

 

So what frequency is on the transverter output?

 

I am a former Radio Officer and i remember that we had on board a transmitter for 410 / 425 / 454 / 468 / 480 / 500 and 512 kHz mostly with 400 Watts. The main working frequency of our coast stastion Norddeich Radio/DAN was 474 KHz. Especially in the winter nights a wide area was covered. It was great. Hermann, DL6BCX

 

Norddeich Radio/DAN on 474 Khz could be heard all the way across the atlantic to the US east coast. Scheveningen Radio/PCH on 464 Khz was also strong.
There are many excellent recordings of Medium Wave CW on the following site:

http://www.radiomarine.org/audio/list?panel=pab1_13#pab1_13

Dave SV1RUX

 

What were the mariners using for antennas aboard ship?

 

I hope 630 meter band is not being developed so that it will become our new ham band while big business takes away another existing allocation we all like.