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Author Topic: 630 meters  (Read 41697 times)
N3OX
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« Reply #15 on: April 02, 2012, 08:51:19 AM »

Getting 1 watt ERP is much more difficult.  It likely will require 50 - 200 watts
output from the transmitter because the antenna will be rather inefficient.

But generating many hundreds of watts down there is easy with cheap transistors so at least we've got that going for us Cheesy
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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
KB1WSY
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« Reply #16 on: July 27, 2012, 05:28:51 AM »

Once I have cut my teeth in ham radio on the 80 and 40 meter bands, I am vaguely thinking of experimenting on 630 meters ... using my BC-453 receiver in "native mode" as the receiver, since the new 472-479 KHz band is squarely within its tuning range.

For a transmitter, there is an intriguing possibility in the ARC-5 series: "Special Use Transmitter, range 0.5 MHz to 0.8 MHz, designation T-15/ARC-5." I will do some further research. Perhaps someone reading this has some knowledge or experience with that one ... I'm assuming this set is very hard to find, though.

Just for the heck of it, I calculated a tank coil. I assumed that nothing was changed in my pending "LCT-65" transmitter i.e. no change in the tuning capacitor and no design changes in the coil: same diameter, same turns per inch as for the other bands. My 80-meter band coil is about 2 inches high and spaced at 6tpi with 1.75" diameter. A coil for the 630-meter band would be 90 inches (4.5 meters) tall! Need to get going on that long PVC pipe and drill a hole in the ceiling.... (Yes, this exercise was meant as a joke!)

73 de Martin, KB1WSY
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AC5UP
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« Reply #17 on: July 27, 2012, 05:40:38 AM »

http://www.lowfer.us/mo/images/mo_4b.jpg
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Never change a password on a Friday                
KB1WSY
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« Reply #18 on: August 06, 2012, 01:44:12 PM »


Nice!!! Now how about this: http://tinyurl.com/c28wfyb?
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W0FM
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« Reply #19 on: August 08, 2012, 12:07:18 PM »

That's a pic of AC5UP's water heater!

WØFM
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N8CMQ
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« Reply #20 on: August 25, 2012, 03:22:45 PM »

At that frequency, could you linear load the earth as your antenna?
Maybe a gama match?
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W8JI
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« Reply #21 on: August 26, 2012, 03:17:28 PM »

I have a complete 100 watt NDB transmitter sitting in my carport.
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K4EJQ
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Posts: 101




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« Reply #22 on: August 26, 2012, 08:07:48 PM »

Tom; My neighbor has not only the NDB transmitter, but the vertical antenna with large top hat as well up at his QTH a few blocks away. I'm building a 475 KHZ "Pixie"-type solid state transmitter to drive a homebrewed single 4CX-350A "Linear" amplifier. That should make a little more noise on an otherwise noisy band. My antenna will be my 160 meter inverted "L" plus additional tuning equipment. Looking forward to it and hope you will join us. 73, Bunky, K4EJQ
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W8JI
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« Reply #23 on: August 27, 2012, 05:10:56 AM »

Tom; My neighbor has not only the NDB transmitter, but the vertical antenna with large top hat as well up at his QTH a few blocks away. I'm building a 475 KHZ "Pixie"-type solid state transmitter to drive a homebrewed single 4CX-350A "Linear" amplifier. That should make a little more noise on an otherwise noisy band. My antenna will be my 160 meter inverted "L" plus additional tuning equipment. Looking forward to it and hope you will join us. 73, Bunky, K4EJQ

Sounds great!

Any idea when we might be getting the band?
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K4EJQ
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« Reply #24 on: September 04, 2012, 11:48:56 AM »

Hello out there in 630 meter land: FYI- wanna CHEAP xtal for your next 630 meter transmitter? Try one of the ceramic resonator / filter units that are being sold on E-Bay and other venues. I bought 100 for about $9.00 shipped from China. They work nicely in place of a crystal and can be VXO'd around the band about 1.5 KHZ or so depending on the variable capacitor you use. They are listed as being 472 Khz( +/- 2 Khz).  I use them in my "Pixie"- style cw exciters on 630, 160, and 80 meters. Stability is good through 80 meters. Your mileage may vary. Enjoy/73, Bunky, K4EJQ
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K4EJQ
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« Reply #25 on: September 16, 2012, 05:45:31 PM »

Hello; Interim amp built from a discarded WRL Globe Scout Model 65 carcass. Driving the 6146 amp stage with a solid state "Pixie"-type transmitter and getting 25 plus watts output on CW. All spurious radiations are down at least 55 dbc at the output of the low-pass filter. Using one of the ceramic resonators mentioned in above post for the VXO. Are we having fun yet? 73, Bunky, K4EJQ
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K4EJQ
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« Reply #26 on: September 20, 2012, 09:36:54 PM »

Hello All; Moving on with the building of the 630 meter station. Finished mods to the existing remote controlled( from the operating position) HF inverted L multi-band tuner allowing 475 Kcs operation. SWR is below 1.25 to 1 @473.5 Kcs. What really panned out was the receiving improvement using the modified tuner and the external low-pass filter to cut out the AM broadcast band intermod ( spurs) on the IC -706 MK2 G on the 630 meter band. CU guys/gals on the band -whenever. 73, Bunky, K4EJQ
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N4AEQ
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« Reply #27 on: September 21, 2012, 02:31:26 AM »

 Sounds like we need a forum devoted to 630 meters, or atleast one that includes homebrew ideas,plans,photo's and not just log info.
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K4EJQ
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« Reply #28 on: September 21, 2012, 12:26:14 PM »

Hello again from the "basement band". Last night -this AM after tweaking of the "aerial" and tuner hearing so many DX NDBs it was unreal. From Canada to the Carib. islands they were coming thru. Yes static crashes hit S9+20 from time to time but no problem copying. Copied several previously unheard WD2SXH beacons in the 630 meter band. Later this afternoon I retuned the NDB band and heard several Piedmont  NC and SC Beacons (150 Mile distant) in the 400-525 KCS portion. Are we having fun yet-we will when we get permission to use it!!!!
CU WHEN.....Bunky, in the basement
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K4EJQ
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« Reply #29 on: September 26, 2012, 11:33:45 AM »

Hello Again from the "basement band". Added a second 6146 to that old Globe Scout carcass I'm using for a "linear" amplifier for my Pixie TX on 475 KCS. Getting over 60 watts output on CW . Running in the AB mode with an adjustable bias supply also added to Scout. Regulated screen supply also an addition. Other than adding more and more radials to the L, just listening to WD2XSH/31 nightly along with a few others and wishing I could answer their CQs, HI. Tell me if I'm boring you with this "monologue". 73 and CU when..., Bunky, K4EJQ, in the basement
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