The New 630m Amateur Band

1
The New 630m Amateur Band

• Rudy Severns
• N6LF, WD2XSH/20
• n6lf_at_arrl.net, www.antennasbyn6lf.com

2
A New Amateur Band

• After many years on the air using experimental
  licenses and intense politicking, at the 2012
  World Radio Conference (WRC) amateurs were
  allocated a new MF band 472-479 kHz.
• Telecom authorities in various countries are now
  in the process of authorizing their amateurs to
  use the band.
• Many Europeans, VE, VK, ZL and even XV are on the
  air and were bugging the FCC to move!

3
630 m Band

• 472-479 kHz.
• Emissions CW and digital modes
• Radiated power limited to 5W EIRP (Effective
  Isotropic Radiated Power)
• No limitations on transmitter power or antenna
  size. i.e. you can use a small transmitter with
  a large antenna or a high power transmitter with
  a small antenna.

4
Common Perceptions!

• A 7 kHz band is too narrow to be of use! The QRM
  will kill you!
• At such a low frequency with only 5W you cant be
  heard down the block!
• The manmade and natural noise levels are so high
  you cant hear anything!
• Its impossible for amateurs on city lots to
  erect an effective antenna.
• No amateur equipment transmits on 630m.
• None of this is true!

5
Why go to 630m?

• If youre a bit tired of the same old stuff 630m
  is a fresh challenge
• Very different propagation
• New very narrow digital modes
• But also the oldest mode CW
• Station-computer integration
• Receiving and transmitting equipment
• Antennas
• Boat anchor resurrection

6
Acknowledgements

• Much of the material presented here has been
  excerpted from the presentations of other
  amateurs
• Fritz Raab W1FR, WD2XSH/14
• John Langridge KB5NJD, WG2XIQ
• Neil Klagge, W0YSE,WG2XSV

7
500 kHz History

• Maritime CW calling/distress frequency since 1906
• 415-495 kHz commercial ship-ship and ship-shore
  working frequencies also Navy
• Rich traditions and history
• Amateurs banned for gt100 years!
• Automated satellite reporting adopted in 1980s
• CW and monitoring of 500 kHz ceased in 1990s
• 500 kHz now unused except by museum stations

8
The spectrum below the BC band
Navigational telex
9
ARRL experimental group

• First operation September 2006, W1FR experiment
  coordinator
• Originally 23 stations were licensed (WD2XSH/1
  thru WD2XSH/23)
• Frequency allocation 495-510 kHz, 20W ERP
• Ultimately it was expanded to 45 licensees with
  added frequencies 461-478 kHz
• This operation and that of many others provided
  the ammunition for the WRC allocation battle!

10
ARRL experimental stations
11
WD2XSH CW QSOs
12
CW DX reception reports
V73
13
CW beacon reception reports /20
14
WD2XSH/14 (W1FR)
15
Original WD2XSH/20 (N6LF)
16
Latest WD2XSH/20 (N6LF)
17
Latest WD2XSH/20 (N6LF)
18
Filters!
19
Boat anchors at N6LF
20
WD2XSH/5 (KW1I)
RBA receiver and an ART13 transmitter
21
WD2XSH/9 (W2ILA)
Maritime reserve XMTR
22
WD2XSH/12 (AI8Z)
HB pair 6146s
23
WD2XSH /15 (W5OR)
SAC H-25 NDB XMTR
24
Nice but you dont have to have it!
25
MF antenna basics!

• Succinct summary of LF/MF antennas by Woodrow
  Smith some 65 years ago
• "the main object in the design of low frequency
  transmitting antenna systems can be summarized
  briefly by saying that the general idea is to get
  as much wire as possible as high in the air as
  possible and to use excellent insulation and an
  extensive ground system.

26
In order of priority

• Make the vertical as tall as you can.
• Use as much capacitive top-loading as practical.
• Use loading coils with as high a Q as possible.
• Put a lot of effort into the ground system,
  making the radial density high near the base of
  the vertical and under the top-loading hat.
• Try to minimize conductor losses by using
  multiple wires and/or large diameter conductors
  (tubing!)
• Use high quality insulators, both at the base and
  at wire ends.

27
T and L antennas
28
Use the available supports
29
Umbrella vertical 1
30
Umbrella vertical 2
31
WD2XSH/14
32
WD2XSH/13 antenna
33
WD2XSH/19 antenna
34
WD2XSH/6 (W5THT) antenna
35
ATU box
36
Inside the ATU
37
Tuning the ATU
38
WD2XSH/20 antenna
39
Latest antenna at N6LF
95 high, 240 across, 128 150 radials on the
ground Theres a very extensive discussion of MF
antennas at www.antennasbyn6lf.com
40
Antenna poles at N6LF
41
Base tuning box
42
Tuning-matching inductor
43
Poles assembled on the ground
44
Pole erected with a crane
45
Propagation

• Daytime ground wave
• WG2XIQ range at 1W ERP about 225 miles on a
  quiet day for a typically equipped receive
  station
• Nighttime sky wave dominates plus some ground
  wave
• Sky wave can extend thousands of miles
• Behavior similar to bottom of the BC band at
  630-meters
• Sometimes there are surprises

46
Start by listening
47
Transmission modes

• CW
• QRSS ultra slow CW
• WSPR-2 -15 (weak signal propagation reporter).
  SNR down to -30 dB or lower!
• 2-way digital modes BPSK31, JT9, JT65, RTTY,
  hellschriber and a wide variety of new modes
  being created and tested almost daily!

48
WSPR K1JTWWW.physics.princeton.edu/pulsar/K1JT/w
sjt.html

• WSPR-2 and -15 is a tool for quantitatively
  testing propagation between a transmitting
  station and a receiving station. Typically the
  WSPR signals are transmitted periodically over a
  period of many hours with the receiving station
  recording the decodes and forwarding them on to
  WSPRnet.org where they are available in the
  database. Example

49
WSPR Mapping
50
WSPR Data

51
Software audio spectrum analyzers

• Waterfall and spectrum displays
• ARGO I2PHD
• Spectran I2PHD, www.weaksignals.com
• Spectrum lab DL4YHF www.qsl.net/dl4yhf
• These are all freebies!
• All these require is an audio signal from your
  receiver.
• They work with modern or boat anchors rx

52
Waterfall displays
WD2XSH/6 MS, /15 AR and /19 IL
53
RX antennas

• Use vertical polarization horizontal antennas
  tend to be very noisy
• Loops
• vertical loops, shielded or not, a quad loop
  works well
• K9AY terminated loops
• E-probe (very short vertical) with or without amp
• Existing HF Antennas dipole, random end fed
  wires, etc.
• Beverages and Snakes (BOG)
• Phased arrays of E-probes

54
Testing your receiver

• NAVTEX
• Maritime WX reports
• 518 KHz and 490 KHz
• RTTY
• Non-directional beacons (NDB)
• Low power, omnidirectional
• Numerous
• http//fivegulf.com/ndb/
• Part 5 Stations
• CW
• PC based digital modes WSPR, MSK, OPERA

55
THE QUEST CONTINUES ...

• Amateurs commercial interests

56
Resources 1

• Compiled by WA3ETD/WG2XKA with minor editing by
  N6LF.
• http//www.500kc.com Main Web Presence for
  WD2XSH ARRL MF Experiment. Lots of links and
  personal web sites from heavy hitters.
• http//www.w1vd.com Jay Rusgroves MF/LF Site -
  gear and info. Jay is the guy behind Advanced
  Antenna Research (AAR). Good stuff and a
  fantastic craftsman.
• http//www.500kc.com/W0RPK_Report/W0RPK_Report.htm
  The updated daily "action report from
  previous day MF activity. Also contains live
  links to many personal Ham/MF websites. Check
  this one for sure! Includes DX records...
• http//members.shaw.ca/ve7sl/ Details on
  broadband MF/HF receive loops and preamps. Good
  Stuff, easy to build.

57
Resources 2

• http//www.w8ji.com/radiation_resistance.htm
  Details regarding small antenna efficiency and
  calculations.
• http//www.strobbe.eu/on7yd/136ant A VERY
  detailed and heavy analysis of LF/ MF antenna
  design. Hours of valuable reading. Don't be
  discouraged when he says it won't work
• http//www.russthom.com/ndb Current list of MF
  Navigation Beacons in the US
• http//www.dxinfocentre.com/ndb.htm THE
  PREMIER list of MF Beacons (Hepburn) continuously
  updated, very organized. Use this to correlate
  calls and frequency.
• http//www.gw3uep.ukfsn.org/index.htm Rog's
  100W TX and many cool designs. Homebrew
  Heaven...don't miss. Check "MF Test Gear".

58
Resources 3

• http//toroids.info/T37-2.php Toroid specs and
  inductance/turn calculator- Get your Al values
  here. (Kits 'n Parts site)
• http//g3xbm-qrp.blogspot.com Everything MF
  and more. Guy never sleeps! There is no way
  Roger has a life outside his garden...currently
  into EARTH ANTENNA systems.
• http//www.antennasbyn6lf.com 2009/13 series
  of QEX articles on ground system experiments and
  analysis. Articles on 630m antennas. Required
  reading!
• http//www.radiomarine.org/pab1_12 Fun site
  dedicated to old-time marine MF.
• http//www.dl5swb.de/html/mini_ring_core_calculato
  r.htm
• ID your mystery toroid.

59
Resources 4

• http//www.electronics-tutorials.com/filters/trap-
  filter.htm
• Deep traps for our transmitters - 2nd and 3rd of
  475 right in the AM BCB and we can't have that!
  Cap across coil, easy. Well, a spectrum analyzer
  sure helps.
• http//w7iuv.com/ Hard core guy way out west.
  Check out his MF preamp.
• http//www.cliftonlaboratories.com/ Jack Smith -
  massive line of preamps, filters,
• active antenna. Plus a wealth of analysis,
  reviews and tech talk. MF oriented. Includes
  improved LPF for the Jackson Harbor 14
  up-converter. Fun spot on the net.
• http//wb9kzy.com/ham.htm
• Jackson Harbor Press, home of the 14
  up-converter. You get both a 4 and 10 mHz
  crystal, he's not making much on this unit.
• WG2XKA_at_gmail.com John sells the 20W TX
  converter as a complete kit with silk-screened
  PCB, available with 3.2 or 4.0 MHz I-F crystal.
  Optional GPS 10 MHz input.

60
Software/Hardware Resources

• http//aade.com/filter.htm Filter design and
  analysis package by the maker of the AADE L/C
  meter.
• http//wsprnet.org/drupal/ WSPR automated beacon
  reporting system
• http//tonnesoftware.com/svcfilter.html Really
  good filter design, using standard values with
  analysis and Monte Carlo.
• http//www.weaksignals.com/ by I2PHD, home for
  Spectran and ARGO weak signal viewers - sound
  card based, MUST HAVE...
• http//www.hdsdr.de/ Home of HDSDR package, my
  favorite, works best with the ensemble II LF
  receiver. Based upon WINRAD system, now free.
• http//fivedash.com/ Tony Parks SOFTROCK page.
  Get your Ensemble II. Also links to Yahoo
  Softrock users group. Lots of really tiny toroids
  to wind.
• http//www.qsl.net/zl1bpu/CMSK/cmsk.htm CMSK
  Software