Marconi Experimental Radio Communications Since 1895		Philip G0ISW Amateur Radio Communications  since 1985

 

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HF (High Frequency) radio signals in the range of 1.8MHz - 30MHz enable Amateur Radio transmissions to travel World-wide, provided that the right conditions exist to reflect the signal sent from the transmitting station (from a layer of the Earth's atmosphere called the Ionosphere) back to the Earth's surface and back again, perhaps several times before it reaches the Receiving station which could be many thousands of miles (km) away on the other side of the World. To see what HF propagation could be like now for your location, please try either the VOACAP online HF propagation prediction tool  or the VOACAP online HF coverage maps.

Ionization levels vary greatly between Day (Left) and Night (Right) causing HF radio waves to reflect off different layers of the Ionosphere or travel straight through them depending upon frequency and angle of transmission. Under certain conditions multiple reflections can occur between the Ionosphere and the ground or Sea to enable Worldwide communications.

The Ionosphere and therefore also the Maximum Useable Frequency (MUF) for HF Radio Communication is greatly affected by the Sun's on average 11 year Solar Cycle. In 2008 the Solar Cycle was thought to be at minimum, with HF radio communications much degraded from Solar Maximum, forecast to occur next in around 2013.

If you already use your computer soundcard for data modes such as PSK31, then you may like to try the new WSPR (Distant Whispers)  software by K1JT, which transforms your station into an automated beacon and weak signal reception hub. You will be amazed how far your low power signals can be heard and can see maps in real time. Great for antenna experimentation too. There is even a searchable WSPR spots database

Below is a map showing my 5W 10MHz WSPR signals reaching VK1UN in Australia using a small HF vertical on 8th April 2011.

The WSPRnet database shows my 10.140195 MHz signal to VK1UN in Australia had a SNR of -28 dB and the distance was my best yet at 16947 km.

The conditions that affect HF signals are in the main determined by the current Solar Cycle, which peaks every 11 years on average, unfortunately in 2010 we were just coming out of the Solar minimum, which means that conditions were poor and many of the higher frequencies above 14 MHz could not be reliably used.

Whether the path is in daylight or darkness also affects which layers of the Ionosphere will reflect HF signals and at what frequency. Amateur Radio FAQ.

HF Propagation prediction from UK by G0KYA

 

Propagation Stats Add Propagation Stats to your ham radio site.

HF links
VOACAP online HF propagation prediction tool	VOACAP online HF coverage maps	Current Space Weather	WWV Solar Data
NB6Z HF Digital modes	DX Summit	N1RZ DXers info all bands	ARRL Propagation predictions
Geophysical alerts description	NOAA Space Weather scales	Space Weather alerts	Current Space Weather warnings
D Region absorption map	Solar Terrestrial Despatch	NOAA Aurora 27 day forecast	GB7MBC (DXcluster for the North of England)
Announced DX Operations	SM3CER Contest Service	'CQ' Contests	DX Central
Solar Cycle 23 progression chart	Topband Propagation	Stealth antennas	Near Vertical Incidence Skywave antennas
IARU Regions 1, 2 & 3 HF Bandplans	DX Foundation	WSPR (Distant Whispers)	DX Summit
RSGB Propagation Forecast	GB2RS Propagation update	Live Aurora map	Greyline Map of Earth
PSK Reporter	GB2RS Propagation update	Live Aurora map	Greyline Map of Earth
RSGB Propagation Studies Committee	NU9N AM & ESSB Audio	PSK31 Readability, strength, quality	Islands on the Air (IOTA)
ARRL US Band Plans	HF Nets	RSGB HF Contest Committee	ARRL Contest Calendar

1.8 MHz (160 metres) 'Top Band' 1.810-2.000 MHz
Latest UK Band Plans	1.8MHz spots Cluster	Topband Propagation	160m propagation prediction table
G4VGO Kite & Balloon antennas	160m antennas	160m/80m coaxial receiving loops	EMPTY
Frequency	Mode	Remarks
1.810-1.838 MHz	CW	Morse Code (1.810-1.850 MHz 400w maximum)
1.838 MHz	USB (PSK31)	PSK31 Activity
1.838-1.840 MHz	All Narrowband Modes	Data modes
1.840-1.843 MHz	All modes
1.843-2.000 MHz	LSB, CW, AM	Voice & Morse Code (1.850-2.000 MHz 50w maximum)
1.843 MHz	LSB, CW	QRP
1.885 MHz	AM	UK AM activity
1.900 MHz	AM	UK AM activity
1.933 MHz	AM	UK AM activity
1.945 MHz	AM	UK AM activity
1.960 MHz	CW	DF Contest Beacons
1.963 MHz	AM	UK AM activity
1.980 MHz	AM	UK AM Net (Sundays 1100 UTC)
1.985 MHz	AM	UK AM activity
1.990 MHz	LSB	GB2RS News Broadcast (Sundays 2130 Local)

80m band (3.5 MHz)

This band is similar to 160m but as the frequency increases the D-layer absorption begins to decrease as it is proportional to the inverse square of the frequency. At daytime most contacts are worked with near countries, up to about 2000 km from your QTH. At night or using the gray line it is possible to exceed 9000 km (e.g. Europe to W, UA or JA). If you wake up in winter a few hours before the sunrise to avoid atmospheric noises you can work most DX stations (e.g. VK, ZL from Europe). In Region 1 the frequencies ranging between 3775-3800 kHz are usually dedicated to DX hunters.

3.5 MHz (80 metres) 3.500-3.800 MHz
Latest UK Band Plans	3.5MHz spots Cluster	80m antennas	EMPTY
EMPTY	EMPTY	80m ARDF	160m/80m coaxial receiving loops
Frequency	Mode	Remarks
3.500-3.580 MHz	CW	Morse Code
3.580 MHz	USB (PSK31)	PSK31 Activity
3.580-3.590 MHz	USB (Narrowband data modes)	Narrowband data modes
3.590-3.600 MHz	USB (AX25 Packet)	Packet Radio or unattended data modes
3.593 MHz	USB (PSK31 & MT63)	GB2RS News Data Broadcast (Sundays 2100 Local)
3.600-3.730 MHz	LSB, AM	Voice
3.600 MHz	AM	UK AM activity
3.615 MHz	AM	VMARS Net (Saturdays 0830 UTC)
3.625 MHz	AM	UK AM activity (National AM Frequency)
3.630 MHz	LSB	Digital Voice (DV)
3.650 MHz	LSB	GB2RS News Broadcast (Sundays 0900 & 1800 Local time)
3.730-3.740 MHz	LSB (SSTV)	SSTV
3.740-3.775 MHz	LSB, AM	Voice
3.740 MHz	LSB	UK & World Scout nets
3.775-3.800 MHz	LSB	Intercontinental working voice

60m band (5 MHz)

This band combines the best characteristics of the 80m (3.5 MHz) and 40m (7 MHz) bands, the 60 meter (5 MHz) band forms a communication bridge when propagation effects make use of 80 or 40m impossible for local-to-medium distance communications – often needed in emergency communication scenarios where there is no existing normal communications infrastructure or it is devastated. Less affected by D-Layer absorption than 80m, the 60 meter (5 MHz) band is an ideal candidate for Near Vertical Incidence Skywave (NVIS), the most commonly used technique capable of providing seamless local-to-medium distance HF communications.  

NVIS communication on the 5 MHz band in simplistic general terms is primarily a daytime event commencing at dawn, with peaking signal strengths in the afternoon and the band closing to SSB voice communications shortly after dusk. However there are exceptions to this general rule and it can be possible for NVIS communication to extend in the evening after dark using weak signal data modes such as Olivia 16/500 to around 21:30z, as at March 2013. Later 5 MHz openings to further away stations are possible via the F layer and QSO's inter G from Shetland to Hereford have been open as late as midnight before the band shuts for all inter G comms.

The Primary user in the UK is the Ministry of Defence (MoD), UK amateurs are only permitted to transmit within this band if they have a current Notice of Variation (NoV) to their FULL amateur radio license issued by OFCOM or RSGB. An NVIS antenna configuration is a horizontally polarized (parallel with the surface of the earth) antenna placed low to the ground to ensure a high angle of takeoff, Vertically polarised antennas are not suitable for NVIS as they produce low angles of radiated signals and therefore the skip distance will be too great for local HF communications.

Within the UK on 5 MHz signal reports prior to 1st January 2013 did not use the conventional amateur radio RST format, but used instead the SINPO table recommended by the ITU, shown below.

UK Beacons (all 10 W maximum)

GB3RAL - Oxfordshire IO91IN    Transmits 00, 15, 30, 45 minutes past the hour    (This beacon is 361km away from my station)

GB3WES - Cumbria IO84QN        Transmits 01, 16, 31, 46 minutes past the hour    (This beacon is 17km away from my station)

GB3ORK - Orkney isles IO89JA   Transmits 02, 17, 32, 47 minutes past the hour     (This beacon is 482km away from my station)

Below is a screen shot of the UK 5 MHz beacons showing their recorded respective signal strengths between the 3rd and 4th December 2012. Of interest is the sharp rise in signal strength level after 0700, which when you compare with the real-time digisonde image beneath you can see the sharp rise in foF2 frequency that occurred at the same time i.e. sunrise here! Windows software used is GB3RAL.exe by Peter G3PLX

COLOUR KEY:
___ Noise
___ GB3RAL
___ GB3WES
___ GB3ORK

Too see the latest maximum useable frequency for Inter-G working via NVIS look at the latest Chilton Ionogram http://www.wdc.rl.ac.uk/wdcc1/iono_menu.html and the fxI figure, in the example below it is 7.10 MHz and is indicated by the green coloured atmospheric reflections.

40m band (7 MHz)

This band is still under the influence of the D-layer and is the lowest band showing an appreciable skip distance, up to 500 km at night. At noon it is hard to work stations located over 800 km away, while working with the gray line or at night, this band is open to DX contacts. This band is slightly influenced by 11-year solar cycle. Atmospheric noises are still present, but not as strong as on the lower bands. QSOs can however be difficult during summer months, but signals are not completely overridden by static. This is also one of the most crowded bands and do not be surprised to find in Europe and during weekends each station within 1 kHz or so from each another. Recently in Region 1 this band was made made accessible to amateurs from 7100 kHz up to 7200 kHz. Note that it is already open to amateurs to 7300 kHz in North and South America.

30m band (10 MHz)

Conditions are similar to the 40m band, but this band works better in summer showing some of the properties of the 20m band. As communications reach 1600 km at daytime and 12000 km or more at night, this band is considered open for 24 hours a day. It is also the band least affected by variations of the solar cycle. However this band is affected by the ionization level of E and F-layers and at night, during the minimum of the solar cycle, it is regularly above the MUF for most DX paths, becoming thus the higher workable frequency for night time communications. With very few exceptions this band is reserved for digital modes and CW.

20m band (14 MHz)

This is the primary HF band most used by Radio Amateurs and open throughout the solar cycle in daylight hours. Indeed, the 20m band is the DX band par excellence and is considered by many hams as the most reliable band for hunting DX stations because atmospheric noises are weak.It is practically usable all the day long as soon as there is propagation, and mainly in summer, and all the more during periods of high solar activity. It is only during the minimum of the solar cycle that this band closes down in the late afternoon and is unusable at night.The 20m band shows an appreciable skip distance reaching about 700 km in daytime and exceeding 1600 km at night. It is thus not suited to local QSOs.

14 MHz (20 metres) 14.000-14.350 MHz
Latest UK Band Plans	14MHz spots Cluster	20m antennas	EMPTY
EMPTY	EMPTY	EMPTY	EMPTY
Frequency	Mode	Remarks
14.000-14.070 MHz	CW	Morse Code
14.070 MHz	USB (PSK31)	PSK31 activity
14.070-14.080 MHz	USB (PSK31, PSK63, MFSK)	Narrowband modes
14.079 MHz	USB (MFSK)	MFSK activity
14.080-14.089 MHz	USB (RTTY)	RTTY
14.089-14.099 MHz	USB (AX25 Packet)	Packet Radio
14.099-14.101 MHz	Reserved for Beacons	Beacons only
14.101-14.112 MHz	USB (AX25 Packet)	Packet Radio
14.112-14.350 MHz	USB, AM	Voice
14.130 MHz	USB	Digital Voice
14.178 MHz	USB	'Audio Net' ESSB (Hi-FI quality SSB speech)
14.195 MHz	USB	DXpedition calling
14.222 MHz	USB	Mobile /M activity (New proposal)
14.230 MHz	USB (SSTV)	SSTV centre of activity
14.260 MHz	USB	IOTA activity
14.285 MHz	USB	QRP Centre of activity
14.286MHz	AM	AM calling
14.290 MHz	USB	UK & World Scout nets (0700UTC daily Summer)
14.295 MHz	USB	Goddard Space Shuttle rebroadcasts
14.300 MHz	USB	Global Emergency Centre of activity
14.342.5 MHz	USB	HFpack Net Primary Portable, Manpack, Mobile
14.345 MHz	USB	VHF Net

 

 

12m band (24 MHz)

This band varies depending on the solar cycle and combines the best from the 15m and 10m bands. One year before  solar cycle maximum and up to one year after this peak, this band allows DX contacts until after sunset with practically any kind of antenna. However, when the solar cycle descends from maximum, this band is open at mid and low latitudes only at daytime, with very few openings after sunset. Near the minimum of the solar cycle this band becomes unusable, except at daytime for the highest latitudes with some North-South openings. This band is open to Sporadic-E traffic between the late spring and early winter. The skip distance reaches 1600 km at daytime and vanishes at night.

10m band (28 MHz)

This band works in the same way as the 12m band, but is characterized by a great variability according to the solar cycle. During the peaks of the solar cycle DX contacts can be established with very low power and over 12000 km away. It is mainly a daytime band, but remains open a few hours after sunset. During moderate solar activity this band opens near noon for some trans-equatorial communications, but is closed for the higher latitudes. During the minimum of the solar cycle this band is straight out dead. There are however some exceptional openings for Ionoscatter, Meteor Scatter and Sporadic-E. This occurs mainly between April and early August allowing multi-hop communication up to 4100 km. This band is relatively quiet compared to the 15m band, for example, but it works globally very well for DX communications.  The skip distance reaches 2000 km at daytime.

Shown below is a screenshot using PSK Reporter of stations heard by me on 28.076 MHz (10m), using JT65 HF mode, on Tuesday 18th October 2011.Amazing conditions considering we are only a little way out of sunspot minimum and already DX is visible on 4 Continents all at the same time.

Here below is the accompanying JT-65 HF software screen grab showing ZS1LS in South Africa, PU3WSF in Brazil and several US stations.

The holder of an Advanced (Full) UK licence may allow an unlicensed person to send a greetings message provided it is under the direct supervision of the licensee, or if a club an authorised club member, who must operate the transmitter and identify the station.

Each greetings message must not be longer than five minutes and each person may send only one message to each station with which the station is in contact. Greetings messages may be sent and received only within the UK, or to and from stations in the United States of America, the Republic of Maldives, Gibraltar, Malta and Falkland Islands.

Greetings messages may also be sent to or from stations in Canada and Pitcairn Islands provided that each greetings message does not exceed two minutes.  When using a digital mode, anyone may type the message for transmission.

                        

Amateur Radio Societies
Radio Society of Great Britain	RSGB News	RSGB Contest	Deutscher Amateur Radio Club (DARC)
ARRL HQ	Vintage & Military ARS	Royal Signals ARS	Eden Valley Radio Society (EVRS)
Radio Amateurs Old Timers Association	Radio Society of Bermuda	Royal Naval Amateur Radio Society	Associazione Radioamatori Italiani
Irish Radio Transmitters Society	Cyprus Amateur Radio Society	Gibraltar Amateur Radio Society	International Amateur Radio Union
British Amateur Television Club (BATC)	Cyprus Amateur Radio Society	Gibraltar Amateur Radio Society	International Amateur Radio Union

 

 

EMC / TVI
RSGB EMC Committee	EMC Leaflets 1-8	RA 179 TV & Radio Leaflet	Ofcom Radio & TV Interference
BBC TV reception advice	EMPTY	EMPTY	EMPTY

 

HF Antenna homebrew design
Near Vertical Incidence Skywave antennas	Stealth antennas	Balloon & kite antennas	Antennex
$4 special	Dipole & inverted 'V' calculator	End-fed halfwave antenna	Low Bands antennas
Wire Loop antennas	Horizontal wire loops	Loop antenna calculator	Empty
Kites & aerials	Loop antenna Yahoo Group	Loop antennas	Antenna design software
Linear loaded inverted 'V'	80/40 Super Loop	'Grasswire' hidden HF antenna	Radialwave

 

For Sale / Wanted Adverts
G3CWI flea market	E-Bay	Freemart

Extended SSB (Lo, Mid, Hi-Fi audio quality)
NU9N AM & ESSB Audio	Spectra Plus 2.32 Real-time Spectrum analyser	W2ONV	W2IHY
W3OZ	Audio Software	Behringer	Heil Sound
N2VU	W2FLA	14.178 MHz Audio Net	W2ONV (SK)

I  became very interested in experimentation with different microphones, and audio mixing, and regularly listen to the US 'Audio Net' on 14.178 MHz each day, where superb SSB audio could be heard. I was saddened to hear that Bill W2ONV had become a silent key in 2007, as he had the best audio I have ever heard on HF and was a true gentleman always helping others. I had the pleasure of previously working Bill on air from my car as EI/G0ISW/M and talking to him across the Atlantic, after having listened to him many times before and since. He will be missed by those Radio Amateurs who knew him.

 

QSL lookup & card suppliers
QRZ.COM		Octavia QSL cards
QSL Factory	Buckmaster	Electronic eQSL cards

Miscellaneous
Radio pictures	DX Zone	HF Nets	IRC #CQDX Chat
Morse Code	Eham.net radio reviews	RSGB HF prediction	Ultimate Radio Mods site
Scout Nets	K2BJ HF Mobile Message board	The AM Window	Maritime Mobile Service Network
Amateur Prefix listing	RSGB EMC pages	Worked All Britain	RSGB DCC
RSGB Spectrum Forum	UK 5 MHz Band	RSGB HF Awards	RSGB News Broadcast schedule
SW broadcast frequencies	RTTY	Empty	Empty
Empty	NB6Z Digital Ham Radio Modes explained	MFSK	Vintage & Military ARS
Bletchley Park Museum	List of Major Amateur Radio Societies	Amateur Radio FAQ	Number (Spy) Stations
Clandestine Radio	Vanity Callsigns	Greyline View	AC6V links
BR68 UK License conditions	GB7MBC (DXcluster for the North of England)	RSARS Nets & frequencies	PRC military radio descriptions

it's private

		Send formatted VHF DX Cluster spot
If you cannot see the full index shown on the left edge of your screen, please go to my main page at  http://www.qsl.net/g0isw © Copyright G0ISW. Page last modified 5th March 2013. All Rights Reserved.