Target HF3 User manual

A GUIDE TO
USING
THE TARGET
HF3
RECEIVER
S H 0 RT W AV E L I STE N I NG
r
0
BY
ALAN. J. MULLEY
luIQ 1

The TARGET HF3 receiver covers the entire spectrumfrom 30 kHz to
30 MHz.
For thebeginner, what does thismean???
The symbol Hz (pronouncedHertz, and namedafter a famous radio
pioneer) representsone complete electromagnetic wave ina second.
A
kilohertz (kHz) isone thousand waves per second, and a Megahertz
(MHz), a millionwaves in a second. The number
of waves per second is
calledthe Frequency.
1 WAVE IN 1 SECOND = 1 HERTZ
Often a reference is made to a stationswavelength rather than it’s
frequency. Highfrequency signals have short wavelengthsand low
frequency signals have long wavelengths. The frequency of a signal in
kHz isgiven by dividing 300,000 by the wavelength in metres.
SHORT
WAVE MEDIUM WAVE
- LONG WAVE
- -
HIGH FREQUENCY LOW FREQUENCY
Why are high frequency waves shorter than low frequency ???
Imaginethat you couldsee a wave travellingpast you at the speed of
light. The wavelengthwould bethe distance betweentwo adjacent
waves.
If you increasethe frequency of the waves then you would get
morewaves inthe same space
so the wavelengthwould be shorter.
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Radiowaves, light, X rays, are all electromagneticwaves. The only thing
that differentiatesthem istheir frequency.
I
For conveniencethe rangeof frequencies usedfor radio
communicationsissplit intobands. Frequenciesbelow 100kHz are
calledVery Low Frequencies(VLF). The LongWave (LW) covers
frequencies between 100kHzand
300 kHz, whilst the MediumWave (M W)
coversthe frequencies between300 kHz and 1.6 MHz (1600 kHz).
'
- VLFl LW
All frequencies between 1.6 MHz and 30 MHz are referredto as Short
Waves
(S W).
MW sw I
The HF3 covers all of these bands inone continuous sweep with steps
of 1kHz. Numbersto the left of the decimal pointare in MHtwhilst
those to the rightare
in kHz.
e.g. 0.198 is expressedas 198kHz or 0.198 MHz
14.386 isexpressed as 14386kHz or 14.386 MHz
Turning the tuning knob slowly advancesthe tuning in 1 kHz steps,
turning a littlefaster the steps change to 10kHz, faster still the steps
become 100 kHz, and a really fast spin will make the steps 1 MHz.
This makes it quick and simple to hop from one end of the spectrumto
the other.
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GETTING STARTED
The HF3 issuppliedwith a simple long wire antenna connectedto a
phono plug. The wire lengthis
30 feet and is a good compromise for
generalcoverage.
A shorter wire will be less sensitive and, whilst a
longer wire may pick up more of the desired signal,
it may also pick up
much more undesirablesignals inthe form of interference.The
antenna wire should be strung up as highas possible and as far away
from mainswiring, striplights,televisions, or any other source of
interference (see Page
9). The shorter black wire from the phono plug
isthe groundterminal. Connectthis to somethingthat is well
grounded.
A cold water pipe or *mains earth is usually adequate. Do
not connect to anything you are not certain is earthed.
*Do not attempt to connect directly to any Mains Supply without the
aid of a qualified Electrician.
Plugthe 12 Volt linefrom the power supply intothe receiver, plug in
the antennaand set the attenuator on the rear of the receiver to it’s
normal position. You are now ready to go.
Switchon the receiver by rotating the volume controlclockwise. The
display
will show the frequency and the mode. Set the mode to AM. To
select mode
USB, AM and LSB press MOD. This rosters through the
modes. Set the Clarify controlto it’s central position. Adjust the volume
to a convenient leveland use the tuning knob to move up and down
the spectrumand listento the AM stations.
To Store a Frequency In memory
Tune to the desired frequency and press MEM. The Smeter then
becomesthe memory location pointer. Select the memory location
usingthe tuning knob. When the desired locationis selected press
MEM, the desired frequency is stored in that locationand the receiver
returned
to normaloperation.
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To Recalla Frequencyfrom memory
Press RCL. The S meter then becomesthe memory location pointer.
Selectthe desired memory locationusing the tuning knob. When the
desiredlocation is selected press
RCL. The desired frequency is
recalled and the receiver returnedto normaloperation.
The
RST key resetsthe microprocessorand revertsto memory
position 1.
Tune to 100kHz and you will hear a fast ticking noise. These are the
pulsesof LORAN C, this is a long range navigation system in use all
over the world.
A little lower infrequency, between80 and 90 kHz you
can hear the carriers of the DECCA system. This systemwas set up in
1944 for the D day landingand has been incontinuous maritime use
ever since. Encrypteddata is transmitted to military submarinesat
VLF. This covers very great distances. Speech is not transmitted.
The Mediumand Longwaves are crowdedwith domestic and foreign
broadcaststations. When tuninga station rotatethe tuning knob to
obtain the highest number on the
Signal Strength Meter.
Tune between 300 and 400 kHz for marine and aeronautical beacons.
These are used by shipping and aircraftto get bearings. Each beacon
transmits a Morsecode ident of it’s name. The Morse is very
slow and
continually repeats, so
if you don’t read Morse, you have plenty of time
to look it up. The ident letters are often a syllableof the airport or
towns name.
Domestic portabletelephones operate at the highfrequency end of the
mediumwave at about 1.6 MHz. At 1.8 MHz the short wave
frequenciesstart.
A quick flip round and you’ll find it’s very different
than the medium wave band.
The BBC broadcasts it’s World Service on several short
- wave
frequencies. Intimes of crisisthe
BBC World Service has beenthe
source of unbiasednewsthe world over. Most countries have their
own overseasbroadcasts. Some follow inthe traditions of the BBC,
others simply use the airwavesfor blatant propaganda.
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Many overseas broadcast stationswelcome contactwith listeners.
This helpsthem to establishtheir listener profiteand assess their
coverage. The station will usually repay the listenerwith give
- away
goodies and a QSL card (fromthe internationalQ code meaning
“acknowledge receipt”). Many people make a hobbyof collecting QSL
cards from
all over the world.
Some transmissions will not containspeech or music, they
will just
consist of warblingtones. These contain some form of data. It may be
a weather chart broadcast to shipping, or a fax or telex to a news
agency. Without a special decoder it cannot be read.
Another form of transmissionfound on short
- wave is single side band
(SSB).
To understandwhat this means it helps to see how it developed. In a
conventional signal a carrier istransmitted.The amplitude(height
of
the wave) of the carrier is modulatedwith speech, hencethe name
“amplitude modulation”(AM).
If the signal is studiedcarefullythen the
result of the modulationproduces a carrier, an upper sideband of
frequencies and a lower sideband of frequencies.
All this takes up space on the radio spectrum. Now, since the upper
and lower sidebands are mirror images of each other it’s not
necessaryto transmit both,
so one isfilteredout inthe transmitter.As
no informationis providedby the carrier that also can befilteredout
leavingonly one of the sidebands. This takes up less space inthe
spectrum and, becauseonly wanted informationis transmitted, makes
better use
of the power available.
This is single sideband or
SSB. The downside of this is, firstly, the
quality of reproductionis not usuallyas good as AM. For this reason it
is only usedfor communications and not for broadcast. Secondly, it is
more difficult to recover the original speech than in AM.
When recovering an
SSB signal,the listener must know which
sideband is beingtransmitted. Fortunatelythere is a convention.
Frequenciesbelow 10 MHz transmitthe lower sideband(LSB), and
those above 10MHz usethe upper sideband
(USB). (There are
exceptionsto this convention, e.g. the R.A.F. VOLMET on 4717 kHz)
5

Tuningthe Amateur bandfrom 3500 to 3800 kHz you will alwaysfind
SSB signals. With the receiver in the AM Mode the speech sounds
severelydistortedand, as there is no carrierthe tuning meter rises
and falls with the voice peaks. Switch to
LSB, set the clarify controlto
it's centre position(pointer uppermost).Tune the receiver untilthe
speech becomes as clear as possible, finally turn the clarify control
untilthe speech seems as near normal as possible. Only
a small
adjustmentof the clarify controlwill change the voice characteristic
from highto low pitch. With a little patience, tuning in
SSB stations
becomes quite natural. Most peoplefind it easier with the volume set
at a low level.
,
When usingthe tuning knob to tune through a bandof frequencies,
place a finger inthe dimple and turn the knob
as if stirringa cup of
tea. This will move gently in
1 kHz steps. Holdingthe knob and twisting
may accelerate ittoo fast and cause larger incrementsteps.
If avery strong station is encounteredwhich causes overload and
distortionthen switchthe attenuator to the
ATTEN position. Remember
to switch it backto normalfor weaker stations. The
HF3 has been
designedto handle comparatively largesignals at the antenna.
A
powerful localtransmitter could still cause severe overload.This would
usually manifest itself as that stationbreakingthrough all over the
spectrum. Insuch cases a filter can be incorporatedin linewith the
antenna plug, talk to your dealer for further details.
When is thebest time to listen ???
Earlyevening is usually a good time to listenwith ever distant stations
being receivedas the night progresses. Daylightconditions are less
favourable. Duringa periodof exceptional activity (
" a lift " ), the
spectrum is crowdedbothday and night. Conditions can swing to the
other extreme with only the more localstations available.
Over short distances, signals follow the contour of the earth (ground
waves), however, long distance propagation relieson the signal
bouncing
off the ionosphere(sky waves). Often the skywavefrom a
distant station is stronger thanthe groundwave from a localstation.
With experiencethe listener
will soon learnthe best time and
conditionsto receivethe stations hewants.
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What can I receive ???
There arethousands of stationsavailableon short wave when the
conditions are right. Many will beam Englishprograms into North
Americaat certaintimes
of the day. On an evening in August, English
broadcastswere receivedfrom the following stations.
All frequencies in kHz
Voice of Vietnam
NorwegianRadio
RadioKuwait
BBC World Service
Brazil Radio
RadioNetherlands
Voice
of Russia
RadioThailand
Voice
of Israel(Jerusalem)
Voice of America
Romania Radio
RAI International(Italy)
RadioArgentina
Islamic Republic
of Iran
Polish Radio(Warsaw)
China Radio International
ChristianScience Monitor
15009 & 9840
7120
11990
6180,6195,9410,12095,15070
15265
13700
11630&11677
721 0
7465,9435,15615
9760
11810 &11940
9670
15345
9022
7285
9920
13770
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RadioAmateurs, from all over the world, were heardon the
following bands:
-
160 Metre Band 1800 to 2000 (LSB)
80 Metre Band 3500 to 3800 (LSB)
40 Metre Band 7000 to 7100 (LSB)
20 Metre Band 1400 to 1435 (USB)
Dozens of other stationswere receivedbut not identifiedas their
languagewas unfamiliar.
Most broadcastsbeamedinto Europehave programsin English,
German and French, as these are the mostcommonly used languages.
Few groups, however are left out.
From Bulgarianto Serbian, From Kinyarwandato Swahili,
if someone
speaks it,then usually, someone broadcasts it.
For those interestedin languages,the BBC broadcasts regular language
courses. (Details on World Service broadcasts).
There are many Comprehensiveguides availablegiving Frequencies
and scheduledtransmission times. Make sure that you get an up to date
copy as schedulesare oftenchanged.
There are plenty of good booksfor the short
- wave listener covering
topics from antennaconstructionto eavesdroppingon clandestine
broadcasts.
For the listener with an interestinAmateur Radiothere are local radio
clubs. Details are usually availablefrom the local libraryor from the
Radio Society
of Great Britain.
Note
It is good practiceto unplugthe antennawhen not inuse. This will
protect the receiverfrom damage during ElectricalStorms.
It isalso good practiceto switch
off the unitand unplugthe Power
Supply from the mainswhen the Receiveris not inuse.
8

ANTENNA
Tie the end of the antenna wire to a piece of string which in turn is tied
to a tall object.
IDEALANTENNA POSITION
If the antenna isto be some distancefrom the receiver, then use 70
ohm co - ax (TV Aerial cable) betweenthe receiverandthe antenna. If an
outsideantenna isnot practical,thenthe antenna can befitted as high
as possibleinthe
loft. Reasonable resultscan beobtainedwith an
indoor antenna, though interferencefrom other electrical equipment may
cause problems. For serious
listening
a good antenna is worth the effort.
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