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Τετάρτη 9 Νοεμβρίου 2011

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Picture of HF wire antenna and mast

Having obtained a callsign, established a station and erected an antenna, the next step is to learn how to operate it. This requires an ability to adjust equipment to transmit a clean signal, as well as a knowledge of basic operating procedures. Part One will focus on the latter, while Part Two looks at some of the specialised operating activities, such as DXing, awards and contests, enjoyed by amateurs. this series concentrates on SSB (voice) and CW (morse), both of which can be used by Foundation licensees.

WHICH BAND?

Amateurs have a range of bands from which to choose. Thus, at any one time, a well-equipped amateur station can contact stations over various distances by selecting the right band. Band conditions vary according to the season, time of day and sunspot activity. Foundation licensees can use the following HF segments:-

3.500 - 3.700 MHz (80 metres)

7.000 - 7.300 MHz (40 metres)

21.000 - 21.450 MHz (15 metres)

28.000 - 29.700 MHz (10 metres)

In very general terms, the lower frequency bands (such as eighty metres) are most used at night, while the higher bands 10 and 15 metres) are more active during the day. 40 metres is an in-between band, permitting short and medium distance coverage during the day and long distance contacts at night. 10 and 15 metres are greatly affected by sunspot numbers, with the ability to make DX (overseas) contacts on them peaking in years of high solar activity. At the moment, we are in the trough of the eleven-year sunspot cycle, so we can look forward to improving conditions in the next few years. At this phase of the sunspot cycle, 15 metres is likely to yield more DX contacts than 10 metres for the Foundation operator, though ten metres can still be productive, particularly during major contests.

Around mid-winter and mid-summer, ten and six metres come alive due to a phenomenon known as 'sporadic-E'. Sporadic-E occurs during all phases of the sunspot cycle and permits distances of approximately 500 to 2000 kilometres to be covered, even with just a few watts and simple antennas. It can occur at any time, but is more prevalent during the day.

The time of day is an important determinant of band conditions. While local contacts are possible on eighty metres during daylight hours (particularly in winter), it is during the evening that the band finds most use, with distances of up to 3000 kilometres being typical when conditions are good. More typically, a 10 watt Foundation licence station can expect regular contacts up to 500 to 1000 kilometres in the evening. An important advantage of eighty metres is the almost blanket coverage that is obtainable; this is in contrast to the higher bands where a 'skip-zone' exists between the limit of ground-wave coverage, and where the sky-wave, reflected from the ionosphere, returns to earth.

40 metres during the day permits the sort of contacts you can get on 80 metres at night, though it's easier to have longer distance contacts (eg 1000 - 3000 km) with low power. At night overseas stations can sometimes be contacted but there can be a lot of interference and 80 metres can be better for contacts within Australia.

For cross-town communication (say up to 20-30 kilometres), any HF band will provide results, though ten metres is preferred, because of its lack of crowding, low band noise, and relative efficiency of mobile antennas. Somewhat longer distances can be spanned on eighty metres, or else on the higher bands when sporadic-E propagation is apparent. DX contacts are most prevalent on 15 and 10 metres (mainly during the daytime), but could be possible on eighty metres if you possess an antenna whose radiation pattern is concentrated at low angles.

Which band is best to start on first? My pick would be 40 metres, since it is capable of short, medium and long distance contacts at various times of the day. Its antenna requirements are also less onerous than 80 metres, and many good contacts can be made with 10 watts. My second preference would be 80 metres. However (a) if you have very little room, (b) you are more interested in overseas contacts, or (c) it's a high sunspot year, 15 metres might be chosen instead. 10 metres also has its moments and is made more accessible as many 27 MHz CB antennas can be converted for use on this band.

THE ANTENNA

It is assumed that an antenna has already been erected. The typical Foundation station may include a dipole or inverted vee for 80 and or 40 metres, a trap vertical or small beam for 10 and 15 metres, and a groundplane, discone, J-pole or similar antenna for VHF/UHF, with different capabilities on different bands in line with the operator's interests. All these antennas can be constructed at home; details are provided in magazine articles and in the standard antenna handbooks.

MAKING CONTACTS

There are more similarities between HF SSB and CW operating procedures than there are differences. In both cases, it is wise to tune across the band you intend to use prior to transmitting. This provides a general impression of band conditions.

Assuming the transceiver and/or antenna tuning unit are properly tuned up (a process which, if performed on-air at all, should be done on a clear frequency at low transmit powers), the process of seeking contacts can begin. There are three main ways of obtaining contacts. These are as follows.

Responding to a CQ call: Tuning across the band may reveal one or more stations calling CQ. A CQ, which is a general call to all amateur stations, is your invitation to respond. Such a response takes the form of sending the other station's callsign, followed by your own, perhaps sent several times if signals are weak.

If the calling station is VK6AA, and your callsign is VK1AA, your response on SSB could be:-

VK6AA, THIS IS VICTOR KILO ONE ALPHA ALPHA, VK1AA.

On CW, you would send:-

VK6AA de VK1AA VK1AA VK1AA K

In this case, 'de' means from, while 'K' is an invitation to transmit (or 'over' on voice)

If the station replies to another station, you may wait until the contact finishes, or move to another frequency. On the other hand, the calling station may ask 'QRZ?'. This indicates that the station heard a signal, but was not able to decipher the callsign. The correct procedure in this case is to repeat your call, possibly speaking (or sending) a little slower this time.

Calling CQ: If no other stations are calling CQ, it is a good idea to issue a call yourself, especially if you have reason to suspect that the band may be open (eg hearing beacons on 10 and 15 metres). After selecting a clear frequency, it is polite to ask if it is in use. On SSB, this is accomplished by announcing your callsign and asking if the frequency is occupied, while CW operators simply send 'QRL?'. If no response is received, the frequency is yours to use.

The length of CQ calls depends on band activity and conditions; if band occupancy is sparse, a longer CQ call is suggested to attract the attention of the casual listener tuning across the band. In order to maximise the chance of obtaining contacts, and to minimise interference with other operators, the Amateur Radio bandplans should be adhered to at all times. Essentially this means not operating SSB on frequencies reserved for CW or digital modes. Bandplans are published annually in the WIA Callbook (Reference One).

On SSB, a typical CQ call is as follows:-

CQ CQ CQ CQ CQ CQ CQ CQ CQ THIS IS VK1AA, VICTOR KILO ONE ALPHA ALPHA, VK1AA, CALLING CQ AND LISTENING

(before calling, make sure you are on the right sideband - LSB for 80m, USB for 15/10m)

A CQ call on CW may be:-

CQ CQ CQ DE VK1AA VK1AA VK1AA K

Higher speed operators may choose to make their calls longer, to increase the chance of the call being heard. However, this should not be overdone; hearing 20 CQs before a callsign is sent will cause most listeners to seek contacts elsewhere.

'Tail-ending': An effective means of obtaining contacts (especially if using low power) is by the use of 'tail-ending'. This means listening in to a conversation, and calling one of the stations involved immediately after the contact ends. Timing is important here, particularly if unable to hear all stations on frequency.

When 'tail-ending', the call made can be just as if one was answering a CQ. If used with care, 'tail-ending' is probably the best way to make contacts on the HF bands.

DURING THE CONTACT

Once contact has been established, the first few exchanges normally entail a swapping of RST signal reports, names and locations ('QTHs') with the other station. From this point, the conversation may extend to the antenna and equipment, and (unfortunately) the seemingly ubiquitous weather report. Discussion beyond this point is a matter for those concerned, though amateur regulations and ethics mean that there are some topics best left alone.

The purpose of signal reports (see Table Four) is to give your contact some idea of how their signals are being received. Signal reports on phone consist of two digits. The first of these is readability (R), on a scale of 1 to 5. The second figure given is the strength (S) of a signal, this time on a scale of 1 to 9. The third digit, used by CW operators to indicate the purity of the received tone, is also on a scale of 1 to 9. Because of the quality of most modern equipment, reports of less than T9 are rare.

Some tend to accept the S-meter as gospel, without realising that S-meter calibrations vary between transceivers. Cases of people refusing to give signal reports if a signal (though perfectly readable) is not moving their meter's needle are not uncommon. If in doubt as to what report you should give, it is best to ignore the meter on your transceiver entirely.

ENDING A CONTACT

If the time that it can take is any guide, many people have trouble ending contacts. On CW, this manifests itself in the endless repetition of 73, BCNU, CUL, CUAGN and other solecisms, while on SSB, many a fictitious saucepan must have boiled over! Try to end contacts cleanly and keep the number of 'final-finals' to a minimum; this makes it easier for other stations who might want to call one of those about to depart.

CONCLUSION

This article, has provided some pointers on basic operating techniques. Join me in August for Part Two, which includes more detailed information on DXing, contests and award hunting.

AMATEUR RADIO ABBREVIATIONS AND PROSIGNS

Table One: CW Procedural Signals (Prosigns)

CQ A general call to all amateur stations

AR end of message, full stop

K "over", invite any station to transmit

KN A specific station only to transmit

BK invite receiving station to transmit

R all received OK

SK end of contact

CL going off the air (clear, switching off)

Note that all two-letter prosigns are sent with the letters merged together (except CQ).

Table Two: Commonly used Q signals for CW work

QRL?: Is this frequency in use? (use this just before calling CQ).

QRM: Man-made interference (eg other stations on/near your frequency).

QRN: Natural interference (eg thunderstorm activity)

QRO: High(er) power.

QRP: Low(er) power - normally 5 watts or less.

QRQ: Send faster (eg QRQ 12: please send faster at 12wpm).

QRS: Send slower (eg QRS 8: please slow down to 8wpm).

QRT: Stop transmitting.

QRX: Please wait (eg QRX 1: please wait one minute).

QRZ? Please call again (used when a station has responded to your CQ call, but you missed their callsign).

QSB: fading signals.

QSK: 'break-in mode' - your equipment allows listening while sending.

QSL?: Can you acknowledge receipt (of message)?

QSO: conversation.

QSY: move to another frequency (eg QSY 3530 means QSY 3.530 MHz).

QTH: transmitting location.

Note: The above lists the most commonly used Q-codes for amateur CW operation. The meanings shown are those that are most used on-air, and vary slightly from the definitions in the standard handbooks. To ask a question, simply attach a question mark (?) to the Q-signal; for instance, QRQ? means 'Shall I send faster?'. While Q-signals are sometimes used on SSB, plain English is probably as effective in most cases.

Table Three: Common abbreviations for CW work

ABT About

AGN Again

AS (please) wait

CQ Calling any station

CUL See you later (similar to BCNU, HP CU AGN, etc)

ES And

FB Fine Business, excellent

GM(N) Good morning (night)

GUD Good

HR Here; Hear

HW How

NR Number (used in contests)

PSE Please

RST Signal report (see later)

SIG Signal

SRI Sorry

TKS, TNX, TU Thank you

UR Your; You're

VY Very

WKD Worked

WL Well; Will

WX Weather

Abbreviations for other words exist, but their use is less prevalent than those in the list presented here. Their use can make CW communication faster and more pleasurable, particularly at slower speeds.

Table Four: Standard Readability and Strength Scale (source: ARRL Handbook)

Readability

1 unreadable

2 barely readable, occasional words distinguishable

3 readable with considerable difficulty

4 readable with practically no difficulty

5 perfectly readable

Strength

1 faint signals, barely perceptible

2 very weak signals

3 weak signals

4 fair signals

5 fairly good signals

6 good signals

7 moderately strong signals

8 strong signals

9 extremely strong signals

Tone

Scale of 1 to 9. Nearly all signals today are T9.

REFERENCE

1. WIA Radio Amateur's Callbook (any year)
Note: This article was written in 1996 but has been adapted to reflect subsequent licensing changes.

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