Shortwave Radio Questions Answered

We present a Listener's Charter to be quietly ignored.

In which we learn that in spite of a BBC Radio Production course, your scribe can't think of enough linking material to cover the great range of topics below.

No matter what radio you have, there will seem to be a thousand and one outside factors that seem to affect reception.

So, under a general heading of rules are made to be broken, here are a few more observations. If you have noticed something not mentioned here, do get in touch via CONTACT US.

Tell Me About Single Sideband. LSB Or USB?

All point-to-point operations on land, sea and air use USB.

All Ham Radio traffic below 10Mhz use LSB.

Therefore, all Ham Radio traffic above 10Mhz use USB.

Attempt to tune sideband stations slowly and steadily. Those with a musical background will find getting the final voice pitch correct is easy. Advances in receiver accuracy mean most sideband transmissions are near enough on the change of the last kilohertz digit. Portable radio users may only have an SSB button that they must use for USB and LSB and they may find final tuning is more critical than on communications class receivers.

If you have an AGC switch, always select the slowest rate for SSB.

Some older radios seem to be anything up to 3kHz off frequency when correctly tuned to a sideband station. This is not a fault, simply the way the radio measures frequency. The correct way to record the frequency of a sideband station is to state the frequency of the carrier, if only it had one, the actual transmitted energy being a nominal 1.5kHz above the carrier for USB and the same amount below the carrier for LSB. The microprocessor-controlled radio has offsets for each mode programmed in, something of a little white lie to conform to convention, since both modes use the same filter. In the very expensive professional sector, separate filters are designed for each sideband, giving textbook - not this one - performance and a correct display.

Those radios that seem badly off channel in the sideband mode are measuring the frequency of the local oscillator needed to tease a signal through whatever filter system they have.

Why Bother With A Logbook?

Keep a logbook - that is, a written record - of all you have in the memories. Most modern memories are secure, but a radio is subject to spikes on the mains supply and via the antenna during storms. So with so many memories it is but human to forget what you had in there. If you have a back-up battery in your radio, the life of these can be so long that they quietly fail and you say so long to your best programming efforts.

Celebrate your radios birthday each year with a new memory back-up battery. It will love you for it. Expect five years from a back-up cell - longer in the latest models.

When you have filled the memory capacity of your radio, audition every channel and place your Top Ten Most Listened To in the channels running from the default setting. This will give you the chance to clear the decks for new findings and leave fewer quiet channels to upset any memory search facility you may have.

We are always interested in what people listen to on our sets, so you may like to put you Top Ten on an email to CONTACT US. The senders of the most original lists may even find themselves on these pages.

Try to keep an easily recallable memory channel free to act as a notepad for some unexpected station. It can then be called up from time to time, usually on the hour, until it identifies itself. Many of the frequencies in this Guide were tracked down by allocating a block of memories for this purpose. It works, too.

Can I Use Time and Frequency Standards?

Unless you are a radio engineer, do not use the Time and Frequency Standards as a reference for internal adjustments to your radio. Some are allocated frequencies in a sub-band around a well-known channel so you may find yourself adjusting error in rather than taking error out. Some standards carry phase-modulated data, which can make tuning difficult. Some standards are for propagation checking only and are not accurate. Like society, standards vary - but we don't foresee ANY adjustments being necessary during the life of a modern product.

Can I Adjust Anything Inside The Radio?

If it was made in the last ten years, it will use a technology that is accurate enough. If it is older than that, swallow your pride, check your credit limits and have it set up professionally.

Never complain about the cost, you are buying the engineer's experience and the support of his Company. You are also subscribing to a team of technicians dwindling in number as no formal training in Higher Education exists for the wide range of disciplines found in a modern communications receiver.

All training is hands-on and therefore expensive even though it plays on a genuine enthusiasm for his subject by the techie. You are also buying access to spares, many of which will be special to your radio.

Test equipment costs are very high and cannot be written off. As radio designers, if we are to maintain the level of development and support you the customer has come to expect, then the test gear will always have to be an order of magnitude better than the best receiver we expect to sell.

This requires constant investment and research. If he will not offer a warranty on his work, then he is either not sure of what he is doing or your Ol' Faithful radio is about to fall off the twig. If your radio has passed its Listen By date then it is likely to be of an age during which many new ideas will have come in to play, so see it not as a death but a new beginning where you can rethink what exactly you use the radio for and look for the best new features that address your changing needs.

I Want To Complain But Not Sure How To?

Check that what you see as a fault has not some other cause. Check and double-check the manual. Be concise in correspondence and reasonable on the telephone. The person on the other end is quite likely to be as keen on radio as you are and like you, is quite human.

Can I Randomly Press Buttons To See What Happens?

It came as quite a surprise to your scribe to see how much processor programming is taken up with fail-safes and how grimly determined a certain type of user is to find a key combination the designer has not thought of, in the sole pursuit of locking the whole thing up.

A reset usually means a loss of memory settings, so best leave alone.

Any Tuning Tips For Good Old AM?

Never be afraid to detune an AM station slightly into one or the other sidebands to get best fidelity. The downside is a display which reads irritatingly off channel with say, the World Service coming up on 12097 for example, but you can't have everything.

In cases of extreme interference an AM station can be treated as two sideband stations back-to-back and tuned in very carefully in either LSB or USB, picking off the sideband with the least interference. Be a gas at parties by telling your host this is the Exalted Carrier Selectable Sideband mode or ECSS. She will spontaneously reply that the new generation of receivers offer even higher fidelity by phase-locked detection in this mode and make mental note to save on Christmas cards next year.

All AM broadcasters are now using some form of audio processing to improve the signal-to-atmospheric noise and interference-ratio. There was a time when the quality of the sound from your radio was determined by how much you were prepared to pay for it. Now, in world radio, audibility is the key. And, to be honest, it can sound dreadful.

No, the problem lies in the audio processing that has slowly changed the sound balance since Abba were in the charts.

It started with wide-band compression. The BBC lead the field with a limiter that gently reduced the dynamic range of all audio frequencies present by the same amount, giving an overall impression of loudness enough to counter reasonable domestic noise.

Then came the active systems. A bank of filters carve up the audio into anything up to six pass-bands. These are then compressed at different rates preset by the broadcaster, the reconstituted audio then going for transmission. In pop radio, some DJs can set their own processing at the desk leading to double compression effects which, as they have no musical analogy, can lead to listener fatigue simply due to the saturation of the sound.

Engineers say processing is here to stay. Radio marketing men will tell you that he who shouts loudest gets the largest audience and so gets to keep the money.

That's fine up to a point but with the CD and AAC setting new standards for source programming and radios improving markedly with each generation - this must be the time for the broadcasters to reassess their use of processing to allow the final level of fidelity to align with the listeners level of investment in equipment.

In other words, you'll get what you pay for. With so much choice now in radio, isn't it time to move the technical goalposts?

What Are The Radio Seasons?

Broadcasters can change their schedules up to four times a year in the running battle with the ionosphere. Lower frequencies are preferred in the Winter, moving up a band or two to get the best coverage in the Summer.

How Can I Let Them Know I'm Listening?

Your favourite station is just dying to hear from you. If you let them know you are out there hanging on their every word, they will put you on the mailing list for programme information and the latest frequency releases.

If a station can't prove to its government that it has an audience by analysis of its listener correspondence then that station ends up in our Where Are They Now? feature, coming soon.

When Is It Best To Listen?

Lower frequencies are better at night, higher ones better in the hours of daylight.

DX, the real long distance stuff, can be heard at dawn and dusk.

Where Did That Station Go?

Advertising copywriters will remember the If you see SID, tell him campaign for British Gas. If you hope to tell him via short-wave radio, then he won't hear you.

In our field, SID is a Sudden Ionospheric Disturbance and it can take out the entire spectrum for short periods of time. Go as low as you can in frequency to steer around him, but no ionosphere means no reflected signals and radio silence. You may hear a faint BBC continuity announcer apologising for this effect. Only the BBC would apologise for an Act of God.

With this in mind, get to know the kind of signal meter readings you would expect from your favourite stations under good conditions. By reviewing who is strong and who is not, you can soon get the feel of what areas of the world are open to you at the times it is possible to listen.

If you have one, the AGC switch can be experimented with as a buffer to the rapid fading found on higher frequencies. It is not a cure, it simply can make listening more pleasant.

Bob Marley Used To Enjoy Jamming. Should We?

With an outbreak of something near world peace, jamming is less of a problem these days. However, there seem to be nations that will always be professionally peeved and don't want you to hear what someone else is saying. If all the tuning tips so far suggested in your fatwa-free Guide have not worked, then try the station another time.

The jamming may be getting to you on a different path and may fade to leave clear reception. The same rule can fade the station you want, but this is life's rich pageant.

Why Do We Need An Attenuator?

Just because you know the dictionary definition of an attenuator, don't feel it is an act of defeat to use one. With two million watts used by some European broadcasters, we are getting signal strengths that can light small torch bulbs. If you are getting a 60 over 9 on the signal meter then by all means record it in the log, then switch in the ATTN to bring it down a bit.

This will drop the surrounding stations by an equal amount giving clearer reception and bring the fades of the wanted station into the AGC range of the radio.

Got It Taped?

Most radios we have encountered so far have a RECORD jack. If yours has some form of phase-locked detection, then a bit of coax to the LINE IN on the music centre - dear old fashioned thing that I am - can do wonders for dear old AM. Then being able to make tapes is about the best log you can keep - the writer's Vortexion machine was a little over the top.

I Was Looking For Spurious Signals And Found Some. What Next?

This is the latest sensation to sweep the nation. You spend an arm and a leg on a radio, short-circuit the antenna socket - the clever ones will do this with a carbon resistor of equal value to the impedance presented at the socket - then tune very slowly through the entire range of the set in USB, listing every whistle you can hear.

And we admit it. There are signals to be heard. A manufacturer worth his salt will report the worst of them in the manual. A synthesised radio works by constant comparison of the frequency you are tuning to a reference signal - a crystal or fast VCO - actually inside the set.

This creates a little signal of its own. The processing required to make that comparison and make the radio easy to operate also produces lots of little signals all their own. If we want our radio to have the range to cover the whole HF spectrum then yes, there will be points on the dial where it will hear itself.

Modern design and layout has reduced these to a level equal to the noise floor so in fairness to the designers, I no longer regard them as a problem.

Should I Modify Equipment At Home?

We have over twenty years product development experience since the days when a short-wave radio meant an ex-Service receiver that needed extensive mods to make it work in a domestic environment.

We do feel that due to the changes in all the technologies used in a modern radio, modification at home will lead to more problems. If you want to be a part of the radio revolution, use the radio for a little while, think long, hard and reasonably about what you feel could be improved and write a concise letter to the set maker.

The pen is far mightier than the soldering iron and cheaper, too.

Why Bother Tuning Around When You Can Scan?

Some portables give the impression that tuning around is a thing of the past. They have adopted clever scanning systems that seem to do away with the tuning knob once and for all.

It pains your writer to admit it, some work very well, but pre-set scan levels can mean they scan over the low level DX stuff. So, for real band searching - go manual. They are good for checking general band conditions, however.

Filters - Which One And When?

Most modern radios will decide as the Mode selected, which is the best filter for the job. Some may have a WIDE/NARROW switch. Wide is best for broadcast speech and music, narrow for SSB use.

You may have a range of bandwidths to allow you to filter out what you can as conditions deteriorate. Filters are the last bastion of experiment in radio, so do not hesitate to talk to your dealer about the options if your radio is designed to take them. Or go DSP.

I Only Speak English So Am I Missing Out?

In a very informal review of all the stations heard during the compilation of this Guide, only about 18% are in English at any one time.

The format of an English transmission by an international broadcaster usually consists of News on the hour followed by a topical commentary then a feature programme. Once this rhythm becomes familiar, along with interval signals and station IDs, then identification while in a foreign language becomes easier.

Is Radio Reception Affected By The Weather?

A debating point from many years at the Human/Receiver Interface. In spite of all that has gone before on the ionospheric effects on reception, the effects of localised weather systems seem to go unreported.

Users of satellites already know how heavy precipitation - rain and especially snow - can affect their reception of Bart Simpson by screening the dish. Over many years your observer has seen how cloud-filled barometric lows seem to improve reception up to about 7Mhz in the area affected, returning to the norm for the season as the weather improves.

Can Radio Designers Learn Anything from Tech Support?

In an article written for AOR UK, we think so.

During my time at Lowe Electronics, I fitted hundreds of 500 and 270Hz filters in receivers for the keen CW man.

Given that the IF signal was stable and within spec after warm-up, I could not help but notice the change in timbre of the note as the filter got up to the same temperature as the radio surrounding it.

And this was after trimming up the carrier insertion frequencies.

AOR's filter tracking takes out not only this error but also acknowledges the manufacturer's own errors declared in their spec. This feature is most noticeable (and useful) in the narrow bandwidths but the assurance of sideband symmetry in the wider AM modes can only reduce phase-cancellation artefacts.

Sorry - what I mean is, it distorts less and sounds better.

Hearing traffic on 5610 USB shows what a well set up sideband filter can sound like. AM Station AFN on 873 from Frankfurt is clearer now as evening falls, BBC Africa on 17830 has just faded out.

A call to PORTISHEAD RADIO on 4384 is very strong. 6950 may well be China, as could 6933. And possibly for the last time as we climb into higher Sunspot Counts, BBC Hong Kong on 3915.

That's the trouble with the AR7030. I have been asked to write a full technical review of it but all I've done is listen to it all day. And now they want to borrow it to see what I have got in the memories!

Life As A Radio Reviewer

It is a late evening in early Autumn. A fetid fog rises from the Derwent lapping languorously at the doors of East Mill. A lone figure, collar turned against the Stygian gloom, eases up to the side door. He taps the Secret Knock, known only to the few. It is A O R in his best 12 words per minute. He will get that M Licence if it is the last thing he does.

A pause. Then a hatch in the door slowly opens. A dusky maiden (here the imagery falls to the ground as the chances of finding a maiden in Old Belper Town are, at best, remote) peers out expectantly. As their eyes meet, she speaks.

Yes?

Richard sent me.

One moment, please.

As the massive steel doors creak open, the figure slides inside, pausing only to look up and down the alley. We negotiate endless stairs and corridors until we find one that has an end.

A little over the top? Well, yes, but there was a real sense of the covert operation as I picked up my demo AR7030 from AOR a few weeks ago. Few receivers have attracted so much attention in my thirty years plus of listening and as I write this, column inches are still being drafted by those in the know when it comes to the close analysis of radio specs.

This reviewer would get kitted out to measure large signal handling only to find himself hooking up the best antenna he can and tuning for a big signal to hear what the radio actually sounds like.

There is no decernable drift. In listening tests, drift was inaudible. Music stations retained their musicality in an ECSS or sideband mode, an acid test.