and makes of suitable radios
can be very useful (and entertaining) to be able to receive local and
international news, weather and sport wherever we are as we tour around
the country without relying on internet connections and satellites with a good old
radio (the electric wireless as some old Qld politician used to say).
However there are many places where satisfactory reception is not
available on the FM band and difficult on the AM band. This page covers some options.
Generally speaking, the most useful radio receiver for your caravan will
be a good quality AM/FM car radio with CD player with the longest
telescopic aerial you can find.
Portable radios, the subject of this page, are for the most part markedly inferior in receiving weak signals by
comparison. But there are exceptions.
Limiting price to below A$500, the following are some of the radios
available in Australia worth a mention.
There are times where you will not have any useful signal,
either no signal or constantly fading in and out.
However there are several of ways of improving the situation . .
* a receiver with better sensitivity and selectivity,
* tuning in to the HF shortwave band (see bottom of this
page for explanation of frequency bands),
* using a suitable external aerial to boost the AM broadcast
Two of these options means purchasing a good quality
multi band portable shortwave radio.
There are a lot of multi band portable shortwave radios around but
most for our purpose are worthless without an external aerial
which I have covered further down the page.
|The exceptions I mentioned previously in approximate order of
how I would rate them is . . .
This isn't necessarily a complete list, I am looking forward
to being able to add the Redsun RP3000 if it is half as
good as overseas reports would indicate.
the Sony ICFSW7600GR at around $385 to $510 depending where you
purchase (Aug 08), is the pick for my money. To do any
better than this you would need to be looking at a communications receiver starting
from four or five
times the price such as the Icom R75, a semi professional bench top HF receiver.
While not quite in that league, the ICFSW7600GR is
still a very good performer and the Sangean ATS909 and
Redsun RP2100 are not far behind.
With the ability to receive weak AM transmissions and world wide HF
stations (including SSB for the Sangean ATS505, Eton/Grundig E5/G5,
Sangean ATS909 and Sony ICFSW7600GR),
you will never be without something to listen to and all in a package not much
bigger then a paperback novel.
The following are all worth a look and rpresent very good
performance for the money.
The Sangean ATS909 shown on the left, a little cheaper at
around $320 to $400 is a close
second but minus
the synchronous detector of the Sony ICFSW7600GR but does have
some other nice features.
Although it does have more
bells and whistles, from my experience, the Sony has the edge
where it counts, better AM & SSB (Single Side Band) reception.
(It was also marketed as Radio Shack DX-398 in USA & Canada, Roberts
R861 in UK & Seimens RK-777 in Europe)
The Sangean ATS505, Sony ICFSW35 and Eton/Grundig E5/G5
at around half that price can give good results also.
Tevion MD81157 from Aldi, shown on the right, not too
bad for the
money at $50 and a better finish than the Sangean ATS505.
covers LW 144 - 281 kHz, MW, SW 5.85 -17.9 MHz and FM with 240
station memory although in a volatile memory.
AM sensitivity and selectivity are not strong points but on par with
others in this price range but FM is comparatively much better.
However, with the external aerial modification described later, this is
very useful on the MW broadcast band, better reception than the
radios in our car or caravan by a noticeable margin.
I also describe a 12V power input modification.
Digitech AR1745, (This is a Redsun
RP300), also for $55.
It features direct key frequency entry as well as rotary knob and
scan keys, 200 station non volatile memory, all of which is
unusual in a cheap radio and is physically much smaller than all
the others described here, pocket size at only 120x75x28mm.
authorities advise you to have a portable radio in times
of emergencies and disasters (bush fires, floods, cyclones
etc), this radio is perfect, very sensitive, compact, good
battery life and comparatively cheap ($55).
Frequency coverage is 520-1710 kHz AM, 2300-7500 & 9500-22000
kHz AM and 70-108 MHz FM.
For a compact single conversion radio, it's performance really
surprised me, a very sensitive AM receiver right through it's coverage
range. In fact, it's ability to
receive weak AM signals isn't too far behind my Sony
7600GR. Selectivity is reasonably good, for
this price range.
It is let down by relatively poor sensitivity on the FM
band and with only 100 KHz tuning steps. But for our
purpose it's the AM broadcast and shortwave performance
On the down side, common with many others with up/down
button volume control it always turns on and off with an
annoying burst of high level audio and coarse steps (a simple little mod goes
part way to lessening the problem), auto scan only stops
on very strong signals, Local/DX switch works on SW and FM
only and the whole rational with the way the 200 station memory
has been implemented needs a re-think.
But those criticisms aside, if you are after a radio that
does an above average job of pulling in weak AM signals that
you can slip into your pocket, this is a ripper.
a performance verses cost basis in a pocket radio, this is the winner
by a good margin.
Digitech AR1747. (This is a Redsun
RP2100 also sold elsewhere as a Kaito KA2100,
shown on the left.)
is a fully featured PLL receiver and like the Sony and Sangean it
is also has dual conversion.
like the better ones from Sony and Sangean described above, this
one covers 520 - 29999 kHz, 87 - 108 MHz FM, no LW (below 510
kHz) but this no great loss as is the lack of SSB.
It has a 50 station
memory (but inconveniently arranged in 10 per "band" of 5).
It also has AM RF gain control and selectable band width
filter (wide band is +/- 6 KHz and narrow band is +/- 3
KHz) as well as several other nice features not usually
found in this price range.
The performance of this radio is outstanding and belies
the price. Sensitivity and selectivity on all bands is as good
as the Sony ICFSW7600GR, it is very difficult to separate
them on this score.
Although minus direct key entry, tuning is quick and
accurate with two speed rotary encoder and a "Q
Tune" (quick tune) key.
Audio is good with a large 125mm speaker and separate bass
and treble controls giving 2.5W maximum audio output.
Power options are varied, external 240VAC and 9VDC as well
as internal space for 4 "D" batteries and 4
"AA" batteries. I power mine from 240VAC
at home, 9VDC in the caravan (with a 12V-9V reducer) and
have 4 "D" alkaline and 4 rechargeable
"AA" Mi-MH fitted, the "D" and
"AA" are selected by switch and the radio has a
feature to recharge the batteries, very convenient.
It also has provision to use a long wire + earth or loop
for the MF band and coax input for HF/FM bands.
It is physically
larger than all the others mentioned on this page at 290x185x70mm
with a reasonably large easily read and informative LC
I find myself using this radio more than my others, it's a
very "likable" radio and as such, I highly recommend
it, I haven't seen one that
even comes close for $139.
For broadcast MF AM (530-1620 kHz), HF AM (1.7-30MHz -
shortwave) and broadcast FM (88-108MHz) it's as good as
anything I have used under $500.
a performance verses cost basis in a larger table/mantle size
radio, I don't know of a better one. I'll have a home
for a RP3000, if and when it is ever released (which
unfortunately is looking increasingly unlikely).
From Eton/Grundig range is the E5/G5
model (shown on the left) for around $225
AM/FM/LW coverage 150 - 29999 kHz, FM 87.50 - 108 Mhz ( 76 - 108 Mhz User Selectable),
PLL Dual Conversion AM/SW Circuitry with SSB, 700 Programmable Memory Presets,
Alpha-Numeric Four Character Memory Bank Labeling,
Tunes Via Auto-Scan, Manual Scan, Direct Key-in Entry and Tuning Knob
Their flagship model E1 (shown on the right) has the lot including sync
detector, switchable bandwidths and a large dot matrix LCD
but is over three time the price of the
For bells and whistles it also trumps
the Sangean ATS909
by a good margin but at over double the Sangean's
(Shown for interest only, would be way over $500 based on overseas prices
at the time of writing, besides I don't believe this E1 model is
All of the radios described on this page use PLL circuitry with
digital frequency readout.
However be aware that with most cheaper receivers, the inherent
sensitivity (ability to receive weak signals) and selectivity
(ability to discriminate between adjacent signals) is usually comparatively
Also those cheapies with PLL
synthesisers and microprocessors,
while they may look good on paper, tend to generate considerable internal electrical noise which means
that any weak signals they might have been capable of receiving
are drowned out.
A half decent car radio will
generally out perform most portable receivers in this price
range. If you are paying less than $100 (Aug 08),
don't expect too much. The Redsun RP2100 (Jaycar No
AR1747) and Redsun RP300 (Jaycar No AR1745) are
There are a few cheap "long range" AM radios, some
under $50, on the market, my
recommendation, don't waste your money, get one those described on this page.
As a rough guide, look for a radio with PLL (Phase Locked
Loop) circuitry and digital frequency readout and
preferably one that uses dual conversion.
Also a keypad is highly desirable for direct frequency
entry and it simplifies storing/retrieving your preset
But beware, there a a few cheap and nasties with a digital frequency display
that are not PLL, don't waste your money, if it doesn't
say PLL, then it almost certainly isn't.
. . .
If I could only have one radio, it would be the Sony
ICFSW7600GR at around $400,
If I could add to that, a mantle size radio, it would
be the Digitech AR1747 ( Redsun RP2100 ) for $139
And if I could add a pocket size radio, it would be Digitech
AR1745 ( Redsun RP300 ) for $55
(Actually I do have all of these -
plus a few more. Prices as
at Aug 09)
If I was on a budget and limited to one radio, it would be the Digitech
AR1747 ( Redsun RP2100 ).
Why the Sony ? Technically, in my experience, they have the edge (of these small
portable types), they are well made with very good fit and finish
and a solid feel. Most importantly, they have a reputation for
reliability and don't look or feel like they have been thrown
Also a full service manual and spare
parts are available (and I have found Sony Aust to be very helpful
One feature that sets this Sony apart from most other portables is
the use of a synchronous detector. This is not a gimmick, it
really works. Briefly, a synchronous detector goes a long
way to reducing the effects of signal fade by replacing the fading
carrier with a stable internally generated one.
Also with the Sony's +/- 1.5kHz fine tuning and excellent
frequency stability, the SSB mode can be useful in reducing the
effects of adjacent signal interference on DSB transmissions by selecting either the
upper or lower sideband as appropriate apart from giving excellent
reception of HF SSB transmissions.
And Sony's flagship ICFSW7600GR is made in Japan too, the only one
here that is, the rest are from China or Taiwan.
How long Sony will continue to make this model is anyone's guess,
mine is that it will eventually be discontinued without being
replaced, the same way their previous flagship model was, the
expect to see all shortwave, world band radios,
particularly the dearer ones, slowly disappear from the
market as broadcasters such as the BBC and Deutsche Welle,
cut back on their shortwave services as listeners abandon
radio in favour of satellite etc.
Due to this lack of demand, manufacturers are
concentrating on cheap AM/FM and digital
radio. So if you are thinking of a decent long
range radio (there is still plenty to listen to and these
radios are vastly superior on the domestic AM and FM bands
too), get one while you still can.
any external aerial with caution and at your own risk.
Familiarise yourself with the potential dangers.
not use any external aerial while there is even a hint of a threat of a
any random crackling noises in the receiver can be an
indication of potential or imminent danger.
Never locate an aerial over or under any power lines.
This can be and is a very lengthy technical subject but I have
tried to reduce it into just some simple practical
The following is some very basic information on the
three types of external aerials for your radio to improve
reception at your camp site.
Aerials that we are interested in here fall into three broad categories,
loop, long wire and active types.
A very simple yet effective do-it-yourself one I will describe
here is the non-resonant broadband aerial to vastly improve the medium
wave broadcast band reception of weak signals particularly
suited to less sensitive radios.
|Only perform the following modification to a battery only
operated radio not one with a mains connection.
The essence of this is to wind 3 or 4 turns of insulated wire
directly on to the ferrite aerial rod inside the radio and
terminate the coil ends to a 3.5mm mono or stereo earphone socket which you will have to fit
somewhere in the case of your radio.
If the radio case is metal not plastic, a
stereo socket would be preferable with the coil terminating on the
tip and ring only.
The aerial itself is nothing more than a length of wire forming a
loop terminated in a matching 3.5mm plug.
Theoretically, the antenna loop length should ideally be as long as convenient
but not exceeding 0.1 wavelength at the highest frequency, which
is approximately 18 metres at 1650 kHz.
Obviously 18 metres is not practical for our traveling needs and
in practice a 6 metre (2M+2M+2M) to 9 metre
(3M+3M+3M) loop is good compromise.
Arrange the wire
such that there is a horizontal component for best effect. The
loop, where length is less than 0.25 wavelength, is
directional with maximum pickup in line (not broadside) and is referred to
as a non resonant magnetic loop.
(Conversely, loops where length is greater than 0.5 wavelength
have maximum pickup broadside, same as a ferrite antenna.)
The loop can be contained in or held in a circular of rectangular
shape by any non-metallic support such as PVC conduit etc or just
hung up like a small clothes line to form a "delta loop"
ideally with roughly equal sides.
My own antenna, shown in the photo on the right, comprises a 2M
PVC conduit spreader supported by a 3.5M telescopic aluminum pole
using two turns of antenna wire giving approx a 12M loop (an
inverted equilateral triangle - not that that's important).
Alternatively, the loop can be arranged in a diamond configuration
with a non-metallic spreader (a length of 25mm electrical conduit
is ideal) and can be more convenient to erect. A 1.5M
spreader will give you a 4M loop and a 2M spreader will give a 5.5
- 6M loop
This is a very simple basic aerial but nevertheless works very well, is simple to implement, does not require constant
retuning, is highly portable, easy to set up and not too
critical on direction - a good compromise. Also,
loop aerials in general are less susceptible to inference than a long wire aerial.
Whilst it's possible that selectivity may be slightly degraded due to the unmatched
loading effect, this is of little concern since, generally
speaking, we are out in the bush
trying to pick up whatever we can. (Trying to
receive a weak distant signal adjacent to a strong local one is
not a priority in this instance.)
And our antenna needs to be simple and easy to throw up at our
Having said that, I haven't noticed any degradation in selectivity
during field testing.
With this modification to a couple of cheap portable radios and
using just 4 metres of aerial wire, stations were picked up
clearly that are totally absent without. The
performance of these radios from the aspect of receiving a weak medium
wave broadcast band AM signal now is almost as good as my Sony IFCSW7600GR
with just this 4 metre loop.
Unfortunately this is difficult but not impossible to implement on the IFCSW7600GR, the
ferrite rod is difficult to access and the radio is so jam packed
full that fitting another socket is difficult and the dramatic improvement seen on the cheaper radios
is not seen with the Sony unless using at least a 8-10M loop
although a 3-4M does give a small but worthwhile improvement.
The same goes for external inductively coupled loops, good results on
cheaper radios, nowhere near us useful with radios the caliber of
I have performed this mod on a Tevion MD81157 which has a
readily accessible ferrite rod and plenty of room for an antenna socket,
with excellent results. It now pulls in
weaker signals than either my car or caravan radios with just a 4
(Why did I buy the Tevion ? It caught my eye for
$19-95 (usually $49-95) in an Aldi sale that I
attended out of curiosity.)
I did this mod on my Sony 7600 by fitting a 3.5mm socket in place of
the wrist strap retaining screw, a very tight fit with some minor surgery
I did it mainly so that I could use the Sony inside our aluminium frame aluminium clad caravan using an outside
aerial and shielded feed cable.
In this instance my aerial consists of a triangular loop as
described and shown in the above photo.
This works extremely well being able to receive all Qld, NSW, Vic
and SA 50Kw ABC transmissions from anywhere in any of those states
at night and several during the day.
A continuously variable RF gain control such as used by the Sony
IFCSW7600GR, the Sangean ATS909 and the Redsun
RP2100 (as opposed to the near useless
Local/DX switch in cheaper radios) is near essential with an
effective external aerial such as this one.
This aerial also gives good results with short wave
- some radios, such as the Sony IFCSW7600GR, that have an
external aerial socket, have a superimposed DC voltage to power an
active aerial. In this case you should not connect a DC
loop to the aerial socket directly, you have to make sure a capacitor is in
series with the loop.
Before you go defacing your radio, wind the turns on the
ferrite aerial rod and just lead them outside the case and connect
it to 4 - 6 M of wire and arrange in a delta fashion as
described with the wire 2 M or more above ground. If you like
the results, you can make the modification permanent.
It will however be the end of any warranty you may have.
I am describing these just as a matter of interest, I don't
believe they are quite as suitable for our wandering needs, my
"cloths line delta loop" above takes a lot of beating in
This is another type of loop aerial consisting of the aerial wire,
several turns of it, contained in a plastic loop (picture a hulla
hoop) ranging in diameter from 300mm to 450mm.
Generally narrow bandwidth, they are tuned with a variable
capacitor to suit the received frequency. They tend to be
The radio needs to be placed in close proximity, usually inside
the loop since, generally speaking, there is no physical
connection needed, they are inductively coupled to the radio.
They are commercially available and are reasonably effective and
the cheaper the radio, the greater the improvement in reception.
There are passive and active (amplified) types.
Picture on the right is an example of a small amplified loop for
the HF band connected to the radio's external input socket.
Then there are small loops (600 - 1200mm) with
inductive or physical connection to the receiver that you can
build yourself, both passive and active.
|Non resonant long wire aerials
Although out in
the bush a length of wire 10 M or more long strung up a few metres
above the ground with one end tied to a tree and the other
attached to the radio's telescopic antenna can be quite effective on the HF and
FM bands, once again, I'd suggest you be
very cautious, especially if there is even a hint of a thunder
activity or if you are picking up random crackles.
Normally only suitable for the HF and FM bands and will have no
effect whatsoever on LW and MW which use the internal ferrite rod
for these bands.
It does however work for a car radio on the MW and FM bands.
However, with the above modification to the radio, a short whip or
length of wire connected to one side of the coil and the other
earthed can give good results for LW and MW but in a camp site
situation, an effective earth may be difficult to
This works very well on a boat where connection to any underwater metallic
object forms an excellent "earth".
This is probably beyond the scope of an introductory article like
this but later, I may also describe a simple ATU (aerial tuning unit) and
also a tunable active RF preselector (tuned
amplifier) circuit for the MW broadcast band, either of which you
could build yourself, for the more
These are a commercially available non directional (in the
horizontal plane) vertical whips with an amplifier.
The radio would need an aerial input socket, not likely to be
found on cheaper portable radios.
Some have small inductive loops which you place near your receiver
for the LW and MW bands for radios without a suitable input
connector for those bands.
Shown on the right is simple yet effective wideband active
you can build for under $10 using a 1M vertical whip for ease of use in a
Modifications to the Tevion MD 81157 receiver
radio lends itself to very simple "improvements" due to
the liberal amount of free space inside such as the aerial modification described
above and a 9 to 30VDC input, much more convenient than the original
6VDC one for several reasons.
The radio received the above aerial modification and in addition,
one side of the winding is connected to the telescopic aerial so
that the new external aerial works well on all bands, LW & AM
as well as HF & FM.
Also, the 8 - 24VDC input modification means the radio can now be used
with the external power simultaneously
with the batteries so that you don't lose your preset stations if
the external power is interrupted.
It can also be made to trickle charge
internal Ni-Mh batteries (don't do this if you are
using non-rechargeable batteries).
Note - This mod is suitable only if the radio is to be used
mostly with external power - reason, the combination of using
lower voltage rechargeable batteries and loss across an isolating diode
means the radio is only seeing about 4.5V instead of 6V, therefore
onset of low voltage shutdown will occur after fewer hours use.
Also, depending on the quality/complexity of the radio circuitry,
lower operating voltage can result in impaired reception
performance. Not applicable to high end radios like
maintain internal operating voltages irrespective of battery voltage, up to their shut down
point, with internal DC-DC converter circuits.
Just a small handful of components costing less than $10
is all that is needed and the two mods improve the performance and
usefulness by a huge amount.
The accompanying photo show the new aerial input socket and the DC power
socket below the original 6V input socket.
Of course, these simple mods can work
with other radios too.
power supply for the Sony ICFSW7600GR
and other 6VDC radios
Sony like many others is operated from 6VDC and that's what
the radio's external power socket wants to see. And in
Sony's case they don't see fit to supply an AC power pack.
- while good 12VDC AC plug packs are very common, good regulated
6VDC ones are not, also
- it would be very useful to be able to operate the radio from the
caravan and/or vehicle 12V battery.
A simple solution to both is to make a 12VDC to 6VDC
reducer. This is easily done with $5 worth of parts
from Dick Smith, Tandy, Jaycar etc.
All you need is the appropriate plug for the radio and a socket to suit
your power supply, a 7806 regulator, tantalum capacitor and a small
enclosure (mine is an old lipstick type dispenser - see photo).
This makes for a compact in-line connection between radio and
Fortunately, the Sony uses a smallish (uncommon) size plug so
that it can't be accidentally confused with the larger diameter more common sizes
found on most 12VDC plug packs.
Now, using this reducer, any voltage between 9 and 30VDC can be
used with the radio. The output is maintained at a
The current capability of the
regulator (which is rated at 1A max,15W
dissipation) will depend on input voltage and size of heatsink
In my case with a nominal 12VDC input and
<250mA output, just a small one is needed which is obviously
contained within the lipstick dispenser.
The same circuit can be adapted to suit 3V, 4.5V or 9V
present receivers (the better ones)
- 30000 kHz AM / SSB
25 - 2000 MHz AM / FM / SSB
- 29999 kHz AM / SSB & 76 - 108
original from long long ago
was a Nordmende from West Germany,
a better than average portable radio in its day
(early ' 60s).
A three band 9 transistor radio covering,
LW - 160 - 280 kHz
MW - 510 -1650 kHz
SW - 1500 - 3500 kHz
Case was vinyl covered plywood
following are some useful
frequencies for listening to ABC shortwave worth programming into your HF receiver.
Keep in mind that the powers-that-be are forever changing many of these
frequency allocations for one reason or another but they are right as far
as I know in mid 08.
|| Frequencies (KHz)
04:00 - 09:00
|| 6020 6080 7240 7240 9660 9710 11650 15230
09:00 - 12:00
|| 9660 13690 15230 15240 17715
12:00 - 16:00
|| 9660 13690 15240 21725
16:00 - 19:00
|| 5995 9660 9710 13690 15240
19:00 - 04:00
|| 5995 6020 9560 9580 9710
The ABC broadcasts from Shepparton, Victoria on
11880kHz during the day and 6080kHz in the evening also,
kHz is a good ABC news transmission "after dark".
Also for AM and FM receivers, a good way to stay informed while you
are away from home with world and local news and sport is with the ABC's
almost 100% news radio stations.
A frequency list is shown on the right.
(They are always expanding this service so check on their web site.)
You can also
visit their web site, there is a lot of interesting information there
including dozens of links to other sites.
|| 102.5 FM
following are the first three "pages" of preset frequencies
that I have stored in my Sony ICFSW7600GR
that I find very useful, all ABC of course.
With the Sony ICFSW7600GR
(or a cheaper radio with the external aerial
modification) you can expect to receive some if not most of the 50Kw transmitters
listed below on pages 1 & 2 at night from almost anywhere.
For instance, reception in SE Qld at night -
- all those listed from Qld - 100% of the
time, no noise
- from NSW - 100% of the time, occasionally
a little noise
- from Vic - 95% of the time, a little noise, occasional
- from SA - 75% of the time, usually some
- from WA - 25% of the time, always some
*The Sony is noticeably less prone to the effects of fading due
to it's synchronous detector
feature although does generate some low level internal noise.
50Kw Vic, SA
Frequency listing nomenclature as pertaining to shortwave listening.
- 510 kHz
30 - 300 kHz
- 1640 (1710) kHz
300 - 3000 kHz
- 30000 kHz
3 - 30 MHz
- 108 MHz
30 - 300 MHz
The Frequency to Wavelength relationship.
Band allocation by
( You will come across some minor
variations to that listed below.)
The formula for converting a
particular Frequency to Wavelength is,
Wavelength (in metres) = V / F
where V = velocity of light (300,000,000 metres per second)
For example, to convert 6.020 MHz
= 300,000,000 / 6,02,000 Hz = 300 / 6.020 MHz = 49.8 M
Electromagnetic Frequency Spectrum