Of The Lowe HF-225
Year Introduced/Discontinued: 1989/1997
Power: Mains, 12 V DC optional
Size: 253 x 109 x 204 mm
Coverage: MW, LW ,SW (0.03-30 MHz continuously)
Value Ratings: HF-225 4/5 HF-225E 5/5
In the first half of 1987, a new shortwave
communications receiver came onto the European market. The Lowe HF-125,
as it was called, was then upgraded to the HF-225. A 19 inch rack
version called the HF-325 was launched in 1990. This offers similar
features, plus a few extras. Designed and built by Lowe Electronics of
Derbyshire England, it is lightweight at 1.9 kg in its standard
2.6 kg if internal Ni-Cd batteries are installed. It measures 253 x 109
x 204 mm making it very compact. It is a double-conversion superhet
design, with a high first intermediate frequency of 45 MHz. There is a
"souped-up" version of the HF-225, called the HF-225 Europa. The Europa
version has better specifications and better filters, but it is more
expensive. The set reviewed here is the standard model!
The set comes with a 12 volt DC power adapter
for use on 220 volts AC current in Europe. This external power supply
gives no problems, providing the transformer box is kept well away from
the receiver (i.e. do not put it next to the receiver, or AC mains
fields tend to couple with the receiver's oscillator circuitry).
The beginner will have no problems connecting up
an antenna, a pair of headphones or a tape-recorder. Lowe electronics
have written a clear, logical instruction manual plus a booklet that
explains what to listen out for when you start tuning around. Part of
its attraction is the simplicity. There are just 9 controls on the
panel, which can be tilted up to face the operator.
Up to 30 frequencies can be stored in the
radio's memory. Data is held in these memories using a lithium battery
back-up. The memory channels can be quickly selected using the manual
tuning knob. The tuning knob itself has a good feel to it, being large
enough and offering a recess for the finger.
A large clear green-coloured back-lit liquid
crystal display shows the frequency being received with a resolution
nearest 1 kilohertz. Frequency display shows the true carrier
whatever the mode selected. The manual tuning knob offers FAST and SLOW
tuning, depending on the speed with which the knob is rotated. The
tuning increments vary with mode selected as follows:
Mode Normal Speed Fast Speed
LSB, USB, CW 8 Hz 250 Hz
AM 50 Hz 500 Hz
FM 125 Hz 500 Hz
AM sync 8 Hz No fast mode available
The standard AM steps proved to be small enough
for comfortable tuning without any annoying "chuffing" effects. If you
select either upper/lower sideband or the CW mode as you would do for
radio amateurs or telex stations, the slowest tuning step drops to 8
This is a considerable improvement over the older HF-125. Since the
receiver is stable, the fine tuning steps allows you to accurately tune
in a radio-teletype station with ease. The receiver also has a
narrow-band FM option for monitoring citizen's band on 27 MHz for
instance, but we didn't test this mode ourselves. The increment chosen
for the AM sync mode is fine, but there is no provision for selecting
either upper or lower sideband. We think this is a limitation. The
keyboard comes as a separate option costing £39.50. It is a good
idea to regard this option as essential, as tuning is made a lot
The keypad can be placed horizontally in front of the set, making it
easy to punch in frequencies. The keyboard software is clever.
Stability and birdies
We put the receiver in a constant temperature
environment (18 Centigrade) and tuned it to 12100 kHz. The set was then
switched to the USB and LSB modes. After an hour, drift was less than
Hz in each instance. This is comparable with receivers in much higher
If you put a shortwave receiver inside a metal
cage so that it's screened off from the outside world, you can then
measure "ghost" signals on the dial generated by the set itself. They
appear as a silent carrier if you're listening on AM or as a whistle if
you're listening on single-sideband. Most sets of this price range
suffer from these so-called "birdies", and you can't get rid of all of
them without drastically increasing the price of the radio. The
designer's aim is to make them as weak as possible and on frequencies
that are outside major broadcast and amateur bands. We measured more
than 25 low level birdies on the HF-225 (i.e. greater than 0.5
microVolt). Most of these disappear below the noise level when you
connect an antenna, but we found 6 "birdies" which were above 1
microVolt, and therefore noticeable. If you try to tune in a station on
these channels, you will get extra distortion or interference generated
by the HF-225 itself. More expensive sets like the Yaesu FRG-8800 and
ICOM ICR-71 have around the same number of birdies too. For a receiver
of this price bracket, the number of birdies on the HF-225 is good, and
better than the HF-150.
In our tests we checked how much signal is
needed at the 50 Ohm input to get a signal + noise/ noise ratio of 10
dB. Sensitivity often varies with frequency, and for that reason the
HF-225 was measured at several points in the spectrum. We checked the
mode (using 60% modulation) and SSB. The 4 kHz filter was selected for
the measurements, being the filter than SW listeners are most likely to
use for broadcast listening.
Sensitivity: In microVolts at 50 Ohms: 10 dB
S+N/N, 60% mod AM, 100% SSB, 1 kHz tone.
MHz 0.2 2.2 8.0 12.1 16.0 26.0
AM 0.66 0.63 0.70 0.73 0.68 0.71
SSB 0.22 0.20 0.20 0.19 0.18 0.28
The receiver's built-in synthesiser generates a
lot of noise between 30 and 70 kilohertz, way down in the very low
frequency part of the spectrum. This masks most of the signals coming
in. But from 100 kHz up to 30,000 kHz, covered continuously on this set
with no breaks, the sensitivity is remarkably uniform. Sensitivity is
also dependent on the chosen bandwidth filter. The following
measurements were taken at 12.1 MHz.
Sensitivity in microVolts, measured at 50 Ohms:
10 dB S+N/N against bandwidth AM 60% at 12.1 MHz.
IF kHz 2.5 4.0 7.0 10.0
Sensitivity 0.49 0.71 0.70 0.78
The receiver offers an analogue signal strength
meter which turns out to be very accurately calibrated, far more than
just a tuning gimmick.
RF Attenuator/ Automatic Gain Control
A push-button attenuator is provided, offering
around 17 dB attenuation when measured at 12 MHz. It consists of a
resistance-network, which can be shorted out of circuit by a diode.
After the initial attenuation is seen on the S-meter, there is no
further indication that the attenuator is switched in.
The AGC is designed to keep the audio level at a
fairly constant level, even though the signal may be fading. Using AM
60%, 1 kHz tone, at 12 MHz the audio level varies by 3 dB for antenna
input between 0.7 microVolts and 120 milliVolts. The speed of the AGC
not selectable, and we found the time constant chosen to be adequate.
The HF-225 offers 4 different selectivity
positions. There is a very wide 10 kHz setting, best suited when your
listening to local medium wave stations, and then the low distortion
audio (less than 3% at 100 mW) sounds very pleasant indeed to our
European ears. The 7 kHz setting is best suited to shortwave when
found a strong clear signal. The 4 kHz option is more useful when the
signal you're listening to is suffering from strong stations operating
on frequencies 5 kHz either side of the one you're trying to monitor.
And finally, if you're trying to dig something out of the noise, or
looking for utility stations, the 2.2 kHz filter is the best suited.
The first IF filter at 45 MHz has a fixed
bandwidth of 15 kHz. In the second IF, use is made of switchable
filters which are cascaded to improve the overall skirt selectivity,
thus giving a 6:60 dB shape factor around 1:1.7. This is above average
for the price range, even though Lowe has raised the price of the
by around £100 since it was first introduced.
Good Dynamic Range
Dynamic range is a measure of how large the
difference in signal strength has to be between a weak and strong
signal, before interference by the strong signal occurs. This is
important if the receiver is to be used for DXing. Again using the
standard CEPT measurements, the two signal generators are tuned to
kHz and 10020 kHz respectively, i.e. 20 kHz apart. For the HF-225, the
dynamic range turns out to be 88 dB.
No active antennas
The Lowe instruction book warns against
connecting huge antennas. We found an active antenna such as the Datong
AD-270 or Dressler ARA 30 was totally unsuitable with the HF-225 in
Europe. With the 20 dB internal attenuator switched on, the active
antennas were delivering signals than the radio could just about
The 10 metres of long wire or dipole recommended in the instruction
gave much better results. Lowe does market a special active antenna for
use with this set, but we did not test this. In practice we found the
medium wave performance to be good. In May 1989 we tested the HF-225
with a medium wave loop, and were able to log North American East Coast
stations during good conditions.
In its day, HF-225 cost £499 including
Value Added Tax in Britain. For an extra £44.95 you can plug in a
keyboard, and then enter frequencies directly into the set. The
here is friendly, simple and logical. For another £49.00, you can
also have a FM board installed, plus a synchronous AM detector. This
mode generally offers better audio fidelity on shortwave signals,
especially during deep fades. Although the synchronous detection system
does perform, it doesn't lock onto very weak signals, and when this
is used, the audio sounds less pleasant. That comment is very
though. But unlike the cheaper SONY ICF-2001D or ICF-7600G, which also
offers synchronous detection, you cannot select between upper and lower
sideband. We would therefore rate the value of the synchronous detector
as only FAIR.
You can also have a rechargeable battery supply,
which is an optional extra. For better fidelity (especially on
medium-wave), Lowe introduced the XLS-1, this being a separate
speaker measuring 190 x 203 x 240 mm. This costs £59.00 in the
A portable carrying case for the set, C-225 is also available.
The manufacturer's specifications check out
perfectly, and Lowe electronics have achieved all the aims they have
themselves. The manual supplied with the radio was particularly clear
and concise. The HF-225 will be of interest to the serious shortwave
listener and beginning DXer looking for a no-frills receiver which
sounds good, and can handle a wide range of signal modes. The cabinet
simple but durable and difficult to scratch. This is important if the
receiver is to be used for portable work. The dynamic range is good for
a receiver of this type, the 3rd order intercept point for interfering
transmitters more than 20 kHz from the desired frequency being 13
dBm...a very acceptable figure.
Voted "Budget Receiver of the Year 1990" by the
World Radio TV Handbook.
February 1997 Update
In January 1997 we were told that only a few
units of the HF-225 and the HF-225 Europa remain in the Lowe warehouse.
Availability of this receiver series is scarce.