Polarised Power Connectors
Perhaps the most important item is one that helps protect expensive equipment against costly reversed polarity mistakes.
Anderson PowerPoles will take care of the polarity
of power leads when making connections to batteries and power supplies. Using Anderson PowerPoles guards against making a
simple rushed mistake that would otherwise be VERY costly indeed!
30 Amp Anderson
PowerPole connections are excellent for use in amateur radio.
Antenna Tuning Unit
described as the Antenna Matching Unit - since an ATU cannot tune an
antenna, it can only match the impedance presented by the antenna
system to the 50 ohm impedance required by the transceiver or receiver.
of my MFJ Antenna Matching Unit
of the MFJ Antenna Matching Unit
The front panel of my LDG
The rear panel of the LDG
Analyser The LDG Z-11 Pro is a real revelation that
saves so much time. The fact that is has 8000 automatic internal
memories (2000 for each of four aerials) means that once memorized the
Z-11 Pro will return to the LC setting for a particular aerial and
frequency combination literally in the blink of an eye. A true 'magic
box' of tricks - well relays, inductors and capacitors actually! http://www.ldgelectronics.com
I have found the antenna analyser to be an invaluable piece of
It is extremely useful for checking and setting up external aerials
since it save one having to keep running up and down stairs to the
shack checking VSWR. With an antenna analyser it is possible to remain
by the antenna while making adjustments and checking.
The analyser can also be used to diagnose faults and to assist in
making many other extremely complex measurements and calculations.
Perhaps it is at its most valuable in everyday use when 'tuning up'
before transmitting. Because an analyser has an internal and adjustable
oscillator, it can be used to check VSWR at and make ATU adjustments
without having to press the PTT on the radio. This prevents any
unnecessary interference to other radio operators. Essential!
MFJ 259B Antenna Analyser
To quote from MFJ
Enterprises; "Read antenna SWR and Complex Impedance
1.8 to 170MHz. Read Complex Impedance as series resistance and
reactance (R+jX) or as magnitude (Z) and phase (degrees). You can
determine velocity factor, coax cable loss in dB, length of coax and
distance to a short or open in feet. You can read SWR, return loss and
reflection coefficient at any frequency simultaneously at a single
glance. Also read inductance in UH and capacitance in pF at RF
frequencies. Large easy-to-read two line LCD screen clearly displays
your information. Built-in frequency counter, Ni-Cad charger circuit,
battery saver, low battery warning and smooth re-duction drive tuning
and much more. Super easy to use! Just set the band switch and tune the
dial -- just like you transceiver. SWR and Complex Impedance are
Noise Bridge - a much lower cost alternative to an expensive antenna analyser
Antenna analysers now tend to be
extremely expensive, but a good noise bridge could be used as a much
lower cost alternative. A noise bridge can be used for measuring the
impedance of antennas and traps at various frequencies. Your H.F
receiver is used as the bridge
A number a circuits are available on the internet and kits are also
available, such as the high quality RX2 from VK3AQZ Kits. Here are some
One of the most useful devices for the shack is a balun, or more to use
a more correct term, a 1:1 choke balun. This will match a balance 75
ohm twin feeder to the unbalanced 50 ohm input of the Antenna Matching
Unit. The Antenna Matching Unit (often referred to as an ATU)
will then transform the impedance presented by the antenna feeder to
the 50 ohms required by the transceiver.
M0MTJ Home Brew 4:1 Balun
A dummy Load is an essential item of amateur
equipment. It allows various tests to be carried out on the
transmitter, such as checking modulation or deviation levels, without
radiating an RF signal from the antenna. This avoids causing
unnecessary interference to other users.
MFJ 260C 300 Watt Dummy Load
Meters for testing electronic and electrical circuits:
AVO Model 9 Meter :
I am the
(rather proud) owner of an AVO Model 9 multimeter. AVO meters were
probably the defacto standard many government agencies, Post Office
telephone engineers, military / NATO as well as civilian markets such as
television repair technicians.
The Model 9 AVO is very similar to the well known (classic) Model 8 AVO,
except that it was originally designed, in the late 1960's, more
specifically for electronics engineers and an export market;
as such it uses international (ISO) symbols
rather than printed words or letters that identify the controls of the
Model 8. The adjustments are 1 - 3 - 10 rather than 1 - 2½ - 10
are used on the Model 8, otherwise the Model 9 and Model 8 are the same.
has a beautiful large clear scale, about 5 inches (12.5 cm) long,
with a silky movement and knife edge pointer with parallax mirror and a high sensitivity of around 20,000 ohms per volt which I was told is higher than some Model 8's. AVO meters should be used lying down with the dial facing upwards to ensure proper accuracy.
The scale of a good analogue, swinging needle, meter is often much
easier to read than the often changing digits of a digital multimeter,
so it's probably important to have both types available for different
situations. - So keep your eyes peeled for a nice Model 8 or Model 9 on
your travels, not only will it look nice it could well be an invaluable
AVO Model 9 multimeter
Digital Multi-Meter - DMM :
Handy, lightweight and versatile, with
many measurement functions such as transistor tester, capacitance and
inductance metering - a Digital Multi-Meter:
Perhaps an obvious requirement! The PSU is needed for powering
transceiver that has no built in mains transformer and for
other station accessories. The PSU needs to be able to provide a clean
and stabilized 13.8 volt supply at the necessary current rating: A
typical 100 watt transceiver would require around 20 Amps when running
at full power.
I use a Palstar PS-30 PSU (also known as EP925 and sold under various brand names), it has short circuit protection and
has an over-current warning indicator,
a galvanised steel case, precision ammeter and voltmeter monitoring,
thermostatically controlled fan that cuts in when the temperature reaches 70 degrees. Terminals are binding posts and snap in
terminals. View User Manual.
I cannot recommend this unit, it's rather cheap and nasty, the fan can
be noisy ( I have replaced mine) and the circuit is not the best. It
does not have Over Voltage Protection; This is dangerous since supplying
a radio with over 16 volts can damage it, possibly beyond repair - so a
power supply that omits Over Voltage Protection is inexcusable. I will
be fitting an over voltage 'Crowbar' protection system as soon as
possible. PR0FRI has a web page of modifications for this PSU, noted below:
- Low Pass Filter
An RF filter may not always be
necessary, but if
transceiver suffers any spurious harmonic output when transmitting an
external filter can filter such products out, thereby preventing or
reducing any possible interference to receivers operating on higher
frequencies, such as televisions and domestic radios etc.
An external speaker is often better than the
loudspeaker built into many radios. An external speaker also allows the
use of external audio filters or digital signal processing units
(DSP's) to be connected to the transceiver.
One speaker is large in a 'home brew' cabinet containing a very high efficiency GL13 10 watt, 6 inch loudspeaker
unit. The drive unit and grill were purchased from Maplin. I find it very good in
Another 'home brew' speaker is shown below. This includes a switchable
low pass filter that can help cut down hiss and noise on weak signals.
This is constructed using an efficient elliptical loudspeaker housed in
an MB5 ABS enclosure. This is convenient size for mobile use. Read more here >
A small home brew speaker using an efficient elliptical drive unit.
This speaker also includes a switchable low-pass filter.
Read more here >
speaker, constructed using a Maplin GL13
6 inch 10
watt drive unit plus grille
personal listening so as not to disturb other people too much.
Headphones may also be helpful when trying to hear weak signals.
'Closed-back' headphones cut out more external noise than 'open-back'
As an alternative to the hand mic that is
supplied with the Kenwood TS-590, I use a separate dynamic microphone
mounted on a goose-neck, PTT operation is by foot switch. Read more here >
The HM-103 hand mic that comes with my Icom
IC706-mk2G seems very good, but I also have a Leson TW-232 Desk Mic
Key for CW
This is my simple HK-705 Hi-Mound straight
Meter / SWR Bridge
Standard type power and SWR meter
Cross Needle type power meter
Guying Antenna Masts and Poles - Clam Cleats "Line-Lok"
Excellent for guy ropes and for binding one pole to another with rope.
Reduction / Digital Signal Processor
For radios without any internal Digital Signal Processing and external DSP unit could be very welcome. The BHI
NEIM 1031 Noise
Module has an adjustable DSP level. Even
without using the DSP noise reduction the BHI unit has a built in 4.5
KHz low pass filter that can make harsh audio sound much more pleasant.
BHI NEIM 1031
A personal computer might not be regarded as an accessory as such, but
it an essential tool. I use the PC for all the usual things
as researching amateur radio subjects on the internet, but it can also
be used for decoding and sending data modes, e.g. CW (Morse),
Packet, PSK31, RTTY, SSTV and keeping a station log book.
obvious tools are soldering iron, pliers, screwdrivers, wire strippers,
screw drivers and watch makers screwdrivers, tweezers, spanners and a
good multimeter. Here are a few more ideas that will prove useful:
Measuring calipers can be of the vernier style or digital variety,
shown below. A caliper is extremely useful for measuring the diameter
of wire, tubes and poles and any other item that is difficult to
measure with a ruler or tape measure.