QRZ! Ham Radio 1/QRZ Ham Radio Callsign Database - December 1993.iso/arrl/best_rig.1

Text File | 1993-11-21 | 13KB | 264 lines

Which Rig is Best - Operating Features and Performance
Part 1 of 2

February 27, 1993

Derived from February 1993 QST "Lab Notes". Copyright 1993
American Radio Relay League, Inc. All rights reserved.

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"What Rig Should I Buy?"

The economy is picking up. The future is looking brighter! You
finally have some cash to spend on Amateur Radio equipment, but
you want to make the right choice. Ask any veteran ham and he or
she will tell you about that #$%&@ radio they purchased. No one
want to throw money away, but how do you know which rig is best?
Ed Hare, KA1CV, ARRL Laboratory Supervisor, with help from Rus
Healy, NJ2L, Senior Assistant Technical Editor (and conductor of
our Product Review column) jumps feet-first into this sticky
topic.

Every day the Technical Department staff answers a variety of
technical questions that arriving by mail and telephone. You don't
have to be a staffer very long before you realize that the same
questions keep popping up again and again. One of the most
difficult to is "I am thinking of buying a new transceiver. Which
one is best?"

Sounds like a simple, straightforward inquiry, doesn't it? Well,
that innocent question is filled with pitfalls. In a supreme act
of bravery or stupidity (you choose!) we're going to tackle that
thorny question this month. We will be referring to a multi-mode
MF/HF transceiver, but the same principles apply to VHF and FM
equipment.

We should point out that the League has a clear policy abut making
rig recommendations -- we don't do it! This policy was written for
some pretty good reasons. (In fact, most of the time spent
answering the question is spent explaining why we really can't
give a single answer to it.) QST features a Product Review column
to help inform our readers about the characteristics, features and
performance of most of the popular or otherwise significant
Amateur Radio equipment that is sold today. The equipment is
subjected to careful testing in the ARRL Laboratory, then is given
to one or more qualified reviewers for a few weeks. Then the
laboratory test-result report and the written comments of the
reviewers are put together by Senior Technical Editor Rus Healy,
NJ2L. Rus carefully considers each word used in the Product Review
column -- your purchase decisions and a manufacturer's reputation
are on line. The result is carefully reviewed by a team of QST
editors, the test engineer in the Laboratory and ARRL management.

This is how it should be -- a lot of careful consideration goes
into the Product Review column to make it a valuable tool to help
our members with their purchase decisions. It would not be fair to
you, or to equipment manufacturers, to undo all of this work by
having the ARRL staff impose their own personal preferences on
you.

Ed Hare, KA1CV, the Laboratory Supervisor, has thought up the best
analogy to cover this situation. He says that rigs are like people
-- each model is different, with strengths, weaknesses and
idiosyncrasies that must be considered. We could no more tell you
which rig is best for you than we could tell you what car to drive
of whom to marry -- either way, it is your preferences that are
important to the choice, and it is you that must live with the
result.

So now that Ed has stuck in his two-cents worth, we will make him
write the rest of the column, so take it away, Ed! -- Steve Ford,
WB8IMY, Assistant Technical Editor.

Thanks, Steve! (I think.) Now if I had a nickel for each time I
have been asked one of these questions, I could retire early! This
is a real tough issue, but let's see if we can help unravel the
facts.

Q: "I am thinking of buying a new transceiver -- which one is
best?"

A: Unfortunately, Steve already told you that we are not going to
answer that, so let me run through the steps of the real answer to
the question. There are four major factor to consider when
deciding which rig to buy -- features, convenience, performance
and you! Each one of these is probably of equal importance to your
choice.

Q: Me? I already know about me -- I want to talk about the
equipment. Why am I on that list?

A: You need to think about all of these factors as they interact
with your needs. To cite a few examples, purchasing a 1500-watt
amplifier may not be the correct choice if you need to operate
from your condominium without bothering your neighbors with
interference. You probably shouldn't buy the latest multi-band,
all-mode VHF transceiver if all you really need is a single-band,
FM mobile so you can use your local repeaters while you are
driving to and from work. You will, of course, have to decide how
the purchase will affect your savings account.

Q: Features? Exactly what do you mean?

A: Performance discusses things common to the function of all
types of radios -- features discusses things that may or may not
be present in any particular radio.

Q: When shopping for a radio, what features should I consider?

Here are the major features, and a brief description, that most
hams consider important in selecting an HF transceiver:

IF Filters: QRM is a way of life in amateur operation. Much like
the noise in a crowded room, when many hams operate the same band
at the same time, they sometimes make it hard for anyone to hear
each other talk. Fortunately, things are a bit easier on radio --
the radio is able to selectively tune in (or tune out) signals.
Most radios come with different filters available, either as stock
or as options, allowing one to use as little bandwidth as
necessary so that you only hear the signals you want to hear.
Receiver filtering is often performed in the intermediate-
frequency (IF) amplifier chain, usually with crystal filters.
(Some older IF filters were mechanical, and digital-signal
processing (DSP) is being used some at IF now, so the future will
probably have many improvements in store for Amateur Radio.)

Many transceivers offer several IF filters according to the mode
selected (a wide filter for SSB, a narrow filter for CW). Check
which IF filters are available, and whether or not accessory
filters are offered as well. For example, many SSB operators
prefer to install 1.8-kHz IF filters in their rigs. CW operators
often choose 500- or 25o-Hz filters.

Audio filters: Filtering can also be done in the audio stages of
the radio, or using an external audio filter. Many radios use
audio filtering as a supplement to the IF filtering. The main
disadvantage of audio filtering is that it is usually done outside
the automatic-gain control (AGC) circuitry of the receiver. Strong
signals that are filtered out by the audio filter may affect the
volume level of the desired signal by pumping the AGC.

Notch filtering: Notch filtering is usually performed in the IF
amplifier, but it can also be done at audio frequencies. This
feature gives you the ability to reject or "tune out" an undesired
CW signal or other heterodyne whistle. It may be implemented by an
adjustable, analog notch-frequency control, or by using digital-
signal processing (DSP) technology. DSP notch filtering can be
particularly useful because it can "seek and destroy" multiple
carriers.

A notch filter can be a useful feature, but it can be added
externally, so if your favorite radio doesn't feature one, you may
be able to install one separately.

Pass-band tuning (PBT), variable-bandwidth tuning (VBT):  PBT and
VBT are two features that increase the flexibility of the receiver
in tuning signals on a crowded band. They work by shifting the
receiver's pass band to avoid a nearby interfering signal, or by
varying the bandwidth of the pass band until the undesired signal
is no longer heard. Both affect the fidelity of the desired
signal, but it is usually better to endure muffled or "tinny"
sounding audio than to suffer interference from another station.

Two VFOs: Dual VFOs have become standard features on most modern
radios. The primary advantage of a dual VFO is the ability to work
split-frequency, transmitting on one VFO and receiving on the
other. They also let you quickly bounce back and forth between two
frequencies or bands.

Noise blanker: A good noise blanker can dramatically reduce
impulse noise. Noise blankers generally work quite well on
automotive ignition noise, and vary in effectiveness on other
types of noise, such as that caused my motors and the like. FM has
substantial inherent noise immunity, so noise blankers are not
usually found in FM rigs.

Memories: Most modern radios also have memory channels in which
you can program your favorite frequencies and modes. Most memory
features will also "remember" the settings of filters and other
controls, making it seems as if you had many separate radios at
your fingertips!

Computer control: Most current transceivers include a computer-
control interface, allowing you to use a computer to control the
radio to do nearly everything that can be done from the front
panel. This comes in handy for logging or contest software,
satellite operating and other applications in which it is
convenient or necessary to control the radio's features via
computer.

General-coverage reception: This is a great feature for hams who
want the ability to listen to international broadcasts and other
signals in addition to Amateur Radio. The next time an
international crisis comes up, you can listen to the action on
your Amateur Radio rig!

Expanded frequency coverage: Now we're talking about expanded
transmit and receive capability. For example, both the Kenwood TS-
690 and the ICOM IC-729 transceivers include 6 meters. Some HF
transceivers feature the ability to add internal or external
transverters or modules that permit operation on the VHF/UHF
bands.

Antenna tuners: While antenna tuners are not required in every
station, they sure can make life easier! A well-designed antenna
tuner will allow you to use antennas that are not resonant at your
desired frequency. You can put up a dipole for one band (40
meters, for instance) and operate on several other bands as long
as you use a low-loss feedline.

A number of transceivers provide built-in antenna tuners that
adjust themselves automatically. Many hams find it handy to have
an antenna tuner right where they need it -- in the radio.

Variety of modes: SSB and CW are standard in most rigs, but others
add AM and FM, too. Yes, there is still AM activity on the amateur
bands and FM flourishes on the high end of 10 meters. If you're an
RTTY or AMTOR enthusiast, look for a rig with an FSK mode. You
don't need FSK to operate RTTY or AMTOR but rigs with FSK often
provide narrower IF and/or audio filters when this mode is
selected. Filtering makes a big difference when the RTTY/AMTOR
subbands are crowded!

13.8-volt operation: If you plan to operate mobile or portable,w
ill the transceiver accept a 13.8 volt power source? Some rigs
feature an internal 13.8 volt dc option whole others offer a dc
accessory supply.

Q: I get the idea -- there are a lot of possible features. I guess
I will have to decide which ones are right for me. Now, earlier
you said that "convenience" was one of the major factors to
consider. What do you mean?

A: It's simple, really. There are many choices that can be made
about how a radio is put together that affect the way it is used.
Are the critical controls located on the front panel? Are the
knobs the right size for your fingers? Is it the right size? You
should also consider the owner's manual -- is it well written?
Does it answer your questions? Basically, you want to decide if
all of the performance and features are "convenient" for you. Even
the appearance of a radio can influence this very personal
decision.

Continued in Part 2

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