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. Thank you for requesting the following information from the ARRL Information mail server. ARRL HQ is glad to provide this information free of charge as a service to League members and affiliated clubs. For your convenience, you may reproduce this information, electronically or on paper, and distribute it to anyone who needs it, provided that you reproduce it in its entirety and do so free of charge. Please note that you must reproduce the information as it appears in the original, including the League's copyright notice. If you have any questions concerning the reproduction or distribution of this material, please contact Mark Wilson, American Radio Relay League, 225 Main St., Newington, CT 06111 (mwilson@arrl.org). "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 ------------------------------------------------------------------