Going Mobile

The Who had a hit tune entitled Going Mobile that may be playing in your head right now.  While the song celebrates the joy of living in a mobile home and traveling caravan-style in the UK, going mobile to hams means using radio equipment in your vehicle.

While some hams have HF radio setups in their cars, mobile predominantly means local VHF/UHF communication.  Besides bring able to talk to our ham buddies while driving around, 2m/70cm capability is particularly useful in case of disaster or other emergency communication (EmComm) situations.  It is perfect for storm spotting and certain public service events.

Mobile operation is popular and important enough that there are a number of US license exam questions involving the topic as you will see below.

Installing and using amateur radio equipment in one’s personal vehicle is too large a topic to cover here so we’ll simply advise you to research details on your own.  Talk to fellow hams and see what/how/why they installed their own gear.

The internet is also a vast resource for [mostly good] info .  One noteworthy site dedicated to mobile ham operation is managed by Alan Applegate, K0BG, and is located here.   It contains exceptionally useful info on most topics presented below.  We encourage you to use this site as a primary reference for your own mobile radio installation and operation.  The ABCs topic is the best place to start.

Before embarking on any of this yourself, there are several important points to consider:

  • Radio type
  • Radio control location
  • Radio mounting
  • Radio power wiring
  • Antenna type and mounting
  • Radio audio/speaker
  • Transmitting while driving
  • Hands-free/Distracted driving laws
  • Noise and interference

We will scratch the surface of each of these topics here:


Radio type-  Choose a mobile radio that best fits your needs, desires, and budget based on several factors:

  • Brand– quality/reliability and/or familiarity/loyalty
  • Transmit power (Watts)
  • Features– Auto power-off, APRS, dual-channel, remote head, cross-band, packet
  • VHF/UHF (V/U) or HF?
  • FM only, or multi-mode?
  • Single-band, dual-band, tri-band, or quad-band?
  • Analog or digital communication, or both?
  • New, reconditioned, or used?

Note that while a hand-held transceiver (HT) can be used in a car, it is significantly limited by its antenna and transmit power.  Both can be improved (linear amplifier and external antenna) but if you really want good mobile performance you should consider a purpose-specific mobile radio.


Radio control location-  Modern mobile transceivers typically feature removable front panels where the operator controls can be positioned in a more convenient, ergonomic, and safe location using a smaller footprint. Continue reading

Antenna Gain

Newer amateur radio operators may read or hear some discussion of antenna gain.  The gist of it usually involves how much stronger signals are with a particular type of antenna.

This concept of antenna gain can be confusing or misleading to new hams because it sort of suggests that some antennas actually amplify received or transmitted RF signals.  Not so.

Like the decibel (dB) antenna ‘gain’ is always relative.  So when we speak of antenna gain it refers to a performance improvement compared to a different type of antenna.

More commonly, gain is used to compare highly directional antennas (beams, dishes) to monopoles or dipoles.

t9a11

While antenna gain usually emphasizes directivity it may also be used to compare two similar types with different characteristics, as efficiency is another contributing factor.  For example, we can observe and measure the relative gain of a stubby “rubber duck” handheld radio antenna (pathetic) vs. a 5/8-wave whip (much better) even though they are both vertical monopoles with the same directivity.

The two types of antennas usually referenced against are isotropic and the simple dipole.  When measuring performance of other antennas, they will often be compared to one of these two.

g9c20

If the gain impovement is relative to the theoretical isotropic antenna, the units should specify the gain as dBi.  If measured against a dipole antenna, the gain should indicate dBd.  Any other comparisons should mention the reference antenna in the text.

Some good references for antenna gain are given below: Continue reading

How Far Can I Communicate?

One of the more interesting questions a new or prospective ham will have is, “how far can I communicate?”  The frustrating answer is, “it depends…” (don’t you hate hearing that?)

dx-map

There are many factors involved in the limits to distance of radio communication.  Carrier frequency is the huge one, followed by operating mode, antenna characteristics and transmit power. Time of day, solar activity and the season (spring, summer, autumn, winter) also have a big impact on range.  Natural (thunderstorms, aurora, geologic, cosmic) and man-made (crowded band, power lines, noisy electronics) interference can also limit or disrupt a radio contact.  Also factor in the use of repeaters (terrestrial and space satellites) or reflective objects (structures, moon, meteor showers), plus unusual weather conditions and you have a lot to consider.

Since many hams get started using VHF/UHF radios for local communication, let’s talk about this first.  VHF/UHF radio wave propagation is normally limited to line-of-sight, meaning the antennas at each end must have a clear path between them (no obstructions such as buildings, trees, and particularly, the earth).

3-20 miles is a realistic range for VHF/UHF hand-held radios on the ground, depending mainly on a clear path and relative height of the two parties.  Throw in a repeater with a high antenna and that range extends considerably.  Raising your own antenna up higher Continue reading

Don’t Settle for Just a HT

zys-ft-60r

Often a new ham’s first radio is a handheld transceiver (HT).  A HT represents the lowest-cost entry point to amateur radio and is relatively easy to set up and use.  Your first on-air experience as a licensed ham may involve a HT on a local VHF/UHF repeater, and that’s fine.

But don’t settle for just a HT as supplied by the manufacturer for your early ham radio experience.  You are almost certainly going to be frustrated and disappointed at its performance to the point of giving up on ham radio and wondering why all these hams are so enthusiastic about the hobby.

Don Keith N4KC makes this point eloquently  in his ‘HT Trap’ article where he discusses how easily a new ham can get discouraged with amateur radio because of the limitations of a stock HT.  I have observed this as well while helping new hams get set up in a local EmComm organization.

Huge improvements in HT performance or ease of use can be accomplished with three accessories.


First and foremost is the Continue reading

Get on the Air Now!

An outstanding resource for amateur radio operators, and new or prospective hams in particular, is a paperback book by Don Keith N4KC entitled, GET ON THE AIR…NOW!

    

There is something for everyone here: Folks who are interested in ham radio, those who just got a license, experienced hams who lose interest, and long-time hams who are looking for something to share with newbies. N4KC covers most of what current and prospective ham radio operators need to know and he does a great job of selling the hobby/interest. And no, he’s not pushing Morse code, although CW operation is one of the more interesting aspects of amateur radio.

The main emphasis of the book is encouraging licensees to actually get on the air and experience real ham radio, not to get frustrated with bad experiences and limited equipment and then give up on our hobby.  He addresses some of the common discouragements and steers us to realistic remedies.  Chapter five is a practical discussion of antennas and I particularly appreciate chapter six with Don’s concise description of what to expect on the HF bands.

gotan TOC

The second half of the book is a comprehensive dictionary of “ham-speak”–amateur radio terms, abbreviations and slang, useful to all hams, new and old.

About $19 with a Kindle version for $9.  Highly recommended and the first item listed on a new site page entitled Recommended Reading.

Practical Skills For the Radio Amateur

While not every ham is technically inclined or particularly handy, amateur radio operators tend to be do-it-yourself (DIY) kind of people who often build, install, and fix their gear and other things.  In many ways hams are some of the original “Makers” and experimenters who have actually helped further the art and science of radio and communications technology.

To encourage and further this historic reputation, consider developing in yourself some of the practical skills that ham radio operators are stereotyped to possess.  While the list rightly could be more extensive, we will suggest four basic ones here:

  • Electronic soldering
  • Using a multimeter
  • Stripping and terminating different kinds of wire and cable
  • Drilling and cutting material (fabrication)

We can’t go into details on these here*, so the reader will need to Continue reading

Antenna Lightning Protection

Many hams have a VHF/UHF radio and antenna for local communication, especially if they are involved in EmComm.  Ideally you have an exterior antenna up high for best performance with your radio. The downside to that is that vertically-oriented VHF/UHF  monopole antennas are a juicy target for lightning strikes.  Basically, they look like a lightning rod.

Lightning Antenna

Lightning wants to go to ground and if the best path is through your antenna and feedline, your radio is likely to be destroyed.  And if you’re right near the radio when it happens, you might be injured, or a fire might be started by the lightning strike.  Bottom line, bad things can happen with an outdoor antenna during a thunderstorm.

Don’t be fooled by simple lightning arrestors on your antenna. Those are good to have but they help only with minor stray lightning bolts.  A direct strike on your antenna cannot be stopped by a simple arrestor; there is too much energy involved to dissipate.  The radio will be destroyed in such a case, along with possible damage and injury.

Examples of lightning arrestors.

So what can you do to protect yourself and your radio from lightning? The best way is to Continue reading