Radios
Radios for RV Use
RV hams generally need radios that are:
- Compact Size
Radios are usually mounted in RVs that have very little extra room.
- Moderate power
Unless you are operating on HF at very low power (such operators are called
QRPers) or are a backpacker, you need a moderate power output level. 2 M
and other VHF/UHF FM radios should be capable of at least 50 watts output.
HF single sideband rigs typically put out 100 watts, which is sufficient
for worldwide operation.
Most amateur
radios are built by one of four companies:
How Radios Are Classified
Radios come in all flavors, but they can generally be classified by three
factors:
- Portability
Radios are designed for fixed, mobile, portable, or handheld use. Fixed
station radios are the largest and handhelds the smallest.
- Bands
Radios are usually desiged with groups of similar bands. Most HF radios
cover 160-10 meters. VHF-UHF radios usully cover at least 2m (s9ngle bander)
and often include 2m+ 70cm (dual-bander), 2m+6m+70cm (tri-bander), or even
2m+6m+1-1/4m+70cm (tri-bander). Some even dip down and include the 10m band.
Recently all-band radios have come onto the market and cover HF and UHF/VHF
bands.
- Mode
HF radios usually cover single sideband (SSB), CW (Morse code), and AM modulation
modes. UHF-VHF mobile and handlheld radios usually cover only FM. All-band
radios usually cover all modulation modes.
Single Band Radios
The most common single band radio is for 2 meter FM. The following
2 meter radios are compact, have an output power of at least 50 watts and
are priced at less than $200.
Multi-Band Radios
Several radios made by Icom, Yaesu, Kenwood, and even Radio Shack cover both
the 2 meter and 70 centimeter ham bands. This permits crossband operation
that in conjunction with a handheld lets your mobile radio act as a repeater.
This is useful when you are hiking and lets you use the power of your mobie
radio with the portability of your handheld.
Handheld Radios
Handheld radio come in single-band (usually 2 m), dual-band (usually 2 m
and 70 cm), and even quad-band (2m, 6m, 1-1/4 m, and 70 cm). Dual band handhelds
can be used with a dual band mobile radio to crossband operation. They can
also be used instead of mobile radios for vehicle-to-vehicle communications
while trailriding. The "rubber ducky" antennas uses on handhelds
are very inefficient, and users should probably use an external antenna.
All Band Radios
Both these radios are compact mobile rigs that put out up to
100 watts depending upon the band. The both require a good power source such
as a vehicle battery.
If you plan
to operate both HF and VHF/UHF while mobile, you will probably be more satisifed
with separate radios for each. Otherwise you will need to switch bands and
retune your antenna each time you move from one to the other.
Battery Powered All Band Radios
- Yaesu FT-817
This radio is a marvel. It covers 70 cm through 160 m. Its small size and
5 watt power output make it a favorite of backpackers.
- Yaesu FT-897
This is the new higher power big brother to the FT-817, covering the same
70 cm through 160 m.. It is capable of 20 watts on internal batteries and
100 watts on external batteries.
Beginners Recommendation
Beginnners should start with a simple 2m FM mobile radio since it is probably
the most widely used band and mode, is least expensive, and requires only
the most basic license. A good low cost radio for beginners is the Yaesu
FT-1500M. You may next want to get a handheld and then to HF when you
upgrade your license.
Antennas
Types of Antennas
- Mobile Whips
Mobile antennas come in different lengths. Common lengths are 1/4 wave
and 5/8 wave, the longer antennas having more gain. They also commonly come
in single band (2m) and dual band (2m and 70 cm) versions. The best know
manufactureres are Black Diamond, Larsen, Comet, and MFJ. Mobile whips come
with mounts for bumpers, hoods, body, luggage racks, glass, etc. They also
come with two different sized screw connections between the base and whip:
NMO and UHF.
- Mobile "Screwdriver"
This is a whip antenna with a moderately long motorized matching section
on the base. The first such antennas were built with electric screwdrivers,
hence the name.
- Wire
Although wire antennas can be purchsed, you can easily make your own.
The most common is the dipole which you can support with a painter's pole
(see below).
- Portable
Portable antennas are normally used by backpackers.
Example are the Buddipole and the
W6ZO Delta Loop.
Operating Locations
- Highway Operation
Mobile antennas are available for the various bands, and some screwdriver
antennas cover all the bands from HF to UHF. However, you will probably
want separate HF and VHF/UHF antennas even if your radio covers both band
segements.
- Campground Operation
For operating at the campground, you can use the same antennas for highway
operation. However, you may want to have a better antenna, such as a temporary
wire or portable antenna, especially for the HF bands.
Feedlines and Connectors
Feedlines conduct the radio signal from your radio to your antenna. The only
practical feedline for RV operation is coaxial cable. Coax for ham applications
typically has a characteristic impedance of 50 ohms and comes in several common
types:
- Standard
This large (~1/2") cable is called RG-8 and is useful mainly for fixed
station applications. It is too large for RV use..
- Mini
This is small (~1/4") cable is best for RV applications. One common
mini cable is known as RG-58 and is similar in size and appearnce to RG-59
cable, which is used in TV and cable applications. A low loss version known
as RG-8X is good for RV use.
- Submini
RG-174 is very thin (~1/8") cable used for very short run in mobile
applications. It is OK for a short run to a widow mount antenna and is great
for squeezing through door seals, but it should not be used to run the length
of an RV.
Better shielded and lower loss cables are the best. Here is a good summary
of cable types.
Most feedlines use UHF Connectors on the ends:
- PL-259
This is the "male" connector.
- SO-239
This is the "female" connector that is usually mounted on a panel
or radio. Inline UHF connectors are becoming more common.
You can cut your own cable to length and solder connectors onto them, but
you can now order cable cut to length with connectors alrady installed from
several Internet vendors.
Installation
- Mounting Radios
The most common method is to mount the radio under the dash or to the engine
cover using the mounting bracket supplied with the radio. Some mount their
radios in the coach living area in a cabinet or on a table next to an easy
chair. Finally, you can make a simple inverted T-shaped floor stand using
1x6 lumber and T-type reinforcement brackets and mount the radio on the
vertical section using the supplied bracket. You can even mount a second
radio on the other side of the stand. Put a drawer handle on the top of
the vertical section and you have a handly way to carry your radio.
- Mounting Antennas
The mounting options are drilling mounting holes in the RV wall or roof,
glass mounting (VHF/UHF only), magnetic mount if you can find suitable metal,
bumper mount, or the roof access ladder. You can also buy or make a receiver
hitch mount.
- Running Power Cables
Power cables should be run directly from the batter to the radio to eliminate
alternator whine. You can get away connecting a small VHF/UHF rig to the
cigarette lighter, but it is not recommended. Usually you can find a rubber
boot in the firewall under the dash to provide access. Sometimes you can
get the power cable through the hole in the boot, but you may have to cut
a small slit.
- Running Antenna Cables
The most vexing problem in RV installations is how to feed the coaxial feedline
to the exterior of the vehicle. Certainly you can drill a hole in the wall
(many have done so successfully), but many don't like that idea. The best
alternative is to feed the cable through a boot in the firewall beneath
the dash. If you mount you antenna on the rear of the vehicle, you can run
the cable along the frame and secure it with zip ties. If you are mounting
a VHF/UHF antenna and have a window near the top of the top of the coach
(many class C's do), you can avoid the problem by using a window mount antenna.
- Grounding
It is essential that you have a good ground for your radio and most antennas.
Of the antennas suitable for RV use only wire dipoles do not need to be
grounded. At your home station you would drive one or more long (typically
8') copper-covered steel rods into the ground , but in an RV you don't have
that luxury. All verticals must have their bases grounded. In a vehicle
such as an RV, you should ground to the frame or metal that is connected
to the frame. If you antenna is mounted to the roof access ladder, attach
a ground strap from the latter to the frame.
- Supports
When operating at the campground with a wire antenna you may will need a
support for the wire. The classic method is to use a strong arm or slingshot
to shoot a rope over a tree limb.
You can also buy a 23' painter's pole (Pro-Lok Model 2324) at Home Depot
or Lowe's and bungee it to the roof access ladder using the RV rear bumper
as a base. You can get really fancy and weld a pipe large enough tol receive
the painter's pole onto a receiver hitch insert. A much taller telescoping
mast can be obtained from DK9SQ.
Accessory Equipment
- SWR meter or antenna analyzer
The impedance of the radio must be matched to the impedance of the antenna
for safe and efficient operation. The best measure of impedance match is
standing wave ratio (SWR). An inexpensive SWR meter can be used to determine
SWR as you match impedances. An antenna analyzer is a more complex test
unit that provides additional ways of testing and analyzing antennas and
feedlines.
- Antenna Coupler
An antennal matcher or coupler can be used to match the SWR of the radio
to that of the antenna. An antenna matcher normally is a box that is placed
beside the radio and matches the impedance of the feedline and antenna combination.
An antenna coupler is a small box that is placed between the antennal and
feedline to match the impedance of the antenna only.
- Electronic Tool Kit
Soldering gun (for antenna connections only--use a low wattage iron for
circuit boards), rosin core solder, diagonal cutters, needle-nose pliers.
Where to Buy Ham Equipment
While there are still a few local ham stores in the major cities,
the best prices are usually available by mail order. Following are several
of the ham radio mail order retailers that serve the United States:
- Amateur Electronic Supply - stores
in Milwaukee, Cleveland, Orlando, Las Vegas
- GigaParts -
online only
- Ham Radio Outlet - stores in Anaheim
(CA), Denver, Phoenix, Salem (NH), Atlanta, Newcastle (DE), Portland (OR),
Sunnyvale (CA), Burbank (CA), Oakland (CA), San Diego, Woodbridge (VA)
- Texas Towers - store in Plano,
Texas
For price comparisons see the Ham
Shopper page.
For used equipment see: