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The Yaesu VX-7R is a slick, compact 11.5cm by 6.5cm handheld
transceiver with a rugged diecast case and rubberized corners.
It is completely waterproof. It offers a rather useful barametric
pressure module in addition to the temperature sensor. It is capable
of up to five watts of FM transmit power on VHF and UHF and receives
signals which range from the AM broadcast band and shortwave through
to one gigahertz. It uses LiIon battery technology which gives
about three days of barometric sensor usage, and about two days of
receive usage, and about a day of two-way usage.
Why did I buy it?
I bought this as a device which I could take back country canoeing and
remain in touch, as it were. Other licenced radio amateurs (hams)
within about 20km are able of holding two-way communications with me.
That is the unit is cabable of 5 watts of FM in VHF and UHF bands.
The question that many ask: why spend a thousand dollars Canadian
on each VX-7R (with options) when you can get a pair of FRS
walkie-talkies for less than 25% of that cost? Well, how much
is life worth? Does your survival ever depend on your being able
to communicate more than a kilometer? Will your well-being ever
be jeopardized if the FRS unit gets wet? Remember, FRS units are
usually only capable of 10% of the transmit power of the submersible
VX-7R, and that is not even factoring the latter unit's military
grade robustness. Leave the FRS to the kids. It's usually worth
spending a bit more for dependable communications equipment,
especially when far from home.
The other reason I bought this is for shortwave receive coverage.
I used to carry along a Grundig YB-400 which did very nicely for
early morning and late evening portable shortwave coverage and it was
also a good alarm clock. The VX-7R does a fine job on the shortwave
coverage, but is not a good alarm clock. It is also a small fraction
of the size of the YB-400 and add to that the wetness of backwoods
camping factor and the rationale for using the Yaesu becomes quite
clear. The point to note, however, is that you do need a long wire
antenna for the VX; do not expect to use the rubber duck that comes
with it for short wave. I pack along the Grundig roll-up antenna
and connect it via alligator clip to the tip of the rubber duck.
The duck gets very poor shortwave reception without such help.
Primary Capabilities
The primary intent of the VX HT is for triband operation, 6m, 2m,
and 70cm. Seemingly as an afterthought, they added low power transmit
capability for the 1.25m (220mhz) band. It does a reasonable job as
a portable, but has some significant shortcomings.
Shortcomings
The built-in microphone is characterized by low audio -- even with
your mouth about a centimeter from the unit, you need to be talking in
a rather loud voice to avoid "low audio" complaints from other hams.
I took the unit to the place I bought it, Radioworld, and they
confirmed that everything was "in spec". It was explained that
the waterproof membrane which encases the unit also prevents
the microphone from being as sensitive as it otherwise might be.
It also helps mute the background noise, mind you. However, if you
are depending on fringe communications, you do need to get either
an external microphone, or you need to bone up on your shouting
techniques.
The other significant downside with this unit is that it is very
prone to interference problems. For example, I cannot take it near
my 17" CRT based computer monitor without getting full scale
noise on 2m. When the monitor goes into low power mode, the problem
is greatly reduced, almost eliminated. I normally keep the HT two
to three meters away while working on the computer. Or, I switch to
my Apple iBook.
The CRT is just one source of interference. During the business
day, between mid-morning and about nine o'clock at night, there is
the frequent sporatic bursts of digital traffic that can take it
anywhere from S2 to S9. It gets so bad, that I often have to just
shut the thing off. Interestingly, it tends to be far worse when I
am in the basement, than when I am outside the house. I keep most
of my computers in the basement. Again, this is on 2m; there is
none of that on 70cm.
To alleviate the interference problem I needed to enable the front
end attenuation feature, which was easy enough to do via the built-in
menu system. This nearly eliminated the intermod related problems.
When in the country, I just disable attenuation to reclaim the
receiver sensitivity.
The interference rejection problems make the VX-7R somewhat less
than ideal for metropolitan use in the VHF bands. If all you want
is two meter coverage and you don't ever have moisture problems,
then the VX is not for you -- specialized 2m units tend to have fewer
interference problems and are less expensive. The VX is excellent,
on the other hand, for metropolitan use in the UHF 70cm band.
For trips into the back country, on the other hand, the VX-7R is
hard to beat. If you are hiking, climbing, or canoeing, this
is an ideal unit for the members of your party to be carrying.
Remember though, VHF/UHF communications are line of sight. If you
have high mountains or huge distances between communicating parties,
VHF/UHF is less than ideal. For longer, more remote trips, you need
to consider factors like range and intervening terrain. For emergency
communications in the Canadian tundra for example, you might want to
consider something which supports shortwave (HF) transmissions due
to the intervening distances. HF transmissions require additional
authorization beyond the Basic Amateur Radio Licence.
Options
Since each charge will only get you a couple days of light usage,
you also will need to take spare batteries. A spare LiIon battery pack
(FNB-80LI) will set you back just under CA$200 with taxes. And if
you have multiple LiIon battery packs, you probably want to consider
getting the optional desk charger (CD-15A). The desk charger does
its job independant of the VX transceiver, and is faster than the
AC adaptor that comes with the base VX-7R package.
For about CA$50 (taxes in) I picked up a battery holder which enables
you to use a pair of standard AA batteries (FBA-23). These permit
several hours of receive and limited low power transmit (up to
1 watt). Using a pair of freshly charged NiCad AA cells, you can
figure on about four hours of receive capacity. If you use alkaline
AA cells, you can expect to get about a day. If you consider that
four AA cells weigh approximately as much as the LiIon pack, you
would need to pack a lot of AA cells. If you depend on two-way
radio coverage, then you better figure on taking a couple of spare
charged LiIon packs, rather than depending heavily on the AA pack
and a bag full of cells.
The LiIon packs can be charged while in the car, whilst attached to
the VX-7R, using optional cigarette lighter adaptor E-DC-5B. This is
in fact the recommended approach while mobile. The alternative
is to use a (third party) power inverter and the desk charger.
Inverters do tend to be quite inefficient, but if short charge times
are more precious than your 12v lead-acid car battery, then these
can be quite handy. I use an auxillary battery in my van so that I
never risk discharging the battery used for the engine -- a diode
permits the auxillary battery to be discharged independent of the
main battery.
To handle the marginal audio problem, I ended up getting the
earbud/microphone combination (VC-27). This is very lightweight and
gives a decent improvement to transmitted audio. The earbud not only
improves your ability to pickout faint signals, but reduces demand on
the audio amplifier, extending battery life. The earbud/microphone
combo was about CA$70 taxes in.
The waterproof nature of the VX-7R means that it can be splashed and
it can be rained on, and it doesn't matter. At other times, however,
the problem is dirt. If you find this applies to your situation,
you do want to get the vinyl case (CSC-88). It was CA$35, and
for back woods operation it is recommended. The PTT and the DTMF
controls operated well through the clear plastic front of the case.
There are a few limitations when using the Yaesu supplied case.
For example, the case will prevent the VX from swinging freely on
the belt clip -- though it will still be somewhat usable. Also,
the case provides no protection for the tuning/volume coaxial control
at the top of the unit.
If extended trips into the back woods, into the fringes of VHF/UHF
coverage, are planned, you should probably get a better antenna than
the basic rubber duck -- you can improve the signal by several db.
Many of these antennas come from other manufacturers and use
BNC connectors rather than the SMA connector used by the VX-7R.
The CA$15 BNC to SMA adaptor is part number CN-3.
The barometric sensor unit is part number SU-1 and is recommended if
you are a weather buff, or you take the VX-7R hiking, or canoeing.
The cost for this was about CA$60 which included installation.
The Yaesu documentation notes that this is not intended as a
replacement for a proper professional quality altimeter. But, it
can be used as an altimeter nevertheless. If you have never used an
altimeter, you need to visit your local library to read up on how to
use one, otherwise you can expect frustration.
The unit supports nicely millibar units as well as american inches.
The barometer and temperature readings are only displayed when the
transceiver is turned off. As such, back lighting for the display
will not be available. Keep a penlight handy.
Also beware, after using the transceiver you need to have it
turned off for a least five minutes before reasonable barometric
readings are possible -- the initial values are skewed and must not
be relied upon. Keep this in mind when configuring the barometric
pressure offset -- get it right the first time, and if you don't
wait a few minute before you try again. You can expect calibrate it
monthly using a high quality stationary barometer and get reasonably
accurate results, though I calibrate mine a couple times a year
using a nearby online weather station.
The temperature sensor requires considerably longer
than five minutes -- fifteen minutes to an hour.
Some Hams use their HTs to get their e-mail via packet radio. I
can offer no experiences though I do note that the manual does make
reference to such modes.
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