TXT October Written by Nigel Ballar

Found at: 0x1bi.net:70/textfiles/file?hamradio/scanhint.ham

                    SCANHINT.TXT    October 1990

                    Written by
                    Nigel Ballard
                    28 Maxwell Road
                    BH9 1DL

Hello again,
This article will just be a mishmash of my scanning hints and tips,
these were gained from both personal discovery, and nicked out of other
and will cover many different subjects.

against the law, something to do with thwarting the policeman hidden
behind a bush armed with a menacing looking hair drier (RADAR GUN). In
the UK however, going mobile with a scanner is not illegal, it is what
you are tuned to that is guaranteed to get you in the Guacamole!
Therefore, possibly the best way to avert the unwanted attention of the
authorities, is to scan covertly.

Firstly, mount the scanner in the glove box, and have the DC supply
controlled via a switch mounted on the dashboard. Therefore if you get
quiet. I guess leaning over to the glove box might indicate you are
t one stage further, use an external speaker, something with a good
the floorplate, but at your ears. If you want to get really
nto the dash. But there's still something that might give you away!

Up until about one year ago, the only purpose built scanner antenna you
could buy in the UK was the rather poorly engineered Radio Shack one. It
they were a dead giveaway. Much like a discone on the roof of a house,
t doesn't take a genius to work out what's on the other end of the
coax. Likewise, with a mobile set-up, you may not wish the local police
or car thieves to know you have something worth either checking out or

As I type, because of the IRAQ/GULF crisis, I have a large amount of
exotic RAF/USAF hardware flying low and fast overhead. I understand they
are buzzing naval frigates off Portland Naval base which is near here.
Anyway, as per usual I digress.

MAKE YOUR OWN...Yep it's compromise time!
Well of course you could buy one, Antenna specialists produce a whole
as we refer to them 'GAS GUZZLERS'. Trouble is, they are pre-tuned to
for example. But maybe your wallet will not stretch to such an item.
Therefore in the time honoured tradition of electronics, we'll build the
bugger ourselves.

buy a fairly robust replacement antenna from your local car mart. Using a
the base of the telescopic whip. When you have bared just enough to see
Get about four metres (do you use metres in the USA?) of good 50 OHM low
loss communications cable with at least 80% outer braid. And using a
considerable amount of heat, thus cooling your joint very quickly. When
you have a good and shiny joint, get some ARALDITE or similar industrial
elements will do their best to degrade the antenna's performance.
out of harms way (BRAKE PEDAL), and attach to your preferred scanner.
s important that the antenna is mounted on good quality bodywork. If
you drive an old rust bucket then performance will be degraded as the
antenna needs a good grounding with your cars bodywork.
This will not be the best scanner antenna you ever used, but it is
covert and cheap, and certainly kills a few hours on a wet and windy
Sunday afternoon.

The easy version is all well and good, but what about K-ROCK-FM, life
Accepting that you still want to use your car radio, then consider the
What's needed here is a simple diplexer. I say simple because no R.F. is
nvolved, therefore the task is very simple.
This is what you need:

Mount the Motorola chassis socket into the plastic box, drill two
about one inch off of each of your coax leads. Insert the leads through
their respective holes. Solder the 50 OHM coax (SCANNER) to the free end
of the capacitor. And solder the the car radio coax to the free end of
the resistor. Join the two outer coax sheaths together and solder them
both to the outer terminal of the chassis Motorola socket. secure the
two coax leads with the two cable ties, this is to stop them being
the coax and the two components. Make sure there is no way that the
nner conductors, or the components can connect with the outer
conductor. Put the lid back on your little box. Solder the Motorola plug
onto the car radio fly lead. Solder your BNC onto the scanner fly lead.
Now, gently remove your car radio from it's dash mounting, pull out the
car radio's antenna lead, push it into your diplexer, take the car radio
fly lead from your diplexer and push that into the car radio antenna
your car radio back into it's dash mounting. And there you have it. You
original antenna. This is not a World beating solution, but for a covert
and VERY cheap compromise, what can you expect?

Always better to connect your radio equipment directly to your car's
battery. This will reduce interference from the ignition system. Also if
like me you have a SAAB TURBO, and the poxy cigar lighter only operates
that after getting carried away at a recent air show, when you decide to
leave, the damn battery is as flat as a pancake.

much immune to car interference, whereas some are not. Try adding chokes
to the coil,distributor,windscreen motor. Or putting an in-line filter on
your scanner power lead.  And always, always put an in-line fuse on the
come with a fuse on the negative line as well. Use the correct size
fuse, as too small and it will keep blowing. Too large and the radio
And finally, always keep a few spare fuses in the trunk.

might like to throw away those cruddy Motorola sockets and replace them

*NOTE #2*
Somebody who fancied himself as a bit of a coax expert once told me
that if you have a 100 foot run of cable going vertically up a building,
the cable loss was greatly less than the same 100 foot running
not, but there may be some truth in it. So the next time you run up
another antenna, try to keep the cable run as short as possible, never
make a very loose loop where the cable enters the building. This serves
two purposes, firstly, it stops the rain travelling up the coax and into
your property. And secondly, sharp turns can cause the coax to pinch,
close to the outer conductor, this will cause a small mismatch, as the
cable is no longer a constant 50 OHMS along it's entire length.

the jumper over to the narrow setting, I now get a better signal to
noise ratio, and distant traffic seems easier to pick out of the noise.

SAFT batteries, and asked if there was a more powerful cell in the same
My YUPITERU MVT-5000 will go nine hours at an air show without failing. I
therefore suggest you invest in some heavier duty cells if you are
unhappy with the life of your current NICADS. A point of interest, the
man from SAFT told me that NICAD technology was soon going to reach
t's limit. Therefore they were now working on Nickel hydride and nickel
charged from flat in sixty minutes!

because size is not everything, or that's what my girlfriend tell's me!
Anyway, battery life is said to be rather poor even with the battery
tell that ICOM UK are working on the problem. As I know this scanner is
not on sale in the USA, and as  I also know that many of you wish to

A japanese radio producer, not currently exporting products to the UK or
USA as yet I think. Anyway they have brought out a new scanner that is
n the same case design as the rather sorry Kenwood RZ-1. The display
LCD elements. And even a fully functioning I/R remote control. So if you
are lucky enough to own a stretched Lincoln Continental and cannot reach
the dash from the back seat, then this might be the scanner for you.
My friends in Japan have tried one, and are less than impressed with it's
most important facts.

Somebody looking over my shoulder, just asked why I kept referring to
coax with this magical 80%. Well firstly, if you go and buy coax, and the
black outer sheath has no manufacturer or classification printed on it,
then I suggest you leave it well alone. Cable companies that produce
and what it's specs are.
Furthermore, the best cable has 100% screen, that is to say if you bare
back some of the plastic sheath, then all you will see is a very tight
and closely knitted copper braid, no white plastic insulator should show
through. The cheaper (and lossier) the cable, the more white insulator
you will be able to see through the gaps in the braid. So the next time
you go cable hunting, forget Radio Shack, and your local C.B. shop.
lowest loss 50 Ohm coax in your required diameter, and ask to borrow a
knife so that you can examine the braid. In the UK we have a Swedish
coax called POPE'S H100, it is a little thinner than usual, so if you
are not very clever, the N-type plugs fall off. Apart from it's very low
losses at 1GHz, it also has a very thick solid centre core, and
underneath the outer braid there is a complete sheet of copper foil
loops, but remember you shouldn't be doing that anyway should you!
However, pound for pound it is still a much better bet than Andrews
Heliax, which if you have ever costed it out, you will know that the

An interesting new item for the cellular market has just been released
over here. Suppose like me you have a portable cellphone, when you are
chatting away on it in the car, much of the measly RF it generates,
new product is a passive antenna. It looks just like an on glass
antenna, except on the inside of the glass is another small rubber
antenna. The theory is that it picks up your signal, passes it to the
outside of the car's bodywork via capacitive coupling, and then
amplifies it via the 3DB gain antenna stuck onto your rear window. I
think it is either a great idea or an elaborate con. If it appears to
must work the other way as well. Certainly food for thought. And as it
uses no components or power, it must be easy for anyone to install.
To work well in the field of reception, I guess you would need one for
lowband VHF, one for highband VHF, one for UHF and one for the CELLULAR
BAND. Therefore if you have more money than sense, you could well
brighten up my day by driving past my house with four assorted length on
antenna theory would be appreciated.

Friends have asked me several times why I don't attach my R-7000 to the
not tried it, but I would be interested to hear from anyone who has. So
f I'm talking about YOU, then why not write an article for the BBs, and
let the rest of us know what's to be heard.

message of encouragement on Howard's BBs. In fact it was John's kind
know that not only what I write is downloaded, but also appreciated.
Thank's John.

upon that interests you, or you simply want me to write about a specific
anything about the subject in question, then I will certainly knock up
an article for you.

Must conclude, as I have spent more time on this article today, than on

Cheers for now   Nigel.