Well, nothing in english seems to be available. There is a link to the
German ebay that will sell me one. There also seems to be something in
Russian, but I can't do much with that.

tom
K0TAR

Stephen Parry wrote:

On Fri, 19 Aug 2005 07:32:25 -0500, Tom Ring
wrote:

Model id Mercedes-Benz badged Truckline CC25 made I think by Becker

I wonder if the radio has a trimmer capacitor like many of the US AM BCB
radios have had over the years. You would normally have to pull the
radio from the dash and inspect it to see. If it does, it may help a
bit to tweak it.

What is the model number of the unit? Maybe we can find an online
user's manual.

tom
K0TAR

Simply tap off at the junction of the two batteries. The truck series two 12
volt batteries to give you 24. Find the the junction where the plus of one
is tied to the minus of the next. Tap off a wire at this point. I would fuse
it at the connection point. This will provide the necessary voltage for the
radio.

CAUTION! I have made the assumption that your truck has the chassis tied to
the negative side of the first battery. In the event you have a positive
ground truck let me know and I will tell you how to get around that problem.

"Stephen Parry" wrote in message
...
On Thu, 18 Aug 2005 12:35:38 -0400, "Fred W4JLE"
wrote:
Fred I think you must be Psychic!
current system is all 24V, yesterday went out and paid £35.00 for a
DC/DC dropper so I could fit a car radio... are you saying that this
will make things worse?
One problem you might look at aside from all the other great suggestions
is
to look at how your radio voltage is derived. Most trucks are 24 volt and
the radios 12 volt.

Are you tapping at the junction of the two twelve volt batteries or does
your truck use a 24 to 12 volt converter? These are usually really noisy
from an electrical standpoint.

"Stephen Parry" wrote in message
.. .
Hi folks, first let me apologise for not lurking, or even reading a
FAQ (I did look and did not find). I know that radio amateurs are a
helpful and friendly bunch, so here goes.
From the UK, for historical reasons, the BBC broadcasts programmes on
Long wave, specifically 1500 metres (198 Khz???). I drive a truck on
the continent of Europe, and would love to listen to this service
whilst on the road (for the cricket!). I know that the signal is
there, and of sufficient strength, as I can receive it OUTSIDE the
truck on an ancient "portable" Inside the steel box (cab) however, too
much noise/too little signal to be useful. The fitted radio has LW,
but again cannot be used for the noise. Could anyone please point me
to some answers to the following:
Antennae: Could I build (buy) some kind of antenna specifically to
receive this emission?
(My old radio has a socket labelled "AM antenna").
Could I build a receiver tuned only to this freq., with no need for a
speaker (run the sound in at headphone type power) that I could
hang/bolt outside the truck (on the roof?), with its own battery and
aerial? If so could someone point me to a diagram of such a beastie?

Stephen Parry wrote:
"Yes I think I do have alternator noise could you explain what I might
do?"

Often the first sign of diode failure is a whine in the loudspeaker of
your radio which varies in pitch with engine speed.

Alternators have no commutator but use silicon diodes to make d-c from
the a-c they generate. It`s usually 3-phase, using (6) diodes in (2)
groups of 3 each in a full-wave rectifier. These are located inside the
alternator. If any of the diodes fails, at least one of the 3 pahases
quits contributing to the alternator output. Maximum output is reduced.
Replace the diodes. The whine goes away and full output is restored to
the alternator when required.

Stephan also wrote:
"I think we might have been divided by our common language!"

What Americans call a hood, I believe, is what the English call a
bonnet. The effectiveness of a screened enclosure depends on good
connections between its pieces.

In a modern diesel truck there may be noise generating electrical
fuel-injection control, rotating belts which generate static discharge
noise, electrical relays and contactors, and other sources of radio
frequency noise.

Noise containment is one goal of the bonnet. The hinge which holds the
bonnet and the latch which locks it are often inadequate in r-f
continuity. Their electrical contact is not good enough.

Wheels rotate on stationary spindles and axles. Rotation can produce
charge which repeatedly arcs across wheel bearings or other points.
Spiral springs are made with a large diameter on one end to rest on a
stationary part of the wheel assembly. The spring tapers down to a small
diameter or point on its other end. This point makes contact with a
hammer-on cap over the nut which holds the wheel on its spindle. The cap
rotates with the wheel. So we have a conducting connection between the
wheel and the non-rotating parts of the vehicle. Only extreme noise
cases require these springs.

Stephen also questioned what I meant by perfect antenna cables. I once
repaired rafios and my experience is that most noisy automobile
receivers got that way from defective antennas and antenna cables.

The base of the antenna needs a good connection to the vehicle body,
which is the other half of the antenna. The vehicle body is the
connection for the cable shield. The shield needs to be continuous to
carry the signal rather than having the body carrying the signal where
it may be exposed to noise currents.

I wrote:
"Keep the antenna away from and shielded from sources of interference."

When one installs an antenna, it should be placed in a quiet receiving
location if possible. It should not be installed on the same side of a
screen as wires carrying interference. The antenna should be installed
on the outside of the truck cab where it has large exposure to the
signal.

When I said bonding, I did mean a clean earth return but I was not
thinking of battery current. I was thinking of r-f currents, signal and
noise.

Radio frequencies don`t penetrate deeply into metal but travel on the
surface. Large surface area is needed for low r-f impedance. Battery
current uses the entire cross section of the metal.

Wires slung under running boards and the chassis are not much used now.
Other noisy conductors may be nearby Broadcast ground waves are
vertically polarized. It makes sense to use a vertical whip for
reception, though almost any wire works.

Stephen`s portable likely has a loop antenna inside which makes it
somewhat bidirectional in azimuth. A vehicle mey be found in any
position. This makes an antenna which is nondirectional in azimuth
desirable.

Best regards, Richard Harrison, KB5WZI