beginner co-ax problem
 

Ok this is going to be simplistic.

I have a CW-80 special and some 19M of 50 ohn coax running to the back
of either a MFJ tuner or directly into the TS-850.

If I screw the shield on the pl259 plug tight onto the chasis socket
then I receive no signals, if I leave it loose but touching I receive
signals. Firest thought a short in the co-ax. Ohm meter reading shows
infinite reading so I assume (rightly or wrongly) no short.

I then took, as an experiement, my 2m areial co-ax, plugged it in and
tuned to a good local MW signal. Exactly the same phenomena occurs.

I transmit fine on 2m. Using the CW-80 I can sucessful transmit when
the plug is loose but I may be getting some rf leak as Mixw is pickin
gup stray characters in transmit strings.

Kust as an experiement I plugged in my RX320 and exactly thesame
phenomena.

Now I am still very new but I also note that the ohm meter across the
socket on the TS850 shows 50 ohm which I guess is corect though the
mobile 2m transmitter shows infinite.

So the botom line is I am struggling to find the cause of the problem.

Any clues?

beginner co-ax problem
 

On Sun, 15 Jul 2007 16:20:34 +0100, Andre C wrote:

Ok this is going to be simplistic.

I have a CW-80 special and some 19M of 50 ohn coax running to the back
of either a MFJ tuner or directly into the TS-850.

If I screw the shield on the pl259 plug tight onto the chasis socket
then I receive no signals, if I leave it loose but touching I receive
signals. Firest thought a short in the co-ax. Ohm meter reading shows
infinite reading so I assume (rightly or wrongly) no short.

Now check for continuity from end-to-end of the coax. Center to center
and shield to shield should have DC continuity. If the coax is already
installed, just place a jumper across one end (center to shield) and then
see if you have continuity. It's likely that an "open" exists perhaps
from a cold solder joint or breakage someplace.

I then took, as an experiement, my 2m areial co-ax, plugged it in and
tuned to a good local MW signal. Exactly the same phenomena occurs.

Without the shield connected to the frame of the radio, it no longer acts
as a shield as you've noticed. This is normal.

I transmit fine on 2m. Using the CW-80 I can sucessful transmit when the
plug is loose but I may be getting some rf leak as Mixw is pickin gup
stray characters in transmit strings.

Kust as an experiement I plugged in my RX320 and exactly thesame
phenomena.

Now I am still very new but I also note that the ohm meter across the
socket on the TS850 shows 50 ohm which I guess is corect though the
mobile 2m transmitter shows infinite.

So the botom line is I am struggling to find the cause of the problem.

Any clues?

If the coax checks fine for continuity, then check your antenna (I'm not
familiar with it) to be sure all connections are solid. It could well be
a manufacturing defect in the antenna.

73, de Nate

--

"The optimist proclaims that we live in the best of all possible worlds,
the pessimist fears this is true."

beginner co-ax problem
 

On 15 Jul, 19:14, Nate Bargmann
wrote:



I then took, as an experiement, my 2m areial co-ax, plugged it in and
tuned to a good local MW signal. Exactly the same phenomena occurs.

Without the shield connected to the frame of the radio, it no longer acts
as a shield as you've noticed. This is normal.

Sorry , I do not understand that bit.

What I meant was when the shield was loose I can pick up the station
but as soon as I tightened it the signal went. This was on the 2m
antenna which in recevie only mode should work. This implied to me
that either both cables are in error or I am doing something very
wrong.

Andre

beginner co-ax problem
 

Coax cable will convey the signal from an antenna to your receiver. If
there is no antenna at the other end of the coax, no appreciable signal
will reach your receiver. The 2 meter antenna is a very poor antenna at
MW, so it will pick up very little MF signal for your receiver to hear.

When you disconnect the coax shield, then the coax itself becomes an
antenna, and you hear signals. You'll get the same effect by connecting
a single wire of the same length to the center conductor of the receiver
antenna connector.

If you connect a decent antenna (that is, decent for use at the
frequency you're listening to with your receiver) to the far end of the
coax, then you'll get a good signal when the coax is properly connected.

Roy Lewallen, W7EL

wrote:
On 15 Jul, 19:14, Nate Bargmann
wrote:


I then took, as an experiement, my 2m areial co-ax, plugged it in and
tuned to a good local MW signal. Exactly the same phenomena occurs.
Without the shield connected to the frame of the radio, it no longer acts
as a shield as you've noticed. This is normal.

Sorry , I do not understand that bit.

What I meant was when the shield was loose I can pick up the station
but as soon as I tightened it the signal went. This was on the 2m
antenna which in recevie only mode should work. This implied to me
that either both cables are in error or I am doing something very
wrong.

Andre