On 3/10/2014 7:11 AM, Phil Allison wrote:
"Ralph Dope"

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly
shielded to connect my audio source to a transmitter across a room. This
cable passes many sources of interference, so the shielding is critical.


** I have a sense of "deja vu" about this question ?

Is the signal stereo or mono ?

A 20 foot long 3.5mm two core cable is not gonna be easy to find at all let
alone with different qualities.

BTW:

Do you REALLY have a problem or are you just imagining one ?

How about some details ?

The solution may NOT be what you have guessed it to be.



.... Phil




Hack a long HDMI cable.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

On 03/10/2014 09:56 AM, Cydrome Leader wrote:
In sci.electronics.repair Ralph D. wrote:
Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

get some electrical conduit.


There should not be a lot of RF in the radio room, compared to near the
antennas. Do all the other stations use EMT for audio? It really isn't
necessary. You can probably use unshielded twisted pair if you know what
you're doing. The Phone Company doesn't use shielded cable for baseband
audio.

dave wrote:

The Phone Company doesn't use shielded cable for baseband audio.


No, but they use twisted pair and they can still pick up a lot of RF.
I've seen over 5 volts of RF on phone lines at AM radio stations that
were wired with 'station wire' instead of twisted pair. The radio
station audio was louder than either party on the line could talk. The
fix was to rip out everything, run 25 pair twisted cable to localized
terminals and use short runs to the phones. There was still some common
mode RF, but at least the lines were usable since it no longer caused
the volume limiter to go into continuous conduction.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

On Thu, 13 Mar 2014, Michael A. Terrell wrote:


dave wrote:

The Phone Company doesn't use shielded cable for baseband audio.


No, but they use twisted pair and they can still pick up a lot of RF.
I've seen over 5 volts of RF on phone lines at AM radio stations that
were wired with 'station wire' instead of twisted pair. The radio
station audio was louder than either party on the line could talk. The
fix was to rip out everything, run 25 pair twisted cable to localized
terminals and use short runs to the phones. There was still some common
mode RF, but at least the lines were usable since it no longer caused
the volume limiter to go into continuous conduction.

Yes, and even in the days of the no real electronics in the phones, there
were tips in the books about keeping RF out of the phones.

The issue becomes more significant when all the phones are made of
electronics, and there's a lot more that can act ad diodes to detect the
signals.

Michael

Ralph D. udtrykte præcist:
Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy schedule)
but would be OK with ordering from one of the Ham sites if turnaround time is
very good. I could not get a good search parameter on Amazon that didn't turn
up thousands of hits that I just don't have time to sift through right now.

Any good cable with known good isolation would be good. I have ferrite chokes
I can use, but would prefer a cable of suitable quality that did not need
them (current cable is getting interference even with them as this is not
just run-of-the-mill 60cycle stuff).

Any good suggestions would be appreciated.


You could go digital/optical with a analog-toslink-analog combo.

There is a combination at the bottom of the ad he
http://amzn.com/B005F20756

It claims only 18 feet, that could be close enough to your approx 20ft,
when there are analog cables in either end.

But I haven't seen an 18ft toslink cable...

There must transmitters which are more powerful, if you need a longer
range.

Leif

--
Husk kørelys bagpå, hvis din bilfabrikant har taget den idiotiske
beslutning at undlade det.

"Leif Neland" wrote in message ...

But I haven't seen an 18ft TosLink cable...

There are couplers.

On 3/13/2014 8:26 AM, William Sommerwerck wrote:
"Leif Neland" wrote in message
...
But I haven't seen an 18ft TosLink cable...

There are couplers.

Monoprice offers this 25 foot Toslink cable for under $5, as well as
longer ones out to 50 foot length.

They work beautifully for the applications I have tried, including the
connection of an AppleTV audio output to a distant A/V receiver in
another room.

http://www.monoprice.com/Product?c_i...seq=1&format=2

"Ralph D." wrote in message
...
Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly
shielded to connect my audio source to a transmitter across a room. This
cable passes many sources of interference, so the shielding is critical.

I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy
schedule) but would be OK with ordering from one of the Ham sites if
turnaround time is very good. I could not get a good search parameter on
Amazon that didn't turn up thousands of hits that I just don't have time
to sift through right now.

Any good cable with known good isolation would be good. I have ferrite
chokes I can use, but would prefer a cable of suitable quality that did
not need them (current cable is getting interference even with them as
this is not just run-of-the-mill 60cycle stuff).

Any good suggestions would be appreciated.


Thanks!


Thanks to everyone for their input. I guess the discussion has about worn
itself out.

After reading what was posted in both groups, I have decided to try this
option first, as I have cable on hand and it would be great if it resolved
for cheap :-)


http://www.amazon.com/Headphone-Jack...5mm+Balun+Cat5



Hopefully I'll have a positive follow-up.


Thanks again.