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!

In article ,
"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.

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.

Look for a cable TV-coax (RG-6, maybe) that has a continuous foil shield.

Isaac

On 3/9/14 23:49 , isw wrote:
In article ,
"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.

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.

Look for a cable TV-coax (RG-6, maybe) that has a continuous foil shield.

Isaac




For this application, you'd want a cable with at least a 95% braid shield.

A more effective solution would be to convert the audio to a balanced
line at one end, and then back to unbalanced at the other. Better CMRR.
Shielded twisted pair, here, will get the job done.

On Mon, 10 Mar 2014 08:24:12 -0700, D. Peter Maus
wrote:

...snip...
For this application, you'd want a cable with at least a 95% braid
shield.

A more effective solution would be to convert the audio to a balanced
line at one end, and then back to unbalanced at the other. Better CMRR.
Shielded twisted pair, here, will get the job done.




might look into high quality cabling like Belden 1800F
John Woodgate in UK and I worked together to extensively analyze that
cabling and exploring 'weaknesses', have LTspice models and he has a lot
of application data.

In article , Ralph D.
writes

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.

Off-the-wall suggestion: run them through a length of copper pipe or
through that flexible metal conduit used in electrical installations?

You'd probably want to earth (ground) just one end to be sure a ground
current didn't flow, causing interference.

--
(\_/)
(='.'=)
(")_(")

"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

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 03/09/2014 08:30 PM, 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.

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!



What type of input does the transmitter have? Balanced +6dB? Unbalanced
50 Ohms? If it's Balanced, use transformers at the send end, or a
balanced line driver (aka Direct Box) of some kind (2 for stereo).
Ground only the receive end of your shields. Use as much "send" as you
can get away with; this will reduce noise at the xmtr input.

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.

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.