random wire question
Brian
where I have my radio. Was wondering if using coax as the lead in and
running a wire from the braided shield at the feed point to a utility ground
right outside the window would help cut down on the noise that's being
generated by I assume my neighbor and perhaps myself. If so, do I just tape
back the braid and connect the inner wire of the coax to the alligator clip
that I attach to the whip on my dx-398? If you need more info please let me
know. Thanks
Brian
Telamon
"Brian" <imagina...@whatthefuck.com> wrote:
It depends. If you have noise sources in the same room or area then yes.
If the area around your radio is RF quiet then no. Chances are these
days it will help if a ground is used that is apart from the utility
ground. The utility ground will be noisy.
Most devices use the utility ground to pass noise in order to pass FCC
specifications. The conducted noise to ground helps prevent devices from
passing this noise on to the hot leads or radiating the noise.
--
Telamon
Ventura, California
Diverd4777
- this might indeed work;
- So give it a try . . .
Dan
In article <SPYJb.23413$IM3....@newsread3.news.atl.earthlink.net>, "Brian"
RHF
1. Read these three Messages that are posted on the
SWL Antennas and AM & FM Antennas eGroup on YAHOO !
* The Classic simple "Random" Wire Antenna
http://groups.yahoo.com/group/SWL-AM-FM-Antenna/message/465
* IMPROVING on the Classic simple "Random" Wire Antenna
http://groups.yahoo.com/group/SWL-AM-FM-Antenna/message/466
* Building 9:1 Matching Transformer for the
Improved Classic simple "Random" Wire Antenna
http://groups.yahoo.com/group/SWL-AM-FM-Antenna/message/467
2. IIRC - The RadioShack DX-398 (Sangean ATS-909) has both a
Whip Antenna and External Antenna Jack:
* Try connecting the Wire from your Inverted "L" Antenna
to both and see which provides the best results.
* Generally the RadioShack DX-398 has a reputation for being
better using an External Antenna connected via the 1/8" Jack
on the Side of the Radio. This is a Stereo Jack and you should
use a Stereo 1/8" Plug with the End-Tip connected to the External
Antenna Wire and the Rear-Barrel connected to the Ground Wire.
NOTE: The Center-Middle-Barrel of the 1/8" Stereo Plug is NOT Used.
3. Read these Messages posted to the RadioShack DX-398
(Sangean ATS-909) eGroup on YAHOO !
* Antenna Connection for a RadioShack DX-398
http://groups.yahoo.com/group/DX398/message/5515
* Antenna Wiring - Help Needed Please for the RadioShack DX-398
http://groups.yahoo.com/group/DX398/message/4063
* Diagram of HOW TO WIRE the External Antenna Plug RadioShack DX-398.
http://groups.yahoo.com/group/DX398/files/MW%20Antenna/antenna.jpg
* External Antenna Troubles and the RadioShack DX-398
http://groups.yahoo.com/group/DX398/message/5939
* MW/LW Reception with External Antenna (Sangean ATS-909)
http://groups.yahoo.com/group/DX398/message/5375
* RadioShack DX-398 (Sangean ATS-909) External Antenna
http://groups.yahoo.com/group/DX398/message/4310
iane ~ RHF
.
.
= = = "Brian" <imagina...@whatthefuck.com>
= = = wrote in message news:<SPYJb.23413$IM3....@newsread3.news.atl.earthlink.net>...
Thanks
Brian
.
Brian
ground rod not in use anymore that I will probably use for this experiment.
I appreciate all of your replies.
Brian
"RHF" <rhf-...@pacbell.net> wrote in message
news:e5e13af8.04010...@posting.google.com...
Brian Denley
One more thing: It's true that a well grounded coax shield will prevent the
lead-in from acting as part of the antenna BUT you actually have to ground
BOTH ends of the shield (on the lead-in) to make this effective. Don't let
my comment stop you from experimenting, however!
Good luck!
--
Brian Denley
http://home.comcast.net/~b.denley/index.html
"Brian" <imagina...@whatthefuck.com> wrote in message
news:SPYJb.23413$IM3....@newsread3.news.atl.earthlink.net...
starman
>
> Brian:
> One more thing: It's true that a well grounded coax shield will prevent the
> lead-in from acting as part of the antenna BUT you actually have to ground
> BOTH ends of the shield (on the lead-in) to make this effective.
I haven't found this to be so in my case. The coax shield on my low
noise inverted-L is grounded only at the bottom of the antenna's single
wire downlead, which is close to the ground. The coax runs about 75-ft
along the ground to the house, then up one story to the receiver. There
is no ground on the receiver end of the coax. The noise from home
applicances is almostly completely gone now with this antenna
configuration.
-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
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RHF
Do you have a separate Ground at the Shack for your equipment
independent of the Ground which is 'outside' at the Antenna ?
( If NOT - IMHO - You Should. )
If YES - Then when you 'connect' the Radio-End of the Coax Cable
to the Radio it is again Grounded.
TBL: Which means you have a Grounding Point at both Ends of the coax Cable.
iane ~ RHF
.
.
= = = starman <sta...@tech.net>
= = = wrote in message news:<3FF9199E...@tech.net>...
Brian Denley wrote:
One more thing: It's true that a well grounded coax shield will
prevent the lead-in from acting as part of the antenna BUT you
actually have to ground BOTH ends of the shield (on the lead-in)
to make this effective.
Starman wrote:
I haven't found this to be so in my case. The coax shield on my
low noise inverted-L is grounded only at the bottom of the antenna's
single wire downlead, which is close to the ground. The coax runs
about 75-ft along the ground to the house, then up one story to the
receiver. There is no ground on the receiver end of the coax.
The noise from home applicances is almostly completely gone now
with this antenna configuration.
.
.
.
Brian Denley
> I haven't found this to be so in my case. The coax shield on my low
> noise inverted-L is grounded only at the bottom of the antenna's
> single wire downlead, which is close to the ground. The coax runs
> about 75-ft along the ground to the house, then up one story to the
> receiver. There is no ground on the receiver end of the coax. The
> noise from home applicances is almostly completely gone now with this
> antenna configuration.
>
Starman:
My random wire coax feedline is also only grounded at one point (the center,
oddly enough) but the fact is that for the feedline to effectively not act
as part of the antenna, the shield must me grounded at BOTH ends. Is one
point better than nothing? Sure.
Like you, I live with it because I find it difficult to implement.
starman
I came to the conclusion that the single ground at the far end of the
coax is 'effectively' preventing the shield from being a common mode
antenna because the noise level is much lower than before I built the
low noise 'Doty-L' antenna system. Another factor is that most of the
coax is laying on the ground. This also helps to reduce common mode
reception on the shield. There's about fifteen feet of coax above the
ground going up to the receiver on the second story. I've also noticed
that the noise level is much higher when I partially remove the antenna
coax connector on the back of the receiver, so that only the center pin
is making contact.
Brian Denley
In fact it was Doty, if I recall, who mentioned to me that you really should
ground both ends of the coax. Like you, I just didn't know how to do that
easily at the 'high' second story end of his coax feedline approach. In
actuallity, my antenna feedline never comes down near the ground so I had to
run a separate gound line (aluminum wire) down to my earth post. I split
the feedline in the center and grounded the shield at the midpoint. It
seems Ok (certainly better than without the ground).
RHF
"I've also noticed that the noise level is much higher when I
partially remove the antenna coax connector on the back of the
receiver, so that only the center pin is making contact."
1. With a Primary Grounding Point at the Antenna:
* If you have a separate Shack-Ground for your equipment
(radios etc) you 'may' NOT Notice this Higher Noise condition
when the 'outer-ring' of the PL-259 Plug is diconnected from the
back of the radio/tuner/switch.
* If you do NOT have a separate Shack-Ground for your
equipment (radios etc) you 'may' Notice a Higher Noise condition
when the 'outer-ring' of the PL-259 Plug is diconnected from the
back of the radio/tuner/switch.
2. A Primary Grounding Point outside and away from the house
offers many advantages for Noise Reduction and Safety.
3. A Secondary Grounding Point inside the house for the equipment
offers additional advantages for Noise Reduction and Safety.
4. This informational webpage presented by "Wellbrook Communications"
* LOW NOISE ANTENNA USING
* THE UNIVERSAL MAGNETIC BALUN
* PLUS THE ANTENNA FEEDER ISOLATOR
Universal Magnetic Balun is specifically designed to reduce noise,
especially mains borne, by isolating the feeder winding of the
Balun matching transformer from the antenna.
GoTo=> http://www.wellbrook.uk.com/longwire.html
Take A Look At the Diagrams On This WebPage - They Tell It All !
5. Another Look at Noise Reducing Antenna Systems
- by Mark Connelly [WA1ION]
GoTo=> http://members.aol.com/WA1ION/nrants.pdf
Here again WA1ION uses a 9:1 Matching Transformer between the
Antenna Element anf the Coax Lead-in-Line and a 'second' 1:1
Matching Transformer in the Shack between the Coax Lead-in-Line
and the receiver.
6. Grounding is KEY to Good Reception
- by John Doty
http://www.hard-core-dx.com/nordicdx/antenna/ground/ground2.html
http://www.hard-core-dx.com/nordicdx/antenna/ground/index.html
7. Impedance Matching Transformers for Receiving Antennas
at Medium and Lower Shortwave Frequencies
- by Bill Bowers, John Bryant and Nick Hall-Patch [VE7DXR]
GoTo=> http://radiodx.com/spdxr/media/imt_doc1.doc
8. The Purpose for a Balun
- by John Doty
GoTo=> http://www.hard-core-dx.com/nordicdx/antenna/feed/balun3.html
"The purpose of a balun is to block common mode waves (current
flowing in the same direction on both conductors of a transmission
line) and pass differential mode waves (current flowing in opposite
directions on the conductors)."
9. The "Grounding-Point" = Ground Rods and Ground Wires ETC.
GoTo=> http://groups.yahoo.com/group/SWL-AM-FM-Antenna/message/425
iane ~ RHF
.
All are WELCOME at the "Antenna Ashram"
GoTo=> http://groups.yahoo.com/group/SWL-AM-FM-Antenna/message/502
.
.
= = = starman <sta...@tech.net>
= = = wrote in message news:<3FFA61E3...@tech.net>...