Chuck: These are in line. Nothing special. One antenna is a random wire
of about 300 ft, in fairly close proximity to a 'space loop' stung up
in several trees. The chokes are in the shack, fed from the antennas and
then using short jumpers as needed to get to the SDR-IQ and the Grundig.
Since the antennas are fairly close to each other there is a fair amount
of interaction between the two. I had stopped using the SDR because of
the broad noise it would throw off. That is gone now, along with a large
amount of noise from my own house and a neighbor's house.
A good example, is WMAC-940 in Macon, roughly 100 miles south. It was
just barely audible because of noise, despite a S7-S8 signal. With the
chokes, its an easy signal to hear now.
At present I do not have the ability to sink a good ground here. But
that is one project that will take place during the "off season"
(summer). That may offer further improvements.
On 6/7/2016 8:28 PM, Chuck Hutton wrote:
Robert:
Did you just insert your new chokes in-line with the coax? Do you have any
shield ground between the antenna and the choke?
Curious Chuck
________________________________________
From: IRCA <[email protected]> on behalf of Robert LaFore
<[email protected]>
Sent: Tuesday, June 7, 2016 11:25 PM
To: [email protected]
Subject: Re: [IRCA] Common-Mode Choke Designed for MW DXing
I just bought a pair of these to reduce some radiation from one antenna
(using an SDR--Radiating Computer generated RF) into another antenna
using a conventional receiver. I put one on each antenna, in the "shack".
These common mode chokes have worked wonders, not only did they
completely eliminate the PC/SDR noise, but they also reduce other
induced noise from the house and neighbors.
At least in my case---I am very satisfied!
Robert LaFore
Acworth GA
On 4/27/2016 11:25 AM, Les Rayburn wrote:
In response to several requests from both MW DX’ers and 160 Meter enthusiasts,
MyAntenna.com has added a new receive-only common-mode choke to their line of
impressive products. This common mode choke can be inserted anywhere in the
feed line to your BOG, active whip, loop, etc. The choke blocks unwanted noise
that is often picked up by the coax as it travels from the antenna back to your
shack.
Many manufacturers claim that their chokes will work over impossible bandwidth
of frequencies, which simply isn’t possible. In contrast, these chokes are
designed to work over a limited range of frequencies. In this case it’s 500 KHz
to 10 MHz.
Common-mode attenuation: ~37dB
Choking Impedance >5,000 Ohms
The choke will allow DC power to pass through to active antennas, and can be
inserted anywhere in the feed line, including inside the shack. For best
results, it’s recommended that the choke be installed about 20 feet from the
antenna. I have no financial relationship with the company, but am a satisfied
customer.
http://myantennas.com/wp/product/cmc-0510-r/
If you have EMI/RFI problems or just want to reduce the noise floor to your
receiver, you can’t go wrong by installing good quality common-mode chokes in
your system.
73,
Les Rayburn, N1LF
121 Mayfair Park
Maylene, AL
EM63nf
Member WTFDA, IRCA, NRC. Former CPC Chairman for NRC & IRCA.
Elad FDM-S2 SDR, AirSpy SDR, Quantum Phaser, Wellbrook ALA1530 Loop, Wellbrook
Flag, Clifton Labs Active Whip.
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IRCA mailing list
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Be sure to register now for the Joint DX Convention
Kansas City, September 9 to 11. Hotel space is filling up.
Registration info:
http://www.nrcdxas.org
Opinions expressed in messages on this mailing list are those of the original
contributors and do not necessarily reflect the opinion of the IRCA, its
editors, publishing staff, or officers
For more information: http://www.ircaonline.org
To Post a message: [email protected]
_______________________________________________
IRCA mailing list
[email protected]
http://montreal.kotalampi.com/mailman/listinfo/irca
Be sure to register now for the Joint DX Convention
Kansas City, September 9 to 11. Hotel space is filling up.
Registration info:
http://www.nrcdxas.org
Opinions expressed in messages on this mailing list are those of the original
contributors and do not necessarily reflect the opinion of the IRCA, its
editors, publishing staff, or officers
For more information: http://www.ircaonline.org
To Post a message: [email protected]
