Palomar Engineers Common Mode Noise Filter

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  • Updated 6 months ago
I wonder if anyone has tried this.  My 6500 with hex beam is generally quiet but I suppose in my esteemed anal tradition I am always looking for improvement.
They claim greatly improved noise (less :)).  The flex is generally so quiet that I wonder how much there is to gain.  I do have some persistent noise in the upper part of 20m.
I would love input.
Gene K3GC
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Gene - K3GC

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Posted 4 years ago

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That depends on whether your little bit of noise is COMMON MODE noise (traveling down the braid of your coax.)  I had 40 dB of Common Mode Noise on the feed line of a 10-40 metre end-fed dipole. I tried a common mode filter from and the noise VANISHED.  TOTALLY.  I've since added chokes to all the other feed lines and I've stuck toroids on every wire connected to my Flex.

In any event, *IT CAN'T HURT*.  If there is any insertion loss, you'd never notice it.

Littleton, Co.
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You may or may not get any results but All I can say is every little bit helps when you are aiming for the cleanest signal possible.

Here is a link.
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Mark - K9MQ

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I've had really good luck with these ferrites from Amazon.  I've put them every where in my shack and they have made a noticeable difference.
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Rob Fissel

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I'll second those uxcell clamp on ferrites. Absolutely no idea what mix they use, but I've had great success with these. I use them on everything to fix specific issues. They're used on coax, ethernet, USB cables, even Romex (AC condenser would kick on when QRO on 80). There also 80% cheaper than the RadioShack clamp ons. 
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Rev. David E. Hamm, K4EET

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I installed a Common Mode Choke on my feedline and got rid of some noise. YMMV but like others have said, it can't hurt anything. Ferrite beads on all of the wire "antennas" in the shack's equipment also helps too. Be sure to wrap the wire around the clamp-on ferrite bead four to six times to be most effective. 73, Dave K4EET
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Tim - W4TME, Customer Experience Manager

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Unless you ground your coax shield at the point where the common mode choke is shunting the currents to ground, the choke will not achieve maximum effectiveness.
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Gene - K3GC

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thanks, Tim good information
Gene K3GC
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Ken - NM9P

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Tim, let me make sure I get this right....
When I attach the lightning arrester at the base of my tower and ground it, then I should put the ferrite chokes AFTER the grounded lightning arrester so that the common mode noise will "choose" to go down that ground there, instead of along the higher resistance path through the stack of beads between the grounded arrester and my shack.....  That makes sense.  

I haven't completed that part of the tower operation yet....Saving up for copper wire and conduit runs......

Ken - NM9P
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Bill Mader

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Grounding has nothing to do with RF current choking.  You (all) should read the excellent material on the subject at  Ward Silver, N0AX, used a lot of it in his very well-received book Grounding and Bonding" for the Radio Amateur.  Unfortunately, there is a lot of misinformation about these subjects.  Another important fact is grounding coax feedline will not improve antenna performance.  73, Bill, K8TE
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Gene - K3GC

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Thanks to all who have replied.  I am not asking about common mode  chokes or ferrites though I make extensive use of both.  My question is regarding this :
Does anyone here have specific experience with this filter?
Gene K3GC
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George Molnar, KF2T, Elmer

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I'd expect the unit you ask about is a common mode choke made by wrapping coax around a ferrite toroid. While I have no experience with the specific unit, the comments above are all excellent. If you have common mode noise, it will help if installed correctly. Otherwise, nope. A lot of "noise" turns out to be real-life RF emissions, passed as they should be from a well-designed and installed antenna system, except that we just don't like them.
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Michael Wheatley

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I use the Palomar 1500W common mode choke at the shack end of my coax.  At the antenna end I use a Palomar Maxi Choker (#MC-1-3000) at the antenna.  I did this at the direction of the Palomart engineers.  I am very happy with the result.

Michael  -- KM6LHD
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That should be EXACTLY the same as the one that solved my problem:
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Peter K1PGV, Elmer

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You guys are always costing me money. I just had to part with more for one of those Common Mode Chokes from MyAntennas. 

And I had to buy the high-power one, too, because of MORE money you guys cost me when I bought an amp from another member here.