The cure for all RF problems
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The cure for all RF problems Expand / Collapse
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Posted Saturday, June 26, 2010 6:35 PM
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This is my e-ham review [Seconded Review]

This is my second review. As for the perfomance of the receiver, this rig gets the highest marks BAR NONE! Well, the Flex 5000, is just a hair better, but there we are splitting hairs.

I am writing this review to persuade my fellow hams to GET RID OF THAT COAX!!!!! I was getting RF on my audio, and I was going nuts. Everytime I would turn on the amp, I would want to throw up. I was just disgusted. Until one night I was on 75m, using my PROIII, and having a chat with a friend that told me to go with a balanced feedline. Now I know, you folks are going to say that won't work it will just add RF.

Wrong, I am using a dual run of RG-6 coax. I am using the two center conductors as a balanced feed line. The braids of the two coaxes are twisted together, and the end of the twisted braid that is going to my shack is going to ground. At the apex the braid is twisted and sealed with liquid electrical tape. ALL MY RF IS GONE. MY SIGNAL IS HUGE! My sheilded balanced feedline lays right next to my RF proned Berhinger audio rack and the Flex 3k. Like I said NO RF!!!!

The other night I was on 160m with my 80m dipole and I fed a kilowatt into the antenna system WITHOUT ANY RF ISSUES!

Bottomline:
Balanced feedlines are the best. Coax sucks. I could careless about SWR. Reflected power always radiates. Get out of your indoctrination about 1/2 wave antennas and coax. Hams from yesteryear would say your crazy for using coax, and I agree!

Now I highly suggest all Flex users to get rid of your coax. Go and get a 1000' spoil of dual run RG-6 coax. Use the two center conductors as a balanced feedline, and twist the two braids of the coaxes together. The one end of the feedline that goes into the shack tie that to the tuners ground lug. At the apex of your antenna twist the braids and seal them from the elements. You will now enjoy not having rf issues! Remember with an unbalanced feedline, there is always some rf coming down on the outside of the braid. This is where are problem is. TRUST ME FOLKS IT WORKS!!!!

Jason M. Griffin Sr.

de NB3K

Post #2853
Posted Sunday, October 31, 2010 6:55 AM
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That sounds like a good idea and will have to try it out since RG6 is free for the asking when approaching a cable guy and explaining you are a ham.  I always did use RG6 for portable QRP work, especially the white cable which is impregnated with some type of sticky waterproofing material and can be buried in the ground without any water getting in.  I suppose it would also make a good feedline to a balanced antenna, although at a lower inpedance which a tuner would handle.  I have the crimping tool and newer waterproofed fittings and then use adaptors from PL59 to type F. 

We suffer from kleptomania and sometimes have to take something for it.
Post #3331
Posted Sunday, January 23, 2011 11:55 AM
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Very interesting. Would this approach work with an antenna requiring a 50 ohm feedline ?

regards
Post #3809
Posted Thursday, January 27, 2011 8:29 AM
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jason_sdr (1/23/2011)
Very interesting. Would this approach work with an antenna requiring a 50 ohm feedline ?

regards


Not sure what antenna "requires" a 50 ohm feedline? Sounds like you may be talking about a G5RV? I'd eliminate the coax, and feed it with balanced line right to the feedpoint. Of course, you'll need to come off of the balanced line outputs off of your tuner. If you don't have that, you'll need a 4:1 balun to go from coax to balanced line.
Post #3835
Posted Monday, April 11, 2011 7:06 AM
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Hello,
this looks like a great idea. I would love to try it to solve my RFI problems. Can I also use RG-58 or is it not good enough for this purpose?
73, Harry, 7Z1HL


7Z1HL - Proud to have the first Flex Radio 3000 in Saudi Arabia
Post #4207
Posted Monday, December 12, 2011 10:10 AM
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You can use anything that you can pretty much imagine. I am running 450 ohm ladder line directly into the shack to the MFJ-976 Legal Limit Balanced Line Tuner. I run the following station,

Mic Marshall R-144 ribbon mic

3 pieces of Behringer gear in my audio chain Mic 2200, DEQ-2496, and DSP-2024p.

I run 1000w on 80m and my dipole runs over the shack from about 30 feet. Unless I plug something into my setup I have no rf.

I use to use coax and I use to be loaded with rf. It would drive me nuts! But ever since I switched to a balanced line and tuner, I have seen no rf at all. Boy oh boy oh boy! The flex 3k is the best radio when it comes to performance/price ratio! There is nothing that comes close to the audio that can be produced through the powersdr. 

Jason M. Griffin Sr.

de NB3K

Post #5203
Posted Saturday, December 24, 2011 2:07 PM
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I resolved my RF problems by trashing my well-known headset for a standard mic and $10.00 headphones. Could not beleive that the headset I had, that was designed for Ham radio, will not filtered or protected against RF..

Justin G0KSC
www.InnovAntennas.com
Post #5250
Posted Sunday, February 12, 2012 4:25 PM
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I am now running 2 runs of coax that are side by side, to 2 different antennas,
coming out of my Ten-Tec 229b tuner;
it is aprox 35 feet from my radio room to the outside of the house where the coax exits near ground level.

73 K2HAT Lee


73 K2HAT fn32
Post #5407
Posted Sunday, March 11, 2012 12:17 PM
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Hi, I can only confirm that the use of balanced feeders is the best way to go. I have a doublet with a total length of 20 Meters the tuner is a Palstar BT1500A and I can tune all the bands from 80 to 10 meters including 6 meters as well. There is no problem with HF in the shack because of the use of coax feeders for each line as described already. The Doublet is hung 10 Meters high. I am now going to make a doublet with a total length of 40 meters perhaps I can then tune to 160 Meters as well.

de Paul OE8PCK
Post #5477
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