IDRick

EscapeVelocity

4.5 inches from the body of the casing (including the bent half loop at the end).

Here is a pic of my recommendation for balun attachment on the Tune-a-Tenna...

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IDRick

Thanks for the picture and the length measurement EV! The longer leads will work well for one of my designs but may be problematic for the other. It'll be good to have some on hand for testing...

EscapeVelocity

You can easily shorten them, just cut the wires down.

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Piggie

Well it so happens I just bought a handful recently to do some experiments. I had one next to the computer and it sure looks like aluminum.

But isn't that better? Even if the screws are steel, the wire also touches the feed parts of the antenna which are aluminum. Even if there is galvanic reaction with the screw, there should not be on the side where it touches the antenna parts.

I wonder if no-ox compound like used in electrical power wiring might be a good idea to use on baluns? It's designed for copper to aluminum interfaces, but I have used the stuff everywhere.

I use it on my automobile bulbs in the old Volvo that where constantly not working because of a bad connection, not a bad bulb, it fixed that.

I had a hard drive connector in a very old computer that would loose power to the hard drive (molex power connector from the old IDE drives). It fixed that problem.

The brake light problem I had was between the aluminum light bulb and a steel holder.

might be the ticket for a balun. A corroded balun connection will pass a good deal of the energy through as a capacitive connection. But the danger is if the connection becomes a dielectric which they normally do, then the junction becomes a diode that will rectify and create harmonics.

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Piggie

EV, I am not so sure that is best way to do them. You are putting a huge piece of metal between the wires. This changes the impedance. of the open wire feeder between the antenna the balun transformer body.

It might be a minor trade off since the length of the open wire feed is so short though. The trade off though might be worth it for mechanical stability. I don't have any equipment to measure it, but I put my balun in front of the antenna and put the coax through the screen, but keep all of it away from the elements and the feed lines on the antenna itself.

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The more I understand, the less I know.

Jim In Seattle

Piggie wrote: ... "But in the end I use CM baluns, except those included with Winegard antennas or such.

Why? I love the fact they are just wires. So many baluns fail where the wire goes into the spade to go under the nut or screw. It's the point of the highest mechanical stress, resulting in certain failure over time with the wire breaking right at the crimp on the spade.

So the CM doesn't have these. One top of that, if you play around and move them as I do, the wires are long enough if they do crystallize the metal to failure, you just strip them off and go again. You can't do this on other models, as the wires are must long enough (this also does reduce loss) but often the wires are stranded and about impossible to securely get again under a nut or screw.

Give me a CM with solid copper long leads."

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Piggy, et al:
I'm new here as of today: I was invited (in a round-about-way) by EV. He and I have communicated a number of times on the AVS Forum.

Regarding baluns, I agree completely with you about the CM units compared to most others, however, they are made in China... The solid copper wires are FAR easier to work with unlike the ones that use twin-lead. Aaaack!

Question: has anyone compared baluns manufactured recently VS ones manufactured in the 1960s or '70s? I wonder if (at UHF frequencies) older baluns work at all, the same, or better than modern ones. Is there a significant design change for new ones to operate at higher frequencies? If so, I'll throw all of my old ones away (actually, I'll keep them as attenuators). Next, I know the wire in old baluns is copper, but what's inside the new ones? Just curious.

By the way, over the past summer I built 4 of my own 'cut-to-channel' Yagis for my home setup and I established 33 channels (and subs) so far, and I made my own baluns from RG-59.

I also tested a bunch of antennas at various elevations under and over my roof last summer: a loop antenna, first vertically and then horizontally polorized, a CM-4221, a CM-4228 (currently in use to receive a very low power translator (used to be 60 watts, recently upped)), an unknown origin small periodic Yagi, a strange corner reflector, and a second corner reflector I rebuilt (pretty much from scratch), now 'cut-to-31' that I have yet to try do to the weather change.

I also setup five others with outside antennas or complete antenna systems and all are as happy as the proverbial Washington State geoduck clam! Thanks in advance,

Jim In Seattle

My edit for EV: I just checked two CM baluns I recently purchased and both have solid copper wires with a 'white-metal' covering. Scratch one with a file or your pocket knife and see what you get.

EscapeVelocity

Hey, Jim in Seattle. Glad you made it over.



Hmmm... Ill try that. Id keep older vintage baluns, as they are likely to be of higher quality build and perhaps tighter tolerances (especially US and Japan built).


Piggie, also the wires arent well insulated and are near the main mast. However I think the mechanical stability is worth it.

Ive also seen this recommended in Salvati's book, here is the pic of an old JFD Bowtie antenna with an RMS T-375 outdoor balun.



Ive also seen mlord with a similar config on a 4 bay....Ill see if I can dredge up that pic.

But I appreciate the heads up. Wish you or I had the equip to test.

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EscapeVelocity

Here it is....however its a bit unclear what is going on there. Looks like maybe a Winegard HD 8800 stacked.

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EscapeVelocity

So I reread the chapter on baluns and the paragraph regarding that picture. It seems that Salvati recommends (as teh pic shows) that the coax cable be tied to the screen in a manner which gives some upward lift to the balun, so that the rigid lead wires can be bent in a manner that do not contact the mast pole.

Thanks for the heads up Piggie. Ill redo a pic with that configuration and change the recommendation paragraph describing that method of install.

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