What's Wrong With My Balun ???
This page is under construction . . .
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I've been an active ham for almost 60 years.
New hams often ask me what I would recommend?
- Which Radio?
- Which Anttenna?
- And even Which Balun?
I'm always amused to read some of the answers to these questions in the various online ham radio groups. Usually, the person asking the question is immediately flooded with a multitude of recommendations, which are all over the map!
My standard reply to such a request is to ask a series of qualifying questions:
- What Radio?
- What do you want to use the radio for? Home QTH? Portable? Both?
- Which bands do you wish to use? Only HF? Only VHF/UHF? Both?
- How much power? (OK, on HF, the choices here are few: 100w or QRP)
- How much money do you wish to spend?
- Which Antenna?
- Which bands do you want the antenna to cover?
- If HF bands: do you want to work DX? Local (NVIS)? Both?
- How much [yard] space to you have available for your antenna?
- How high can your mast be?
- How much money do you wish to spend?
- Which Balun?
- What kind of antenna do you want to use this balun for?
- Which bands should it cover?
- How much power do you plan to run?
- SSB:______? CW:______? Digi-Modes:______?
- Where will the antenna be erected? (describe the area surrounding the antenna)
- And to all of the above:
- Can you read, comprehend and follow instructions in plain English?
- Can you use a screwdriver, soldering iron, etc., or do you have two left hands?
(These are serious questions. You'd be surprised how many people don't trust themselves to build anything!)
With this information, I then begin a dialog with the OM/YL to be sure I understand his/her unique situation. THEN I think about it, check out the location on googlemaps, consider the options, and finally I offer my suggestion(s).
Anything less is wasting my time and the time of the person asking for recommendations.
AGAIN: What's Wrong With My Balun ?
There are several possible answers:
- Nothing
- It is Broken/Defective.
- It is not a Balun at all; it is just a transformer!
- Nothing is wrong with it, but it is the wrong Balun for the application you are using it with.
We'll focus briefly on answers # 1, 2, & 3, then take a careful look at #4.
Answer #1: Nothing;
This means you have chosen the right balun design for the chosen application and it has been designed and built correctly (i.e., the Toroid is the correct Ferrite-mix and it is wound with the correct number of turns of transmission line).
Answer #2: It is Broken or Defective:
If you are capable, try to repair it. Often you will find that the balun has burned up inside. This is typically due to using wire or cable that is not Teflon-insulated; especially is it is just enamel-insulated wire. In this case you'll probably have to replace it - but this time choose a balun which is built better (i.e., using Teflon-insulated transmission line).
Answer #3: It is not a Balun at all; it is just a transformer
This usually only applies to 4:1 "Current" (Guanella) Baluns. Due to a misleading photo in Jerry Sevick's otherwise excellent boon on building Baluns and Ununs - where he shows building a 4:1 Current Balun on a single Toroid core. This does not work in HF antenna applications.
In order for this Balun to work properly in HF antennas, you must wind it onto two separate Toroid cores, where each transmission line has its own dedicated core.
The single-core version that Sevick shows in his book only works in "floating applications" (i.e., 100% ground-independent), such as networks. HF antennas are never ground independent.
Unfortunately, nearly every Balun manufacturer fails to understand this important point, and builds and sells a single-core versions of this Balun. They might as well be selling Snake Oil, because it simply is not a Balun; it is just a transformer. It does transform the impedance correctly (4:1) but it does not perform the fundamental job that every Balun is tasked to do: impede Common Mode Current.
BUYER BEWARE !
Answer #4: Nothing is wrong with it, but . . .
it is the wrong Balun for the application you are using it with.
This answer is going to take a lot of time. There are many parts to it.
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to be continued . . .