Tech Articles
Antenna Matching Problems When Using Ladder Line or Open Wire Feedlines
Most matching problems occur when the antenna system
presents an extremely high impedance to the tuner. An antenna system should be
considered everything from the tuner to the tip of the antenna. High impedance
feedline is usually considered that which has over 300 ohms impedance and are typically are 300 ohms, 450 ohms and 600 ohms in impedance. When
the antenna impedance is much lower than the feedline impedance, an odd
quarter-wavelength feedline converts the low antenna impedance to a v
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3rd Nov 2019
Effect of Stray Capacitance on Testing
We
occasionally receive emails from customers who feel their balun is
defective because they are unable to replicate our test results. This is
due in large part to the effect of stray capacitance picked up by the
testing method they use.
For example, 3 pF of stray capacitance represents a reactance of about 1.7K ohm at 30MHz which will appear to be in parallel with the load. This will seriously affect readings at higher frequencies if the capacitance is not properly eliminated.
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12th Sep 2019
Noise Sources, RFI and their Suppression
With the advent of new technology in TV's, power supplies/chargers, new lighting products and other modern devices, there is an unfortunate downside from the electronic noise many of these items generate. To that end, we receive numerous emails and calls seeking a remedy to the ever increasing noise floor in our receivers.
No question that baluns are one of the answers, but they are not the sole answer and in some cases are not the answer at all. To better understand this statement it is import
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20th Mar 2017
But I Only Run 100 Watts!
As with most equipment, we have become accustomed to determining our needs relative to power handling capability and the output power being used. However, when it comes to baluns and ununs, this rating or capability should not be used as a primary decision maker. The reasons for this are many and varied but here are a few of the most important.When a balun or unun is wound correctly, which is an important differentiator, a higher power rating will also mean a higher efficiency, low SWR and exc
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18th Oct 2015
Baluns for Multiband Antennas fed with Open Wire or Ladder line
At least once a week we receive a request a for high ratio balun (6:1, 9:1, 12:1) to manage the transition from high impedance ladder line / open wire feedline to coax. This is a common misconception and when using a loop, doublet or double extended Zep (and several others) for multiband operation will result in "operational frustration". This is because any type of open wire (including ladder line and twinlead) will present nearly the same complex impedance of the ante
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20th Nov 2014