Matching Antennas to a feed line is possible using several methods. The λ/4 match is the most well known one because of it's simple calculation. Often, however, cables with the calculated line impedance are not available. You can get (or make by parallel use) cables with 12,5 Ω, 16,67 Ω, 25 Ω, 37,5 Ω, 50 Ω and 75 Ω, some old 60 Ω TV cable and 93 Ω characteristic impedances. You may find speaker cable with 100 Ohms, and WIREMAN Flat cable with 300 Ω oder 450 Ω. If your calculation is close to one of these by chance, SWR=1 match at resonance is possible and λ/4 match is a good choice. If not, you can do better:
Exact match is possible also using regularly available RF cable. Calculation, however, is more demanding.
There are solutions for that in the Interent. But few are error free: You may well get wrong or negative length results. Often functions are password protected and not correctable. Or you get Java applets, that today's browsers can no longer make use of because of malware danger. This situation made the author write his own program.
The EXCEL program LINE-MATCH by Hans Jacobi, DJ7BA, shows three match methods simultaneously: Parallel Stub, Serial Insert, and λ/4 match. All results are checked by complex line equations, for making sure that results are indeed error-free.
By displaying everything side by side you can compare and find your own best solution easily. Yo can also compare the effect of a frequency change to band end.
LINE-MATCH was written for EXCEL and should work from Office 2000 or later - using EXCEL's complex calculations. You may have to install the option 'analysis functions' for that. An alternative is the use of the EXCEL compatible CALC from Freeware OpenOffice. You can get it from: www.openoffice.de . Complex calculations are included with the standard installation already, but CALC does not understand the nice Microsoft VBA controls properly. So for CALC please use an .ods version of LINE-MATCH. The .ods versions deutsch or english will also permit random values for the characteristic line impedance. This may be helpful, if you want to use a self-designed cable, like a so-called chicken-ladder line.
Copyright: The program is designed to provide maximum use for RF electronic students and Radio Amateurs. Thus functions are not password protected. But you must not pass on the program to others if you changed it. The proper way to do changes is: Send a fault report to the author. I will check your request and use it if deemed good. This helps to avoid circulation of more calculation errors in the internet. Believe me, errors happen easily and are published easily, too. Thank you for understanding. The program was tested in great detail. But nobody is perfect. So, please send me your fault reports, if you find a fault.