VE7BQH's Antenna Tables are published by Lionel Edwards VE7BQH and widely circulated for more than the past two decades in a Microsoft Excel spreadsheet format (.xls file). The idea was to promote G/T as a definitive reference of the overall merit of a yagi antenna, the more positive figure the better a yagi design would be regarded!
Lionel's tables are produced by computer simulations using a number of antenna modelling programmes and so the results may not necessarily be confirmed in real world antenna testing!
See example below WA8C9 which has lowest temperature and best G/T despite being shortest design by far...
|Tsky = 290K Tearth = 5400K (Residential)|
1 Ant (dBi)
|* Ta (°K)|
@ 30° Elev
|* G/Ta (dB/°K)|
@ 30° Elev
|GTV28W||1.78||3.696||40||48||13.36||27.7||504.0||-7.77||V Split Dipole||17.75|
It is important to consider that the tables ignoring the noise temperature due to the inevitable loss (mandatory loss), which are an inseparable part of the receiving system. Plus one or two examples with the inevitable loss (mandatory loss).
The original G/T proposer for Amateur Radio VHF/UHF use was Rainer DJ9BV who suggested in his work an antenna elevation angle of 30° (the red line) for universal comparison purposes.
In the early days Lionel Edwards used Yagi Analysis v3.54 (DOS program) by SM2IEV to calculate yagi antenna G/T. However, Pop YU7EF worked with and adopted TANT (also a DOS program) by Sinisa YT1NT/VE3EA which he describes as more precise, particularly when calculating values for a 4 yagi group.
Meanwhile Lionel VE7BQH also moved to TANT and used this exclusively for several years to populate his tables until quite recently that is. However, in the latest tables presentation AGTC_lite by F5FOD/DG7YBN has also been brought into play!
In recent times I have observed for myself and reported to Hartmut DG7YBN that at an antenna elevation angle of around 30° both in TANT and AGTC_lite can produce different results (which can be significant) with certain designs and/or stacking distances! A working example of this anomaly and also optimal stacking distance improvements can be seen below (click on images for full size view)...
|4 x WA26075 in TANT (DL6WU stacking)||4 x WA26075 in TANT (Optimal stacking)||4 x WA26075 in AGTC (Optimal stacking)|
It can be argued that antenna manufacturers insisting on their own optimal stacking distances being used in the table can gain an unfair advantage over those designers bound to use DL6WU stacking distances!
Also VSWR Bandwidth does not represent an accurate assessment of antenna Q and the likelyhood to perform as predicted in software model. It would be better to adopt an average Q-factor value (144-146MHz)!
FOR THE TABLE TO MAINTAIN ITS INTEGRITY AND A LEVEL PLAYING FIELD ALL ENTRANTS MUST BE TREATED THE SAME REGARDLESS OF THEIR OWN STATUS!
Download link... for the latest official VE7BQH Antenna Tables.gnumeric (Save Link As)
Gnumeric Spreadsheet is an open-source spreadsheet program. It is available cross-platform, for Windows, Linux, and UNIX operating systems. The .gnumeric file format is compressed and allows download of the VE7BQH Antenna Tables in a smaller file size than even .zip format!
Windows users can easily use Gnumeric Portable without even fully installing!