[TowerTalk] SteppIir vs C31XR

[Joe Subich, W4TV]

Natan writes: 

> Why not convince Steve and Ward to resurrect their toys and do 
> a 2nd generation comparison of antennas using the C31XR and the 
> SteppIr.  At least you would have a standard to compare forward 
> gain, f/b and possibly other parameters too.  

It is relatively easy to do that comparison for yourself if you 
already have the second edition of the K7LXC/N0AX "Tribander Test 
Report."  The K7LXC/N0AX report includes all of the raw data for 
both the C31XR and the C3.  Field test data for the two and three 
element SteppIR at www.steppir.com/pdf/gain%20fb%20brochure.pdf 
was taken using the K7LXC/N0AX protocols (dipole comparison at 
48').  

The two sets should be directly comparable; the protocols were 
designed to allow multiple tests and multiple locations to be 
compared directly without the need to test all antennas at all 
locations.  

I've also done model comparisons of the SteppIR and Force12 
antennas which correlate well with the two sets of field test 
results and Force12's claimed gain and F/B numbers  


The SteppIR 4 element yagi vs. Force 12 C-31XR at 74' above 
flat ground (gain in dBi): 

                  C-31XR         SteppIR             elev.
    Band        Gain   F/R     Gain     F/R 
     20         14.0    20     15.0     20        13 degrees
     17             n/a        15.7     22        10 degrees
     15         14.3    22     16.1     22         8 degrees 
     12             n/a        16.2     22         7 degrees
     10         15.6    21     16.6     11         7 degrees 
      6             n/a        18.7     20         4 degrees 

The C-31XR numbers are Force-12 published specifications and 
confirmed by modeling with AO.  The SteppIR numbers are from 
modeling in AO/YO (6 meter values include the optional passive 
elements). 


The SteppIR 3 element yagi vs. Force 12 XR-5 at 74' above 
flat ground (gain in dBi).  

                  XR-5           SteppIR             elev.
    Band        Gain   F/R     Gain     F/R 
     20         12.6    16     13.4     20        13 degrees
     17         12.6    16     13.8     21        10 degrees
     15         12.8    17     14.2     21         8 degrees 
     12         12.6    20     14.8     14.5       7 degrees
     10         12.5    21     15.2     11         7 degrees 
      6             n/a        16.0     20         4 degrees 

The XR-5 numbers are Force-12 published specifications *NOT* 
confirmed by modeling with AO.  The SteppIR numbers are from 
modeling in AO/YO (6 meter values include the optional passive 
element).  

73, 

   ... Joe, W4TV