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Horizontal Stacking - JBX08WB, JBX14WB, JBX21WB

 

jbx14wb_stacked_001.jpg (50851 bytes)
JBX08WB JBX14WB JBX21WB

 

Description:

This is a comparison between the three different JBX antennas recently tested. Results are based on 36" spacing between stacked antennas. Results and comments below.

Individual tests for each antenna can be found here:

02/15/02 Horizontal Stacking - JBX21WB
03/25/02 Horizontal Stacking - JBX14WB
03/26/02 Horizontal Stacking - JBX08WB

Dish6000 Signal Levels


Spectrum Analyzer Waveforms:

Mt. Wilson Stations (15 mile distance)

JBX08WB

36" spacing

JBX14WB

36" spacing

JBX21WB

36" spacing

jbx08wb 036.jpg (62553 bytes)

Channel 31

jbx14wb_ab 008.jpg (63180 bytes)

Channel 31

WB-31AB-36.jpg (63150 bytes)

Channel 31

jbx08wb 037.jpg (62772 bytes)

Channel 36

jbx14wb_ab 009.jpg (61304 bytes)

Channel 36

WB-36AB-36.jpg (61864 bytes)

Channel 36

jbx08wb 038.jpg (61303 bytes)

Channel 42

jbx14wb_ab 010.jpg (63342 bytes)

Channel 42

WB-42AB-36.jpg (59323 bytes)

Channel 42

jbx08wb 039.jpg (61594 bytes)

Channel 53

jbx14wb_ab 011.jpg (61361 bytes)

Channel 53

WB-53AB-36.jpg (61714 bytes)

Channel 53

N/A

 

Channel 59

N/A

 

Channel 59

WB-59AB-36.jpg (59648 bytes)

Channel 59

jbx08wb 040.jpg (61216 bytes)

Channel 60

jbx14wb_ab 012.jpg (62288 bytes)

Channel 60

WB-60AB-36.jpg (60696 bytes)

Channel 60

jbx08wb 041.jpg (61611 bytes)

Channel 61

jbx14wb_ab 013.jpg (63309 bytes)

Channel 61

WB-61AB-36.jpg (62399 bytes)

Channel 61

jbx08wb 042.jpg (61509 bytes)

Channel 65

jbx14wb_ab 015.jpg (61842 bytes)

Channel 65

WB-65AB-36.jpg (60045 bytes)

Channel 65

jbx08wb 043.jpg (60544 bytes)

Channel 66

jbx14wb_ab 016.jpg (63532 bytes)

Channel 66

WB-66AB-36.jpg (60486 bytes)

Channel 66


Conclusion:

  • The shape of the waveforms are very similar, the main difference being gain. The level of gain can be seen in the height of the signal waveform, the large graduation lines represent 10dB. The JBX14WB has similar gain to the JBX08WB on the lower channels, the upper channels show a increase in gain on the JBX14WB. The JBX21WB has higher gain than both on all channels.
  • As you can see, the difference in measured gain between the JBX21WB and the JBX14WB is only 2-3dB. This proves how important it is not to lose gain due to poor quality coax cable or loose connections. With RG-11 cable at 100', you can save an extra 2dB of noise free gain compared to RG-6 cable that would have otherwise been lost in the cable.
  • I found the multipath reduction from stacking to be about the same on all three antennas. Antenna selection should be based on your location and potential strength of signal, see below for my recommendations on antenna selection.
  • The JBX08WB stacked should work well in areas where signal gain is high (line of site at 15-30 miles), but severe multipath is preventing reliable reception. If surrounding building are the cause of multipath, this setup should work well.
  • The JBX14WB stacked should work well in areas where signal gain is average (line of site at 30-60 miles), but severe multipath is preventing reliable reception. If line of site is being blocked by small rolling hills in the distance causing multipath or long line of sight distances are involved, this antenna should provide a good signal.
  • The JBX21WB stacked should work well in areas where signal gain is very low and no line of sight with transmitters. It will also work well for picking up very distant weak signals. If a large mountain range is in your signal path or you are trying to get signals from over 60 miles away, this antenna setup is going to be your best bet.

Quad Stacked?quad_014.jpg (54075 bytes)

Well, I did not have four identical antennas, so I decided to try a quad using two 14's and two 08's. I just connected all four antennas to a 4-way splitter with equal length coax and it worked great! I would say it is just about equal to two JBX21WB's. This is not really a practical setup though, since the cost and weight are more than using two 21's, but since I had these antennas laying around, I just had to give it a try. It would be a option for someone looking to put something powerful in a attic. The turning radius for stacked JBX14WB's is 48". You could do a quad stack with the 08's and get the turning radius down to 36". Certainly worth thinking about to get around the "wife acceptance factor" compared to a roof antenna.

 

  


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