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Diamond X-50A

The Diamond X-50A is a 2m/70cm vertical.

Specifications:
Band: 2m/70cm
Gain (dB): 4.5/7.2
Max Power Rating: 322 kph
Wind Rating: 217 kph (no ice)
Height (feet): 1.707 m
Connector: UHF
Element Phasing: 3-1/4l, 3-5/8l

The antenna was selected over other Diamond models because it had a single strong fibreglass radome, and was less likely to be plagued by the reliability issues common to many longer co-linear arrays. In the event, it has withstood 20 years of service without any problems.

This report is of measurements of the 20 year old antenna as part of a routine check of its performance. The measurements were made with a Rigexpert AA-600 hand held analyser, looking into 15m of RG213 coax with the X-50A at the end.

Fig 1:

Fig 1 shows the antenna mounted on a tripod mount for iron roof. It is used for local FM and repeater activity.

Fig 2:

Fig 2 shows a plot of the VHF SWR at the line input. This the the VSWR seen by the transceiver. TLLC  modeled line loss at 147MHz is 1.2dB under these mismatch conditions.

Fig 3:
 

Fig 3 shows a plot of the VHF SWR at the feed point calculate from the measurements at line input and the nominal characteristics of the feed line (15m of RG213). This plot gives a historical record of the antenna itself.

Fig 4:

Fig 4 shows a plot of the UHF SWR at the line input. This the the VSWR seen by the transceiver. TLLC  modeled line loss at 440MHz is 2.3dB under these mismatch conditions. (Intention is at some time to fit LMR400 for about 1.3dB mismatched line loss.)

Fig 5:

Fig 5 shows a plot of the UHF SWR at the feed point calculate from the measurements at line input and the nominal characteristics of the feed line (15m of RG213). This plot gives a historical record of the antenna itself.

Pattern

The following patterns are from the datasheet.

Fig 6:

Fig 6 shows pattern at 147MHz.

Fig 7:

Fig 7 shows the pattern at 450MHz.

Links / References

Changes

Version Date Description
1.01 10/09/2013 Initial.
1.02    
1.03    
1.04    
1.05    

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