2025 20m Antenna Repair: Difference between revisions
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== 7th September 2025 == | == 7th September 2025 == | ||
Following replacement of the balun onto the tower, a transceiver was connected to the antenna, and it was confirmed that no audible signal was produced on the 20m antenna. Upon further testing with a NanoVNA, it was determined that, after connecting directly to the 20m feedline, an SWR of >10 was present across the 20m band, with extremely random readings across the hf bands. It was additionally determined that 20m SWR would range as high as ~75 for significant periods of time in the feedline was moved or disturbed in any way. Followup testing will be conducted by connecting directly to the 20m beam to determine if poor performance is the result of feedline degradation. The suggested present course of action is to prepare for a feedline replacement, although station engineers do acknowledge that solder joints and mechanic crimp or bolted connections may be at fault. A full visual survey will be conducted at a later date by a tower climber. | Following replacement of the balun onto the tower, a transceiver was connected to the antenna, and it was confirmed that no audible signal was produced on the 20m antenna. Upon further testing with a NanoVNA, it was determined that, after connecting directly to the 20m feedline, an SWR of >10 was present across the 20m band, with extremely random readings across the hf bands. It was additionally determined that 20m SWR would range as high as ~75 for significant periods of time in the feedline was moved or disturbed in any way. Followup testing will be conducted by connecting directly to the 20m beam to determine if poor performance is the result of feedline degradation. The suggested present course of action is to prepare for a feedline replacement, although station engineers do acknowledge that solder joints and mechanic crimp or bolted connections may be at fault. A full visual survey will be conducted at a later date by a tower climber. | ||
== May 2026 == | |||
The replacement Rotor (A Donated AC motor ORION 2800 and Control Box) was prepped, holes drilled in the rotating plate for the mast jaws, and installed on the tower by Skylar and Will. They installed the tri-bander at 180 degrees at rotor stop thinking they could adjust it electronically in the shack like the old M2 RC2800 Controller. New feedline was installed on the tower, and it was found that the N connector installed on the balun was not installed correctly causing the center pin not to contact the female connector on the feedline. After replacement, the Antenna came alive. | |||
At this writing the Antenna is aligned incorrectly for the rotor stops. The 30yo donated controller cannot be aligned in the shack, but relies on the Antenna to be orientated North at full CCW position (Zero Degrees). | |||
(08/06/26 - WB9YZU) The Heading issue has been remedied and Heading indication is closer to reality, but is <u>Approximate</u>. | |||
This rotor is capable of a 60-90degree overrun in the CW direction. This means that Headings greater than 360 means the beam is pointed NE. Rotor Delays may be experienced, I think the caps in the rotor controller may need upgrading as it appears they have been replaced before. | |||
Edited by: Ron WB9YZU 08/06/26 | |||
[[Category:20m/15m/10m Beam]] | [[Category:20m/15m/10m Beam]] | ||
Latest revision as of 12:55, 6 August 2026
On 4th April 2025 the feed line to 20m antenna broke off the balun. The original connection was spliced coax without a connector.
The balun termination was replaced with an n-type connector, connected to the antenna via 1/4" 20 stainless hex bolts. Female (jack) termination located on feedline, male (plug) termination located on antenna balun due to coax comparability with connectors on hand*. Repairs on the 7th September 2025.
*NQ9Z flip-flopped the sizes for connectors by accident.
7th September 2025
Following replacement of the balun onto the tower, a transceiver was connected to the antenna, and it was confirmed that no audible signal was produced on the 20m antenna. Upon further testing with a NanoVNA, it was determined that, after connecting directly to the 20m feedline, an SWR of >10 was present across the 20m band, with extremely random readings across the hf bands. It was additionally determined that 20m SWR would range as high as ~75 for significant periods of time in the feedline was moved or disturbed in any way. Followup testing will be conducted by connecting directly to the 20m beam to determine if poor performance is the result of feedline degradation. The suggested present course of action is to prepare for a feedline replacement, although station engineers do acknowledge that solder joints and mechanic crimp or bolted connections may be at fault. A full visual survey will be conducted at a later date by a tower climber.
May 2026
The replacement Rotor (A Donated AC motor ORION 2800 and Control Box) was prepped, holes drilled in the rotating plate for the mast jaws, and installed on the tower by Skylar and Will. They installed the tri-bander at 180 degrees at rotor stop thinking they could adjust it electronically in the shack like the old M2 RC2800 Controller. New feedline was installed on the tower, and it was found that the N connector installed on the balun was not installed correctly causing the center pin not to contact the female connector on the feedline. After replacement, the Antenna came alive.
At this writing the Antenna is aligned incorrectly for the rotor stops. The 30yo donated controller cannot be aligned in the shack, but relies on the Antenna to be orientated North at full CCW position (Zero Degrees).
(08/06/26 - WB9YZU) The Heading issue has been remedied and Heading indication is closer to reality, but is Approximate.
This rotor is capable of a 60-90degree overrun in the CW direction. This means that Headings greater than 360 means the beam is pointed NE. Rotor Delays may be experienced, I think the caps in the rotor controller may need upgrading as it appears they have been replaced before.
Edited by: Ron WB9YZU 08/06/26