[BC] RE: Slant wire feeds

[Lewis Munn]

All,
   
  The AM station in Glasgow, MT has a slant wire feed also.  I have measured it, and it is not any flatter than a similar series fed tower, or a skirt fed unipole I saw in Hillsdale, Michigan years and years ago.
   
  The major advantages I have seen are in lightning protection, and in getting transmission lines up the tower.
   
  A disadvantage is that he actual RF currents at the real base of the tower end up to be quite high, so there needs to be extraordinarily good grounding of the tower base to a good ground system.
   
  And it is a good idea to check it physically a bit more often...not just put it in and forget it for 40 years.
   
  I recently redid the base area grounding for a slant fed system, and appeared to recoup about a 5% field gain by putting in extra-heavy strapping over the somewhat corroded #6 wire that had been used to ground the tower base originally.
   
  As an aside, a bunch of copper transmission lines, if properly bonded to the tower, makes the tower loss itself smaller and increases the effective field.  Did a DA tuneup in Fargo, ND, and both towers had 3-1/2" FM lines up them bonded every 20 feet.
   
  The tuneup showed that rather than the 1 ohm loop loss of a galvanized tower permitted in the Rules, we had about 1/3 ohm loop loss, and the pattern was expanded to the very limits in every direction.
   
  Looey Munn
  Roundup, MT 

Paul Smith W4KNX <paul at amtower.com> wrote:
  WIBQ 1220 Sarasota, FL has a slant wire
			
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