[Antennas] tuning my 4-BTV

[Dick KF4NS]

I guess I left that out of my original message, I have a RadioWorks T-4 line isolator at the feed point. It is considered an UNUN.

Will update the group when I get things checked again after adjusting the radials. Right now I have NO low SWR point so I suspect the pigtails. I might have pulled one loose. Will check continuity and go from there.

73, Dick KF4NS
St Petersburg, FL 33714 USA
Keep The Glow!
  ----- Original Message ----- 
  From: K3vw at aol.com 
  To: kf4nsradio at verizon.net 
  Sent: Tuesday, April 10, 2012 4:34 PM
  Subject: Re: [Antennas] tuning my 4-BTV


  I suggest putting a 2 to 1 un-un at the feed point.Or cut an electrical 1/4 wave transformer out of 75 ohm coax at the feed point. Willy K3VW

  In a message dated 4/9/2012 6:24:57 P.M. Eastern Daylight Time, kf4nsradio at verizon.net writes:
    I need some advice on tuning my 25 year old Hustler 4-BTV (never used). It is mounted centered on my 
    house roof over shingles and the house has aluminum gutters. I installed it on a 5ft metal tripod with 
    14ga metal pipe covered with PVC pipe.

    The radials are 2 ea. band 14ga poly insulated stranded wire. Each was cut to spec in original Hustler 
    manual and DX engineering specs excluding fold-back of about 1ft at end of the 8 radials. Each is 
    terminated with a ceramic insulator then tied down to screw eyes with RADIO WORKS kevlar+dacron .075 in. 
    dia. rope and tensioned with adjustable line tensioners. (same was done for guy lines attached just above 
    the spider hub (no insulator).

    Radials do not come closer than 6 ft. to the gutters (40M closest) and are sloped as instructed and 
    spaced at 45deg. angles from antenna base. Hope I did not leave anything out. Oh, yea, the house roof is 
    70ft long rectangle with 40M and 20M run to the farthest corners in an 'X' configuration, the others 
    spaced evenly along the longest sides of the rectangle.

    Here are the MFJ-259 test readings (did not include X) all taken at shack end of RG-8X feedline, readings 
    were close to these at antenna base before connecting feedline but were swinging too much to be useful. 
    B/W shown < 2:1 SWR:

    10M = min. SWR freq 28250 khz 1.2:1 SWR 42ohms, B/W 28.0-29.0 khz  40-98 ohms Z

    15M = min SWR freq 20942 khz 1.1:1 SWR 57ohms, B/W 21.0-21.2 khz 65-76 ohms Z

    20M = min SWR freq 14000 khz 1.2:1 SWR 62ohms, B/W 14.0-14.21 khz 63-33 ohms Z

    40M = min SWR freq 7182 khz  1.4:1 SWR 45ohms, B/W 7.0-7.3 khz 95-27 ohms Z

    First thing I will try is adjust the length of radials. Of concern is the wide spread of the Z under 2:1 
    SWR.


    Any ideas will be greatly appreciated. THANKS

    73, Dick KF4NS
    St Petersburg, FL 33714 USA
    Keep The Glow! 

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