[Antennas] Thanks all (my new wire dipole)

Thu Jul 2 11:57:47 EDT 2009

Hi,
Back on 8 June I asked for suggestions for a multiband wire antenna to 
replace my old Alpha Delta DX-EE shorty fan dipole and Inverted Vee's. I 
had considered a 50' "G5RV JR" but felt uneasy about relying on it using a 
long section of (lossy) coax cable to get it's match. Space is limited and 
anything put up must basically fit in a 14x60 foot space (I still have the 
Butternut HF-2V vertical for 75/40M).
At the suggestion of one list member I decided to go with a 88 foot, 
non-resonate dipole fed with window-line and bent at the ends to fit the 
space. The window-line connects directly to the MFJ-993B auto-tuner through 
what amounts to a DPDT toggle switch. I tried to find quality knife switch 
to switch it from balanced feed to the current balun in the tuner to 
"Marconi Fed" on the coax switch (so I can ground it), but I couldn't find 
one (just the RadioShack junk). I hope to be able to use this critter for 
limited 160M operation that way too (another reason to improve my ground 
system).
Anyway, after reading some various antenna forums on the web (Googling for 
"Knife Switch", a wonderful resource) I went down to Lowes and bought two 
high quality 20 Amp "three way" light switches and a plastic electrical box. 
These are basically a heavy duty SPDT switch. I was afraid that it would 
cause a huge impedance bump in the line and affect tuning, especially at 
10M. But in checking before and after results with the tuner (same total 
lead-in length both times), the switch had absolutely NO affect on tuning on 
any band! NOTE: The switch metal is NOT grounded and the plastic box 
provides good isolation between the two legs of the lead-in.
The apex of the antenna is roughly 27-28 feet above the sheet-metal roof 
(determined by walking away and eyeing it against the 32 foot vertical), the 
North end runs about 24 feet before it slopes West and down. The South End 
runs about 32-33 feet before it slopes East and down, so the antenna isn't 
perfectly balanced.
The feed-in runs East at right angles and down before it is bent North to 
enter the entrance pipe to the shack, and is well supported against 
wind-sway by Dacron rope. Pictures may be seen on my Multiply site, here 
(Multiply greatly reduces the resolution of the pictures). . .
http://ko6bb1.multiply.com/photos/album/25/New_wire_antenna_Field-Day_2009_from_Home#
HOW WELL DOES THE ANTENNA PERFORM?
With the auto-tuner it loads well on all bands 80-10M, even the WARC bands 
(Of course even a dummy load tunes well ;-) Being shorter than an 80M 
dipole I DID NOT expect it to load on 80-75M, but it does. ALSO, it DOES 
perform very well on 75M. All the usual West Coast nets that I frequently 
check into tell me that I have a much bigger signal than before or that I 
have on the Butternut vertical and that it's doing the job. But 40M is 
where it REALLY shines. It is much quieter than the old Alpha Delta 
(Because of it's balanced feed?) and I rarely have to call more than once to 
get into any of my nets (unless some big guns call at the same time :) 
Even when other stations are calling, it seems that Net Control comes back 
to me on the "first call" MUCH more often than before. . .
I operated field day with it and I was very pleased with it's performance. 
On 75/40 M I did constant comparisons against the Butternut vertical. As 
expected, sometimes the vertical was better, sometimes the dipole. That 
probably depends on direction/distance or what polarization the other 
station has. But more often than not, signals were stronger with a quieter 
background on the dipole. I also have a 20M 1/4 vertical up, working 
against the metal roof. Sometimes it outperforms the wire dipole but not 
very often! It's not in those pictures, but is mounted on the short pole 
you can see in this picture.
 http://ko6bb1.multiply.com/photos/album/25/New_wire_antenna_Field-Day_2009_from_Home#7So again, thank you all for the advice that steered me away from putting upa G5RV JR! I'm a happy camper, and after trying various antennas at this QTHfor the past 9 years I can truthfully say that I think things are finallyabout as good as they'll get, at least as long as I live here (probably forlife since it's paid for).73 de Phil, KO6BBhttp://ko6bb1.multiply.com/ (My OTR Blog)http://www.qsl.net/ko6bb/ (Web Page)DX begins at the noise floor!RADIO: Yaesu FT-2000.Antennas: Butternut HF-2v, 88' Ladder-Line fed dipole.Merced, Central California, 37.3N 120.48W CM97sh