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Following your advice to start with the standard dimensions for the Vector 400 I started over again on the rebuild and did that for the over all lengths of the Vertical and the cone radials. Additionally I made sure the loop was exactly what it should be. Bob had questioned the dimensions of my dog bone on the gamma, so I rebuilt it, but stronger than before using 3/4" x 3/16" aluminum bar instead of 1/2" x 1/8" as before. I also used the idea we hasd discussed about some stand off of the radials at the bottom of the cone where they attached to the vertical. Because the EZnec model seemed to work out better with some stand off we considered the possibility that the real antenna might benefit from that. too. Previously my antenna.s radials went straight out from the vertical at the prescribed angle of about 30 degrees, but did not stand off. I made the mount for the bottom of the radials with right at 1-1/4" stand off before the cone tubes began their ascent toward the hoop.

At that point I still seemed to be unable to get a good match on the MFJ-259b, so I decided that for whatever reason my gamma match was not able to match my antenna. I made another gamma match using increased diameters for the gamma tube, and the gamma rod. The length of the tube remained the same as before. The rod I had was about 4" shorter than the original length, but I thought I'd try it before buying another. It worked just fine. Additionally I followed the suggestion you had made about the possibility that the brass fittings at the bottom of the gamma tube may have been read by the RF as a part of the gamma tube length and removed the brass fittings from the bottom using instead an aluminum "el". Whether this actually helped or not I can not say, but I do know it slimmed up the parts at the conjunction of the feedpoint and the cone radials where there may have been some capacitance that was not contributing toward the mismatch of the antenna to 50 Ohms. Regardless, I now had a Gamma tube that was 5/8" x 17", a rod that was 1/2" x 32" with the ability to bring the match right into line.
When I had this done I found the antenna had less apparent bandwidth than the previous version, but I felt it was a healthier antenna over all.

I have built a vertical tubing dipole both ways. I would have to revisit the non-gamma dipole to answer the question. I also would have to rebuild the one with the gamma to find out.

In the next few days I will be sending my analyzer in for recalibration. I dropped it on the concrete floor. It now will not read 50 Ohms on any proven 50 Ohm load. It reads a consistent 63 Ohms instead.

<blockquote data-quote="HomerBB" data-source="post: 395454" data-attributes="member: 8569">Following your advice to start with the standard dimensions for the Vector 400 I started over again on the rebuild and did that for the over all lengths of the Vertical and the cone radials. Additionally I made sure the loop was exactly what it should be. Bob had questioned the dimensions of my dog bone on the gamma, so I rebuilt it, but stronger than before using 3/4&quot; x 3/16&quot; aluminum bar instead of 1/2&quot; x 1/8&quot; as before.&nbsp; I also used the idea we hasd discussed about some stand off of the radials at the bottom of the cone where they attached to the vertical. Because the EZnec model seemed to work out better with some stand off we considered the possibility that the real antenna might benefit from that. too. Previously my antenna.s radials went straight out from the vertical at the prescribed angle of about 30 degrees, but did not stand off. I made the mount for the bottom of the radials with right at 1-1/4&quot; stand off before the cone tubes began their ascent toward the hoop.At that point I still seemed to be unable to get a good match on the MFJ-259b, so I decided that for whatever reason my gamma match was not able to match my antenna. I made another gamma match using increased diameters for the gamma tube, and the gamma rod. The length of the tube remained the same as before. The rod I had was about 4&quot; shorter than the original length, but I thought I&#039;d try it before buying another. It worked just fine. Additionally I followed the suggestion you had made about the possibility that the brass fittings at the bottom of the gamma tube may have been read by the RF as a part of the gamma tube length and removed the brass fittings from the bottom using instead an aluminum &quot;el&quot;. Whether this actually helped or not I can not say, but I do know it slimmed up the parts at the conjunction of the feedpoint and the cone radials where there may have been some capacitance that was not contributing toward the mismatch of the antenna to 50 Ohms. Regardless, I now had a Gamma tube that was 5/8&quot; x 17&quot;, a rod that was 1/2&quot; x 32&quot; with the ability to bring the match right into line. When I had this done I found the antenna had less apparent bandwidth than the previous version, but I felt it was a healthier antenna over all.I have built a vertical tubing dipole both ways. I would have to revisit the non-gamma dipole to answer the question. I also would have to rebuild the one with the gamma to find out.In the next few days I will be sending my analyzer in for recalibration. I dropped it on the concrete floor.&nbsp; It now will not read 50 Ohms on any proven 50 Ohm load. It reads a consistent 63 Ohms instead.</blockquote>

[QUOTE="HomerBB, post: 395454, member: 8569"] Following your advice to start with the standard dimensions for the Vector 400 I started over again on the rebuild and did that for the over all lengths of the Vertical and the cone radials. Additionally I made sure the loop was exactly what it should be. Bob had questioned the dimensions of my dog bone on the gamma, so I rebuilt it, but stronger than before using 3/4" x 3/16" aluminum bar instead of 1/2" x 1/8" as before. I also used the idea we hasd discussed about some stand off of the radials at the bottom of the cone where they attached to the vertical. Because the EZnec model seemed to work out better with some stand off we considered the possibility that the real antenna might benefit from that. too. Previously my antenna.s radials went straight out from the vertical at the prescribed angle of about 30 degrees, but did not stand off. I made the mount for the bottom of the radials with right at 1-1/4" stand off before the cone tubes began their ascent toward the hoop. At that point I still seemed to be unable to get a good match on the MFJ-259b, so I decided that for whatever reason my gamma match was not able to match my antenna. I made another gamma match using increased diameters for the gamma tube, and the gamma rod. The length of the tube remained the same as before. The rod I had was about 4" shorter than the original length, but I thought I'd try it before buying another. It worked just fine. Additionally I followed the suggestion you had made about the possibility that the brass fittings at the bottom of the gamma tube may have been read by the RF as a part of the gamma tube length and removed the brass fittings from the bottom using instead an aluminum "el". Whether this actually helped or not I can not say, but I do know it slimmed up the parts at the conjunction of the feedpoint and the cone radials where there may have been some capacitance that was not contributing toward the mismatch of the antenna to 50 Ohms. Regardless, I now had a Gamma tube that was 5/8" x 17", a rod that was 1/2" x 32" with the ability to bring the match right into line. When I had this done I found the antenna had less apparent bandwidth than the previous version, but I felt it was a healthier antenna over all. I have built a vertical tubing dipole both ways. I would have to revisit the non-gamma dipole to answer the question. I also would have to rebuild the one with the gamma to find out. In the next few days I will be sending my analyzer in for recalibration. I dropped it on the concrete floor. It now will not read 50 Ohms on any proven 50 Ohm load. It reads a consistent 63 Ohms instead. [/QUOTE]

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