<p dir="ltr">Dan, <br>
Antenna specs are "free space" calculations, NOT real world. Dipole resistance, as you said, varies. <br>
Objects within 2 _ 3 wavelengths can affect resonancs. And RF ground is seldom @ earth surface, and that affects resonance / pattern.<br>
We "tune" the SWR with a "matchbox" to get as mutch as we can to the antenns, and NOT damage the transmitter. <br>
To get max signal out, use a field strength meter.<br>
Del</p>
</br></br><div class="device_aol_et_org_dt_dd_quote"></div><hr style="border:0;height:1px;color:#999;background-color:#999;width:100%;margin:0 0 9px 0;padding:0;"></hr><span style="font-size:14px; color:#999999;">On Wednesday, February 3, 2021 Daniel Eaton via Harc <<span style="color:#0000A0">harc@humboldt-arc.org</span>> wrote:</span><br></br><div id="yiv1791233682"><html><div><div>Hi Howard: </div><div>Check this out and let me know what you think. Do you have a VSWR meter placement issue?</div><div><br clear="none"></div><div>This is a restatement of your paragraph 2.</div><div><div><a rel="nofollow noopener noreferrer" shape="rect" target="_blank" href="https://forums.qrz.com/index.php?threads/placement-of-swr-power-output-meter.608247/">https://forums.qrz.com/index.php?threads/placement-of-swr-power-output-meter.608247/</a></div></div><div><br clear="none"></div><div><br clear="none"></div><div>73, </div><div>Dan KB6DE</div><div><br clear="none"></div><div class="yiv1791233682yqt0998287684" id="yiv1791233682yqt99137"><div><br clear="none"><div class="yiv1791233682gmail_quote"><div class="yiv1791233682gmail_attr" dir="ltr">On Wed, Feb 3, 2021 at 11:31 AM Howard, KB6NN via Harc <<a rel="nofollow noopener noreferrer" shape="rect" ymailto="mailto:harc@humboldt-arc.org" target="_blank" href="mailto:harc@humboldt-arc.org">harc@humboldt-arc.org</a>> wrote:<br clear="none"></div><blockquote class="yiv1791233682gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">I have been trying to put into words why a dipole, resonant on a frequency we want to operate on may not show a 1:1 SWR. From experience I know that such an antenna does not always show a low SWR, and that the placement of the antenna is important (height above ground, nearby objects, etc.) in determining the SWR of an otherwise resonant antenna.<br clear="none">
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Also important is the method of feeding the antenna and connecting it to the radio. I also have been saying that SWR, when measured at the transceiver, is an indication of the match between the radio and the antenna system, not [just] the antenna itself - the antenna system includes anything from the antenna jack on the back of the radio all the way up to and including the antenna itself.<br clear="none">
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Another thing I say is that the matchboxes commonly called "antenna tuners" are matchboxes, not antenna tuners. They are impedance matching devices. If the radio wants a 50 ohm load, the matchbox makes sure that, whatever the actual impedance of the load (antenna system), a match to 50 ohms is obtained.<br clear="none">
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I found an article that says it better than I can, and has examples: <a rel="nofollow noopener noreferrer" shape="rect" target="_blank" href="https://hamradioschool.com/good-swr-and-antenna-resonance/">https://hamradioschool.com/good-swr-and-antenna-resonance/</a><br clear="none">
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Thanks for reading,<br clear="none">
Howard<br clear="none">
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KB6NN<br clear="none">
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