2m-window-loop - Revision history

Cmounts: /* The Story */

2012-06-24T16:52:25Z

The Story

2012-01-09T03:15:16Z

(measured) SWR charts

2012-01-09T03:11:52Z

2012-01-09T03:11:00Z

2012-01-09T02:54:37Z

2012-01-09T02:31:35Z

2012-01-09T02:30:03Z

2012-01-09T02:28:16Z

2012-01-09T02:24:05Z

2011-12-26T03:43:16Z

← Older revision		Revision as of 16:52, 24 June 2012
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	Originally, I tried this on the inside of the window of my van, as my employer had elected to move our company to a new building where the only place you can park has very low ceilings, and this seemed like the only solution (besides putting up and taking down an antenna daily).  It seemed to work out pretty well, so I figured I'd try it again.		Originally, I tried this on the inside of the window of my van, as my employer had elected to move our company to a new building where the only place you can park has very low ceilings, and this seemed like the only solution (besides putting up and taking down an antenna daily).  It seemed to work out pretty well, so I figured I'd try it again.
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		+	[[Category:Projects]][[Category:Member Projects]][[Category:Completed Projects]]

	== (measured) SWR charts ==		== (measured) SWR charts ==

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 [[Image:2mSWR.png]]
-The antenna wasn't designed for 70cm, but resonant antennas usually have a dip in SWR at λ / 3.  Again, not the design band, doesn't work as well here, but you might get some use out of it here.  This graph was measured every 1 MHz.
+The antenna wasn't designed for 70cm, but resonant antennas usually have a dip in SWR at λ / 3.  Again, not the design band, doesn't work as well here, but you might get some use out of it here.  It's pretty much hopeless on the common simplex and repeater frequencies.  This graph was measured every 1 MHz.
 [[Image:70cmSWR.png]]

@@ Line 11: / Line 11: @@
 The antenna appears to work fairly well on 2-meters, despite being not terribly high up. It's not perfect - it is very much a compromise - but it is pretty all right for what it is.
-Theoretically, the antenna should work on 70cm/440, as resonant antennas usually resonate at their intended frequency and all of its odd harmonics. I recently was able to draw up a chart of this as my [[MFJ269B|meter]] began mysteriously started working again today, and the graph can be found below.
+Theoretically, the antenna should work on 70cm/440, as resonant antennas usually resonate at their intended frequency and all of its odd harmonics. I recently was able to draw up a chart of this as my [[MFJ269B|meter]] mysteriously started working again today, and the graph can be found below.
 [[Image:N8vi-window-loop.jpg|right]]

@@ Line 11: / Line 11: @@
 The antenna appears to work fairly well on 2-meters, despite being not terribly high up. It's not perfect - it is very much a compromise - but it is pretty all right for what it is.
-Theoretically, the antenna should work on 70cm/440, as resonant antennas usually resonate at their intended frequency and all of its odd harmonics. I have been unfortunately unable to verify this empirically, as my antenna analyzer appears to have given up the ghost.
+Theoretically, the antenna should work on 70cm/440, as resonant antennas usually resonate at their intended frequency and all of its odd harmonics. I recently was able to draw up a chart of this as my [[MFJ269B|meter]] began mysteriously started working again today, and the graph can be found below.
 [[Image:N8vi-window-loop.jpg|right]]

@@ Line 17: / Line 17: @@
 Originally, I&nbsp;tried this on the inside of the window of my van, as my employer had elected to move our company to a new building where the only place you can park has very low ceilings, and this seemed like the only solution (besides putting up and taking down an antenna daily).&nbsp; It seemed to work out pretty well, so I&nbsp;figured I'd try it again.
-== SWR charts ==
+== (measured) SWR charts ==
-Here's an SWR chart for the design band, 2 meters.  I've included a graph through the SWR meter in the shop also, so you can see what weirdness that imparts on the SWR.
+Here's an SWR chart for the design band, 2 meters.  I've included a graph through the SWR meter in the shop also, so you can see what weirdness that imparts on the SWR.  This graph was measured once every 500KHz in band and once every .1 change in SWR out of band.
 [[Image:2mSWR.png]]
-The antenna wasn't designed for 70cm, but resonant antennas usually have a dip in SWR at λ / 3.  Again, not the design band, doesn't work as well here, but you might get some use out of it here.
+The antenna wasn't designed for 70cm, but resonant antennas usually have a dip in SWR at λ / 3.  Again, not the design band, doesn't work as well here, but you might get some use out of it here.  This graph was measured every 1 MHz.
 [[Image:70cmSWR.png]]

@@ Line 9: / Line 9: @@
 The antenna is matched with a half wavelength of coax. This takes the unbalanced signal coming in from the transmitter and sends half of it straight into one side of the balanced antenna, while delaying the other half of the signal 1/2 wavelength and feeding it into the other side of the balanced antenna 180 degrees out of phase.
-The antenna appears to work fairly well on 2-meters, despite being not terribly high up. More testing is required though.
+The antenna appears to work fairly well on 2-meters, despite being not terribly high up. It's not perfect - it is very much a compromise - but it is pretty all right for what it is.
 Theoretically, the antenna should work on 70cm/440, as resonant antennas usually resonate at their intended frequency and all of its odd harmonics. I have been unfortunately unable to verify this empirically, as my antenna analyzer appears to have given up the ghost.

@@ Line 1: / Line 1: @@
 = The e-room 2-meter window antenna  =
 [[Image:I3-window-loop.jpg|left|308x409px]] We have forever had a 2-meter/440 amateur radio rig in the e-room, but no antenna. I decided to fix this with some of the copper foil tape I'd recently found use for prototyping SMD boards.
@@ Line 15: / Line 17: @@
 Originally, I&nbsp;tried this on the inside of the window of my van, as my employer had elected to move our company to a new building where the only place you can park has very low ceilings, and this seemed like the only solution (besides putting up and taking down an antenna daily).&nbsp; It seemed to work out pretty well, so I&nbsp;figured I'd try it again.
 [[Image:2mSWR.png]]
 [[Image:70cmSWR.png]]

← Older revision		Revision as of 02:24, 9 January 2012
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	Originally, I tried this on the inside of the window of my van, as my employer had elected to move our company to a new building where the only place you can park has very low ceilings, and this seemed like the only solution (besides putting up and taking down an antenna daily).  It seemed to work out pretty well, so I figured I'd try it again.		Originally, I tried this on the inside of the window of my van, as my employer had elected to move our company to a new building where the only place you can park has very low ceilings, and this seemed like the only solution (besides putting up and taking down an antenna daily).  It seemed to work out pretty well, so I figured I'd try it again.
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		+	[[Image:2mSWR.png]]
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		+	[[Image:70cmSWR.png]]