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Long inverted V not working well, why?
On Sat, 12 May 2007 13:03:31 +0000, Dave wrote:
1. on what band did you do these tests? Mostly 80 and 40, since those are the frequencies near where my two reference dipoles are cut (the one I mentioned, cut a bit above 80 meters, and a second 40-meter dipole at the same elevation, 17 feet, fed from the same coax feedline). 2. what where your criteria for evaluating 'better'? swr, rx noise, rx signal strength, tx field strength, tx signal measurements by someone at some distance from you? The only criterion I have available right now is received signal strength. I don't yet have the resources to do transmit signal strength measurements. 3. at what distance were the stations you compared, Some were regional, less than 200 miles away, and so of course I would have expected the low dipole to perform well, perhaps better than the inverted vee. However, others were 500 to 1000 miles away, in places like Virginia and Georgia (I'm in New Hampshire). Consistently, they came in as well, or nearly so, and sometimes better, on the dipole than on the V. 4. at what time of day/night, and on what date I work at home, and so I am able to get on the air several times during each day. I ran some tests on the ECARS net at 7255 during the day, generally from about 10 AM until about 3 PM EDT, and on 80 meter CW and 75 meter SSB during the early to mid evening. I did this every day for about the last week and a half or so (for reference, today is Saturday, May 12). 5. over how long of a period of time have you made these observations? As noted above, about the last week and a half or so. 6. in what directions were the stations relative to each of the v's? There is only one V, and the other is a dual band dipole (75 and 40 meters fed with one coax). The V and the 75-meter dipole are oriented roughly east and west, and the 40-meter dipole is oriented roughly east-southeast and west-northwest. Most of the stations I tested with were in Ohio down through Florida, and so were about 260 degrees true down to about 210 degrees true ... especially in the case of the Ohio stations, not really optimal for the antenna orientation, and yet an inverted vee should have been much less sensitive to that than a dipole. 7. how close together are the v's? The V and the dipole are approximately 30 feet apart horizontally and 50 feet apart vertically at their feedpoints, hence their feedpoints are a bit under 60 feet apart. 8. what is supporting the v's? The V is supported by a tall tree in the back yard. The tree doesn't have many branches or much foliage, and what it does have are high up, mostly higher than the feedpoint. The dipole is supported by trees on each end. |
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