[Antennas] Vertical

2002年9月28日 19:55:24 -0700

When you are talking about verticals, are talking about a specific 
vertical, the 1/4 wl?
What would happen if you used a dipole in a vertical position? For some of 
the people a loaded 40m dipole in a vertical configuration maybe a good 
thing. I was thinking of such.
Chris opr VE7HCB
At 12:01 PM 2002年09月28日 -0700, Jim Shaw wrote:
>Timely topic as I just was weighing the pros and cons of a new.
>>1-looks like you found true value in your beach front location! Might want
>to read
>"Antennas Here are Some Verticals on the Beach....." by N6BV ("The ARRL
>Antenna compendium #6", pg 216). You have salt water reflections so that is
>likely a positive. Wish I had the same ability! Not sure if your other
>antennas also benefit from that.
>>2-Elevating a vertical, any vertical, even just a little bit, usually pays
>dividends as well. See "Elevated Vertical Antenna Systems: Is your vertical
>system performance up to snuff? If not, maybe it needs a lift - in
>elevation above ground that is!". (ARRL "Vertical Antenna Classics, KB8I, pg
>108). Your homebrew vertical has the radials elevated above ground so that
>is, IMHO, a positive as well.
>>Over the last several months I used MINNEC 3 to model many different
>possible vertical configurations for my QTH. Nice thing about modeling is
>that you can change the height by just inputting a single number of how high
>above ground you want the antenna. In every case, elevating the vertical
>and radials above ground, even just a foot, improved performance as
>predicted by the model. At 1 WL above ground, the verticals appear to be a
>real competitor to the dipole at the same height.
>>Yes, some commercial verticals are made for elevated mounting. However,
>back in the 70s, I had a 5BTV (a vertical made for so-called 'ground
>mounting') that I tried mounting in many different ways (ground w/lots of
>radials, roof w/4 radials, etc.). My conclusion way back then (from
>admittedly limited tests) was that any vertical performed better if
>elevated. Nice to have modeling software these days as the tests are much
>easier to run with it. Same conclusion though. Higher the better!
>>>73 de Jim WA6PX
>[email protected]
>>-----Original Message-----
>From: [email protected]
>[mailto:[email protected]]On Behalf Of Charles Greene
>Sent: Saturday, September 28, 2002 10:54 AM
>To: Antennas
>Subject: [Antennas] Vertical
>>>Hi,
>>I made up a 20 meter vertical for portable use and installed it on my sea
>wall for test. It is full size, and I used some junk 1" Alunimum tubing I
>had in my attic. It has two radials elevated 1' above the ground. I made
>the radiator slightly short and the radials about 2' long to bring up the
>feed impedance to 50 ohms and also the impedance of the radials so one of
>them does not hog the current which it is inclined to do if all radials are
>at zero ohms. The first contact I made was day before yesterday, and I got
>a S9+20 report from the Fiji islands, running 30 watts on PSK31. Then I
>ran some tests on it. It is loacted about 50' farther away from the house
>than my 6BTV and G5RV. Using Spectrogram, I determined the noise ground
>floor was 10 db (voltage) lower than the 6BTV and 16 DB lower than the
>G5RV. The received signals were about the same as the other two, with a
>slight edge, 1 to 2 Db stronger. On comparitive reports I have received on
>transmit, it is running "slightly" to 1 S unit more than the other two. On
>DX, it is at the edge and 8' above sea level at high tide of Narragansett
>Bay, 4 miles wide at this point. On the other two antenna, my 6BTV has 22
>radials of 480' of wire, and the G5RV is 30 ft high. Both seem to work
>well. I knew the G5 was noiser than the 6BTV, but that usually does not
>come into play unless the signals are so weak they are in the noise level.
>>I really can't explain why the vertical is so low noise (my house isn't
>that noisy), and I would have guessed it would have performed a little less
>well than the fixed antenna with a fair number of radials. I can
>understand why it is better on the long haul stuff, as it has nothing
>between it and the frezonal zone a mile of two away. I would appreciate
>any comments.
>>73, Chas, W1CG
>K2 #462
>>- - -
>>Your moderator for this list is:
>Larry Wilson KE1HZ [email protected]
>_______________________________________________
>Antennas mailing list
>[email protected]
>http://mailman.qth.net/mailman/listinfo/antennas
>>- - -
>>Your moderator for this list is:
>Larry Wilson KE1HZ [email protected]
>_______________________________________________
>Antennas mailing list
>[email protected]
>http://mailman.qth.net/mailman/listinfo/antennas