Topband: Vertical antennas aren't always best for DX everywhere - the facts
n4is at n4is.com
n4is at n4is.com
Thu Nov 22 13:39:24 EST 2018
I can comment on horizontal polarization. I am experiencing both polarization since 1980; with a vertical and a inverted V at 30m and 40m later; also with high DRF receiving antennas like the HWF and VWF since 2006.
Here my 2 cents.
There are 3 steps.
1. Make the power out of your antenna.
2. Get the wave up to be refracted down.
3. After refracted the wave get propagated.
These 3 different things need attention. I will comment 3 to 1
* Does not matter the original polarization after the wave refract it splits in horizontal and vertical polarization.
* The propagation is different for both waves, ordinary and extraordinary.
* The attenuation is also different during the path. It is normal for me here in South Florida, 23 degree North, to hear VK6 on horizontal HWF 30 minutes before SR coming from 210 degree SSW, and nothing on the VWF vertical, then at Sunrise’ the signal change to direct path W and peak at SR only on the VWF, no copy on the HWF.
* W8JI did not have a horizontal RX antenna with high RDF to compare with high RDF RX antennas.
* The direction is very important, N-S is affected by the inclination of the earth magnet field. Signals from south are stronger on horizontal, there is less attenuation near the equator for horizontal pol.
* Working stations from Africa or pacific , W -E, it’s is normal to experience long and deep QSB, The polarization shift slowly between vertical and horizontal, the signal is Q5 on the Horizontal WF, after few minutes fade and become Q5 on the Vertical WF.
* This is the same on 160 80 , but on not on 40m where horizontal polarization is always better.
* Ground interaction between matter (ground) and radio frequency wave is the same everywhere on 160m. Horizontal signal has a -1 factor and cancel signals near the ground, The inverted V or Dipole is always near to the ground on 160m (500ft), the irradiation patter is 50% vertical and 50% horizontal.
* My first experience with a ¼ wave full size vertical was in Brazil back in 1990, I worked 9V1XQ with 400 w using the ¼ TX vertical. Few month later I installed a inverted V at 120 ft. high.
* All A/B tests did show 10 db improvement on the inverted V over the vertical with a poor ground plane.
* The issue is what kind of test you can do. Well we test SSB with local guys , 4000 miles QSO’s on CW, but it is hard to test with 8000 miles or more.
* Before 2000, PY1RO had a 20 years sked with Mike VK6HD near SR and never completed one QSO. In the last 20 years there was several QSO’s PY-VK6 with signals coming from NNE near SS. Hard to tell if the vertical TX antenna was used or not on the VK6HD side.
* Vertical for 160m on South America used to be very rare. Nowadays we have several great signals using ¼ wave vertical, LU8DPM , PP5JR, PY2RO and others. The difference between them and the guys using an inverted V are at least 10 db better here in Florida for the vertical antenna.
* W4ZV , Bill always tell me to get and inverted V to work pacific, Bill loves his inverted V. Here in my QTH, I don’t have the space for one, but I never feel necessary because I work pacific with my Vertical and listening on the HWF all the time.
Using the HWF in my city lot I just don’t hear any manmade noise from the city around me, I have common node noise under control. The signals are always weak then the HWF, but always with better signal to noise ratio then the VWF.
The issue in 160m is that the HWF needs to be above 85ft. 90 is good, 120 is better and 160ft at K9CT or 200ft like W8LRL is just fantastic.
The HWF works very well on 80m at 60ft high and above. RDF makes a huge difference on RX signal to noise ratio.
My measurements over the last 10 year indicate for each one db increase on RDF the signal to noise ration increases two db.
On 160m RX there are two very different propagation path, one horizontal and another vertical. But for TX. If it is V or H does not matter, what only matter is the irradiated power efficiency to get the wave refracted by the ionosphere.
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