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Re: Topband: Non-resonant receive antennas

To: "'Milt -- N5IA'" <>, "'James Rodenkirch'" <>, "'Top Band Contesting'" <>
Subject: Re: Topband: Non-resonant receive antennas
From: "JC" <>
Date: Thu, 18 Dec 2014 10:57:02 -0500
List-post: <">>

Thanks to share with us your experience during XZ0A. When I started playing
with the HWF I was surprised to hear XU7ACY almost every day between 11:10z
and 11:20z SSW, during 2010 and 2011 , that happened 50% of the day from
October to April. 

This kind of propagation I called it TELP, Trans Equatorial Long Path. The
signals arrive from 40 degree elevation mostly horizontal polarized  20
minutes before SR  SSW and 20 minutes after SS SSE. With the HWF I was able
to work south Asia almost in  a daily base when my colleges  nearby only
could hear them few day with vertical polarized antennas.  

The reason why I do believe this propagation is around the equatorial line
is due the observation for this kind of propagation from the south
hemisphere. Analyzing several long path QSO's from PY's on 160m, there is a
common point , in all QSO's the signal was arriving near SS or SR coming
from NNW or NNE. 

In both cases, from north hemisphere or south hemisphere the signal is
really coming from the equatorial zone. K9LA demonstrated with a ray trace
analyze that the signal refract almost 120 degree at 40 degree angle, you
can check that on K9LA web page.

I think what I experienced with XU, DU and even JA long path SSW  is the
same propagation mechanism you mentioned during XZ0A. Very few
DX-expeditions uses that propagation mode and do not install any RX antenna
to receive SSW and/or  SSE. The XU7ACY extravagance QSO's was due the fact
Perter was active  every day and he installed a SSE /NNW reversible
beverage. DU7ET was using a high inverted V broadside N/S that receives
horizontal SSE. It is hard d to work DU from Florida until Robert installed
that antenna, we worked him Jan, Feb, Mar, Apr, and June this year on 160m,
we just missed him during May and I don't know why. By the way  Robert
worked WAS on 160 with that antenna from DU7ET.

73's N4IS

-----Original Message-----
From: Topband [] On Behalf Of Milt --
Sent: Thursday, December 18, 2014 9:56 AM
To: James Rodenkirch; Top Band Contesting
Subject: Re: Topband: Non-resonant receive antennas


If the arrival angle of the signals is high, then definitely the low dipole
will perform stupendously.

At XZ0A in 2000 we were having trouble the first few evenings receiving
signals at our sunset and for a couple of hours afterwards.  The Beverage RX
antennas were working very effectively after that time period, for the
entire night time.

Our conclusion was that the signals were arriving not only skewed (what
signals we were hearing were best on the VK/ZL Beverage and not the direct
path on the JA/NA Beverage) but also high arrival angle.

I installed a full sized dipole at 20' AGL, suspended by bamboo poles at the
center (centered on the helicopter landing zone as we suspected the Myanmar
Generals were not going to come visit us) and terminated in the jungle on
either side of the helo landing spot.

The dipole was oriented east/west, broadside to the N/S.

Immediately at the start of that day's Topband operation the NA signals came
right up out of the noise floor shortly before sunset.  Q5 copy signals on
the dipole were barely discernable while listening on the VK/ZL Beverage.

For 3 weeks we enjoyed this RX signal capability during the early evening
time period.

BUT, when it was time for the signal path to change it did so within a 5
minute period every night.  It was like someone was disconnecting one
antenna and connecting the other, so dramatic was the switch of RX path from
skewed, high arrival angle to direct path, much lower arrival angle over a
period of a few short minutes.  It was like clock work each evening.

The low dipole RX antenna allowed an XZ0A 160 M contact to be entered in
hundreds of NA log books which most likely would have never happened without

My personal experience with low (10' AGL), full sized (1/4 WL) horizontal
loops at my home station is they work very well for high arrival angle
signals but are nearly deaf to low angle signals.

Good luck, and YMMV.  The low dipole is a specialty RX antenna.  And you can
never have too many RX antennas.

If anyone would like to see photos of the low dipole at XZ0A, send me a
direct request.

73 de Milt, N5IA

-----Original Message-----
From: James Rodenkirch
Sent: Thursday, December 18, 2014 7:26 AM
To: Top Band Contesting
Subject: Topband: Non-resonant receive antennas

I noticed JC's comment below about a low dipole as a receiving antenna.

Did I interpret that correctly?  I've read of a Dipole on the ground as a
low noise receive antenna for 160 but.........can a non resonant dipole
installed at low heights be better, as a receive antenna, than a vertical or
L antenna? How about a non-resonant dipole, say, two feet above ground, at a
length of 100 feet? Would you feed it with coax or figure out the Zo at 160
and use a suitably wound xfmr to match to 50 ohms???

Just athinkin' of ways to use available low horizontal space, albeit the
available space is insufficient for a beverage.

Thoughts???  72, Jim Rodenkirch K9JWV

> From:
> To:;
> Date: Wed, 17 Dec 2014 23:11:10 -0500
> Subject: Re: Topband: 8 circle: DXE vs Hi-Z
> Hi guys
> Polarization does play a lot on 160m for two reasons. I can say that 
> because I am using my HWF (two horizontal flags end fire) since 2009. 
> The first one is local man made noise that propagate only vertical due 
> the attenuation on the horizontal component near the ground. And 
> Second the DX signal always come in both polarization.
> The result form the two reasons is an optimized signal to noise ration 
> using horizontal polarization.
> I have both WF with the same RDF, during SR or SS there is almost no 
> sky noise coming from the back because of the darkness, however local 
> man made noise comes from any direction, especially if you live in a 
> city lot like I do. Most of the time the noise is coming at the same 
> direction you want to hear the DX, and if you add power line noise the 
> situation deteriorates a lot for the VWF due vertical polarization. 
> Using my HWF I normally get 10 dB better SNR than my VWF that has the 
> same RDF and same aperture of 74 degree measures, I can turn the 
> antenna and measure it, they are not optimized for best F/B, I 
> optimized them for maximum rejection of local man made noise.
> The HWF is not a dipole. The two phased loops take of angle us 40 
> degree and there is a huge attenuation for signals above 60 degree. 
> Low dipole is a huge issue if the dipole is resonant, it will interact 
> with all other receiver antennas and will destroy directivity of all 
> of them, if you want to use a low dipole make it not resonant. Gain in 
> not important so it  can be short as a 30 m dipole and still will hear 
> the same way. Another issue with low dipoles is the amount of energy 
> absorbed from the TX antenna. If you connect a power meter and a 50 
> ohms load o the low dipole and transmit KW on the TX antenna, you can 
> measure several WATTS at the low dipole .
> You
> can burn you front end with a low resonant dipole.
> Adding to all that there is another very interesting observation from 
> my last 5 year using a high RDF horizontal RX antenna, when the TX 
> signal refract on the ionosphere the signal split in two waves, that 
> was very well explained by K9LA. What I observed is that these two 
> waves does propagate in different directions. I normally receive VK6 
> near my SR with better SNR horizontal from 210 degree SSW and with 
> better SNR from 280 degree vertical.
> Sometimes the horizontal peak is 20 minutes before the vertical peak 
> that is most of the time at my SR.
> 73's
> N4IS
> JC
> -----Original Message-----
> From: Topband [] On Behalf Of 
> John Kaufmann
> Sent: Wednesday, December 17, 2014 8:59 PM
> To:
> Subject: Re: Topband: 8 circle: DXE vs Hi-Z
> Good points about polarization.  If the signals and/or noise are 
> polarized predominantly in one state, then RDF may not be a good 
> predictor of SNR performance, particularly if the antenna receives 
> predominantly in an orthogonal polarization.  On the other hand, if 
> the polarization state of the signals and noise evolve randomly with 
> no preference for any one state, which is often assumed for skywave 
> signals, then RDF will be--on average--a good receiving metric, 
> subject to the previous stated qualifications about the spatial 
> distribution of the received noise.  However, some of the past 
> discussions on this reflector about preferential polarization of 
> skywave signals on 160 may call into question the assumption of 
> randomly polarized signals.
> 73, John W1FV
> -----Original Message-----
> From: Topband [] On Behalf Of 
> Richard
> (Rick) Karlquist
> Sent: Wednesday, December 17, 2014 3:19 PM
> To: Lee K7TJR; 'Terry Posey'; 'John Kaufmann';
> Subject: Re: Topband: 8 circle: DXE vs Hi-Z
> All this discussion about RDF overlooks the issue of polarization.  If 
> you make an array of verticals with a certain RDF (assuming noise 
> comes from all directions uniformly), the array will be better than an 
> individual vertical by the RDF factor.  However, what I have found is 
> that a horizontally polarized antenna, such as a low dipole frequently 
> receives considerably better than a vertical.  In that case, you would 
> be better off using an array of low dipoles.  The reason why 
> horizontal polarization can be better is that the horizontal component 
> of terrestrial based noise is highly attenuated over distance as a 
> ground wave.
> Rick N6RK
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