Diversity Receiving Antennas

[Dave Van Wallaghen]

Hi all,

This is only somewhat off topic I think. As I've been playing with
diversity reception with my K3, I started researching using Beverage
antennas and found some good info on the web and in my ARRL books. Right
now, I'm just using an unterminated long wire (about 350') and plugging
it directly into the Aux RF port with no impedance transformer. As is,
it is working nicely for me on 20-40m when I operate during the day out
in my yard. With diversity receive enabled on the K3, I'm able to copy
weak signals masked by QSB and the normal summer QRN. It always seems to
me that I can hear the signal in one ear or the other if not both most
of the time.

So, I started looking at doing a real implementation of a Beverage on my
property as I do have some room to play with. I could run one east and
west for about 400' or so and another north and south for 550' or so if
I run it through my neighbors lots along a fence line (they don't really
use this area of their property). As I was researching the various
implementations, I came across the K9AY loop which looked pretty
interesting. I thought I might combine using the two aforementioned
beverages with a K9AY oriented in a NW-SE & NE-SW orientation.

In much of the literature I've read about this antenna, I see with the
designed dimensions, most use it for 80m & 160m. But I've also read a
couple of articles that state it should be good from 300 khz - 30 Mhz.
At this point, I really don't do a lot of operating on 80m or 160m and
kind of stick around the 20m, 30m and 40m bands. I'm not a contester and
primarily a CW op, but like to work weak signals and run QRP.

So my question to the group is, for those using diversity reception (or
separate receive antennas), and using a K9AY - does it perform well on
the HF bands for this purpose? I would also like any input from those
who have both Beverages and K9AY for comparison. And, does it make sense
to use the setup as I described? Since I can only run Beverages in a
couple of directions, I thought the K9AY use in the other directions
would cover a lot of bases.

I you think this is way too OT, please feel free to contact me
privately. I don't want to clog up the reflector if no one else thinks
this is of interest.

Thanks in advance & 73,
Dave W8FGU

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[Bill W4ZV]

Dave Van Wallaghen wrote

So my question to the group is, for those using diversity reception (or
separate receive antennas), and using a K9AY - does it perform well on
the HF bands for this purpose? I would also like any input from those
who have both Beverages and K9AY for comparison. And, does it make sense
to use the setup as I described? Since I can only run Beverages in a
couple of directions, I thought the K9AY use in the other directions
would cover a lot of bases.

I've never used a K9AY but I know it's S/N is several dB inferior to a decent Beverage.  There's a good comparison of RX antennas below:

http://www.w8ji.com/receiving.htm (scroll down to comparison chart)

Another comparison in in ON4UN's Low Band DX-ing (4th edition) on page 7-97.

The short answer is...the K9AY is better than nothing, occupies little space and can be switched in 4 directions...but it's not in the same ballpark as a good Beverage.  I'm also not sure how well the K9AY works on the higher bands, but you might want to consider a RX 4-square which can be comparable to a good Beverage in 4 directions and which can be used up to 30 MHz.  DX Engineering and HiZ Antennas both make broadbanded RX 4-squares that work well at HF:

http://www.dxengineering.com/Sections.asp?ID=117&DeptID=12#Top
http://www.hizantennas.com/

These systems are not cheap but should work much better than a K9AY.

BTW, it's really doubtful your Beverage is actually working correctly.  Both ends should be terminated in the characteristic impedance (~500 ohms) to work correctly, so you need a non-inductive 470 ohm resistor on the far end and a 9:1 matching transformer on the feed end.  Transformers can be made to work well up to at least 20m (maybe even 15m) but require some care in construction.

This is not the place to go into a Beverage tutorial but there is a wealth of information on W8JI's website and in ON4UN's 4th edition (or you can wait for his 5th edition which should be out next year).

73,  Bill  W4ZV

[Dave Van Wallaghen]

Thanks for the reply Bill. I will certainly take a look at the 4-square.

And I agree about my unterminated long wire. That is how I got to this point when looking to implement a Beverage the right way. I knew I was pretty far off when I looked it up in the ARRL books ;-)

I planned on trying to construct two of them in opposite orientations, I just thought the K9AY might be ok for the in between orientations.

Thanks for the great feedback and I'll take a look at that 4-square.

73,
Dave W8FGU
-----Original Message-----
From: Bill W4ZV <[hidden email]>

Date: Sun, 26 Jul 2009 19:24:04
To: <[hidden email]>
Subject: Re: [Elecraft] [OT]  Diversity Receiving Antennas





Dave Van Wallaghen wrote:
>
> So my question to the group is, for those using diversity reception (or
> separate receive antennas), and using a K9AY - does it perform well on
> the HF bands for this purpose? I would also like any input from those
> who have both Beverages and K9AY for comparison. And, does it make sense
> to use the setup as I described? Since I can only run Beverages in a
> couple of directions, I thought the K9AY use in the other directions
> would cover a lot of bases.
>

I've never used a K9AY but I know it's S/N is several dB inferior to a
decent Beverage.  There's a good comparison of RX antennas below:

http://www.w8ji.com/receiving.htm (scroll down to comparison chart)

Another comparison in in ON4UN's Low Band DX-ing (4th edition) on page 7-97.

The short answer is...the K9AY is better than nothing, occupies little space
and can be switched in 4 directions...but it's not in the same ballpark as a
good Beverage.  I'm also not sure how well the K9AY works on the higher
bands, but you might want to consider a RX 4-square which can be comparable
to a good Beverage in 4 directions and which can be used up to 30 MHz.  DX
Engineering and HiZ Antennas both make broadbanded RX 4-squares that work
well at HF:

http://www.dxengineering.com/Sections.asp?ID=117&DeptID=12#Top
http://www.hizantennas.com/

These systems are not cheap but should work much better than a K9AY.

BTW, it's really doubtful your Beverage is actually working correctly.  Both
ends should be terminated in the characteristic impedance (~500 ohms) to
work correctly, so you need a non-inductive 470 ohm resistor on the far end
and a 9:1 matching transformer on the feed end.  Transformers can be made to
work well up to at least 20m (maybe even 15m) but require some care in
construction.

This is not the place to go into a Beverage tutorial but there is a wealth
of information on W8JI's website and in ON4UN's 4th edition (or you can wait
for his 5th edition which should be out next year).

73,  Bill  W4ZV



--
View this message in context: http://n2.nabble.com/Diversity-Receiving-Antennas-tp3331122p3331589.html
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[Joe Subich, W4TV-4]

> I've never used a K9AY but I know it's S/N is several dB
> inferior to a decent Beverage.

The K9AY directivity falls off pretty badly at 40 meters
and it becomes bidirectional broadside on 20.  On 15 the
pattern is almost reversed and on 10 it's high angle.
This behavior is expected because the K9AY is more than a
full wave loop on 20 and 2+ waves on 10.  


> you might want to consider a RX 4-square which can be
> comparable to a good Beverage in 4 directions and which
> can be used up to 30 MHz.

The receive four square antennas are lucky to maintain
performance over a 4:1 frequency range even with what
W8JI calls "crossfire feed."  The diagonal (corner to
corner) distance needs to stay below approximately 5/8
wave to retain a unidirectional pattern but when
the size becomes too small in terms of wavelength, the
signal levels are too low to be useful in the lowest band.
The minimum effective size tends to be somewhat less than
1/8 wave per side on the lowest band (e.g., around 50'
for 160 meters).  

73,

   ... Joe, W4TV
 

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Bill W4ZV
> Sent: Sunday, July 26, 2009 10:24 PM
> To: [hidden email]
> Subject: Re: [Elecraft] [OT] Diversity Receiving Antennas
>
>
>
>
>
> Dave Van Wallaghen wrote:
> >
> > So my question to the group is, for those using diversity reception
> > (or
> > separate receive antennas), and using a K9AY - does it
> perform well on
> > the HF bands for this purpose? I would also like any input
> from those
> > who have both Beverages and K9AY for comparison. And, does
> it make sense
> > to use the setup as I described? Since I can only run
> Beverages in a
> > couple of directions, I thought the K9AY use in the other
> directions
> > would cover a lot of bases.
> >
>
> I've never used a K9AY but I know it's S/N is several dB
> inferior to a decent Beverage.  There's a good comparison of
> RX antennas below:
>
> http://www.w8ji.com/receiving.htm (scroll down to comparison chart)
>
> Another comparison in in ON4UN's Low Band DX-ing (4th
> edition) on page 7-97.
>
> The short answer is...the K9AY is better than nothing,
> occupies little space and can be switched in 4
> directions...but it's not in the same ballpark as a good
> Beverage.  I'm also not sure how well the K9AY works on the
> higher bands, but you might want to consider a RX 4-square
> which can be comparable to a good Beverage in 4 directions
> and which can be used up to 30 MHz.  DX Engineering and HiZ
> Antennas both make broadbanded RX 4-squares that work well at HF:
>
> http://www.dxengineering.com/Sections.asp?ID=117&DeptID=12#Top
> http://www.hizantennas.com/
>
> These systems are not cheap but should work much better than a K9AY.
>
> BTW, it's really doubtful your Beverage is actually working
> correctly.  Both ends should be terminated in the
> characteristic impedance (~500 ohms) to work correctly, so
> you need a non-inductive 470 ohm resistor on the far end and
> a 9:1 matching transformer on the feed end.  Transformers can
> be made to work well up to at least 20m (maybe even 15m) but
> require some care in construction.
>
> This is not the place to go into a Beverage tutorial but
> there is a wealth of information on W8JI's website and in
> ON4UN's 4th edition (or you can wait for his 5th edition
> which should be out next year).
>
> 73,  Bill  W4ZV
>
>
>
> --
> View this message in context:
> http://n2.nabble.com/Diversity-Receiving-Antennas-tp3331122p33

31589.html
Sent from the [OT] mailing list archive at Nabble.com.
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[Jim Brown-10]

On Sun, 26 Jul 2009 19:24:04 -0700 (PDT), Bill W4ZV wrote:

>The short answer is...the K9AY is better than nothing, occupies little space
>and can be switched in 4 directions...but it's not in the same ballpark as a
>good Beverage.

Yes. K9AY Loops and similar antennas are what you want if you don't have room
for a Beverage. My 550 ft Beverages, designed for 160M and roughly 8 ft off the
ground so that deer don't take them down, work very well all the way up to 20M.
15M hasn't been open enough for me to figure out if they're working up there.
:)

73,

Jim K9YC  





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[Bill W4ZV]

Dave et al,

A diversity RX antenna doesn't need to be complicated.  All you need is something that is somewhat different than your TX antenna.  By "different" I mean:

1. different polarization (e.g. a vertical if you're using a Yagi).
2. different takeoff angle (e.g. a low tribander you're using a high one)
3. different azimuth angle (e.g. a tribander pointed in a different direction)

Your "Beverage" was probably acting like a low horizontally polarized antenna with a high takeoff angle, so it filled several of the above criteria.  If you do use another Yagi, take precautions to limit the RX ANT input when transmitting.

73,  Bill

[Dave Van Wallaghen]

Jim,

Out of curiosity, how many beverages do you have and in what directions? I've seen designs for two wire beverages that are reversible in direction. Would you happen to have any of those?

And yes, 6-8' in height is  what I'm going to need as well for all of my flower and tree eating, four legged friends ;-)

73,
Dave W8FGU
------Original Message------
From: Jim Brown
Sender: [hidden email]
To: Elecraft List
Subject: Re: [Elecraft] [OT]  Diversity Receiving Antennas
Sent: Jul 27, 2009 2:36 AM

On Sun, 26 Jul 2009 19:24:04 -0700 (PDT), Bill W4ZV wrote:

>The short answer is...the K9AY is better than nothing, occupies little space
>and can be switched in 4 directions...but it's not in the same ballpark as a
>good Beverage.

Yes. K9AY Loops and similar antennas are what you want if you don't have room
for a Beverage. My 550 ft Beverages, designed for 160M and roughly 8 ft off the
ground so that deer don't take them down, work very well all the way up to 20M.
15M hasn't been open enough for me to figure out if they're working up there.
:)

73,

Jim K9YC  





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[Dave Van Wallaghen]

Bill,

Yes, I would agree with you. My transmitting doublet runs N and S while my unterminated wire runs E and W with a height difference of almost 30'. So I'm sure it meets the criteria you laid out.

For my more permanent installation I plan to use one of the ICE RF limiters on the Beverage input.

Thanks again for your comments. I'm starting to get a better picture of what I'm going to do.

73,
Dave W8FGU
------Original Message------
From: Bill W4ZV
Sender: [hidden email]
To: [hidden email]
Subject: Re: [Elecraft] [OT]   Diversity Receiving Antennas
Sent: Jul 27, 2009 7:21 AM


Dave et al,

A diversity RX antenna doesn't need to be complicated.  All you need is
something that is somewhat different than your TX antenna.  By "different" I
mean:

1. different polarization (e.g. a vertical if you're using a Yagi).
2. different takeoff angle (e.g. a low tribander you're using a high one)
3. different azimuth angle (e.g. a tribander pointed in a different
direction)

Your "Beverage" was probably acting like a low horizontally polarized
antenna with a high takeoff angle, so it filled several of the above
criteria.  If you do use another Yagi, take precautions to limit the RX ANT
input when transmitting.

73,  Bill
--
View this message in context: http://n2.nabble.com/Diversity-Receiving-Antennas-tp3331122p3333262.html
Sent from the [OT] mailing list archive at Nabble.com.
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