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KD8NNU

diversity receive antennas

What do folks use for diversity receive antennas.

Do you have a dedicated receive antenna or just a different TX antenna
from the antenna farm.

I am looking for ideas on what to do next as I have the big loop and the
dipole.

Right now I have no idea on what I should do next.

Thanks
Don

~73
Don
KD8NNU
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Ron Leech

diversity receive antennas

*You could try a**small _1m_ loop from **Pixel TechnologiesIt has a amp
that shuts off on tx *
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Don Wilhelm-4

Re: diversity receive antennas

In reply to this post by KD8NNU

Don,

You should get a variety of answers - there are some using dedicated
receive antennas, and there are others who are using two transmit
antennas. It depends on what they have available.

It is nice to have one antenna with vertical polarization and another
with horizontal polarization, but two antennas separated by some
distance can work too. Use what you have.

If you only have 2 antennas, I suggest that you connect the subRX to use
the Non-Transmit antenna connected to the KAT3. To use that, you will
need to connect the TMP cable between the KAT3 and the SubRX AUX antenna
input.

73,
Don W3FPR

On 1/8/2012 5:25 PM, [hidden email] wrote:

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Jack Smith-6

Re: diversity receive antennas

The chief driver of diversity gain is antenna separation. The usual
recommendation is 10 wavelengths separation for low correlation fading.
That's impractical for most amateur installations, particularly on the
lower frequency bands where diversity gain may be the most desired.

I've made some measurements using simultaneous capture of signal levels
with two identical spectrum analyzers and two antennas that suggest
around 3 dB diversity gain is achievable with ~0.5 wavelengths
separation, but I'm hesitant to put too much faith in that figure as it
used two rather different antennas - an 80 meter band inverted vee and
one of my Z1501 active antennas. Nonetheless, the data clearly showed
increasing diversity gain with increasing antenna separation measured in
terms of wavelengths over the frequency range 760 KHz - 15 MHz, with
some diversity gain possible with tiny separation - 0.1 wavelength. Not
a lot of gain, but enough to measure after post processing analysis.

Although about 3 dB diversity gain was achieved around 0.5 wavelength
separation, that does not mean a 3 dB improvement at all times. Rather,
that's the mean of the gain probability distribution. A certain
percentage of the time, the gain may be 0 dB and for a certain
percentage of the time it may be 6 or 8 dB or more. The percentage of
time 6 or 8 dB diversity gain is seen with 0.5 wavelength separation is,
of course, small, with smaller gains being more frequent.

Jack K8ZOA

On 1/8/2012 6:48 PM, Don Wilhelm wrote:

> Don,
>
> You should get a variety of answers - there are some using dedicated
> receive antennas, and there are others who are using two transmit
> antennas. It depends on what they have available.
>
> It is nice to have one antenna with vertical polarization and another
> with horizontal polarization, but two antennas separated by some
> distance can work too. Use what you have.
>
> If you only have 2 antennas, I suggest that you connect the subRX to use
> the Non-Transmit antenna connected to the KAT3. To use that, you will
> need to connect the TMP cable between the KAT3 and the SubRX AUX antenna
> input.
>
> 73,
> Don W3FPR
>
> On 1/8/2012 5:25 PM, [hidden email] wrote:
>> What do folks use for diversity receive antennas.
>>
>> Do you have a dedicated receive antenna or just a different TX antenna
>> from the antenna farm.
>>
>> I am looking for ideas on what to do next as I have the big loop and the
>> dipole.
>>
>> Right now I have no idea on what I should do next.
>>
>> Thanks
>> Don
>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

Guy, K2AV

Re: diversity receive antennas

A lot of answers to diversity questions seem to be based on using diversity
to feed electrical devices that combine signals before they are heard.
This was most often done to defeat signal level fading. Some very accurate
technical answers to that are heard based on 100% electronic process.

However, there is a different KIND of diversity, where one signal is fed to
the left ear, without any correction, and the same signal from a different
antenna and identical phase-locked RX is fed to the right ear, without any
correction. This allows the brain to decide what is different between the
two signals, frequently producing a sense of stereophonic aural spatiality.
This latter is far more useful for SSB and CW reception. Frequent
descriptions of this have the incoming sky wave noise spread around the
audio horizon, while the discrete signals come from a single point on the
audio horizon. There are some number of other effects, but always seeming
to make difficult signals easier to copy.

With this latter kind of useful diversity, a NE beverage in one ear and a
NW beverage in the other can produce considerable improvements in weak
signal copy. This is a completely different diversity strategy than
hearing multiple sources to reduce or eliminate fading.

73, Guy.

On Sun, Jan 8, 2012 at 7:14 PM, Jack Smith <
[hidden email]> wrote:

> The chief driver of diversity gain is antenna separation. The usual
> recommendation is 10 wavelengths separation for low correlation fading.
> That's impractical for most amateur installations, particularly on the
> lower frequency bands where diversity gain may be the most desired.
>
> I've made some measurements using simultaneous capture of signal levels
> with two identical spectrum analyzers and two antennas that suggest
> around 3 dB diversity gain is achievable with ~0.5 wavelengths
> separation, but I'm hesitant to put too much faith in that figure as it
> used two rather different antennas - an 80 meter band inverted vee and
> one of my Z1501 active antennas. Nonetheless, the data clearly showed
> increasing diversity gain with increasing antenna separation measured in
> terms of wavelengths over the frequency range 760 KHz - 15 MHz, with
> some diversity gain possible with tiny separation - 0.1 wavelength. Not
> a lot of gain, but enough to measure after post processing analysis.
>
> Although about 3 dB diversity gain was achieved around 0.5 wavelength
> separation, that does not mean a 3 dB improvement at all times. Rather,
> that's the mean of the gain probability distribution. A certain
> percentage of the time, the gain may be 0 dB and for a certain
> percentage of the time it may be 6 or 8 dB or more. The percentage of
> time 6 or 8 dB diversity gain is seen with 0.5 wavelength separation is,
> of course, small, with smaller gains being more frequent.
>
> Jack K8ZOA
>
>
> On 1/8/2012 6:48 PM, Don Wilhelm wrote:
> > Don,
> >
> > You should get a variety of answers - there are some using dedicated
> > receive antennas, and there are others who are using two transmit
> > antennas. It depends on what they have available.
> >
> > It is nice to have one antenna with vertical polarization and another
> > with horizontal polarization, but two antennas separated by some
> > distance can work too. Use what you have.
> >
> > If you only have 2 antennas, I suggest that you connect the subRX to use
> > the Non-Transmit antenna connected to the KAT3. To use that, you will
> > need to connect the TMP cable between the KAT3 and the SubRX AUX antenna
> > input.
> >
> > 73,
> > Don W3FPR
> >
> > On 1/8/2012 5:25 PM, [hidden email] wrote:
> >> What do folks use for diversity receive antennas.
> >>
> >> Do you have a dedicated receive antenna or just a different TX antenna
> >> from the antenna farm.
> >>
> >> I am looking for ideas on what to do next as I have the big loop and the
> >> dipole.
> >>
> >> Right now I have no idea on what I should do next.
> >>
> >> Thanks
> >> Don
> >>
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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Vic Rosenthal

Re: diversity receive antennas

In reply to this post by KD8NNU

I use either a vertical active antenna vs. my dipole on 40 and 80, or a ferrite loop on
160 vs. the vertical transmitting antenna. My idea is to use different polarization so
they will not fade the same way. It seems to work.

I have not found diversity useful on the higher bands where I have a beam because the
signal picked up by the beam is so much stronger than that from the verticals. Of course
if I had a pair of beams separated by a few wavelengths, that would be cool!

On 1/8/2012 2:25 PM, [hidden email] wrote:

--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/

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Arie Kleingeld PA3A-2

Re: diversity receive antennas

In reply to this post by KD8NNU

Don,

I use all antennas available and that make sense.
For example: next CQ160 I will transmit and listen on a vertical and
have a receive 4-square connected to the sub RX.
With macro's I can easily switch to diversity (lsn A-B), main ant (lsn
AA) and 4square (lsn BB).

On a 20m single band effort I used 2 beams that were rotated 90 degrees
apart, listening in diversity only.

(Just for the curious people: I use the antennas of our clubstation
PI4D :-) )

73,
Arie PA3A

Op 8-1-2012 23:25, [hidden email] schreef:
> What do folks use for diversity receive antennas.
>
>
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MontyS

Re: diversity receive antennas

In reply to this post by KD8NNU

Here is another vote for Pixel Technologies active loop. Because its preamp is keyed off when you transmit, its separation from the transmit antenna is less important. Pixel went out of its way to be sure QSK works smoothly. My 80 meter dipole runs within 20 feet of it without problems.

It has very good signal capture and does not require gain settings different from the transmit antenna. It works through 10 meters, but not 6 meters. Mine is on an inexpensive RCA TV rotor with 16 memories. Switching to diversity mode always achieves different receive characteristics, but as many have noted diversity is most useful on weak, fading signals.

Monty K2DLJ

On Jan 8, 2012, at 5:25 PM, [hidden email] wrote:

> What do folks use for diversity receive antennas.
>
> Do you have a dedicated receive antenna or just a different TX antenna
> from the antenna farm.
>
> I am looking for ideas on what to do next as I have the big loop and the
> dipole.
>
> Right now I have no idea on what I should do next.
>
> Thanks
> Don
>
> ~73
> Don
> KD8NNU
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

Barry N1EU

Re: diversity receive antennas

In reply to this post by KD8NNU

goldtr8 wrote

What do folks use for diversity receive antennas.

ANY two antennas delivering reasonable signal strength on the rx band can be quite useful for stereo diversity reception.

I've been using diversity since 2003, on the Orion and the K3 (see http://n1eu.com/K3/diversity.htm )

Even two dipoles at different heights in the same direction can be quite useful - you've got arrival angle diversity. So just experiment - antennas need not be elaborate or widely spaced.

I often use tx antenna plus Beverage on all bands (yes Beverage is often helpful on 15M and occasionally on 10M) and normally use two Beverages on 160M/80M.

Besides any advantage in improving signal readability, the stereo effect that diversity provides is a very enjoyable listening experience.

Barry N1EU

wc1m

Re: diversity receive antennas

I use diversity primarily on 40m in contests. I have the transmit antenna, a
2-el beam at 110', in my left ear and a 4-square on the AUX port in my right
ear. The antennas are separated by about 320 feet.

I couldn't testify as to whether there's any diversity gain, but there's no
question that the setup is extremely effective when there's QSB on the band.
It's also quite helpful when there's noise, like static crashes, that might
be picked up more by one of the antennas than the other. A surprising thing
I've learned is that sometimes signals are louder on the 4-square that I
would have expected. Normally, when I switch back and forth in
non-diversity, the beam is almost always considerably louder. But when
listening in diversity, the 4-square is sometimes as loud as, or louder
than, the beam. That's the magic of arrival angles and one reason why stacks
are great to have!

Both of the antennas have 20-25 dB F/B, so another bonus to this
configuration is that if I hear a station calling from the direction
opposite to where I'm working, I can quickly switching the 4-square to that
direction -- even while transmitting.

But Guy really hit the nail on the head. The most remarkable effect is how
the spatial positioning of signals makes copy much easier, especially in
large pileups where many stations may be close in frequency. The different
signal arrival angles, and the resulting different position in the audio
sound stage, become the distinguishing factor when loudness and pitch are
the same. It doesn't bother me that I might be hearing the station primarily
in one ear because I'm used to operating SO2R.

Of course, I can't use diversity when I'm tuning the second radio, but I use
it primarily for working large pileups when the rate is so high I can't tune
the second radio anyway. When the rate drops, I leave diversity on and
switch to listening to both radios. The run radio is in my left ear and I
hear the beam. So it's no different than when I do SO2R with diversity off.
If a station calls me on the run radio, I just switch back to both ears on
the run radio and I'm in diversity.

I've sometimes used diversity on 80 and 160, using a wire transmit antenna
and a beverage. It's helpful, but nowhere near as effective as it is on 40m.

73, Dick WC1M

-----Original Message-----
From: Barry N1EU [mailto:[hidden email]]
Sent: Monday, January 09, 2012 7:46 AM
To: [hidden email]
Subject: Re: [Elecraft] diversity receive antennas

goldtr8 wrote
>
> What do folks use for diversity receive antennas.
>

ANY two antennas delivering reasonable signal strength on the rx band can be
quite useful for stereo diversity reception.

I've been using diversity since 2003, on the Orion and the K3 (see
http://n1eu.com/K3/diversity.htm )

Even two dipoles at different heights in the same direction can be quite
useful - you've got arrival angle diversity. So just experiment - antennas
need not be elaborate or widely spaced.

I often use tx antenna plus Beverage on all bands (yes Beverage is often
helpful on 15M and occasionally on 10M) and normally use two Beverages on
160M/80M.

Besides any advantage in improving signal readability, the stereo effect
that diversity provides is a very enjoyable listening experience.

Barry N1EU

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