Topband: Delaware DX report

[Jon Zaimes]

The weeks approaching the equinox have brought steady VK/ZL/KH6 openings
before sunrise.

 

This morning we had a pleasant surprise with JH1HDT calling in at 10:30z for
our first JA of the season. A bit later than in many years, but always a
nice benchmark. Signal was skewed a bit, peaking on the 750-foot west
Beverage, with no copy on the NW (direct path) phased pair and nil either on
the SW Beverage. There might have been another JA calling afterward but
couldn't pull out.

 

E6GG was worked at 1045z, just a few minutes before our sunrise.

 

The band conditions were quiet today, with little QRN.

 

73/Jon AA1K

Delaware

www.aa1k.us

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Topband: Thanks to K3LR and DX Engineering! (Was: RE: DX Engineering 4-Square RX Antenna: Element Amplifiers?)

[Jeff Maass K8ND]

Thanks to all who replied with suggestions and information!

Tim Duffy K3LR responded on behalf of DX Engineering, and offered to have
our 4-square amplifiers checked-out and calibrated to match within +/- 0.1
dB. They are also going to look at the DXE-RFS controller to assure that it
is functioning correctly to switch the delay lines and antenna feeds when
commanded. All this at no cost to us, including shipping!

Thanks to Tim and to DX Engineering for this fantastic response!

We've been using the DXE 4-Square RX antenna system at PJ2T since 2006. When
operating on 160 and 80-meters from just 12 degrees North of the Equator,
receiving antennas that work are very important.   The DX Engineering
antenna has been an important resource in some very successful PJ2T CQWW CW
and CQWW 160 CW Contest operations, including four consecutive 1st Worldwide
finishes in the CQWW 160 CW Contest. 

Thanks again, Tim K3LR!

73,  Jeff  K8ND

 

From: Jeff Maass K8ND [mailto:jma...@k8nd.com] 
Sent: Tuesday, September 22, 2015 9:17 PM
To: 'cq-cont...@contesting.com' mailto:cq-cont...@contesting.com> >
Cc: 'Jim Galm (j...@w8wts.com  )' mailto:j...@w8wts.com> >
Subject: DX Engineering 4-Square RX Antenna: Element Amplifiers?

 

In January, Jim W8WTS and I were at PJ2T for CQWW 160 CW, and we both noted
that our DX Engineering 4-square RX antenna did not appear to perform as
well as usual. It is a 98-foot configuration using 102-inch whips.

It is set up "field day style" for contests when we use it (i.e. not set up
permanently), and so we thought that perhaps all the handling over the years
might have caused problems with the feed and delay cables. We had a Array
Solutions AIM-4170C VNA with us, and confirmed that all the cables were
still  in good shape and were of the correct lengths. 

We decided to bring home the four DXE ARAV3 active antenna amplifiers to
diagnose at home (we left the four whips on Curacao!). W8WTS has an Array
Solutions VNA-2180 2-port device, and captured curves for inputs and
outputs. His analysis is shown below. Screen captures of the resulting
curves are in an archive at:
http://www.k8nd.com/Radio/PJ2T_DXE_4-Square_amps_ photos.zip
 .

 

"Each amp has a port a sweep and a port b sweep.  There is also a reference
pair of sweeps with the amplifier jumpered out of the circuit, to verify
that the ports are calibrated correctly.  The port a sweep shows the
impedance looking into the antenna port.  We want the input impedance to be
extremely high; higher is better.  There is a peak in the Z because of the
parallel LC filter on the input of the AVA-2 that rejects out of band
signals.  You can see that they are all set correctly to peak on 1.8 Mhz.  

 

"The port b sweep shows the magnitude and angle of S21.  S21 is the forward
voltage gain of the amplifier.  We want the forward voltage gain to be
exactly 1, which is shown on the graphs as 0 dB.  The four amplifiers have
different gains at 1.8 MHz, but they are very close.  The lowest is amp 1 at
1.2 dB and the highest is amp 4 at 1.4 dB.  A gain difference of 0.2 dB is
very small, but it might make a difference. "

 

They appear to be working OK, but what we don't know is: 

  QUERY: How much of a gain discrepancy is tolerable in the element
amplifiers in a DXE four square?

73,  Jeff  K8ND

 

 

 

 

 

 

 

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Topband: K1FK to JA Via 160-Meter Long Path

[Dave Bowker via Topband]

Carl, K9LA, has posted an interesting analysis of a skewed path TopBand QSO in 
the August 15 'Monthly Feature' on his site.
http://k9la.us/Aug15_K1FK_to_JA_on_160m_via_Long_Path.pdf

Dave, K1FKFort Kent, ME
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Re: Topband: Thanks to K3LR and DX Engineering! (Was: RE: DX Engineering 4-Square RX Antenna: Element Amplifiers?)

[john]

yes,, says a lot,, a whole lot for dx engineering73 john

On 9/24/2015 4:58 PM, Jeff Maass K8ND wrote:

Thanks to all who replied with suggestions and information!

Tim Duffy K3LR responded on behalf of DX Engineering, and offered to have
our 4-square amplifiers checked-out and calibrated to match within +/- 0.1
dB. They are also going to look at the DXE-RFS controller to assure that it
is functioning correctly to switch the delay lines and antenna feeds when
commanded. All this at no cost to us, including shipping!

Thanks to Tim and to DX Engineering for this fantastic response!

We've been using the DXE 4-Square RX antenna system at PJ2T since 2006. When
operating on 160 and 80-meters from just 12 degrees North of the Equator,
receiving antennas that work are very important.   The DX Engineering
antenna has been an important resource in some very successful PJ2T CQWW CW
and CQWW 160 CW Contest operations, including four consecutive 1st Worldwide
finishes in the CQWW 160 CW Contest.

Thanks again, Tim K3LR!

73,  Jeff  K8ND

  


From: Jeff Maass K8ND [mailto:jma...@k8nd.com]
Sent: Tuesday, September 22, 2015 9:17 PM
To: 'cq-cont...@contesting.com' mailto:cq-cont...@contesting.com> >
Cc: 'Jim Galm (j...@w8wts.com  )' mailto:j...@w8wts.com> >
Subject: DX Engineering 4-Square RX Antenna: Element Amplifiers?

  


In January, Jim W8WTS and I were at PJ2T for CQWW 160 CW, and we both noted
that our DX Engineering 4-square RX antenna did not appear to perform as
well as usual. It is a 98-foot configuration using 102-inch whips.

It is set up "field day style" for contests when we use it (i.e. not set up
permanently), and so we thought that perhaps all the handling over the years
might have caused problems with the feed and delay cables. We had a Array
Solutions AIM-4170C VNA with us, and confirmed that all the cables were
still  in good shape and were of the correct lengths.

We decided to bring home the four DXE ARAV3 active antenna amplifiers to
diagnose at home (we left the four whips on Curacao!). W8WTS has an Array
Solutions VNA-2180 2-port device, and captured curves for inputs and
outputs. His analysis is shown below. Screen captures of the resulting
curves are in an archive at:
http://www.k8nd.com/Radio/PJ2T_DXE_4-Square_amps_ photos.zip
 .

  


"Each amp has a port a sweep and a port b sweep.  There is also a reference
pair of sweeps with the amplifier jumpered out of the circuit, to verify
that the ports are calibrated correctly.  The port a sweep shows the
impedance looking into the antenna port.  We want the input impedance to be
extremely high; higher is better.  There is a peak in the Z because of the
parallel LC filter on the input of the AVA-2 that rejects out of band
signals.  You can see that they are all set correctly to peak on 1.8 Mhz.

  


"The port b sweep shows the magnitude and angle of S21.  S21 is the forward
voltage gain of the amplifier.  We want the forward voltage gain to be
exactly 1, which is shown on the graphs as 0 dB.  The four amplifiers have
different gains at 1.8 MHz, but they are very close.  The lowest is amp 1 at
1.2 dB and the highest is amp 4 at 1.4 dB.  A gain difference of 0.2 dB is
very small, but it might make a difference. "

  


They appear to be working OK, but what we don't know is:

   QUERY: How much of a gain discrepancy is tolerable in the element
amplifiers in a DXE four square?

73,  Jeff  K8ND

  

  

  

  

  

  

  


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Re: Topband: K1FK to JA Via 160-Meter Long Path

[k1zm--- via Topband]

Hi guys


You have both surfaced a topic that is of great personal interest to me as I 
have worked JA on 160m around 2100z both from K1ZM on Cape Cod and from VY2ZM 
on PEI many many times.
 
The conventional wisdom is that signals propagate SE over Africa and VK6 on 
Topband at 2100z but I no longer believe this to be cast in concrete.
 
Why?
 
I have had many many contacts with JH7PFD starting as early as 2024z from PEI 
and Kin san has many beverages from which to select.  Among them are ones that 
look at 220 degrees and some that look over the North pole on either side.
 
Carl suggests here in his posting that the JA's listen at 220 degrees for NA at 
this time - but time and time again Kin-San has reported that my160m  signal is 
inaudible from the SW near his SR - instead he hears me from the NE which is 
short path.

On my side. I can aim my 160M antenna such that it is firing due North with 
6.0db of directional gain and I too hear Kin san and JA8ISU at this time from 
this heading - and not out of the SE path.

Now how can this be true? Well, if one takes a look at the plot that Carl has 
included in his article, you can see the RED short path to which he refers is 
also in darkness at 2100z - and my postulation and Kin-san's is that the true 
path by which we are communicating is over North pole and not over VK6 at all.

This observation has been reported by some other JA observants as well.

I should note, though, that from NY, Cape Cod and from PEI on 80m the 80m path 
is indeed SE and SW at 2100z  but not on Topband which has always puzzled me.

What makes this so had to fathom is that the window of opportunity to do this 
occurs each Winter season from roughly 05 Dec to 15 January typically each year 
and that so few of us have truly directive Xmit and Rx antennas on Topband with 
which to make really precise observations.

Bottom Line for me?

This160m path is over the North and not over Vk6 on Topband and having worked 
HUNDREDS of JA's on 160m at 2100z from VY2ZM - I do believe my own ears and 
equipment.- despite what I had always previously thought.

By the way - this path has (to my knowledge) only been worked from Eastern 
Canada, Maine, Mass and in Connecticut (by K1KI on the Mass/Conn line).  I know 
it has been heard (not worked) from RI on 160m by John W1XX - but no qso's that 
I am aware of have ever been made further South of New England on Topband.  The 
overlapping darkness that is needed to sustain propagation just does not make 
it down to even W2 usually on Topband.

Hope this adds something to the mix.

73 JEFF   K1ZM/VY2ZM

 


 
 
-Original Message-
From: Dave Bowker via Topband 
To: topband 
Sent: Thu, Sep 24, 2015 4:03 pm
Subject: Topband: K1FK to JA Via 160-Meter Long Path


Carl, K9LA, has posted an interesting analysis of a skewed path TopBand QSO in
the August 15 'Monthly Feature' on his
site.
http://k9la.us/Aug15_K1FK_to_JA_on_160m_via_Long_Path.pdf

Dave,
K1FKFort Kent, ME
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Re: Topband: K1FK to JA Via 160-Meter Long Path

[John Kaufmann]

I just wanted to add another data point to this subject.   I have heard LP
JA's on 160 on several occasions from my location in FN42 (eastern MA),
anywhere from 2120Z to 2200Z in December and January, going back to 1994 or
thereabouts.  I was never able to work any because they were working Europe
and it was not possible for me to break through the Europeans.  

I would estimate that I have heard about 10 different JA stations on LP.
With one exception, they were all from the SE direction, received on a  150m
long Beverage aimed at 140 degrees.  The one exception was one time when I
heard JA1JRK and another JA (I forget the call) peaking from the NE
direction after my sunset.  However, I have not heard any LP JA on 160 in
over 10 years. 

W1 to JA via LP is indeed a very difficult path on 160.  It occurs only very
rarely here and the openings are very short.  Also, as noted, we have to
compete with Europe, which has an opening to JA at the same time.

73, John W1FV

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