Topband: Hardening the 8 Circle Receiving Array

[Mark Robinson]

I  have the DX Engineering 8 circle receiving array sized for 80/160m . 
It has been a fantastic performer but I have suffered damage to the 
active antenna amplifiers on two separate occasions due to nearby 
lightning strikes.


I am looking at a way to protect these amplifiers.  I was wondering if I 
can add a pair or  dual series pair (4 diodes in total) of back to back 
diodes - say 1N3600,  across the input to ground terminals on each 
amplifier.  Will this affect the performance of the array in any way ?


73 Mark N1UK


_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Ground for K9AY Loop

[Peter Bertini]

I had a similar issue with my K9AY loop.  It was very non directive, even
with a short ground rod.  I added four ground
radials laid under the loops to the apex points where they met
the ground anchors.  That fixed the problem. I also added
four of those cheap TV ground rods at each corner and
tied the ends of the each radial to a rod.  Directivity is
superb now.
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Circle arrays

[w5zn]

Greetings Jacques!

As you know I have several years experience with vertical arrays here at 
W5ZN using all three of the current popular versions on 160, the BSEF-8, 
HiZ-8 and the YCCC-9. They all work well and all have their own unique 
characteristics. Having been to your QTH I know you have a great 
location so the first question anyone must ask when contemplating a 
vertical array is how much room can I allocate to the array. That 
question is obvious because the BSEF 8 vertical array requires a 350 ft 
diameter circle, the Hiz-8 160 needs 200 ft and the YCCC-9 needs about 
120-140 ft. For the last two "active" arrays you will also need to 
consider any adjacent objects that could interfere. The BSEF passive 
array can sit in the woods or partially in a wooded area without any, or 
very little impact.


If you have a 180 ft diameter area available I would try to squeeze out 
another 20 ft or so and go with a HiZ-8 160. The performance will be 
exceptional.


I wrote a paper a couple of years ago comparing the BSEF-8 and the HiZ-8 
on 160 meters. I had just installed the YCCC-9 and just mentioned it as 
I only had a couple of month of data from it to compare. I really need 
to update that paper as I have two more years of comparison data now, 
Lee has made some nice improvements to the HiZ system and I also did 
some additional component tweaking on the BSEF array. I need to get that 
updated this winter.


GL with the project Dave.

73 Joel W5ZN
Your Margarita buddy  :-))

On 2019-10-14 08:34, David Olean wrote:

I am pondering an eight circle array.  At present my only ham band
that I am QRV on is 160 meters. A few years ago I had 28 thru 24 GHz
all percolating, but the maintenance was killing me. i was a slave to
the station. Now I am having fun! Rather than tweaking with noise
figure meters and VNAs, I now do all my work with wrenches and
chainsaw.

There are several choices for 8 circle arrays.  My question is how
much benefit would I get from the single band version as opposed to a
dual or three band choice?  Reading the hype is always fraught with
danger.  Practical experience is always better.  My thinking is that
if there is a distinct advantage, I would go with a 160 only setup and
forego the other bands.  I can carve out a 200 ft circle with a little
chainsaw action. I have about 180 ft of field available now, so can
get the room with not too much trouble.

I also better hook up my 160 transceiver quick. It is still packed
away from Field Day!!

Comments?


Dave K1WHS

_
Searchable Archives: http://www.contesting.com/_topband - Topband 
Reflector

_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Shunt feed question

[Wes]

Because you're using a shunt capacitor.  This in conjunction with the inductive 
reactance forms an L-network.  As I said before, you need a series capacitor. 
Move the tap to get 50 +jX and then add -jX.


Wes  N7WS


On 10/15/2019 1:30 PM, Marty Ray wrote:

Thanks for the response Herb. I can obtain a good match using the 65 ft tap 
point, but my question is why my analyzer is measuring a change in the 
feedpoint resistance (real component of R + jX).

Regards,
Marty


On Oct 15, 2019, at 3:19 PM, Herbert Schoenbohm  
wrote:

Best to use a 3 or 4 wire cage feed and you will find the match easier.  You 
should tap the tower at 50 feet and work down till you find the sweet spot.  A 
500 to 750 vac variable will take care of any measure inductive component.

Herb, KV4FZ


On Tue, Oct 15, 2019 at 3:10 PM Marty Ray  wrote:
I am shunt feeding a 70 ft Trylon tower with a Tennadyne T12.10-30HD LPDA at 70 
ft and a full size 40m rotatable dipole at 79 ft, (the top of the mast is ~85 
ft). Both antennas have relays that electrically bond them to the tower when 
the shunt feed is in use.

I have tried two shunt tap points, one at 65 feet and another at 45 feet. Using 
a Rig Expert AA-55 Zoom, the Rs measured a little over 100 ohms on the 65 foot 
version and 49 ohms on the 45 foot version. In both cases, adding the shunt 
capacitor caused Rs to drop by approximately 50 percent, (to around 60 ohms and 
23 ohms respectively).

I expected Rs to not change much, if any. I tried a vacuum variable, an air 
variable and a silver mica. Same result.

Has anyone seen this happen before?

Regards,
Marty N9SE
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector



_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Circle arrays

[W0MU Mike Fatchett]

I think there is a lot to be lost when you go down to a 100 ft radius, 
which is what DXE calls for when you want 160/80/40,  from what it 
should be on 160.  Many people do not have the real estate either.


On 10/16/2019 10:30 AM, David Olean wrote:

TNX Mike

That is the crux of the situation.  I am not so interested in other 
bands but was wondering how much I would lose on 160 with a multi band 
design.  I don't want to lose much at all!


My brother who is a ham thinks I am crazy to even contemplate a circle 
array.  My goal is to use the circle array as a diversity antenna with 
my beverages used on the other receive channel.  I believe it will be 
a good choice. He thinks my beverages are just fine, but I believe 
that a diversity setup will be a big jump in performance.  I sure hope 
I am right!! It is a lot of work.


Dave K1WHS

On 10/15/2019 6:51 PM, W0MU Mike Fatchett wrote:
If your joy is 160 then go with the array that will maximize the 
results. Multiband arrays are going to be compromise and degrade your 
160 performance.  You need to determine what is more important.  You 
still might be able to use a 160 array on the other bands but not 
optimally.


W0MU

On 10/14/2019 8:34 AM, David Olean wrote:
I am pondering an eight circle array. At present my only ham band 
that I am QRV on is 160 meters. A few years ago I had 28 thru 24 GHz 
all percolating, but the maintenance was killing me. i was a slave 
to the station. Now I am having fun! Rather than tweaking with noise 
figure meters and VNAs, I now do all my work with wrenches and 
chainsaw.


There are several choices for 8 circle arrays.  My question is how 
much benefit would I get from the single band version as opposed to 
a dual or three band choice?  Reading the hype is always fraught 
with danger.  Practical experience is always better.  My thinking is 
that if there is a distinct advantage, I would go with a 160 only 
setup and forego the other bands. I can carve out a 200 ft circle 
with a little chainsaw action. I have about 180 ft of field 
available now, so can get the room with not too much trouble.


I also better hook up my 160 transceiver quick. It is still packed 
away from Field Day!!


Comments?


Dave K1WHS

_
Searchable Archives: http://www.contesting.com/_topband - Topband 
Reflector


_
Searchable Archives: http://www.contesting.com/_topband - Topband 
Reflector


_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Shunt feed question

[Lee STRAHAN]

  Marty,
  You may be seeing errors in your readings due to broadcast pickup. This is 
common when modern R+Jx measurement tools are connected to large antenna 
structures. Others have described ways around this problem before here on the 
topband chat.
Lee  K7TJR  OR


Thanks for the response Herb. I can obtain a good match using the 65 ft tap 
point, but my question is why my analyzer is measuring a change in the 
feedpoint resistance (real component of R + jX). 

Regards,
Marty

> 
> Best to use a 3 or 4 wire cage feed and you will find the match easier.  You 
> should tap the tower at 50 feet and work down till you find the sweet spot.  
> A 500 to 750 vac variable will take care of any measure inductive component.
> 
> Herb, KV4FZ
> 
>> On Tue, Oct 15, 2019 at 3:10 PM Marty Ray  wrote:
>> I am shunt feeding a 70 ft Trylon tower with a Tennadyne T12.10-30HD LPDA at 
>> 70 ft and a full size 40m rotatable dipole at 79 ft, (the top of the mast is 
>> ~85 ft). Both antennas have relays that electrically bond them to the tower 
>> when the shunt feed is in use. 
>> 
>> I have tried two shunt tap points, one at 65 feet and another at 45 feet. 
>> Using a Rig Expert AA-55 Zoom, the Rs measured a little over 100 ohms on the 
>> 65 foot version and 49 ohms on the 45 foot version. In both cases, adding 
>> the shunt capacitor caused Rs to drop by approximately 50 percent, (to 
>> around 60 ohms and 23 ohms respectively).
>> 
>> I expected Rs to not change much, if any. I tried a vacuum variable, an air 
>> variable and a silver mica. Same result. 
>> 
>> Has anyone seen this happen before?
>> 
>> Regards,
>> Marty N9SE

_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Shunt feed question

[Joe Subich, W4TV]

On 2019-10-15 4:30 PM, Marty Ray wrote:
I can obtain a good match using the 65 ft tap point, but my question 

> is why my analyzer is measuring a change in the feedpoint resistance
> (real component of R + jX).

Because the *shunt* capacitor creates an L network with the impedance
(R +/- jX) at the bottom of the gamma arm.  Mathematically you are doing
a series to parallel conversion.  For normal gamma operations where the
tap point can be set to achieve close to a 50 Ohm 'real' impedance one
wants the single capacitor *in series* with the gamma arm to "tune out"
the residual (typically) series inductance (+jX).

The alternative is an *OMEGA* match (two capacitors - one shunt from the
gamma arm to ground then another in series with the center conductor of
the coax to the junction of the gamma rod/shunt capacitor).  The omega
match is generally used with an antenna too short that has a high real
"R" at the end of the gamma rod - the shunt capacitor transforms the R
down to 50 Ohms and the series capacitor (or inductor in some cases) 
tunes out the residual X.


73,

   ... Joe, W4TV


On 2019-10-15 4:30 PM, Marty Ray wrote:

Thanks for the response Herb. I can obtain a good match using the 65 ft tap 
point, but my question is why my analyzer is measuring a change in the 
feedpoint resistance (real component of R + jX).

Regards,
Marty


On Oct 15, 2019, at 3:19 PM, Herbert Schoenbohm  
wrote:

Best to use a 3 or 4 wire cage feed and you will find the match easier.  You 
should tap the tower at 50 feet and work down till you find the sweet spot.  A 
500 to 750 vac variable will take care of any measure inductive component.

Herb, KV4FZ


On Tue, Oct 15, 2019 at 3:10 PM Marty Ray  wrote:
I am shunt feeding a 70 ft Trylon tower with a Tennadyne T12.10-30HD LPDA at 70 
ft and a full size 40m rotatable dipole at 79 ft, (the top of the mast is ~85 
ft). Both antennas have relays that electrically bond them to the tower when 
the shunt feed is in use.

I have tried two shunt tap points, one at 65 feet and another at 45 feet. Using 
a Rig Expert AA-55 Zoom, the Rs measured a little over 100 ohms on the 65 foot 
version and 49 ohms on the 45 foot version. In both cases, adding the shunt 
capacitor caused Rs to drop by approximately 50 percent, (to around 60 ohms and 
23 ohms respectively).

I expected Rs to not change much, if any. I tried a vacuum variable, an air 
variable and a silver mica. Same result.

Has anyone seen this happen before?

Regards,
Marty N9SE



_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Topband: Ground for K9AY Loop

[K9AY]

Pete,

There are lots of references for driving ground rods -- e.g. starting a hole 
with a shovel and filling with water (as lubricant). For best performance, 
numerous users have found that 4 radials extending beyond the footprint of the 
loop keep things stable as weather changes. Put them directly under the loop 
wires. 

FYI, all of my personal loops have worked fine with just a 4-foot ground rod. 
The only special thing is that I bury the feedline and control wires to 
minimize common-mode.

73, Gary
K9AY

---
de N4ZR...

The loop is finished, but I'm having a devil of a time getting a ground 
rod in at the base.? It's been over a month since the last rain here, 
and the soil is really hard.? Seems like I read someplace that you could 
substitute a couple of 50-foot on the ground radials for a ground rod if 
necessary.? True?

PS even without the ground, or the feedline chokes, directivity seems 
pretty good on high AM BC stations.

Any advice much appreciated

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Shunt feed question

[N4ZR]

FWIW, I had a shunt feed on my 97-foot Rohn 25 with stacked tribanders 
and a shorty forty on it. I spent a long time trying to find a 50-ohm 
tap point on the tower and was never successful, so I changed to an 
Omega match, which was very easy to adjust once the local broadcast 
station on 1550 KHz switched to night-time power (6 watts!) and stopped 
scrambling my antenna analyzer.


73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

On 10/15/2019 3:19 PM, Herbert Schoenbohm wrote:

Best to use a 3 or 4 wire cage feed and you will find the match easier.
You should tap the tower at 50 feet and work down till you find the sweet
spot.  A 500 to 750 vac variable will take care of any measure inductive
component.

Herb, KV4FZ

On Tue, Oct 15, 2019 at 3:10 PM Marty Ray  wrote:


I am shunt feeding a 70 ft Trylon tower with a Tennadyne T12.10-30HD LPDA
at 70 ft and a full size 40m rotatable dipole at 79 ft, (the top of the
mast is ~85 ft). Both antennas have relays that electrically bond them to
the tower when the shunt feed is in use.

I have tried two shunt tap points, one at 65 feet and another at 45 feet.
Using a Rig Expert AA-55 Zoom, the Rs measured a little over 100 ohms on
the 65 foot version and 49 ohms on the 45 foot version. In both cases,
adding the shunt capacitor caused Rs to drop by approximately 50 percent,
(to around 60 ohms and 23 ohms respectively).

I expected Rs to not change much, if any. I tried a vacuum variable, an
air variable and a silver mica. Same result.

Has anyone seen this happen before?

Regards,
Marty N9SE
_
Searchable Archives: http://www.contesting.com/_topband - Topband
Reflector


_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector


_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Circle arrays

[David Olean]

TNX Mike

That is the crux of the situation.  I am not so interested in other 
bands but was wondering how much I would lose on 160 with a multi band 
design.  I don't want to lose much at all!


My brother who is a ham thinks I am crazy to even contemplate a circle 
array.  My goal is to use the circle array as a diversity antenna with 
my beverages used on the other receive channel.  I believe it will be a 
good choice. He thinks my beverages are just fine, but I believe that a 
diversity setup will be a big jump in performance.  I sure hope I am 
right!! It is a lot of work.


Dave K1WHS

On 10/15/2019 6:51 PM, W0MU Mike Fatchett wrote:
If your joy is 160 then go with the array that will maximize the 
results. Multiband arrays are going to be compromise and degrade your 
160 performance.  You need to determine what is more important.  You 
still might be able to use a 160 array on the other bands but not 
optimally.


W0MU

On 10/14/2019 8:34 AM, David Olean wrote:
I am pondering an eight circle array.  At present my only ham band 
that I am QRV on is 160 meters. A few years ago I had 28 thru 24 GHz 
all percolating, but the maintenance was killing me. i was a slave to 
the station. Now I am having fun! Rather than tweaking with noise 
figure meters and VNAs, I now do all my work with wrenches and chainsaw.


There are several choices for 8 circle arrays.  My question is how 
much benefit would I get from the single band version as opposed to a 
dual or three band choice?  Reading the hype is always fraught with 
danger.  Practical experience is always better.  My thinking is that 
if there is a distinct advantage, I would go with a 160 only setup 
and forego the other bands.  I can carve out a 200 ft circle with a 
little chainsaw action. I have about 180 ft of field available now, 
so can get the room with not too much trouble.


I also better hook up my 160 transceiver quick. It is still packed 
away from Field Day!!


Comments?


Dave K1WHS

_
Searchable Archives: http://www.contesting.com/_topband - Topband 
Reflector


_
Searchable Archives: http://www.contesting.com/_topband - Topband 
Reflector

_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Shunt feed question

[Gene Smar via Topband]

Marty:

 Did you mean it literally when you wrote you added the shunt capacitor,
that is, did you put the cap from the shunt wire/coax center conductor
junction to ground?  The cap in a "shunt-feed" arrangement goes in series
between the coax center conductor and the shunt wire up the side of the
tower.  Its purpose is to cancel the series inductive reactance of the shunt
wire, just like in a gamma match.

 Maybe a bit more detail of the feed arrangement would help us help you
trouble-shoot.  Good luck.


73 de
Gene Smar  AD3F


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Marty Ray
Sent: Monday, October 14, 2019 7:45 PM
To: topband@contesting.com
Subject: Topband: Shunt feed question

I am shunt feeding a 70 ft Trylon tower with a Tennadyne T12.10-30HD LPDA at
70 ft and a full size 40m rotatable dipole at 79 ft, (the top of the mast is
~85 ft). Both antennas have relays that electrically bond them to the tower
when the shunt feed is in use. 

I have tried two shunt tap points, one at 65 feet and another at 45 feet.
Using a Rig Expert AA-55 Zoom, the Rs measured a little over 100 ohms on the
65 foot version and 49 ohms on the 45 foot version. In both cases, adding
the shunt capacitor caused Rs to drop by approximately 50 percent, (to
around 60 ohms and 23 ohms respectively).

I expected Rs to not change much, if any. I tried a vacuum variable, an air
variable and a silver mica. Same result. 

Has anyone seen this happen before?

Regards,
Marty N9SE
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Topband: BevFlex-4X - RX antenna

[Tim Duffy]

Thinking about the Fall Stew coming up this Saturday, I will be trying out
the BevFlex-4X that W9XT is now manufacturing.

 

Here is the flyer:

 

https://static.dxengineering.com/global/images/technicalarticles/ums-bevflex
-4x.pdf

 

And the BevFlex-4X details:

 
https://www.dxengineering.com/parts/ums-bevflex-4x

 

73

Tim K3LR

 

 

_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector