Re: Topband: Relationship Between Ground Wave and Low-Angle Radiation

[N4ZR]

Hank - any RBN node-op can make his output available at a local user 
telnet port.  That's a built-in feature of the RBN Aggregator, thanks to 
W3OA.


73, Pete N4ZR
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On 9/13/2019 5:06 PM, HP wrote:

Arrgghhh - maybe you have a deal with W3LPL -to give you his RX output - this 
wont work otherwise because of the delay for next RBN output - - but maybe you 
have someone around to give you a CW signal to use and read out levels yourself 
.

Hank


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Re: Topband: YCCC 9 Circle preamp failure

[VE6WZ Steve]

Paul is absolutely correct.
The op-amp is a configured as non-inverting.

I incorrectly “assumed” it was wired to invert simply because all of the 
pre-amps show the same 180 phase shift.

Steve






From Babcocks iPhone

> On Sep 13, 2019, at 1:56 PM, Paul Christensen  wrote:
> 
> Steve,
> 
> I recently ran into an identical problem with an Alpha 89 amplifier. A pair 
> of 0.01 uF/100V caps had failed on the plate choke clapper arm relay. The 
> caps are used on the relay coil as an RF bypass to ground. In time, RF caused 
> the caps to become leaky.  With 1KW RF applied on some bands, the clapper 
> relay would open and close by itself. The caps are now replaced with leaded 
> MLCC types rated for 1KV.
> 
> BTW, the op-amp circuit in your video is non-inverting, not inverting. If an 
> inversion is taking place, it's occurring due to the winding direction of the 
> 1:1 transformer's secondary with respect to the primary.
> 
> Paul, W9AC 
> 
> 
> 
> -Original Message-
> From: Topband  On Behalf Of VE6WZ_Steve
> Sent: Friday, September 13, 2019 2:55 PM
> To: topband 
> Subject: Topband: YCCC 9 Circle preamp failure
> 
> After 2.5 years of flawless operation, earlier this summer my YCCC 9 circle 
> rx array started to develop some strange inter-mod noise, and random junk 
> showed up on 160m when using the array.
> 
> I isolated the problem to be the .1 uF coupling capacitors on the input of 
> the amps. This happened on 4 of the 9 amplifiers.
> The most likely cause is from TX overload because this array is only about 
> 125’ from my parasitic TX array. (the TX antenna is detuned when on RX and 
> presents no issue on receive).
> At first I suspected a nearby lightning strike, but the 4 failed amps happen 
> to be the closest to the TX array, nothing else in the amp was damaged, and 
> there was no other evidence of a lightning event at the station.
> 
> Here is a link to a YouTube video I made showing how I isolated the problem. 
> Using my scope I show how the output from the damaged amp has significant 
> phase and amplitude distortion, and using the multimeter the failed caps are 
> evaluated.
> 
> https://youtu.be/t6oux3MStDw 
> 
> If you have one of these arrays, I show how it is very easy to test the 
> pre-amps in the field using your multi-meter to confirm if a similar fate has 
> occurred in your system.
> 
> 73, de steve ve6w
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
> 
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Re: Topband: Relationship Between Ground Wave and Low-Angle Radiation

[HP]

Arrgghhh - maybe you have a deal with W3LPL -to give you his RX output - this 
wont work otherwise because of the delay for next RBN output - - but maybe you 
have someone around to give you a CW signal to use and read out levels yourself 
. 

Hank 


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Re: Topband: YCCC 9 Circle preamp failure

[lloydberg]

I'm running the YCCC RX array. I had to add 100K carbon resistors
between the input terminal and ground as a static drain or the input
caps would puncture and burn out the Integrated Circuit.
73
Lloyd - N9LB 

-From: "VE6WZ_Steve" 
To: "topband"
Cc: 
Sent: Friday September 13 2019 2:10:48PM
Subject: Topband: YCCC 9 Circle preamp failure

 After 2.5 years of flawless operation, earlier this summer my YCCC 9
circle rx array started to develop some strange inter-mod noise, and
random junk showed up on 160m when using the array.

 I isolated the problem to be the .1 uF coupling capacitors on the
input of the amps. This happened on 4 of the 9 amplifiers.
 The most likely cause is from TX overload because this array is only
about 125’ from my parasitic TX array. (the TX antenna is detuned
when on RX and presents no issue on receive).
 At first I suspected a nearby lightning strike, but the 4 failed amps
happen to be the closest to the TX array, nothing else in the amp was
damaged, and there was no other evidence of a lightning event at the
station.

 Here is a link to a YouTube video I made showing how I isolated the
problem. Using my scope I show how the output from the damaged amp has
significant phase and amplitude distortion, and using the multimeter
the failed caps are evaluated.

 https://youtu.be/t6oux3MStDw [1] 

Links:
--
[1] https://youtu.be/t6oux3MStDw
[2] https://youtu.be/t6oux3MStDw>
https://youtu.be/t6oux3MStDw;
 / 
 If you have one of these arrays, I show how it is very easy to test
the pre-amps in the field using your multi-meter to confirm if a
similar fate has occurred in your system.
 
 73, de steve ve6w
 _
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Re: Topband: Relationship Between Ground Wave and Low-Angle Radiation

[HP]

Now that I think about it a bit -- I wonder if you put up a small vertical off 
to the side toward the W3LPL RBN and fed some power into it 
as a reference signal then fed the tower with that little vertical open and fix 
up switching so you could switch between the two several 
times for each reading and get a repeatable delta - then add radials and look 
at the new deltas if this trial worked out ?? 

Closest RBN I have on160 is KO7SS down on Mt Lemon in Tuscon (107 miles) and I 
have never been able to tell anything because of qsb over such short periods of 
time - takes me about 5 min to change the two configurations I want to compare. 

Hank K7HP 

- On Sep 13, 2019, at 6:31 AM, N4ZR  wrote: 

| I don't think I've ever read anything on this topic. Basically, what
| I'm asking is, could ground wave to a fairly nearby Skimmer be used as
| an analogue to low-angle radiation to assess the effectiveness of radial
| systems on an inverted L? W3LPL is about 30 miles from me and has a
| very capable Skimmer Server-based RBN node.

| --

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

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| Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
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Re: Topband: YCCC 9 Circle preamp failure

[Paul Christensen]

Steve,

I recently ran into an identical problem with an Alpha 89 amplifier.  A pair of 
0.01 uF/100V caps had failed on the plate choke clapper arm relay.  The caps 
are used on the relay coil as an RF bypass to ground.  In time, RF caused the 
caps to become leaky.  With 1KW RF applied on some bands, the clapper relay 
would open and close by itself.  The caps are now replaced with leaded MLCC 
types rated for 1KV.

BTW, the op-amp circuit in your video is non-inverting, not inverting.  If an 
inversion is taking place, it's occurring due to the winding direction of the 
1:1 transformer's secondary with respect to the primary.

Paul, W9AC 



-Original Message-
From: Topband  On Behalf Of VE6WZ_Steve
Sent: Friday, September 13, 2019 2:55 PM
To: topband 
Subject: Topband: YCCC 9 Circle preamp failure

After 2.5 years of flawless operation, earlier this summer my YCCC 9 circle rx 
array started to develop some strange inter-mod noise, and random junk showed 
up on 160m when using the array.

I isolated the problem to be the .1 uF coupling capacitors on the input of the 
amps.  This happened on 4 of the 9 amplifiers.
The most likely cause is from TX overload because this array is only about 125’ 
from my parasitic TX array.  (the TX antenna is detuned when on RX and presents 
no issue on receive).
At first I suspected a nearby lightning strike, but the 4 failed amps happen to 
be the closest to the TX array, nothing else in the amp was damaged, and there 
was no other evidence of a lightning event at the station.

Here is a link to a YouTube video I made showing how I isolated the problem.  
Using my scope I show how the output from the damaged amp has significant phase 
and amplitude distortion, and using the multimeter the failed caps are 
evaluated.

https://youtu.be/t6oux3MStDw 

If you have one of these arrays, I show how it is very easy to test the 
pre-amps in the field using your multi-meter to confirm if a similar fate has 
occurred in your system.

73, de steve ve6w
_
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Topband: YCCC 9 Circle preamp failure

[VE6WZ_Steve]

After 2.5 years of flawless operation, earlier this summer my YCCC 9 circle rx 
array started to develop some strange inter-mod noise, and random junk showed 
up on 160m when using the array.

I isolated the problem to be the .1 uF coupling capacitors on the input of the 
amps.  This happened on 4 of the 9 amplifiers.
The most likely cause is from TX overload because this array is only about 125’ 
from my parasitic TX array.  (the TX antenna is detuned when on RX and presents 
no issue on receive).
At first I suspected a nearby lightning strike, but the 4 failed amps happen to 
be the closest to the TX array, nothing else in the amp was damaged, and there 
was no other evidence of a lightning event at the station.

Here is a link to a YouTube video I made showing how I isolated the problem.  
Using my scope I show how the output from the damaged amp has significant phase 
and amplitude distortion, and using the multimeter the failed caps are 
evaluated.

https://youtu.be/t6oux3MStDw 

If you have one of these arrays, I show how it is very easy to test the 
pre-amps in the field using your multi-meter to confirm if a similar fate has 
occurred in your system.

73, de steve ve6w
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Relationship Between Ground Wave and Low-Angle Radiation

[N4ZR]

Rick, I misled you with the reference to low-angle radiation. I'm 
broadly aware of how ground conductivity in the Fresnel zone works.  
What I'm interested in doing is characterizing how much my signal 
improves as I add radials - sort of like a distant field-strength meter.


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 9/13/2019 12:39 PM, Richard (Rick) Karlquist wrote:

On 9/13/2019 6:31 AM, N4ZR wrote:
I don't think I've ever read anything on this topic.  Basically, what 
I'm asking is, could ground wave to a fairly nearby Skimmer be used 
as an analogue to low-angle radiation to assess the effectiveness of 
radial systems on an inverted L?  W3LPL is about 30 miles from me and 
has a very capable Skimmer Server-based RBN node.




A radial system has nothing to do with take off angle.
Take off angle is strictly affected by ground conductivity
over a much large area than even a "big" radial field.

If you want to improve your inverted L, change it to a
top loaded vertical (IE "umbrella" wires).  That will make a lot more 
difference than adding radials.


Rick N6RK
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Re: Topband: Relationship Between Ground Wave and Low-Angle Radiation

[Michael Tope]

On 9/13/2019 6:31 AM, N4ZR wrote:
I don't think I've ever read anything on this topic.  Basically, what 
I'm asking is, could ground wave to a fairly nearby Skimmer be used as 
an analogue to low-angle radiation to assess the effectiveness of 
radial systems on an inverted L?  W3LPL is about 30 miles from me and 
has a very capable Skimmer Server-based RBN node.



Hi Pete

Perhaps you could try some RBN tests without changing anything 
significant on either end of the system over a period of time just to 
see if you can get a stable baseline. A transmit beacon on a timer that 
lets it transmit from 11:30 AM to 12:30 PM every day for a month would 
give you a pretty sizeable dataset. Then you could pull down the RBN 
records to see how much variability there was in signal strength over a 
large set of measurements.


73, Mike W4EF..
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Re: Topband: Relationship Between Ground Wave and Low-Angle Radiation

[Artek Manuals]

Pete

Interesting idea to be sure...Regardless of the "theoretical" answer. I 
would suggest you take daily readings (probably between 11AM and 1PM) 
for a month and log those before starting to add radials. If day in and 
day out you get variation of more than a few tenth's of a db the W3LPL 
RBN is not likely a good choice� for this project.


How many radials do you have now and� how many are you prepared to add? 
AS you get more and more radials the incremental effect of going from 4 
to 8 will be much more noticeable than going from 24 to 28


Dave
NR1DX





On 9/13/2019 9:31 AM, N4ZR wrote:
I don't think I've ever read anything on this topic.� Basically, what 
I'm asking is, could ground wave to a fairly nearby Skimmer be used as 
an analogue to low-angle radiation to assess the effectiveness of 
radial systems on an inverted L?� W3LPL is about 30 miles from me and 
has a very capable Skimmer Server-based RBN node.




--
Dave
manu...@artekmanuals.com
www.ArtekManuals.com


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Re: Topband: [TowerTalk] Skip Distance

[Guy Olinger K2AV]

Just remembered one other thing, the hours I use are SOLAR noon to SOLAR 2
pm. Where I live daylight time 10 am is 9 am standard time, and 8:50 am
Solar time.  In Lexington, Ky, USA that would be 8:23 AM. So during summer,
I wait until 1 pm to measure. HOWEVER...

Even then there can be residual propagation. I send a test CQ at 1.5 kw,
and look at what pops up on RBN. If it only hits W4KAZ, I'm fine. If I hit
KC4YVA, 149 miles away in Richmond, VA, I know there is reduced absorption
and the reading to KAZ could be affected. There have been days when at 2 pm
solar I was hitting YVA at 20 dB. Most days at 8:30 am solar, I'm still
hitting RBN's in Ohio over 400 miles away. So you can't just do it any day
at a certain time. You have to test for sky wave first.

73, Guy K2AV

On Fri, Sep 13, 2019 at 11:41 AM Clive GM3POI  wrote:

> Try it at midday.  73 Clive GM3POI
>
> -Original Message-
> From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Roger D
> Johnson
> Sent: 13 September 2019 10:11
> To: Towertalk Reflector; Top Band Reflector
> Subject: Re: Topband: [TowerTalk] Skip Distance
>
> These test were in late morning to early afternoon.
>
> 73, Roger
>
> On 9/12/2019 9:02 PM, Roger D Johnson wrote:
> > I've been running some tests on my 8 circle array with K1JB. Joe is 17
> miles
> > away and I sometimes notice deep fading on his signal. Makes plotting the
> > antenna pattern very difficult. Is it possible to have skywave
> contamination
> > at this short range?
> >
> > 73, Roger
> > ___
> >
> >
> >
> > ___
> > TowerTalk mailing list
> > towert...@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
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Re: Topband: Relationship Between Ground Wave and Low-Angle Radiation

[Richard (Rick) Karlquist]

On 9/13/2019 6:31 AM, N4ZR wrote:
I don't think I've ever read anything on this topic.  Basically, what 
I'm asking is, could ground wave to a fairly nearby Skimmer be used as 
an analogue to low-angle radiation to assess the effectiveness of radial 
systems on an inverted L?  W3LPL is about 30 miles from me and has a 
very capable Skimmer Server-based RBN node.




A radial system has nothing to do with take off angle.
Take off angle is strictly affected by ground conductivity
over a much large area than even a "big" radial field.

If you want to improve your inverted L, change it to a
top loaded vertical (IE "umbrella" wires).  That will make a lot more 
difference than adding radials.


Rick N6RK
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Re: Topband: [TowerTalk] Skip Distance

[Clive GM3POI]

Try it at midday.  73 Clive GM3POI

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Roger D
Johnson
Sent: 13 September 2019 10:11
To: Towertalk Reflector; Top Band Reflector
Subject: Re: Topband: [TowerTalk] Skip Distance

These test were in late morning to early afternoon.

73, Roger

On 9/12/2019 9:02 PM, Roger D Johnson wrote:
> I've been running some tests on my 8 circle array with K1JB. Joe is 17
miles 
> away and I sometimes notice deep fading on his signal. Makes plotting the
> antenna pattern very difficult. Is it possible to have skywave
contamination
> at this short range?
> 
> 73, Roger
> ___
> 
> 
> 
> ___
> TowerTalk mailing list
> towert...@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
> 
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Re: Topband: [TowerTalk] Skip Distance

[Roger D Johnson]

These test were in late morning to early afternoon.

73, Roger

On 9/12/2019 9:02 PM, Roger D Johnson wrote:
I've been running some tests on my 8 circle array with K1JB. Joe is 17 miles 
away and I sometimes notice deep fading on his signal. Makes plotting the

antenna pattern very difficult. Is it possible to have skywave contamination
at this short range?

73, Roger
___



___
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towert...@contesting.com
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Topband: Relationship Between Ground Wave and Low-Angle Radiation

[N4ZR]

I don't think I've ever read anything on this topic.  Basically, what 
I'm asking is, could ground wave to a fairly nearby Skimmer be used as 
an analogue to low-angle radiation to assess the effectiveness of radial 
systems on an inverted L?  W3LPL is about 30 miles from me and has a 
very capable Skimmer Server-based RBN node.


--

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

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