Topband: Topband Digest, Vol 119, Issue 24
Mike Greenway
K4PI at BELLSOUTH.NET
Tue Nov 20 19:17:47 EST 2012
Keep me posted as I need that on 80 and 160 but would be happy for just 80
Will be in the CQ WW this weekend. Got a HI Z 8 vert array going at the
farm.. Sound pretty good..
-----Original Message-----
From: topband-request at contesting.com
Sent: Tuesday, November 20, 2012 12:00 PM
To: topband at contesting.com
Subject: Topband Digest, Vol 119, Issue 24
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Today's Topics:
1. Where to ground the Beverage feedline? (Martin)
2. Re: Converting a full-size G5RV to a T for 160m
(Michael G. Carper)
3. Re: Where to ground the Beverage feedline? (Jim Brown)
4. Re: Where to ground the Beverage feedline? (Tom W8JI)
5. XW2CW (George)
6. Re: XW2CW (George)
7. Re: Toroidal common mode choke (ZR)
8. KD9SV Dual Band Pre-Amp and F.E.S. (Rick Arzadon)
9. Re: Where to ground the Beverage feedline? (Jim Brown)
10. Looking to improve TX antenna Efficiency (Steven Raas)
11. Re: Where to ground the Beverage feedline? (Jim Brown)
12. Re: Where to ground the Beverage feedline? (Thomas Herrmann)
13. Re: Where to ground the Beverage feedline? (Martin)
14. Re: Toroidal common mode choke (Tom W8JI)
15. antenna wire (Jorge Diez - CX6VM)
16. Re: Where to ground the Beverage feedline? (Tom W8JI)
17. Re: antenna wire (Shoppa, Tim)
18. Re: Toroidal common mode choke (donovanf at starpower.net)
19. 2011 ARRL 160 Meter Contest Certificates (Kutzko, Sean, KX9X)
20. Re: Where to ground the Beverage feedline? (Herb Schoenbohm)
----------------------------------------------------------------------
Message: 1
Date: Mon, 19 Nov 2012 18:33:19 +0100
From: Martin <dm4im at t-online.de>
To: topband at contesting.com
Subject: Topband: Where to ground the Beverage feedline?
Message-ID: <50AA6D5F.7060701 at t-online.de>
Content-Type: text/plain; charset=ISO-8859-15; format=flowed
Topbanders,
please comment on this :
The feedline of a beverage is buried all the way from the feedpoint to
the shack. There it goes up vertically about 5meters, enters the shack
side by side with other feedlines and is- after about another 5meters -
connected to the radio .
The cable is fitted with a common mode choke near the radio.
Where should i ground the feedline? Is it a good idea to ground it where
it comes off of the soil? Should it ( additionally) be grounded at the
radio? Should i install another common mode choke at the feedpoint?
All comments welcome.
--
Ohne CW ist es nur CB..
73, Martin DM4iM
------------------------------
Message: 2
Date: Mon, 19 Nov 2012 14:17:12 -0500
From: "Michael G. Carper" <mike at wa9pie.net>
To: <topband at contesting.com>
Subject: Re: Topband: Converting a full-size G5RV to a T for 160m
Message-ID: <006501cdc68a$7b7d05f0$727711d0$@wa9pie.net>
Content-Type: text/plain; charset="us-ascii"
Thanks for all the replies. I've also found this article by AD1B in CQ from
1995 to be helpful.
http://techdoc.kvindesland.no/radio/antennas/20061010171110285.pdf
Thus far, the (102') G5RV is up at about 50' and I'm not using it in a T
configuration. It's loading up on 160m like a regular G5RV. I know that's
not optimal, BUT...
I only need 30 more countries on 160m for DXCC and we'll be moving by March.
So I'm not going to get all fancy with another inverted-L... or putting down
a full ground field. I'll do the best I can to work 30 more with the G5RV
or by following the attached article.
Mike, WA9PIE
-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Michael
G. Carper
Sent: Sunday, November 18, 2012 7:09 PM
To: topband at contesting.com
Subject: Topband: Converting a full-size G5RV to a T for 160m
Hey guys.
I saw a few items in a Google search where guys had converted their
full-size G5RV into a T antenna on 160m. It had something to do with adding
the obligatory counterpoise and shorting the feedline. This would turn the
antenna from a horizontal radiator to a vertical radiator.
Anyone have any info on this? Or can you refer me to a source?
Mike, WA9PIE
_______________________________________________
Topband reflector - topband at contesting.com
------------------------------
Message: 3
Date: Mon, 19 Nov 2012 11:45:52 -0800
From: Jim Brown <jim at audiosystemsgroup.com>
To: topband at contesting.com
Subject: Re: Topband: Where to ground the Beverage feedline?
Message-ID: <50AA8C70.7010202 at audiosystemsgroup.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On 11/19/2012 9:33 AM, Martin wrote:
> Should i install another common mode choke at the feedpoint?
Absolutely! And bond the shield to ground on both sides of the choke.
73, Jim K9YC
------------------------------
Message: 4
Date: Mon, 19 Nov 2012 15:25:10 -0500
From: "Tom W8JI" <w8ji at w8ji.com>
To: <topband at contesting.com>
Subject: Re: Topband: Where to ground the Beverage feedline?
Message-ID: <46BB6DCE8B504FDA91D77671EE034A56 at tom0c1d32a93f0>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
> On 11/19/2012 9:33 AM, Martin wrote:
>> Should i install another common mode choke at the feedpoint?
>
> Absolutely! And bond the shield to ground on both sides of the choke.
>
I totally disagree with that advice.
1.) If the feedline is bonded to the same ground on both sides of the choke,
any choke would do no good at all. It would be shorted.
2.) If a proper Beverage feed transformer is used, the feedline already has
no common mode connection. He could ground it or let it float, and common
mode coupling would be nearly zero with a proper beverage feed transformer
(isolated primary and secondary).
3.) He said the feeder is buried. If the feeder is buried for any distance,
or even laid on earth for any distance, the feeder already has a good CM
attenuator.
The only thing necessary in almost any installation is an isolation
transformer at the antenna feedpoint. There could be an exception with a
feeder routed or suspended in the air, or grouped with things carrying
significant common mode, out to the antenna area.
At my QTH, the only isolation is at the antenna feed transformer. There are
modest impedance CM ferrite sleeves on phono and BNC connected cables to
help mitigate less-than-zero connector ground resistances inside the shack,
but nothing at all outside.
Even when the feeder elevates to cross roads near power lines, sometimes a
span of 20-30 feet and 20 feet high, I've never found a reason to install a
CM choke or sleeves. I doubt there are many cases when needed outside the
ground panel.
73 Tom
------------------------------
Message: 5
Date: Mon, 19 Nov 2012 20:15:39 -0500
From: "George" <w8uvz at voyager.net>
To: <Topband at contesting.com>
Subject: Topband: XW2CW
Message-ID: <C922774B45C945F880B185B57C5E6FFC at none1HP>
Content-Type: text/plain; charset="utf-8"
See this callsign active today on 80 CW, with a single spot on 160. Would
this op be Rudi, DK7PE ? as some of the spotters identified him as Rudi,
Rudy?
This would be good news if true as Rudi is a superb low band CW op.
Other possibility seems to be an OD5 op who planned to be QRV from Cambodia.
This info from DX Bulletins ? but without a callsign given.
Can someone help, please
73 George W8UVZ
------------------------------
Message: 6
Date: Mon, 19 Nov 2012 21:43:34 -0500
From: "George" <w8uvz at voyager.net>
To: <Topband at contesting.com>
Subject: Re: Topband: XW2CW
Message-ID: <39EC3D7D32844128BC675F9CB413DAC1 at none1HP>
Content-Type: text/plain; format=flowed; charset="utf-8";
reply-type=original
Several Low Band Ops did cfm that the XW2CW operation is by Rudi, DK7PE.
See QRZ.com XW2CW
Good News, of course
GL
73 George W8UVZ
-----Original Message-----
From: George
Sent: Monday, November 19, 2012 8:15 PM
To: Topband at contesting.com
Subject: Topband: XW2CW
See this callsign active today on 80 CW, with a single spot on 160. Would
this op be Rudi, DK7PE ? as some of the spotters identified him as Rudi,
Rudy?
This would be good news if true as Rudi is a superb low band CW op.
Other possibility seems to be an OD5 op who planned to be QRV from Cambodia.
This info from DX Bulletins ? but without a callsign given.
Can someone help, please
73 George W8UVZ
_______________________________________________
Topband reflector - topband at contesting.com
------------------------------
Message: 7
Date: Sun, 18 Nov 2012 19:38:01 -0500
From: "ZR" <zr at jeremy.mv.com>
To: "Tom W8JI" <w8ji at w8ji.com>, <topband at contesting.com>
Subject: Re: Topband: Toroidal common mode choke
Message-ID: <8C73C26458B94066A406CE2958EB372F at computer1>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
----- Original Message -----
From: "Tom W8JI" <w8ji at w8ji.com>
To: <topband at contesting.com>
Sent: Sunday, November 18, 2012 6:58 PM
Subject: Re: Topband: Toroidal common mode choke
>> Also the difference between Mix 31 and 43 is not great and was used for
>> decades successfully before 31 was introduced.
>
>
> For a non-critical application like this almost anything would work with
> enough core depth and/or turns, but they are not nearly the same. There is
> a large difference between 43 and 31 material.
>
> 31 has an initial perm of 1500 and slopes down with increasing frequency,
> with a Q of unity at around 3 MHz.
>
> 43 has an initial perm of 900 and slopes down at 1 MHz, with a Q of 1 at
> around 15 MHz.
>
> Both have a curie temp of around 130 C.
>
> About half the permeability is not the same, and the Q=1 being five times
> higher in frequency is certainly not the same. 31, with lower Q across
> HF, is a significantly better suppression material.
On paper I agree but what about real world? Topbanders seemed to do quite
well with the old 43 mix and the resultant lower impedance.
How much is good enough?
I havent changed any of the 43 material in the house since they removed the
noise from each consumer device; some have been in place for over 30 years
going back to the prior QTH. As new stuff is added I use 31 mix, seems to
work the same.
Carl
KM1H
------------------------------
Message: 8
Date: Mon, 19 Nov 2012 06:11:31 -0800 (PST)
From: Rick Arzadon <n8xi_1 at yahoo.com>
To: "topband at contesting.com" <topband at contesting.com>
Subject: Topband: KD9SV Dual Band Pre-Amp and F.E.S.
Message-ID:
<1353334291.62911.YahooMailNeo at web110408.mail.gq1.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1
I used the above to get help with DXCC on 160M and 80M.
THEY WORKED!!
I don't really have the room for the antennas.
Therefore, I am looking for a good home for my:
1) KD9SV Dual Band (160/80M) Pre-Amp and
2) KD9SV Front-End-Saver (the Solid State one)
You can see them at http://www.radio-ware.com/ under KD9SV
in the left panel under catalog # SV-DB and SV-FESSS.
I also have the paperwork (Description, Connection Drawing, Schematics)
and a copy of the February 1997 CQ article/schematic of the F.E.S.
If you are interested please Email me:
n8xi_1 at yahoo.com? -or- n8xi at juno.com
Tel# 313-561-4839?- also good at qrz.com
Thanks and 73,
Rick - N8XI
------------------------------
Message: 9
Date: Mon, 19 Nov 2012 20:44:47 -0800
From: Jim Brown <jim at audiosystemsgroup.com>
To: topband at contesting.com
Subject: Re: Topband: Where to ground the Beverage feedline?
Message-ID: <50AB0ABF.4060205 at audiosystemsgroup.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On 11/19/2012 12:25 PM, Tom W8JI wrote:
> If the feedline is bonded to the same ground on both sides of the
> choke, any choke would do no good at all. It would be shorted.
I was not suggesting the same ground electrode, rather widely spaced
electrodes.
73, Jim K9YC
------------------------------
Message: 10
Date: Tue, 20 Nov 2012 00:23:18 -0500
From: Steven Raas <sjraas at gmail.com>
To: topband at contesting.com
Subject: Topband: Looking to improve TX antenna Efficiency
Message-ID:
<CABOEzZrou6C3_OwNYV3ZOXx2zMdAxLZ5Qk+4qEV=8SnJ+7a=bg at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Last 'Season' was my 1st real dive into 160m. Running a 'InvL' ( which
I will describe lower in detail ) and 100w, I managed to pull 19 DXCC
and 48 states cfmd. I am in looking into ways to improve my TX antenna
efficiency, for this season w/o getting to crazy . (rx antennas are in
the works and a different topic )
Current TX antenna is as follows: (Tuned in shack / not self reasonant )
Main Element: 32 feet vertical - 90 deg bend ( the 'L' ) which runs
43' horzontally pointing north. Then, another 90 deg bend, and
ascending 26' in length ( from 30' up to about 11' above ground
running from west to east. ), then..you guessed it.. another 90 deg
bend that now runs to the south flat top for 27' ( @ 11' up )
Ground radials qty 24. Min length 22' - max length 62' ( from az 330
deg - 70 deg with the longer radials pointed from 35-60 deg az)
The FCP idea is not practicle for me @ this point in time.
My Thought.. add a Coil @ the 30' point of the main vertical run made
from perhaps 1/8th inch copper tubing ( refrigerant line ) in a fairly
large diamater ( 16-20" ), perhaps 14-20 turns even spaced, using
perhaps drilled lexan as spacers.. Try extending the vertical run
another 8-10' or so.. and then the rest of the antenna as is. Going
above 40' vertical is not an option @ this point in time either. ( yes
i know the more vertical the better its just a no-can-do for now)
At the moment the antenna's best 'swr' is at roughtly 1818 khz @ 2:1
there is no resonant point that I can find within the 160m band. ( no
antenna anyalizer either - Mabey santa will provide ) My best guess is
that in its current configuration... the antenna is probabally in the
8-12 ohm area.. I have nothing solid to back that up however.
At the feed point I have a coaxial choke, 21 turns on a 8" form, the
cable is similar to RG213 , with the exception the center conductor is
solid. ( its actually 50 ohm quad shielded cable i got form a place I
used to work, HP node cluster inter connect cable. .405" & blue in
color, i cant remember the vf on it but i did spec it out a while
back, and its ok for HF use. )
Or, tuning the antenna @ the base with a variable cap. of sufficent
size, or perhaps even both?
I know there is NO magic that can come..im just trying to improve on
what I have and can do @ this point in time.
Suggestions, thoughts, flames and raised brows are all welcome.
Steve Raas
N2JDQ
------------------------------
Message: 11
Date: Tue, 20 Nov 2012 00:43:22 -0800
From: Jim Brown <jim at audiosystemsgroup.com>
To: topband at contesting.com
Subject: Re: Topband: Where to ground the Beverage feedline?
Message-ID: <50AB42AA.3070208 at audiosystemsgroup.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On 11/19/2012 12:25 PM, Tom W8JI wrote:
> 3.) He said the feeder is buried. If the feeder is buried for any
> distance, or even laid on earth for any distance, the feeder already
> has a good CM attenuator.
Um -- what did you say was the typical skin depth of soil at 2 MHz?
Somehow, I seriously doubt it was down that far. :)
73, Jim K9YC
------------------------------
Message: 12
Date: Tue, 20 Nov 2012 11:07:04 +0100 (CET)
From: "Thomas Herrmann" <dl1amq at web.de>
To: topband at contesting.com
Subject: Re: Topband: Where to ground the Beverage feedline?
Message-ID:
<trinity-4d0afb82-867b-4b33-b8ca-c1e92c87db96-1353406024546 at 3capp-webde-bs08>
Content-Type: text/plain; charset=UTF-8
I learned NOT to ground Beverage feedline on antenna side.
Using K9AY Remote-Powered Preamplifier PRE-1 the feedline IS grounded as far
as the preamp mounting bracket should be grounded.
How to overcome ? Any hints, please.
73 de Thomas, DL1AMQ
------------------------------
Message: 13
Date: Tue, 20 Nov 2012 12:40:00 +0100
From: Martin <dm4im at t-online.de>
To: topband at contesting.com
Subject: Re: Topband: Where to ground the Beverage feedline?
Message-ID: <50AB6C10.5020500 at t-online.de>
Content-Type: text/plain; charset=ISO-8859-15; format=flowed
Topbanders,
thank you for the comments so far.
With the initial setup the feedline crossed the entire run in the air,
high enough to let even cars with antennas pass under it.
After i buried the feedline, the antenna had become so quiet that i
checked for loose connections at the feedpoint and the termination
resistor. Amazing.
The feedline is buried about 3-4 inches for the first 7-8 meters, then
about 1 inch for the rest (about 20m).
The transformer is a BN73-something binocular core, wound as suggested
by W0BTU and others.
Someone suggested to ground the feedline where it leaves the ground (at
the shack end), will this improve things?
--
Ohne CW ist es nur CB..
73, Martin DM4iM
------------------------------
Message: 14
Date: Tue, 20 Nov 2012 08:42:26 -0500
From: "Tom W8JI" <w8ji at w8ji.com>
To: <topband at contesting.com>
Subject: Re: Topband: Toroidal common mode choke
Message-ID: <2EABCED2B5A843B5B450E2F3A0449BC9 at tom0c1d32a93f0>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
> On paper I agree but what about real world? Topbanders seemed to do quite
> well with the old 43 mix and the resultant lower impedance.
>
> How much is good enough?
That's a good point.
It seems we tend to go to extremes of black and white and abandon common
sense or reasoning in everything we do these days. That pattern has crept
into some very simple things, perhaps so one answer fits all and no one ever
says "it depends".
> I havent changed any of the 43 material in the house since they removed
> the noise from each consumer device; some have been in place for over 30
> years going back to the prior QTH. As new stuff is added I use 31 mix,
> seems to work the same.
I've never been a big proponent of peppering a system with beads, because
often a common-mode series impedance by itself is the least efficient way to
do mitigation. It takes a terrible CM signal levels to cause problems, if
connectors are good and the antenna is a reasonable distance away. If the
antenna isn't a reasonable distance away, then correcting the source is
often better.
It's really a big soup of things, and I think some of this has gone beyond
sensible solutions. I lived years without problems without any ferrite
cores, BUT I grounded feeders sensibly and looked at the system. It all
about ratios and changes in CM impedances.
Once something fixes something, it all seems the same. After all, fixed is
fixed.
Correct me if I am wrong, but it seems we think noise all comes from common
mode and if we add increased suppression things get better and better with
nearly no limits. We become almost anorexic with suppression. What really
happens is once antenna noise dominates, which can even happen without any
suppression at all in many systems, all the rest is a wasted effort. In
other systems once the feedline has reasonable suppression, direct radiation
takes over. We can add a billion beads to the feeder and nothing changes.
There should be more focus on telling people how to find problems, and less
on treating every system the same.
I was visiting a friend and he told me stories about building massive bead
strings a few feet long on Yagi antennas!! Someone should stop the bead
madness enveloping us, and get us back to rational thought.
73 Tom
------------------------------
Message: 15
Date: Tue, 20 Nov 2012 11:58:09 -0200
From: "Jorge Diez - CX6VM" <cx6vm.jorge at gmail.com>
To: <topband at contesting.com>
Subject: Topband: antenna wire
Message-ID: <50ab8c75.a638ec0a.69f1.659a at mx.google.com>
Content-Type: text/plain; charset="us-ascii"
Hello
Wich antenna wire do you use for large delta loops for 160 and 80 mts, or
other wire antennas?
I did something with Polys-13 from DavisRF, but not sure if I need a thicker
wire to run high power
My 80 mts delta loop wire is very dark over 5 years, and was broken at one
of the corner where I have insulator and RF is to high
73,
Jorge
CX6VM/CW5W
------------------------------
Message: 16
Date: Tue, 20 Nov 2012 09:00:13 -0500
From: "Tom W8JI" <w8ji at w8ji.com>
To: <topband at contesting.com>
Subject: Re: Topband: Where to ground the Beverage feedline?
Message-ID: <AC1E52B4720F4BE8BA8EB4C9B104F52F at tom0c1d32a93f0>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
> Um -- what did you say was the typical skin depth of soil at 2 MHz?
> Somehow, I seriously doubt it was down that far. :)
Common mode suppression requirements depend on things:
1.) The sensitivity of the antenna to all signals, either bad unwanted
signals like noise or good wanted signals. This is the good signal and bad
noise power output of the antenna.
2.) The level of unwanted signals and noise fed down the feeder towards the
antenna.
3.) The ratio of series and shunt impedances along the system, but only
**if** the system has enough unwanted CM junk to overcome antenna signal
power.
For some reason beyond my understanding, I think we are going far over the
top of what is reasonable....and it is getting worse.
I was at a friend's house and he told me about installing very long bead
strings in Yagi antenna feeders. Please, let's all stop this needless bead
insanity and get back to some common sense.
Any conductor very near earth for a long distance has considerable
attenuation along the conductor. If it didn't, we could bury our NVIS
antennas or run longwires laid right on dirt with high efficiency. It's all
about ratios everywhere in the system, including the CM injected and signal
level sensitivity of the antenna.
I make enough measurements of antennas here every year, some right in my
driveway near noise sources, to know when something is getting overblown.
73 Tom
------------------------------
Message: 17
Date: Tue, 20 Nov 2012 14:19:25 +0000
From: "Shoppa, Tim" <tshoppa at wmata.com>
To: Jorge Diez - CX6VM <cx6vm.jorge at gmail.com>,
"topband at contesting.com" <topband at contesting.com>
Subject: Re: Topband: antenna wire
Message-ID:
<303A17BD5F8FA34DA45EEC245271AC0B2524677C at JGEX2K10MBX2.wmata.local>
Content-Type: text/plain; charset="us-ascii"
I doubt the wire broke at corner because RF is too high. Mechanical dressing
at any corner is far more relevant.
The stranded Polystealth is good stuff, will survive bends without good
mechanical stress relief much better than solid copper, but
it too will break at a corner after enough flexing if not dressed
appropriately.
Also note that polystealth is copper clad steel, with a rather thin coat of
copper, and will show some rust of the steel core wherever the copper is
nicked. Nothing against polystealth I've had 130 feet of it over my house
for many years now. It is so much easier to deal with than solid copperweld.
I would still be entwined in a snake of wire if I had tried to put up 130
feet of similar gauge solid copperweld over my house.
I advocate the way to build a long lasting corner, involves two separate
antenna wires dressed appropriately (large radius loop through insulator and
no tight corners) through the insulator, with the two wires connected by a
flexible electrical jumper that has no mechanical stress applied.
I learned the above dealing with both solid copperweld and solid copper
ladder line at corners. At any corner or support where the wind would whip
the ladder line, the wire was guaranteed to break. But stress relieve the
corners with large radius loops, good mechanical dressing and a flexible
electrical jumper that has no stress on it, and it'll last forever.
Tim N3QE
-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Jorge
Diez - CX6VM
Sent: Tuesday, November 20, 2012 8:58 AM
To: topband at contesting.com
Subject: Topband: antenna wire
Hello
Wich antenna wire do you use for large delta loops for 160 and 80 mts, or
other wire antennas?
I did something with Polys-13 from DavisRF, but not sure if I need a thicker
wire to run high power
My 80 mts delta loop wire is very dark over 5 years, and was broken at one
of the corner where I have insulator and RF is to high
73,
Jorge
CX6VM/CW5W
_______________________________________________
Topband reflector - topband at contesting.com
------------------------------
Message: 18
Date: Tue, 20 Nov 2012 10:42:14 -0500 (EST)
From: <donovanf at starpower.net>
To: topband at contesting.com
Subject: Re: Topband: Toroidal common mode choke
Message-ID: <201211201542.071105 at ms10.lnh.mail.rcn.net>
Content-Type: text/plain; charset=us-ascii
In the real world, receiving (or transmitting) problems are often caused by
faults rather than by inadequate design. The most common problems are
connectors and deteriorated coaxial cable caused by poor installation
practices and moisture entry.
Faults are best found through regular inspections, rather than (as many of
us do) waiting for the fault to become so severe that its obvious. A DX
resistance measurement of your transmission line performed inside your shack
takes only a few seconds and will reveal many of the most common faults. A
VSWR sweep with an MFJ-259 or your favorite instrument is also very useful.
VNA and TDR measurements are also very helpful if you have that capability
(you should!).
Keep records of your measurements so that changes will be apparent. Any
change is cause for an investigation.
73
Frank
W3LPL
---- Original message ----
>Date: Tue, 20 Nov 2012 08:42:26 -0500
>From: "Tom W8JI" <w8ji at w8ji.com>
>Subject: Re: Topband: Toroidal common mode choke
>To: <topband at contesting.com>
>
>> On paper I agree but what about real world? Topbanders seemed to do quite
>> well with the old 43 mix and the resultant lower impedance.
>>
>> How much is good enough?
>
>That's a good point.
>
>It seems we tend to go to extremes of black and white and abandon common
>sense or reasoning in everything we do these days. That pattern has crept
>into some very simple things, perhaps so one answer fits all and no one
>ever
>says "it depends".
>
>> I havent changed any of the 43 material in the house since they removed
>> the noise from each consumer device; some have been in place for over 30
>> years going back to the prior QTH. As new stuff is added I use 31 mix,
>> seems to work the same.
>
>I've never been a big proponent of peppering a system with beads, because
>often a common-mode series impedance by itself is the least efficient way
>to
>do mitigation. It takes a terrible CM signal levels to cause problems, if
>connectors are good and the antenna is a reasonable distance away. If the
>antenna isn't a reasonable distance away, then correcting the source is
>often better.
>
>It's really a big soup of things, and I think some of this has gone beyond
>sensible solutions. I lived years without problems without any ferrite
>cores, BUT I grounded feeders sensibly and looked at the system. It all
>about ratios and changes in CM impedances.
>
>Once something fixes something, it all seems the same. After all, fixed is
>fixed.
>
>Correct me if I am wrong, but it seems we think noise all comes from common
>mode and if we add increased suppression things get better and better with
>nearly no limits. We become almost anorexic with suppression. What really
>happens is once antenna noise dominates, which can even happen without any
>suppression at all in many systems, all the rest is a wasted effort. In
>other systems once the feedline has reasonable suppression, direct
>radiation
>takes over. We can add a billion beads to the feeder and nothing changes.
>
>There should be more focus on telling people how to find problems, and less
>on treating every system the same.
>
>I was visiting a friend and he told me stories about building massive bead
>strings a few feet long on Yagi antennas!! Someone should stop the bead
>madness enveloping us, and get us back to rational thought.
>
>73 Tom
>
>_______________________________________________
>Topband reflector - topband at contesting.com
------------------------------
Message: 19
Date: Tue, 20 Nov 2012 11:36:40 -0500
From: "Kutzko, Sean, KX9X" <kx9x at arrl.org>
To: <cq-contest at contesting.com>
Cc: topband at contesting.com
Subject: Topband: 2011 ARRL 160 Meter Contest Certificates
Message-ID:
<145372871023544E98881538F29B1DFC041F29D8 at cartagia.ARRLHQ.ORG>
Content-Type: text/plain; charset="US-ASCII"
Hi folks-
Certificates for the 2011 ARRL 160 Meter Contest were mailed today. Look
for them in your mailbox soon.
As always, you can track the progress of ARRL contest awards processing
at the following page on the ARRL site:
http://www.arrl.org/plaques-and-certificates
73,
Sean Kutzko, KX9X
Contest Branch Manager
ARRL, the national association for Amateur Radio
225 Main St.
Newington, CT 06111
860-594-0232
skutzko at arrl.org
------------------------------
Message: 20
Date: Tue, 20 Nov 2012 13:00:03 -0400
From: Herb Schoenbohm <herbs at vitelcom.net>
To: jim at audiosystemsgroup.com
Cc: topband at contesting.com
Subject: Re: Topband: Where to ground the Beverage feedline?
Message-ID: <50ABB713.10804 at vitelcom.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Only if this before buying all those expensive 3' Type 31 Ferrite Rings
I could have saved some money. I though that having many 250-350 foot
lengths of RG-6 feedlines running all over the radial system (ROG's or
radials on the ground) as well as having nearby 80 and 40 meter
verticals that during some contests where I am operating on 160 and a
guest is operating via remote control on 80 and 40, that trapping as
much RF from the Receive Only coax shields made sense. on some
Beverages I would get a de-sense making copy of weak signals very
problematic. So I installed 12 turns on a 3 inch ferrite on both sides
of a common ground bus and several ground rods outside and about 20 feet
from the shack. I also have inline a KD9SV band pass filter with the
Beverage bank output and now it is possible to co-exist with other
operators on higher bands running full power.
Maybe getting a higher quality flooded coax meant for direct burial
would have been a better way to go but this is not convenient with the
low cost of cable TV RG-6 even here. The coax shield at the feed
transformer on both the single wire and reversible Beverages is not
grounded, only the Beverage side secondary has a ground connection.
So now I am not sure if I have really been wasting time this way. f it
helps the debate I plan to take a very noisy Chinese switching supply
running from a car battery and an 800 watt inverter and lay it running
on several RG6 runs coming back to the shack at about 200 feet away
while checking the difference in noise reduction.
I thought that these toroid rings, although expensive, would buy me so
isolation from cable induce noise, whatever the source. Winding some
turns through these toroids of the AC power cable on the wife's
entertainment center as made all IX vanish in the living room. But if
it was wrong to buy all these type 31 ferrite rings, keep you eyes on
e-Bay soon.
Herb, KV4FZ
On 11/20/2012 12:44 AM, Jim Brown wrote:
> On 11/19/2012 12:25 PM, Tom W8JI wrote:
>> If the feedline is bonded to the same ground on both sides of the
>> choke, any choke would do no good at all. It would be shorted.
>
> I was not suggesting the same ground electrode, rather widely spaced
> electrodes.
>
> 73, Jim K9YC
> _______________________________________________
> Topband reflector - topband at contesting.com
------------------------------
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End of Topband Digest, Vol 119, Issue 24
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