EFHW

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Re: EFHW

Dan Presley
I also wanted to thank Frank for a great suggestion.He hit it right on the nose. I always forget about the usefulness of an RF ammeter. When I was a kid in the ’60’s hanging around the OT’s a couple of them used these in the open wire lines to tune for maximum current. No concern of SWR as that wasn’t important with pi and linked outputs in your tube rigs! Now I just have to figure out a way to do this in the field…I still have some wonderful Weston meters one of the guys gave me lo those many years ago.
Dan Presley  N7CQR
[hidden email]


> On Feb 12, 2017, at 10:45 AM, [hidden email] wrote:
>
> Dan's original post concerned the effectiveness and practicality
> of various EFHW configurations in a man pack environment.
> Since he had already decided that his radiating element will
> be 1/2 wavelength long, the primary concern is power transfer
> efficiency vs. practicality of the solution in a weight and space
> constrained man pack environment.
>
>
> For the entire history of radio, RF ammeters have been used to
> evaluate the efficiency of alternative matching systems and their
> associated radial/counterpoise systems. An RF ammeter could
> be placed in Dan's EFHW antenna -- ideally in the center -- to
> compare the relative performance of practical man pack EFHW
> implementations.
>
>
> 73
> Frank
> W3LPL
>
>
> ----- Original Message -----
>
> From: "Don Wilhelm" <[hidden email] <mailto:[hidden email]>>
> To: "Wes Stewart" <[hidden email] <mailto:[hidden email]>>, [hidden email] <mailto:[hidden email]>
> Sent: Sunday, February 12, 2017 6:29:07 PM
> Subject: Re: [Elecraft] EFHW
>
> Wes,
>
> I do not doubt what you are saying about 1/2 wave verticals, but most
> EFHW antennas are mounted as a sloper or a horizontal antenna.
>
> For portable operation, the main concern is for the ability to feed the
> antenna, and not about maximizing the far field strength.
>
> 73,
> Don W3FPR
>
> On 2/12/2017 12:34 PM, Wes Stewart wrote:
>> Alas, if only this was true.
>>
>> Google "radial system design and efficiency in hf verticals" and you
>> should get a cached version of Rudy Severns' paper of the same name. In
>> it he states:
>>
>> "Alternately we can graph efficiency in terms of Ga as shown in figures
>> 3 and 4. Unfortunately this also shows how inefficient verticals are
>> even over very good ground. Very depressing! For example, with very good
>> soil (0.02/30) and 128 1/2-wave radials, the efficiency of a 1/4-wave
>> vertical is still only -2.76 dB (53%)!"
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Re: EFHW

k6dgw
In reply to this post by Ken K6MR
Well, the KFBK Franklin is two vertical 180 deg co-linear elements
center fed [in-phase, I think], so I guess it would be about 1,600 ft
[almost 500 m].  A couple of the TV towers in Walnut Grove down in the
Delta are 2,000 ft [600 m], but they're not center fed. [:-)  I think
most "half-wave" BC verticals are close to but not exactly 180 deg.  
IIRC, KFI [640 KHz] in Los Angeles has a 725 ft tower which is almost
exactly 180 deg  but has a capacity hat that extends it to an effective
195 deg or so. When you drive by it on I-5, it is one very tall tower.

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 2/12/2017 9:29 PM, Ken K6MR wrote:
> Yep, flamethrower of No. Cal.  The groundwave coverage is amazing.
>
> Imagine how big that thing would be if they were on 580 instead of 1530  :^)
>
> Ken K6MR
>

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Re: EFHW

k6dgw
In reply to this post by donovanf
In the 1960's, you could work the world with 20 watts to a window
screen.  Peak of Cycle 19 was in the front half of the 60's. [:-)

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 2/13/2017 9:41 AM, [hidden email] wrote:
> I used a 20 meter "Happy Accident Ground Plane" mounted 50 feet
>
> up in a maple tree for many years when I was in Rhode Island during
> the 1960s and worked the world with it.
>
> 73
> Frank
> W3LPL
>

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Re: EFHW

donovanf
Hi Fred,


When I started DXing in about 1962, Solar Cycle 19 was quite weak
and reached its minimum in 1964, the year I made the #1 USA low
power score in the ARRL CW DX Contest using my 20 meter Happy
Accident Ground Plane and a variety of other wire antennas suspended
from that same maple tree in an urban area in the city of Providence, RI


http://www.sws.bom.gov.au/Images/Educational/The%20Sun%20and%20Solar%20Activity/Solar%20Cycle/Solar%20Cycle%2019.png 


My antennas are a little better now...


https://www.qrz.com/db/W3LPL 


73
Frank
W3LPL



----- Original Message -----

From: "Fred Jensen" <[hidden email]>
To: [hidden email]
Sent: Monday, February 13, 2017 7:33:11 PM
Subject: Re: [Elecraft] EFHW

In the 1960's, you could work the world with 20 watts to a window
screen. Peak of Cycle 19 was in the front half of the 60's. [:-)

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 2/13/2017 9:41 AM, [hidden email] wrote:
> I used a 20 meter "Happy Accident Ground Plane" mounted 50 feet
>
> up in a maple tree for many years when I was in Rhode Island during
> the 1960s and worked the world with it.
>
> 73
> Frank
> W3LPL
>

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Re: EFHW

Nr4c
In reply to this post by Charlie T, K3ICH
Frequency where reactance equals zero.

Sent from my iPhone
...nr4c. bill


> On Feb 11, 2017, at 3:29 PM, Charlie T, K3ICH <[hidden email]> wrote:
>
> Define "resonance".
>
> Chas
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Fred
> Jensen
> Sent: Saturday, February 11, 2017 2:40 PM
> To: [hidden email]
> Subject: Re: [Elecraft] EFHW
>
> Ummm ... A full-wavelength wire is not resonant?
>
> 73,
>
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>> Lynn W. Taylor, WB6UUT
>> Sent: Friday, February 10, 2017 12:13 PM
>> To: [hidden email]
>> Subject: Re: [Elecraft] EFHW
>>
>> Just a reminder, folks.
>>
>> If it's not a half-wave, then it's a non-resonant wire.
>>
>>
>
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EFHW

Edward A. Dauer
In reply to this post by Dan Presley
Same sort of experience here.  In 1957 if my DX-20 could load it, I transmitted with it.  I didn’t know any better. I should say, however, that when I lived in R.I. during the peak years of Cycle 19 and in New Haven during the peak years of Cycle 21, having the ocean as a neighbor didn’t hurt either.  Certainly better than the thick layer of decomposed granite my shack sits on now.

Ted, KN1CBR

 
    ------------------------------
   
    Message: 23
    Date: Mon, 13 Feb 2017 14:42:35 -0500 (EST)
    From: [hidden email]
    To: [hidden email]
    Subject: Re: [Elecraft] EFHW
    Message-ID:
    <[hidden email]>
    Content-Type: text/plain; charset=utf-8
   
    Hi Fred,
   
   
    When I started DXing in about 1962, Solar Cycle 19 was quite weak
    and reached its minimum in 1964, the year I made the #1 USA low
    power score in the ARRL CW DX Contest using my 20 meter Happy
    Accident Ground Plane and a variety of other wire antennas suspended
    from that same maple tree in an urban area in the city of Providence, RI
   
   
    http://www.sws.bom.gov.au/Images/Educational/The%20Sun%20and%20Solar%20Activity/Solar%20Cycle/Solar%20Cycle%2019.png 
   
   
    My antennas are a little better now...
   
   
    https://www.qrz.com/db/W3LPL 
   
   
    73
    Frank
    W3LPL
   
   
   
    ----- Original Message -----
   
    From: "Fred Jensen" <[hidden email]>
    To: [hidden email]
    Sent: Monday, February 13, 2017 7:33:11 PM
    Subject: Re: [Elecraft] EFHW
   
    In the 1960's, you could work the world with 20 watts to a window
    screen. Peak of Cycle 19 was in the front half of the 60's. [:-)
   
    73,
   
    Fred ["Skip"] K6DGW
    Sparks NV DM09dn
    Washoe County
   
    On 2/13/2017 9:41 AM, [hidden email] wrote:
    > I used a 20 meter "Happy Accident Ground Plane" mounted 50 feet
    >
    > up in a maple tree for many years when I was in Rhode Island during
    > the 1960s and worked the world with it.
    >
    > 73
    > Frank
    > W3LPL
    >
   
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Re: EFHW

Brian D
In reply to this post by k6dgw
1530KHz is about 200m wavelength so 2 half waves in phase would be about
200m tall, approx 650'





Fred Jensen <[hidden email]> wrote:

> Well, the KFBK Franklin is two vertical 180 deg co-linear elements center
> fed [in-phase, I think], so I guess it would be about 1,600 ft [almost 500
> m].  A couple of the TV towers in Walnut Grove down in the Delta are 2,000
> ft [600 m], but they're not center fed. [:-)  I think most "half-wave" BC
> verticals are close to but not exactly 180 deg. IIRC, KFI [640 KHz] in Los
> Angeles has a 725 ft tower which is almost exactly 180 deg  but has a
> capacity hat that extends it to an effective 195 deg or so. When you drive
> by it on I-5, it is one very tall tower.
>


--
Brian Duffell G3VGZ  Yarm    England
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Re: EFHW

Nr4c
In reply to this post by Jim Brown-10
Has there been a day this year that this topic wasn't discussed?

Someone please bury this dead horse.

Or start a new reflector on EFHW antennas. PLEASE!

Sent from my iPhone
...nr4c. bill


> On Feb 12, 2017, at 11:55 PM, Ron D'Eau Claire <[hidden email]> wrote:
>
> That's correct Jim. I meant close to 90 degrees (1/4 wavelength). Some of
> the "big guns" do have 1/2 wave tall antennas, but most are near 1/4 wave
> tall.
>
> Tnx for catching that.
>
> 73, Ron AC7AC
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Jim
> Brown
> Sent: Sunday, February 12, 2017 5:31 PM
> To: [hidden email]
> Subject: Re: [Elecraft] EFHW
>
> Not true, Ron. Most AM broadcast transmitting antennas are in the range of
> 80-90 electrical degrees (a quarter wave).  Nearly all of the Class I clear
> channel stations use antennas that are at least 180 electrical degrees. You
> can see this data for any US station at
>
> https://www.fcc.gov/media/radio/am-query
>
> WLW's tower is 189.3 degrees.  So is WLS.  WGN is 195 degrees. WBZ uses an
> array of four towers that are 188.5 degrees.  WIND on 560 kHz near Chicago,
> has an array of four 100 degree towers. The station where I worked in my
> home town has an array of four 82 degree towers.  And so on.
>
> 73, Jim K9YC
>
>> On Sun,2/12/2017 9:13 AM, Ron D'Eau Claire wrote:
>> Most BCB (0.5 to 1.6 MHz) antennas are 1/8 wavelength high (or less) which
> necessitates an extensive ground system.
>
>
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Re: EFHW

Eric Swartz - WA6HHQ, Elecraft
Administrator
Folks, I just returned from 5 days on the road for the Orlando Hamcation hamfest and saw this huge thread. As per list guidelines, please self moderate (i.e. - End) OT threads like this after 5-10 posts. Please do not wait for me to jump in.

Lets end the thread at this time - this topic has certainly been beaten to death.. ;-)

73,
Eric
Moderator etc.
elecraft.com
_..._

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Re: EFHW

Raymond Benny
Thank you Eric!

Let's keep the talk to Elecraft products!

Ray,
N6VR



On Mon, Feb 13, 2017 at 7:23 PM, Eric Swartz - WA6HHQ, Elecraft <
[hidden email]> wrote:

> Folks, I just returned from 5 days on the road for the Orlando Hamcation
> hamfest and saw this huge thread. As per list guidelines, please self
> moderate (i.e. - End) OT threads like this after 5-10 posts. Please do not
> wait for me to jump in.
>
> Lets end the thread at this time - this topic has certainly been beaten to
> death.. ;-)
>
> 73,
> Eric
> Moderator etc.
> elecraft.com
> _..._
>
> ______________________________________________________________
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--
Ray,
N6VR
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Re: EFHW

Elecraft mailing list
In reply to this post by Eric Swartz - WA6HHQ, Elecraft
It was nice to see you again Eric, and enjoyed your presentation again in Orlando !
Look for Elecraft there next year !!

73 de Ed
N7EDK

Sent from my iPhone

> On Feb 13, 2017, at 21:23, Eric Swartz - WA6HHQ, Elecraft <[hidden email]> wrote:
>
> Folks, I just returned from 5 days on the road for the Orlando Hamcation hamfest and saw this huge thread. As per list guidelines, please self moderate (i.e. - End) OT threads like this after 5-10 posts. Please do not wait for me to jump in.
>
> Lets end the thread at this time - this topic has certainly been beaten to death.. ;-)
>
> 73,
> Eric
> Moderator etc.
> elecraft.com
> _..._
>
>

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Re: EFHW

Eric Swartz - WA6HHQ, Elecraft
Administrator
Thanks Ed! It was a great show for us this year and we enjoyed talking with
everyone.
Eric
/elecraft.com/

On 2/14/2017 2:50 PM, Edward Kacura wrote:

> It was nice to see you again Eric, and enjoyed your presentation again in Orlando !
> Look for Elecraft there next year !!
>
> 73 de Ed
> N7EDK
>
> Sent from my iPhone
>
>> On Feb 13, 2017, at 21:23, Eric Swartz - WA6HHQ, Elecraft <[hidden email]> wrote:
>>
>> Folks, I just returned from 5 days on the road for the Orlando Hamcation hamfest and saw this huge thread. As per list guidelines, please self moderate (i.e. - End) OT threads like this after 5-10 posts. Please do not wait for me to jump in.
>>
>> Lets end the thread at this time - this topic has certainly been beaten to death.. ;-)
>>
>> 73,
>> Eric
>> Moderator etc.
>> elecraft.com
>> _..._
>>
>>

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