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CW power output and remote tuners

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Kurt Bilinski

CW power output and remote tuners

Background:
I got into ham radio back in the 1970s, getting my
license at age 12, then life moved on and my license expired. Recently, going
through my dad’s stuff after he passed away, I found his license, which brought
back many fond memories, so I decided to get back into it.

Now:
I just passed the Technician and General test (no call sign
yet) and have been looking at the state of the art - HOLY SMOKES have things
changed! Anyhow, after a lot of research, I’ve decided to get a K3, but before
that, I need an antenna. The K3 (with amp) outputs 100W. I’m pretty sure
that I’m going with an inverted-L antenna, which requires a remote antenna
tuner at its base. One promising remote tuner
is the SG-230, but it can only handle “80
watts continuous.” My question: In CW mode, how much power does the K3
output? (assuming worst-case key down 100%).

If the answer is “100W”, what remote tuner are you guys
using with inverted-Lsand your K3s? Yes, I know that the K3 can have a built-in tuner, but I
don’t think it can work with an
inverted-L.

Kurt – currently call-sign-less, but who was once WB6DSW.

(I understand about keeping posts short, but this is my intro post. Follow-ons will be shorter :)
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Kenneth Christiansen-2

Re: CW power output and remote tuners

Hi Mini Builder Kurt

I run a K3 at 100 watts to a H-Gain Hy-Tower with a MFJ-927 tuner at the base. It is specified to match from 6 to 1600 ohms and handle 200 watts SSB and CW. It gets the 12 volts feed on the same coax as the RF signal. I have had my MFJ-927 for several years and in North Dakota it has had to work from 35 degrees below zero to 110 degrees above with no problem.

I know you will get many more recommendations so I won't feel bad whatever you decide. Good luck and welcome back to ham radio.

73

Ken W0CZ
[hidden email]

Sent from my iPad

> On Dec 20, 2013, at 8:44 PM, Mini Builder <[hidden email]> wrote:
>
> Background:
> I got into ham radio back in the 1970s, getting my
> license at age 12, then life moved on and my license expired. Recently, going
> through my dad’s stuff after he passed away, I found his license, which brought
> back many fond memories, so I decided to get back into it.
>
> Now:
> I just passed the Technician and General test (no call sign
> yet) and have been looking at the state of the art - HOLY SMOKES have things
> changed! Anyhow, after a lot of research, I’ve decided to get a K3, but before
> that, I need an antenna. The K3 (with amp) outputs 100W. I’m pretty sure
> that I’m going with an inverted-L antenna, which requires a remote antenna
> tuner at its base. One promising remote tuner
> is the SG-230, but it can only handle “80
> watts continuous.” My question: In CW mode, how much power does the K3
> output? (assuming worst-case key down 100%).
>
> If the answer is “100W”, what remote tuner are you guys
> using with inverted-Lsand your K3s? Yes, I know that the K3 can have a built-in tuner, but I
> don’t think it can work with an
> inverted-L.
>
> Kurt – currently call-sign-less, but who was once WB6DSW.
>
> (I understand about keeping posts short, but this is my intro post. Follow-ons will be shorter :)
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

ny4g

Re: CW power output and remote tuners

In reply to this post by Kurt Bilinski

Hello Mini Builder

Welcome back. The K3 internal tuner is the best choice. I have used tuners of every stripe and Elecraft internal tuners have a very wide tuning range and will match everything that my other tuners won't. Why do you need a remote tuner? If you only have one antenna - you need a multiband antenna that is a wire. An inverted L will need a lot of radials to be efficient and is good for the low bands. Various wire antennas which do not need radials will do you better for 40-10m. A K3 tuner will tune an inverted L provided you cut it right. It will also tune wires of every stripe.

Ariel NY4G

Sent from my iPad

> On Dec 20, 2013, at 9:44 PM, "Mini Builder" <[hidden email]> wrote:
>
> Background:
> I got into ham radio back in the 1970s, getting my
> license at age 12, then life moved on and my license expired. Recently, going
> through my dad’s stuff after he passed away, I found his license, which brought
> back many fond memories, so I decided to get back into it.
>
> Now:
> I just passed the Technician and General test (no call sign
> yet) and have been looking at the state of the art - HOLY SMOKES have things
> changed! Anyhow, after a lot of research, I’ve decided to get a K3, but before
> that, I need an antenna. The K3 (with amp) outputs 100W. I’m pretty sure
> that I’m going with an inverted-L antenna, which requires a remote antenna
> tuner at its base. One promising remote tuner
> is the SG-230, but it can only handle “80
> watts continuous.” My question: In CW mode, how much power does the K3
> output? (assuming worst-case key down 100%).
>
> If the answer is “100W”, what remote tuner are you guys
> using with inverted-Lsand your K3s? Yes, I know that the K3 can have a built-in tuner, but I
> don’t think it can work with an
> inverted-L.
>
> Kurt – currently call-sign-less, but who was once WB6DSW.
>
> (I understand about keeping posts short, but this is my intro post. Follow-ons will be shorter :)
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

Kurt Bilinski

Re: CW power output and remote tuners

Thanks, guys.

My reasoning for thinking that I need a remote tuner is that
1. It’s recommended in about every reference I've seen, and B. What’s the
alternative? I assume it means going straight to coax (probably through a
balun) at the feed point, and putting up with whatever mismatch there is,
correct? Anyone know how much of a mismatch the K3 can handle? I know it's around 10:1 SWR, but what about impedance?

Yes, I know about the importance of a good ground on an inverted-L, that's definitely on the list.

On Friday, December 20, 2013 7:06 PM, Ariel Jacala <[hidden email]> wrote:

Hello Mini Builder

Welcome back. The K3 internal tuner is the best choice. I have used tuners of every stripe and Elecraft internal tuners have a very wide tuning range and will match everything that my other tuners won't. Why do you need a remote tuner? If you only have one antenna - you need a multiband antenna that is a wire. An inverted L will need a lot of radials to be efficient and is good for the low bands. Various wire antennas which do not need radials will do you better for 40-10m. A K3 tuner will tune an inverted L provided you cut it right. It will also tune wires of every stripe.

Ariel NY4G

Sent from my iPad

> On Dec 20, 2013, at 9:44 PM, "Mini Builder" <[hidden email]> wrote:
>
> Background:
> I got into ham radio back in the 1970s, getting my
> license at age 12, then life moved on and my license expired. Recently, going
> through my dad’s stuff after he passed away, I found his license, which brought
> back many fond memories, so I decided to get back into it.
>
> Now:
> I just passed the Technician and General test (no call sign
> yet) and have been looking at the state of the art - HOLY SMOKES have things
> changed! Anyhow, after a lot of research, I’ve decided to get a K3, but before
> that, I need an antenna. The K3 (with amp) outputs 100W. I’m pretty sure
> that I’m going with an inverted-L antenna, which requires a remote antenna
> tuner at its base. One promising remote tuner
> is the SG-230, but it can only handle “80
> watts continuous.” My question: In CW mode, how much power does the K3
> output? (assuming worst-case key down 100%).
>
> If the answer is “100W”, what remote tuner are you guys
> using with inverted-Lsand your K3s? Yes, I know that the K3 can have a built-in tuner, but I
> don’t think it can work with an
> inverted-L.
>
> Kurt – currently call-sign-less, but who was once WB6DSW.
>
> (I understand about keeping posts short, but this is my intro post. Follow-ons will be shorter :)
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net/
> Please help support this email list: http://www.qsl.net/donate.html

Re: CW power output and remote tuners

In reply to this post by Kurt Bilinski

Kurt, I have a K3 with tuner and amp. I have a 65 foot tower with a 3 element SteppIR antenna. Before Hurricane Ike I installed an inverted L with a homemade 80 meter trap. The tower supports the trap and the 80 meter portion runs from a ground stake with 5 50 foot long radials. Ike broke all the elements off my beam and while I had the beam down for repair I used the inverted L on all bands, 160 through 6 with a RG8X feed about 125 feet long and the internal tuner on the K3. I have also used the K3 with internal tuner to tune a 106 foot long wire on a submarine on all bands. I recommend you buy the K3 with the amp and tuner and skip the remote tuner. Remember, the vertical part of the inverted L does nearly all the work and the horizontal part contributes very little, so make the vertical part of the wire as long as you can. With 50 or 60 foot vertical it will be a good dx antenna.

Willis 'Cookie' Cooke
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart

________________________________
From: Mini Builder <[hidden email]>
To: "[hidden email]" <[hidden email]>
Sent: Friday, December 20, 2013 8:44 PM
Subject: [Elecraft] CW power output and remote tuners

Background:
I got into ham radio back in the 1970s, getting my
license at age 12, then life moved on and my license expired. Recently, going
through my dad’s stuff after he passed away, I found his license, which brought
back many fond memories, so I decided to get back into it.

Now:
I just passed the Technician and General test (no call sign
yet) and have been looking at the state of the art - HOLY SMOKES have things
changed! Anyhow, after a lot of research, I’ve decided to get a K3, but before
that, I need an antenna. The K3 (with amp) outputs 100W. I’m pretty sure
that I’m going with an inverted-L antenna, which requires a remote antenna
tuner at its base. One promising remote tuner
is the SG-230, but it can only handle “80
watts continuous.” My question: In CW mode, how much power does the K3
output? (assuming worst-case key down 100%).

If the answer is “100W”, what remote tuner are you guys
using with inverted-Lsand your K3s? Yes, I know that the K3 can have a built-in tuner, but I
don’t think it can work with an
inverted-L.

Kurt – currently call-sign-less, but who was once WB6DSW.

(I understand about keeping posts short, but this is my intro post. Follow-ons will be shorter :)
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html
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Gary Smith-2

Re: CW power output and remote tuners

In reply to this post by Kurt Bilinski

Kurt,

I have 5 separate wire antennas: a 160M Inv-L, a 80M inv-L, a 40M
vert, a 30M vert & a 20M vert. I've got 45 or so long radials
attached to a radial plate. An Ameritron RCS-8V Remote Coax Switch
allows me to select which of the 5 antennas to use. I have no
external tuner to the K3. I use those antennas for these bands. I do
have an internal tuner in the K3 to make its circuitry happy & not
fold back power.

16o Inv-L = 160M, 15M, 12M, 10M +6M
80 Inv-L = 80M, 17M + 12M
40M vert = 40M + 15M
30M vert = 30M
20M vert = 20M

SWR readings via a LP-100A Watt Meter
160M = 1.19 SWR
80M = 1.70
40M = 1.48
30M = 2.05
20M = 1.79
17M = 1.29 (80M inv-L)
15M = 2.39 (160M inv-L) + 1.12 (40M Vert)
12M = 2.38 (160M inv-L) + 1.69 (80M Inv-L)
10M = 1.91 (160M Inv-L)
6M = 1.45 (160M Inv-L)

I have no problem loading my tube amp into this system and on 15M &
12M I listen on each of the two antenna options for the loudest
signal that I want to work & use that antenna. Though I do get 6M,
there's enough coax loss that I don't bother doing much on 6M other
than give out points for those in 6M contests that can hear me.
Pretty much though if I can hear it I can work it (unless it's a
pileup on a new DXpedition, then I have to wait till those with nice
beams start to taper off) Hihi.

I would like 1.1 across the bands but I don't know that it will make
any difference on either end. YMMV

Just another option
73,

Gary
KA1J

<snip>

> I´ve decided to get a
> K3, but before
> that, I need an antenna. The K3 (with amp) outputs 100W. I´m
> pretty sure
> that I´m going with an inverted-L antenna, which requires a remote
> antenna
> tuner at its base. One promising remote tuner
> is the SG-230, but it can only handle "80
> watts continuous." My question: In CW mode, how much power does
> the K3
> output? (assuming worst-case key down 100%).
>
> If the answer is "100W", what remote tuner are you guys
> using with inverted-Lsand your K3s? Yes, I know that the K3 can have
> a built-in tuner, but I
> don´t think it can work with an
> inverted-L.
>
> Kurt - currently call-sign-less, but who was once WB6DSW.
>

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Jim Brown-10

Re: CW power output and remote tuners

In reply to this post by Kurt Bilinski

On 12/20/2013 7:22 PM, Mini Builder wrote:
> My reasoning for thinking that I need a remote tuner is that
> 1. It’s recommended in about every reference I've seen, and B.

That's probably because the writers aren't good engineers. See below.

> What’s the
> alternative?

Coax to a turner in the shack. Depending on the type of coax, the length
of the coax and the degree of mismatch, loss in the coax may be a lot
less than you think. If you're going to put the tuner in the shack,
spend the money for bigger coax -- a good RG8 or RG213 designed for
transmitting that has a robust copper braid shield.

> I assume it means going straight to coax (probably through a
> balun)

Not a balun, a common mode choke. See http://k9yc.com\RFI-Ham.pdf

> at the feed point, and putting up with whatever mismatch there is,
> correct? Anyone know how much of a mismatch the K3 can handle? I know it's around 10:1 SWR, but what about impedance?
>
> Yes, I know about the importance of a good ground on an inverted-L,

Ground is the wrong word, and the wrong concept. What is needed is a
good radial field, or, second best, a good counterpoise. Indeed, a
connection to the earth degrades antenna performance!

See the piece on my website about getting on 160M from a small lot. It's
mostly about antennas, and the radial/counterpoise concept is thoroughly
discussed. http://k9yc.com\publish.htm Obviously, divide the lengths
by 2 for 80M, by 4 for 40M, and so on. While you're on that website,
take a look at the Power Point about "If I Could Mount My HF Vertical on
My Roof, Should I?" And the "remote tuner or tuner in the shack?" is
addressed in the Power Point about the 43 Ft vertical.

Welcome back to the hobby! Antennas are one of the most fun parts for
me. (Contesting is first.)

73, Jim K9YC

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Re: CW power output and remote tuners

In reply to this post by Kurt Bilinski

Kurt, I have yet to find any reasonable antenna that my K3 tuner will not match except extremely short. There are no absolutes in antennas. The remote antenna matching device will be a little more efficient and will depend on what kind of coax you use and how long the coax. Bear in mind that a lot of people use QRP which is more loss than a horrendous swr on 100 feet of small coax. From what you are telling us, you will be much better off with the built in tuner. The K3 will put out at least 100 watts on all bands through 6 meters.

Willis 'Cookie' Cooke
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart

________________________________
From: Mini Builder <[hidden email]>
To: "[hidden email]" <[hidden email]>
Sent: Friday, December 20, 2013 9:22 PM
Subject: Re: [Elecraft] CW power output and remote tuners

Thanks, guys.

My reasoning for thinking that I need a remote tuner is that
1. It’s recommended in about every reference I've seen, and B. What’s the
alternative? I assume it means going straight to coax (probably through a
balun) at the feed point, and putting up with whatever mismatch there is,
correct? Anyone know how much of a mismatch the K3 can handle? I know it's around 10:1 SWR, but what about impedance?

Yes, I know about the importance of a good ground on an inverted-L, that's definitely on the list.

On Friday, December 20, 2013 7:06 PM, Ariel Jacala <[hidden email]> wrote:

Hello Mini Builder

Welcome back. The K3 internal tuner is the best choice. I have used tuners of every stripe and Elecraft internal tuners have a very wide tuning range and will match everything that my other tuners won't. Why do you need a remote tuner? If you only have one antenna - you need a multiband antenna that is a wire. An inverted L will need a lot of radials to be efficient and is good for the low bands. Various wire antennas which do not need radials will do you better for 40-10m. A K3 tuner will tune an inverted L provided you cut it right. It will also tune wires of every stripe.

Ariel NY4G

Sent from my iPad

> On Dec 20, 2013, at 9:44 PM, "Mini Builder" <[hidden email]> wrote:
>
> Background:
> I got into ham radio back in the 1970s, getting my
> license at age 12, then life moved on and my license expired. Recently, going
> through my dad’s stuff after he passed away, I found his license, which brought
> back many fond memories, so I decided to get back into it.
>
> Now:
> I just passed the Technician and General test (no call sign
> yet) and have been looking at the state of the art - HOLY SMOKES have things
> changed! Anyhow, after a lot of research, I’ve decided to get a K3, but before
> that, I need an antenna. The K3 (with amp) outputs 100W. I’m pretty sure
> that I’m going with an inverted-L antenna, which requires a remote antenna
> tuner at its base. One promising remote tuner
> is the SG-230, but it can only handle “80
> watts continuous.” My question: In CW mode, how much power does the K3
> output? (assuming worst-case key down 100%).
>
> If the answer is “100W”, what remote tuner are you guys
> using with inverted-Lsand your K3s? Yes, I know that the K3 can have a built-in tuner, but I
> don’t think it can work with an
> inverted-L.
>
> Kurt – currently call-sign-less, but who was once WB6DSW.
>
> (I understand about keeping posts short, but this is my intro post. Follow-ons will be shorter :)
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net/
> Please help support this email list: http://www.qsl.net/donate.html

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k6dgw

Re: CW power output and remote tuners

In reply to this post by Kurt Bilinski

On 12/20/2013 8:15 PM, Ron D'Eau Claire wrote:
> 1) A good ground is only important when the length is significantly
> less than 1/2 wavelength. Otherwise the impedance at the feed point
> will be relatively high, meaning a ground is needed only to keep the
> rig from floating to a problematic RF potential as I explained in my
> first post.

Ron is correct, a half-wave is *nearly* insensitive to "grounding" [i.e.
radial field]. However, strangely enough, feeding an EFHW, it really
helps to have a radial hanging off the coax shield at the balun/xfmr at
the antenna ... about 6in [15cm] long on 20m. Learned this from EZNEC
and verified it in the real universe.
>
> 2) You want adequate distance between you and the radiator to comply
> with the FCC RF exposure guidelines. You need spacing at the higher
> frequencies. There are a variety of guidelines for that, but I always
> use 2 meters at 30 MHz. It's less on the lower frequency bands.

Sadly, RF exposure may be the least of your worries if you're close to
the antenna. I have a 3" pipe that runs vertically from a 1 ft sq
utility box in the wall, opens under the desk and in the wall outside in
the carport, weather head on the top. It carries all my coax up and to
the messenger to the tower. I decided to mount a GAP Titan vertical on
the pipe just below the weatherhead. The antenna works great ... as an
antenna ... but it is 12ft over my head in the shack.

All seems well in the shack on 40 and 30m. Alas, on 20 and above, at
500W, everything electronic in the shack either forgets everything it
ever knew, or goes totally berserk. Still working on ferrite therapy.

Don't know about the exposure issue [math major, not biomed], but in the
late 50's/early 60's [late teens/very early 20's] working at the TV
station to support myself in college, I got $50 twice a year to climb
the tower [~400ft] and replace the clearance lamps which was an FAA
requirement. Station had the gear, they had it inspected twice a year
by the mfr, they sent me to climbing school at PG&E [power company], I
climbed inside the tower on a ladder, and had a fall arrester on the
steel cable down the center. A work-out to the top, but I was really
young and it wasn't exactly the most dangerous thing I'd ever do.

I climbed in the middle of the day, TX was on a ridge just off the
Pacific and the wind was constant and cold. We were also on the air,
10KW visual and 10KW aural, and at the top lamps, where the mast started
up to the turnstile antenna, I would linger a little because I got warm
for the trip down. :-) OSHA today would have a major cow. The station
hired riggers to service the beacon on top, it had a automatic spare.
$50 was a lot then, the first check fixed the brakes on my old truck,
lack of which was probably far more dangerous than the tower. :-)

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org
>
> 73 Ron AC7AC

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Kurt Bilinski

Re: CW power output and remote tuners

Thanks for all the input!

Sorry, I misspoke about grounding - yes, I know that it's not really "ground", but a grid against which the signal is balanced. It's very promising to hear that the K3's internal tuner will work, as it's less money and one less thing to deal with. Haven't decided where the antenna will go, but it'll probably be 20-30 feet from the K3, using RG-8U. Also haven't decided whether to string up wire off a tree, or build a "flag pole", stringing the horizontal wire off the top. Going that route would allow around a 50-ft vertical section without being too obvious.

FWIW, the name "Mini Builder" is getting auto-appended by Yahoo; I may change accounts to fix that. It comes from me having built several cars from scratch - you can waste hours at http://www.kimini.com/, and http://www.midlana.com/, but I know this isn't the place for that.

On Friday, December 20, 2013 9:29 PM, Fred Jensen <[hidden email]> wrote:

On 12/20/2013 8:15 PM, Ron D'Eau Claire wrote:
> 1) A good ground is only important when the length is significantly
> less than 1/2 wavelength. Otherwise the impedance at the feed point
> will be relatively high, meaning a ground is needed only to keep the
> rig from floating to a problematic RF potential as I explained in my
> first post.

Ron is correct, a half-wave is *nearly* insensitive to "grounding" [i.e.
radial field]. However, strangely enough, feeding an EFHW, it really
helps to have a radial hanging off the coax shield at the balun/xfmr at
the antenna ... about 6in [15cm] long on 20m. Learned this from EZNEC
and verified it in the real universe.
>
> 2) You want adequate distance between you and the radiator to comply
> with the FCC RF exposure guidelines. You need spacing at the higher
> frequencies. There are a variety of guidelines for that, but I always
> use 2 meters at 30 MHz. It's less on the lower frequency bands.

Sadly, RF exposure may be the least of your worries if you're close to
the antenna. I have a 3" pipe that runs vertically from a 1 ft sq
utility box in the wall, opens under the desk and in the wall outside in
the carport, weather head on the top. It carries all my coax up and to
the messenger to the tower. I decided to mount a GAP Titan vertical on
the pipe just below the weatherhead. The antenna works great ... as an
antenna ... but it is 12ft over my head in the shack.

All seems well in the shack on 40 and 30m. Alas, on 20 and above, at
500W, everything electronic in the shack either forgets everything it
ever knew, or goes totally berserk. Still working on ferrite therapy.

Don't know about the exposure issue [math major, not biomed], but in the
late 50's/early 60's [late teens/very early 20's] working at the TV
station to support myself in college, I got $50 twice a year to climb
the tower [~400ft] and replace the clearance lamps which was an FAA
requirement. Station had the gear, they had it inspected twice a year
by the mfr, they sent me to climbing school at PG&E [power company], I
climbed inside the tower on a ladder, and had a fall arrester on the
steel cable down the center. A work-out to the top, but I was really
young and it wasn't exactly the most dangerous thing I'd ever do.

I climbed in the middle of the day, TX was on a ridge just off the
Pacific and the wind was constant and cold. We were also on the air,
10KW visual and 10KW aural, and at the top lamps, where the mast started
up to the turnstile antenna, I would linger a little because I got warm
for the trip down. :-) OSHA today would have a major cow. The station
hired riggers to service the beacon on top, it had a automatic spare.
$50 was a lot then, the first check fixed the brakes on my old truck,
lack of which was probably far more dangerous than the tower. :-)

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org

>
> 73 Ron AC7AC

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Re: CW power output and remote tuners

Kurt, 20 to 30 feet of RG-213 will give you an acceptable loss even on 6 meters and almost none on the lower bands. I have over 200 feet of RG-213 feeding my SteppIR and it works pretty well on 6 meters. I feed my L with about 125 feet of RG-8X and it works very well on 160 and 80. Study the difference between a balun and an unun. You feed a balanced antenna with a balun (balanced antenna to unbalanced coax feed) and an unbalanced antenna with an unun or unbalanced to unbalanced. Neither is a magic device and both are just transformers. Vendors enclose them in PVC to keep you from seeing what is really there. All you really need to feed an inverted L is a choke made from six to eight turn coil of coax at the feed point of the antenna to keep the current off the outside of the shield. Buy an ARRL Antenna Handbook and study it. Don't try to do it all before you build your first antenna as it will take too long, but it is chock full of
good information that you can spend a lifetime absorbing. Just read about your first antenna, build it, and make it work. You can use a tree if you have a tall one or the pole, but the tree will be easier and much less expensive so start with the tree of you can. Fifty feet is tall enough to give you good results on 160 and better results on the other bands. I will stay with my recommendation to forget the external tuner and stay with the K3 tuner.

Willis 'Cookie' Cooke
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart

________________________________
From: Mini Builder <[hidden email]>
To: "[hidden email]" <[hidden email]>
Sent: Saturday, December 21, 2013 12:06 AM
Subject: Re: [Elecraft] CW power output and remote tuners

Thanks for all the input!

Sorry, I misspoke about grounding - yes, I know that it's not really "ground", but a grid against which the signal is balanced. It's very promising to hear that the K3's internal tuner will work, as it's less money and one less thing to deal with. Haven't decided where the antenna will go, but it'll probably be 20-30 feet from the K3, using RG-8U. Also haven't decided whether to string up wire off a tree, or build a "flag pole", stringing the horizontal wire off the top. Going that route would allow around a 50-ft vertical section without being too obvious.

FWIW, the name "Mini Builder" is getting auto-appended by Yahoo; I may change accounts to fix that. It comes from me having built several cars from scratch - you can waste hours at http://www.kimini.com/, and http://www.midlana.com/, but I know this isn't the place for that.

On Friday, December 20, 2013 9:29 PM, Fred Jensen <[hidden email]> wrote:

On 12/20/2013 8:15 PM, Ron D'Eau Claire wrote:
> 1) A good ground is only important when the length is significantly
> less than 1/2 wavelength. Otherwise the impedance at the feed point
> will be relatively high, meaning a ground is needed only to keep the
> rig from floating to a problematic RF potential as I explained in my
> first post.

Ron is correct, a half-wave is *nearly* insensitive to "grounding" [i.e.
radial field]. However, strangely enough, feeding an EFHW, it really
helps to have a radial hanging off the coax shield at the balun/xfmr at
the antenna ... about 6in [15cm] long on 20m. Learned this from EZNEC
and verified it in the real universe.
>
> 2) You want adequate distance between you and the radiator to comply
> with the FCC RF exposure guidelines. You need spacing at the higher
> frequencies. There are a variety of guidelines for that, but I always
> use 2 meters at 30 MHz. It's less on the lower frequency bands.

Sadly, RF exposure may be the least of your worries if you're close to
the antenna. I have a 3" pipe that runs vertically from a 1 ft sq
utility box in the wall, opens under the desk and in the wall outside in
the carport, weather head on the top. It carries all my coax up and to
the messenger to the tower. I decided to mount a GAP Titan vertical on
the pipe just below the weatherhead. The antenna works great ... as an
antenna ... but it is 12ft over my head in the shack.

All seems well in the shack on 40 and 30m. Alas, on 20 and above, at
500W, everything electronic in the shack either forgets everything it
ever knew, or goes totally berserk. Still working on ferrite therapy.

Don't know about the exposure issue [math major, not biomed], but in the
late 50's/early 60's [late teens/very early 20's] working at the TV
station to support myself in college, I got $50 twice a year to climb
the tower [~400ft] and replace the clearance lamps which was an FAA
requirement. Station had the gear, they had it inspected twice a year
by the mfr, they sent me to climbing school at PG&E [power company], I
climbed inside the tower on a ladder, and had a fall arrester on the
steel cable down the center. A work-out to the top, but I was really
young and it wasn't exactly the most dangerous thing I'd ever do.

I climbed in the middle of the day, TX was on a ridge just off the
Pacific and the wind was constant and cold. We were also on the air,
10KW visual and 10KW aural, and at the top lamps, where the mast started
up to the turnstile antenna, I would linger a little because I got warm
for the trip down. :-) OSHA today would have a major cow. The station
hired riggers to service the beacon on top, it had a automatic spare.
$50 was a lot then, the first check fixed the brakes on my old truck,
lack of which was probably far more dangerous than the tower. :-)

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org

>
> 73 Ron AC7AC

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Jim Brown-10

Re: CW power output and remote tuners

On 12/21/2013 6:56 AM, WILLIS COOKE wrote:
> Kurt, 20 to 30 feet of RG-213 will give you an acceptable loss even on 6 meters and almost none on the lower bands. I have over 200 feet of RG-213 feeding my SteppIR and it works pretty well on 6 meters. I feed my L with about 125 feet of RG-8X and it works very well on 160 and 80.

Right -- IF the SWR at the antenna is not too high, and if the feedline
is not too long. Every edition of the ARRL Handbook since at least the
50s has a graph of the increased loss due to mismatch. It's in the
chapter on Transmission Lines.

> Study the difference between a balun and an unun. You feed a balanced antenna with a balun (balanced antenna to unbalanced coax feed) and an unbalanced antenna with an unun or unbalanced to unbalanced. Neither is a magic device and both are just transformers.

WRONG! Which is why I so strongly object to the word "balun," which is
used to describe at least a half dozen very different electrical
components. Yes, there are some transformers, mostly autotransformers,
that are called baluns. But the most commonly used things that are
called "baluns" are really common mode chokes. The function of a common
mode choke is to BLOCK common mode current on the cable.

> Vendors enclose them in PVC to keep you from seeing what is really there. All you really need to feed an inverted L is a choke made from six to eight turn coil of coax at the feed point of the antenna to keep the current off the outside of the shield.

A coil of coax is a VERY misguided attempt at a common mode choke,
because it is an inductor, and in the common mode circuit, a feedline
shorter than a quarter wave is capacitive, so the inductor can resonate
with the capacitance of the line and cause common mode current to
increase! In other words, there are many practical situations in which
a coil of coax does not work at all, and makes things worse.

To make an effective common mode choke (often called a "current balun"
to disguise how it works), we need a choke that is predominantly
RESISTIVE at the frequency(ies) of interest. We achieve that by winding
turns on a ferrite material that is very lossy at the frequency(ies)
where we want the choke to be effective. A Fair-Rite #31 core is
effective from VHF down to 160M and the AM broadcast band; #43 material
is effective from about 4 MHz up to VHF. Study http://k9yc.com/RFI-Ham.pdf

> I will stay with my recommendation to forget the external tuner and stay with the K3 tuner.

Agreed -- IF it's big coax, not too long, and the mismatch between the
antenna and the feedline is 10:1 or better.

73, Jim K9YC
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Vic Rosenthal

Re: CW power output and remote tuners

In reply to this post by Kurt Bilinski