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KX2 Antenna Curiosity

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Bob McGraw - K4TAX

Re: Center-fed antennas

I used my Johnson Matchbox at our Field Day event about 3 years ago.   I
went through each band and several frequencies on each band and compiled
a written chart identifying the settings for each band/frequency.
After 2 hours of trying to work stations on 20M, the radio failed and
they came to wake me from my late night nap.   The result is the
Matchbox was adjusted for 80M in the CW portion and the operators were
complaining of high SWR and no power output on 20M.   It took 2 hrs for
them to observe this?    I was amazed at the number of "Extra Class"
operators at the site that thought the tuner was automatic and would
change with band / frequency changes on the radio. The radio by the way
WAS NOT an Elecraft product.

73

Bob, K4TAX

On 10/10/2019 7:35 PM, Don Wilhelm wrote:

> Joe,
>
> I agree completely, bring your Johnson Matchbox to the next Field Day!
> Or even your old plug-in coil open frame link coupled balanced tuner.
>
> Who has a link coupled tuner (like the Johnson Matchbox) these days?
> Those are big boat anchor box these days (and hard to find). I have
> one that sees little use, but I am not willing to part with it. It
> does a good job when needed.
>
> Most autotuners are of the L-network design and the manual tuners are
> typically T-network - the L-network can be a high pass or a low pass
> filter, but the more common T-network is always a high pass filter.
> If one has an old Collins tuner, it may be a Pi-network which is a low
> pass filter.
>
> As you pointed out, the link coupled tuner is a bandpass filter, but
> fixed tune bandpass filters will do just as well for multi-station
> operation.
>
> 73,
> Don W3FPR
>

K2bew

Re: Center-fed antennas

That's a sad commentary on the state of modern ham radio....
To, k2bew

On Thu, Oct 10, 2019, 10:12 PM Bob McGraw K4TAX <[hidden email]> wrote:

> I used my Johnson Matchbox at our Field Day event about 3 years ago. I
> went through each band and several frequencies on each band and compiled
> a written chart identifying the settings for each band/frequency.
> After 2 hours of trying to work stations on 20M, the radio failed and
> they came to wake me from my late night nap. The result is the
> Matchbox was adjusted for 80M in the CW portion and the operators were
> complaining of high SWR and no power output on 20M. It took 2 hrs for
> them to observe this? I was amazed at the number of "Extra Class"
> operators at the site that thought the tuner was automatic and would
> change with band / frequency changes on the radio. The radio by the way
> WAS NOT an Elecraft product.
>
> 73
>
> Bob, K4TAX
>
>
>
> On 10/10/2019 7:35 PM, Don Wilhelm wrote:
> > Joe,
> >
> > I agree completely, bring your Johnson Matchbox to the next Field Day!
> > Or even your old plug-in coil open frame link coupled balanced tuner.
> >
> > Who has a link coupled tuner (like the Johnson Matchbox) these days?
> > Those are big boat anchor box these days (and hard to find). I have
> > one that sees little use, but I am not willing to part with it. It
> > does a good job when needed.
> >
> > Most autotuners are of the L-network design and the manual tuners are
> > typically T-network - the L-network can be a high pass or a low pass
> > filter, but the more common T-network is always a high pass filter.
> > If one has an old Collins tuner, it may be a Pi-network which is a low
> > pass filter.
> >
> > As you pointed out, the link coupled tuner is a bandpass filter, but
> > fixed tune bandpass filters will do just as well for multi-station
> > operation.
> >
> > 73,
> > Don W3FPR
> >
>
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Bob McGraw - K4TAX

Re: KX2 Antenna Curiosity

In reply to this post by Tim McDonough N9PUZ

The only issue I've encountered with single band antennas, to staff a
Field Day site to operate 2 or 3 stations per band, and 5 bands, there
needs to be some 10 to 15 antennas erected.    Where as a single 135 ft
wire with a balanced feed system, a good 1:1 balun, and a good tuner
{not one of those internal radio 3:1 tuners} will allow each station to
operate 5 bands with one antenna.   Thus 3 stations = 3 antennas.   That
greatly simplifies operation and installation.

After all Field Day was conceived to allow hams to operate under less
than ideal conditions and to commence operation as expediently as
possible.   I don't think installing 10 to 15 antennas for 2 or 3
stations falls under the definition of expediently.

I totally agree with Joe, W4TV where he says "The one "multiband"
antenna one can use in a multi-transmitter
configuration is the flat-top with open wire feeders and a *Link
coupled* tuner. The link coupled tuner is a bandpass filter
that significantly reduces harmonic/broadband noise just like the "Q" of
a single band antenna."

The optimum end result of any multi transmitter site is to have clean
transmitters.   We've been begging for better receivers, now it is time
to beg for cleaner transmitters.

73

Bob, K4TAX

On 10/10/2019 1:59 PM, Tim N9PUZ wrote:

> If you are talking about a single band dipole then any half wave dipole cut
> to the standard formula and fed with good quality coax should work well. If
> you want a "multi band" dipole then I would recommend cutting it for the
> lowest frequency you plan to operate and feeding it with balanced line.
> Even the best coax can have a lot of loss under high SWR conditions
> (between your tuner and the antenna feedpoint) whereas even at 1 10:1 SWR
> balanced line does not have much loss. The radiation pattern of a multi
> band configuration can vary a lot from band to band.
>
> The end fed wire you describe is not specific to the KX2. You typically
> want the longest wire possible that is NOT a half wavelength or even
> multiple on any band you want to operate. The main reason for this is when
> a wire is a half wave or an even multiple the impedance at the end of the
> wire can be very high and it is more difficult for most tuners to obtain a
> match there. By it NOT being a half wave, the impedance is lower and a wide
> range tuner like the one in your KX2 can match it more easily and present
> the proper impedance to the radio.
>
> Here is an article that suggests good lengths for a "random wire" antenna.
> The lengths aren't really very random, they are specifically chosen to be
> easier to match. At 58.5 feet you arrived at one of the good lengths.
>
> <https://udel.edu/~mm/ham/randomWire/>
>
> Tim N9PUZ
>
> On Thu, Oct 10, 2019 at 11:03 AM Joseph Shuman via Elecraft <
> [hidden email]> wrote:
>
>> I have had my KX2 with the ATU for about 10 months and operate on 40m QRP
>> SSB from various locations. Experimenting with different antennas I have
>> experienced best results with a 58.5’ wire tossed about 25’ up a tree with
>> a 16.5’ counterpoise. I ran the same length wire from my house to the
>> workshop, grounded the shield side of the cable, and have seen similar
>> results to the field setup.
>>
>> Is there some engineering/design factor of the KX2 for this type of
>> antenna setup? I am planning to setup a Dipole at home, but as a newbie am
>> wondering if the “ideal” Ham Dipole can be expected to improve performance.
>>
>> Keeping Watch-
>> shu
>>
>> Joe Shuman
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k6mkf

Re: Center-fed antennas

In reply to this post by Bob McGraw - K4TAX

Extra Class licensees vs. Extra Class Operators ... huge delta there ...

-- 73 de Mike Flowers, K6MKF, NCDXC - "It's about DX!"

> On Oct 10, 2019, at 4:12 PM, Bob McGraw K4TAX <[hidden email]> wrote:
>
> I used my Johnson Matchbox at our Field Day event about 3 years ago. I went through each band and several frequencies on each band and compiled a written chart identifying the settings for each band/frequency. After 2 hours of trying to work stations on 20M, the radio failed and they came to wake me from my late night nap. The result is the Matchbox was adjusted for 80M in the CW portion and the operators were complaining of high SWR and no power output on 20M. It took 2 hrs for them to observe this? I was amazed at the number of "Extra Class" operators at the site that thought the tuner was automatic and would change with band / frequency changes on the radio. The radio by the way WAS NOT an Elecraft product.
>
> 73
>
> Bob, K4TAX
>
>
>
>> On 10/10/2019 7:35 PM, Don Wilhelm wrote:
>> Joe,
>>
>> I agree completely, bring your Johnson Matchbox to the next Field Day! Or even your old plug-in coil open frame link coupled balanced tuner.
>>
>> Who has a link coupled tuner (like the Johnson Matchbox) these days? Those are big boat anchor box these days (and hard to find). I have one that sees little use, but I am not willing to part with it. It does a good job when needed.
>>
>> Most autotuners are of the L-network design and the manual tuners are typically T-network - the L-network can be a high pass or a low pass filter, but the more common T-network is always a high pass filter. If one has an old Collins tuner, it may be a Pi-network which is a low pass filter.
>>
>> As you pointed out, the link coupled tuner is a bandpass filter, but fixed tune bandpass filters will do just as well for multi-station operation.
>>
>> 73,
>> Don W3FPR
>>
>
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Jim Brown-10

Re: Center-fed antennas

In reply to this post by alorona

On 10/10/2019 4:56 PM, Al Lorona wrote:

> an undue fear of noise, which some hams have,

NO fear of noise is undue. It is EVERYWHERE, and it gets worse every day!

73, Jim K9YC

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Vic Rosenthal

Re: Center-fed antennas

In reply to this post by Lyn WØLEN

Things I’ve learned by experience:

In 63 years as a ham, I’ve had several :-) HF antennas. The ones that gave me the greatest overall satisfaction have been balanced, horizontal antennas. The worst have been verticals with inadequate radial systems or low random-length wires. Inverted Vs with angles less than 90 degrees between the wires are not much good, either.

There is no simpler way to make an efficient multiband antenna than to feed a dipole of at least 1/2 wavelength at the lowest frequency with open wire line. With some care in choosing the length of the line, a 1/4 wave dipole can work almost as well. I’ve worked over 300 countries on CW in the last 5 years on the bands from 40-10m with a 10m long rotary dipole, in an urban area (it is up 35m on a building and I run a kW, I admit). I regularly bust pileups on 40m with it.

1:1 baluns work to feed open wire lines, but can become inefficient in some circumstances and heat up. It’s possible to solve this by compensating for reactance with a pair of capacitors or inductors before the balun, but a better solution is a true balanced antenna tuner.

“True Ladder Line” is a good product, but it’s easy to make your own, and you can use no. 12 (2 mm) wire for lower loss.

Sometimes a 4:1 balun may give a better match, but it will be less efficient (heat) and do a poorer job of keeping RF out of the shack.

Nothing has worked better for me at cleaning up RF in the shack than an old Johnson Matchbox, a true balanced tuner.

Victor 4X6GP

> On 10 Oct 2019, at 23:56, Lyn Norstad <[hidden email]> wrote:
>
> I'm having great success with a horizontal center-fed "dipole" that has been sized (360 feet long) to be an Extended Double Zepp (4.7 dbi gain) and cut for the low end of 80 meters. I feed it with 600 ohm "True" Ladder Line from a Balun Designs Hybrid Balun (1:1 Current and 4:1 Voltage all in one case). A short run of coax from the balun to my KAT500, and I am in business at any frequency on 160 - 6 meters.
>
> It's oriented to be an effective NVIS radiator in a N-S pattern on 80m, by design, and to have major lobes on the other bands in other directions - also by design. For me, it's the most efficient and effective way to utilize our lot space (400 feet clear) and still be "under the radar" in our HOA.
>
> Birds seem to like it, and I find that it seems to be especially attractive to Hummingbirds, my XYL's favorites. A win-win, in my book.
>
> 73
> Lyn, WØLEN
>
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of Al Lorona
> Sent: Thursday, October 10, 2019 3:25 PM
> To: [hidden email]; David Gilbert
> Subject: [Elecraft] Center-fed antennas
>
> My experience with single vertical or sloping wires is exactly the same as AB7E's. I have, over almost twice as many Field Days as Dave, come to a similar conclusion, with the slight difference being my preference for an "all-band dipole" fed with balanced line. This obviates the balun and reduces feedline loss to negligible, so obviously I am maximizing efficiency at the expense of any other possible advantage. (I can usually hear much better than I can be heard... so thus far this has been a valid decision.)
>
> To sum up what I and what I think Dave are saying, you can't beat a horizontal, center-fed wire up as high as you can get it. Its simplicity, the flexibility it gives you to QSY (with a good tuner), and its high efficiency are almost unbeatable.
>
> As a side note, the center-fed horizontal wire I have used here at home is totally non-resonant. I don't even know how long it is. Once you give up the obsession with resonant antenna length, you gain a huge freedom of choice.
>
> In the bottom of the sunspot cycle, these advantages are somewhat reduced because an op, especially on Field Day, might opt to forget about any band higher than 20 meters -- and these days even 20 is questionable. This means you can probably make do with coaxial cable and a balun for operation on 2 or 3 bands but the general idea still holds.
>
> Al W6LX
>
>
>> Yes, a center fed normal dipole with the middle (high current portion)
>> higher off the ground (say 50 feet for 40m) and a common mode choke at
>> the feedpoint would almost assuredly perform better.
>>
>> 73,
>> Dave AB7E
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Vic Rosenthal

Re: Center-fed antennas

In reply to this post by Joe Subich, W4TV-4

You bet. The Johnson Matchbox is as good as any expensive band pass filter.

Victor 4X6GP

> On 11 Oct 2019, at 2:57, Joe Subich, W4TV <[hidden email]> wrote:
>
>
> The one "multiband" antenna one can use in a multi-transmitter
> configuration is the flat-top with open wire feeders and a
> *Link coupled* tuner. The link coupled tuner is a bandpass filter
> that significantly reduces harmonic/broadband noise just like the
> "Q" of a single band antenna.
>
> 73,
>
> ... Joe, W4TV
>
>
>> On 2019-10-10 7:44 PM, Don Wilhelm wrote:
>> Bob,
>> Bandpass filters at each station will help a lot, but they do not have infinite out of band rejection.
>> There is still a huge benefit with single band antennas. My club uses both.
>> Last Field Day (3F operation) one station got on the air with a multiband vertical, and all other operators jumped on that operator to shut him down quickly! The multi-band antenna radiated harmonics of the radio. Even though the transmitter met the -43 dB harmonic required by the FCC, the proximity of the multiband antenna to other antennas caused problems (that station was not using a bandpass filter).
>> So for Field Day multi-station operation, single band antennas, bandpass filters and transmitters with low phase noise are important. We were not able to orient the antennas end to end due to space considerations at the EOC site, so we had to compromise on that, which makes the other factors very important.
>> I need to point out that as an experiment, a 2nd station used an antenna on 20 meters separated from the main 20 meters, and we were able to operate one on CW (K3) at the same time as the other station (Icom) used digital and SSB modes. We had some mutual interference, but it was minimal. The K3 did not interfere much with the Icom due to the K3's low phase noise, but the Icom did raise the background noise level on the K3.
>> 73,
>> Don W3FPR
>
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Richard Corfield

Re: Center-fed antennas

In reply to this post by alorona

I don't do field day. I've been using monoband dipoles so far for portable
operations due to cost and weight constraints. They work incredibly well,
and I hope to go out with a high Q antenna for 30m and a long pole to try
end fed vertical. (My long pole seems stuck in the post! Courier emailed.).
That said, an antenna which really should be 30m only due to its resonant
matching circuit can be operated on neighbouring bands using the KX3's
tuner. I've had contacts over reasonable distance on 40m with it.

The multiband antennae seem attractive for things like SOTA and single
station operation. At the moment I need to drop my antenna and change links
around to change band. It doesn't take too long to be fair. I'll experiment
with a multiband off centre fed antenna which, even if it ends up too heavy
to carry up a mountain, could make a useful home station antenna. At the
moment my portable setup is set up in the garden but I wonder how well the
home made antenna will stand up to our increasingly winter weather.

- Richard

On Fri, 11 Oct 2019 at 00:57, Al Lorona <[hidden email]> wrote:

> Fair enough, but it kinda goes without saying that in a group FD with 1
> station per band they'll use resonant, single-band antennas. If this is our
> best argument against the 'multiband dipole', then that antenna still holds
> its own pretty well in a multitude of other situations.
>
> I have always found a deep resistance and opposition to this antenna.
> Whether it's an unwillingness to use antenna tuners, which many hams have,
> or an undue fear of noise, which some hams have, or a belief that open-wire
> line is noisier/weirder/harder/impossible-to-go-through-walls, which many
> hams believe, the visceral reaction against this antenna always amazes and
> baffles me.
>
> Please forgive my belligerence... the Dodgers lost and I've been in a sour
> mood all day.
>
> Al W6LX
> ______________________________________________________________
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Elecraft mailing list

Re: KX2 Antenna Curiosity

In reply to this post by Bob McGraw - K4TAX

I'd like to suggest that one very good reason for using centre-fed and external matching unit is because the harmonic pickup from nearby stations is much reduced compared to multi-band antennas. This is best implemented when the antenna is as near perfectly balanced as possible to avoid feedline pickup. A *proper* choke to cancel out-of-balance currents should be helpful in this regard.

For single station field days, I've used the Spiderbeam 807 off-centre-fed inverted V dipole on a f/g pole which is a fast way to get on air without an external matching unit to fiddle with. Common mode current is virtually zero. It's a great solution for beginners reducing the fiddle factor, ie plug and play KISS. Less to carry out into the field as well.

David G3UNA/G6CP
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Gwen Patton

Re: KX2 Antenna Curiosity

I have a KX3 instead of a KX2, but I frequently go out in the field to play
radio at local parks and other scenic spots. I have a number of antennas,
but one of my favorites is one I built recently, a link dipole for 40, 30,
and 20. It's tuned for the CW portions of the bands, so it doesn't need
much tuning, but if I want to work phone I hit the internal tuner just to
tweak it a little bit. I suspend it on top of a 20-foot telescopic
fiberglass pole from SOTABeams, secured in a drive-on mount and held down
by one of the tires of my E-150 conversion van. I run it in inverted-V
configuration, using stakes or photographers' sandbags at the far ends if
the location doesn't like stakes.

I didn't bother with baluns or anything. I just wired the coax to the
midpoint and trimmed it up that way using an analyzer. I get good results
with it on CW or phone, easily going from the Philadelphia suburbs to the
Michigan Upper Penninsula on 40m phone with 10 watts. If I find that I'm
getting stray RF, I have a big isolator choke I can run the line through
that clobbers it nicely.

73,
Gwen, NG3P

On Fri, Oct 11, 2019 at 6:55 AM CUTTER DAVID via Elecraft <
[hidden email]> wrote:

> I'd like to suggest that one very good reason for using centre-fed and
> external matching unit is because the harmonic pickup from nearby stations
> is much reduced compared to multi-band antennas. This is best implemented
> when the antenna is as near perfectly balanced as possible to avoid
> feedline pickup. A *proper* choke to cancel out-of-balance currents should
> be helpful in this regard.
>
> For single station field days, I've used the Spiderbeam 807 off-centre-fed
> inverted V dipole on a f/g pole which is a fast way to get on air without
> an external matching unit to fiddle with. Common mode current is virtually
> zero. It's a great solution for beginners reducing the fiddle factor, ie
> plug and play KISS. Less to carry out into the field as well.
>
> David G3UNA/G6CP
> ______________________________________________________________
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--

-+-+-+-+-
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http://quarktime.net
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rich hurd WC3T

Re: KX2 Antenna Curiosity

Simple is good

On Fri, Oct 11, 2019 at 07:07 Gwen Patton <[hidden email]> wrote:

> I have a KX3 instead of a KX2, but I frequently go out in the field to play
> radio at local parks and other scenic spots. I have a number of antennas,
> but one of my favorites is one I built recently, a link dipole for 40, 30,
> and 20. It's tuned for the CW portions of the bands, so it doesn't need
> much tuning, but if I want to work phone I hit the internal tuner just to
> tweak it a little bit. I suspend it on top of a 20-foot telescopic
> fiberglass pole from SOTABeams, secured in a drive-on mount and held down
> by one of the tires of my E-150 conversion van. I run it in inverted-V
> configuration, using stakes or photographers' sandbags at the far ends if
> the location doesn't like stakes.
>
> I didn't bother with baluns or anything. I just wired the coax to the
> midpoint and trimmed it up that way using an analyzer. I get good results
> with it on CW or phone, easily going from the Philadelphia suburbs to the
> Michigan Upper Penninsula on 40m phone with 10 watts. If I find that I'm
> getting stray RF, I have a big isolator choke I can run the line through
> that clobbers it nicely.
>
> 73,
> Gwen, NG3P
>
> On Fri, Oct 11, 2019 at 6:55 AM CUTTER DAVID via Elecraft <
> [hidden email]> wrote:
>
> > I'd like to suggest that one very good reason for using centre-fed and
> > external matching unit is because the harmonic pickup from nearby
> stations
> > is much reduced compared to multi-band antennas. This is best
> implemented
> > when the antenna is as near perfectly balanced as possible to avoid
> > feedline pickup. A *proper* choke to cancel out-of-balance currents
> should
> > be helpful in this regard.
> >
> > For single station field days, I've used the Spiderbeam 807
> off-centre-fed
> > inverted V dipole on a f/g pole which is a fast way to get on air without
> > an external matching unit to fiddle with. Common mode current is
> virtually
> > zero. It's a great solution for beginners reducing the fiddle factor, ie
> > plug and play KISS. Less to carry out into the field as well.
> >
> > David G3UNA/G6CP
> > ______________________________________________________________
> > 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
> > Message delivered to [hidden email]
> >
>
>
> --
>
> -+-+-+-+-
> Jenny Everywhere's Infinite: Quark Time
> http://quarktime.net
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--
72,
Rich Hurd / WC3T / DMR: 3142737
Northampton County RACES, EPA-ARRL Public Information Officer for Scouting
Latitude: 40.761621 Longitude: -75.288988 (40°45.68' N 75°17.33' W) Grid:
*FN20is*
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Wes Stewart-2

Re: Center-fed antennas

In reply to this post by Vic Rosenthal

I don't suppose your callsign has anything to do with the success of your
antennas.:-)

Wes N7WS

On 10/10/2019 10:54 PM, Vic Rosenthal wrote:

> Things I’ve learned by experience:
>
> In 63 years as a ham, I’ve had several :-) HF antennas. The ones that gave me the greatest overall satisfaction have been balanced, horizontal antennas. The worst have been verticals with inadequate radial systems or low random-length wires. Inverted Vs with angles less than 90 degrees between the wires are not much good, either.
>
> There is no simpler way to make an efficient multiband antenna than to feed a dipole of at least 1/2 wavelength at the lowest frequency with open wire line. With some care in choosing the length of the line, a 1/4 wave dipole can work almost as well. I’ve worked over 300 countries on CW in the last 5 years on the bands from 40-10m with a 10m long rotary dipole, in an urban area (it is up 35m on a building and I run a kW, I admit). I regularly bust pileups on 40m with it.
>
> 1:1 baluns work to feed open wire lines, but can become inefficient in some circumstances and heat up. It’s possible to solve this by compensating for reactance with a pair of capacitors or inductors before the balun, but a better solution is a true balanced antenna tuner.
>
> “True Ladder Line” is a good product, but it’s easy to make your own, and you can use no. 12 (2 mm) wire for lower loss.
>
> Sometimes a 4:1 balun may give a better match, but it will be less efficient (heat) and do a poorer job of keeping RF out of the shack.
>
> Nothing has worked better for me at cleaning up RF in the shack than an old Johnson Matchbox, a true balanced tuner.
>
> Victor 4X6GP

Martin Sole-3

Re: Center-fed antennas

Ha ha, that's a good one, I too have a 20dB callsign. Not always but I'm
sure on occasion it helps. I often get 10 to 20 over nine reports
running 100 watts to a 2 element (Force 12 C3 @ 24m) from Europe when
more powerful stations from there make only 5-6 to 5-7 here.

Martin, HS0ZED

On 11/10/2019 19:32, Wes wrote:

> I don't suppose your callsign has anything to do with the success of
> your antennas.:-)
>
> Wes N7WS
>
> On 10/10/2019 10:54 PM, Vic Rosenthal wrote:
>> Things I’ve learned by experience:
>>
>> In 63 years as a ham, I’ve had several :-) HF antennas. The ones that
>> gave me the greatest overall satisfaction have been balanced,
>> horizontal antennas. The worst have been verticals with inadequate
>> radial systems or low random-length wires. Inverted Vs with angles
>> less than 90 degrees between the wires are not much good, either.
>>
>> There is no simpler way to make an efficient multiband antenna than
>> to feed a dipole of at least 1/2 wavelength at the lowest frequency
>> with open wire line. With some care in choosing the length of the
>> line, a 1/4 wave dipole can work almost as well. I’ve worked over 300
>> countries on CW in the last 5 years on the bands from 40-10m with a
>> 10m long rotary dipole, in an urban area (it is up 35m on a building
>> and I run a kW, I admit). I regularly bust pileups on 40m with it.
>>
>> 1:1 baluns work to feed open wire lines, but can become inefficient
>> in some circumstances and heat up. It’s possible to solve this by
>> compensating for reactance with a pair of capacitors or inductors
>> before the balun, but a better solution is a true balanced antenna
>> tuner.
>>
>> “True Ladder Line” is a good product, but it’s easy to make your own,
>> and you can use no. 12 (2 mm) wire for lower loss.
>>
>> Sometimes a 4:1 balun may give a better match, but it will be less
>> efficient (heat) and do a poorer job of keeping RF out of the shack.
>>
>> Nothing has worked better for me at cleaning up RF in the shack than
>> an old Johnson Matchbox, a true balanced tuner.
>>
>> Victor 4X6GP
>
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Lyn WØLEN

Re: Center-fed antennas

In reply to this post by Rick WA6NHC-2

Rick -

You may have a balun issue. I had problems too until I switched to the 1:1 / 4:1 hybrid (based on antenna analyzer measurements). And now, 160m matches fine for me. In fact, I made over 200 contacts (FT8, and mostly stateside) on 160m last week.

The KAT500 is "supposedly" limited to matching up to a 10:1 SWR. That added 4:1 balun really brought the 160m impedance down to a manageable (and matchable) level.

My ladder line feed is about 160 feet, then the balun, and finally about 13 feet of RG8XU to the KAT500.

73
Lyn, WØLEN

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Rick WA6NHC
Sent: Thursday, October 10, 2019 6:17 PM
To: [hidden email]
Subject: Re: [Elecraft] Center-fed antennas

I have over 200 countries on a similar antenna, though I had to use
another tuner than the KAT500, for 160M. Average height was about 35'.

Just keep the coax short, like under 10' and as much center fed wire as
you can put in the air, it'll play. It won't rock your world, it'll
make you work for some of the DX, but that teaches patience and
operating technique, still win-win.

Rick nhc

On 10/10/2019 1:56 PM, Lyn Norstad wrote:

> I'm having great success with a horizontal center-fed "dipole" that has been sized (360 feet long) to be an Extended Double Zepp (4.7 dbi gain) and cut for the low end of 80 meters. I feed it with 600 ohm "True" Ladder Line from a Balun Designs Hybrid Balun (1:1 Current and 4:1 Voltage all in one case). A short run of coax from the balun to my KAT500, and I am in business at any frequency on 160 - 6 meters.
>
> It's oriented to be an effective NVIS radiator in a N-S pattern on 80m, by design, and to have major lobes on the other bands in other directions - also by design. For me, it's the most efficient and effective way to utilize our lot space (400 feet clear) and still be "under the radar" in our HOA.
>
> Birds seem to like it, and I find that it seems to be especially attractive to Hummingbirds, my XYL's favorites. A win-win, in my book.
>
> 73
> Lyn, WØLEN
>
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of Al Lorona
> Sent: Thursday, October 10, 2019 3:25 PM
> To: [hidden email]; David Gilbert
> Subject: [Elecraft] Center-fed antennas
>
> My experience with single vertical or sloping wires is exactly the same as AB7E's. I have, over almost twice as many Field Days as Dave, come to a similar conclusion, with the slight difference being my preference for an "all-band dipole" fed with balanced line. This obviates the balun and reduces feedline loss to negligible, so obviously I am maximizing efficiency at the expense of any other possible advantage. (I can usually hear much better than I can be heard... so thus far this has been a valid decision.)
>
> To sum up what I and what I think Dave are saying, you can't beat a horizontal, center-fed wire up as high as you can get it. Its simplicity, the flexibility it gives you to QSY (with a good tuner), and its high efficiency are almost unbeatable.
>
> As a side note, the center-fed horizontal wire I have used here at home is totally non-resonant. I don't even know how long it is. Once you give up the obsession with resonant antenna length, you gain a huge freedom of choice.
>
> In the bottom of the sunspot cycle, these advantages are somewhat reduced because an op, especially on Field Day, might opt to forget about any band higher than 20 meters -- and these days even 20 is questionable. This means you can probably make do with coaxial cable and a balun for operation on 2 or 3 bands but the general idea still holds.
>
> Al W6LX
>
>
>> Yes, a center fed normal dipole with the middle (high current portion)
>> higher off the ground (say 50 feet for 40m) and a common mode choke at
>> the feedpoint would almost assuredly perform better.
>>
>> 73,
>> Dave AB7E
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Eric Swartz - WA6HHQ

Re: Center-fed antennas

Administrator

Wow! We're way over the single topic posting limit on this thread. Let's end it
for now in the interest of helping others survive email overload.

73,
Eric
/mooderator.. elecraft.com/

On 10/11/2019 8:52 AM, Lyn Norstad wrote:

Rick WA6NHC-2

Re: Center-fed antennas

In reply to this post by Lyn WØLEN

Lyn,

That was at the old QTH in CA, here I'm using an inverted L for most
bands (temporarily) and a dipole for 80M (which came down in a
windstorm, couldn't take the weight of the 10' branch that hit it). The
match for 80M on the L is well beyond the range of the KAT500.

I'm shifting to a SteppIR DB36 (80-6M) and will single band the Inverted
L. The tower is up, I'm assembling the antenna now, in a race to beat
winter (already snowed twice in the last two weeks).

Next year, I'll make a new L in a better location and add a tuning
circuit to the L to allow it to resonate on 80/160M, giving me an option
for 80, rotatable dipole or vertical (and two RBOG) or diversity a few
different ways. Because of the lower noise here, the L plays well on
160M and I've enjoyed spending considerable time on the band.

My original point was to encourage simply putting up some wire; it will
radiate and it's a cheap and fun way to learn. Center fed makes it much
easier to tame (but that depends on what each leg is near too). Because
of local conditions (and lack of height), my dipole was 370', ~60' of
450 ohm window line, 4:1 common mode choke, 10' of coax. It had plenty
of pointy pattern spikes, not always in the needed direction and on 40M
it absolutely ROCKED. It was specifically NON-resonant on any ham band
yet provided some gain on most bands, once the tuner managed the load.

Even the existing (will be moved/rebuilt next spring) 160M Inverted L
was a 20 minute install that shouldn't work(but gave me over 100 Top
Band DX contacts last winter); simply a piece of wire over a tree (at
65'), a 1:1 CMC bonded to a water pipe for counterpoise (NOT efficient)
and coax to the shack. It's brought a lot of fun to ham radio (now that
I can hear without sub/urban noise).

73,
Rick wa6nhc
North Idaho

On 10/11/2019 8:52 AM, Lyn Norstad wrote:

> Rick -
>
> You may have a balun issue. I had problems too until I switched to the 1:1 / 4:1 hybrid (based on antenna analyzer measurements). And now, 160m matches fine for me. In fact, I made over 200 contacts (FT8, and mostly stateside) on 160m last week.
>
> The KAT500 is "supposedly" limited to matching up to a 10:1 SWR. That added 4:1 balun really brought the 160m impedance down to a manageable (and matchable) level.
>
> My ladder line feed is about 160 feet, then the balun, and finally about 13 feet of RG8XU to the KAT500.
>
> 73
> Lyn, WØLEN
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of Rick WA6NHC
> Sent: Thursday, October 10, 2019 6:17 PM
> To: [hidden email]
> Subject: Re: [Elecraft] Center-fed antennas
>
> I have over 200 countries on a similar antenna, though I had to use
> another tuner than the KAT500, for 160M. Average height was about 35'.
>
> Just keep the coax short, like under 10' and as much center fed wire as
> you can put in the air, it'll play. It won't rock your world, it'll
> make you work for some of the DX, but that teaches patience and
> operating technique, still win-win.
>
> Rick nhc
>
>
> On 10/10/2019 1:56 PM, Lyn Norstad wrote:
>> I'm having great success with a horizontal center-fed "dipole" that has been sized (360 feet long) to be an Extended Double Zepp (4.7 dbi gain) and cut for the low end of 80 meters. I feed it with 600 ohm "True" Ladder Line from a Balun Designs Hybrid Balun (1:1 Current and 4:1 Voltage all in one case). A short run of coax from the balun to my KAT500, and I am in business at any frequency on 160 - 6 meters.
>>
>> It's oriented to be an effective NVIS radiator in a N-S pattern on 80m, by design, and to have major lobes on the other bands in other directions - also by design. For me, it's the most efficient and effective way to utilize our lot space (400 feet clear) and still be "under the radar" in our HOA.
>>
>> Birds seem to like it, and I find that it seems to be especially attractive to Hummingbirds, my XYL's favorites. A win-win, in my book.
>>
>> 73
>> Lyn, WØLEN
>>
>>
>> -----Original Message-----
>> From: [hidden email] [mailto:[hidden email]] On Behalf Of Al Lorona
>> Sent: Thursday, October 10, 2019 3:25 PM
>> To: [hidden email]; David Gilbert
>> Subject: [Elecraft] Center-fed antennas
>>
>> My experience with single vertical or sloping wires is exactly the same as AB7E's. I have, over almost twice as many Field Days as Dave, come to a similar conclusion, with the slight difference being my preference for an "all-band dipole" fed with balanced line. This obviates the balun and reduces feedline loss to negligible, so obviously I am maximizing efficiency at the expense of any other possible advantage. (I can usually hear much better than I can be heard... so thus far this has been a valid decision.)
>>
>> To sum up what I and what I think Dave are saying, you can't beat a horizontal, center-fed wire up as high as you can get it. Its simplicity, the flexibility it gives you to QSY (with a good tuner), and its high efficiency are almost unbeatable.
>>
>> As a side note, the center-fed horizontal wire I have used here at home is totally non-resonant. I don't even know how long it is. Once you give up the obsession with resonant antenna length, you gain a huge freedom of choice.
>>
>> In the bottom of the sunspot cycle, these advantages are somewhat reduced because an op, especially on Field Day, might opt to forget about any band higher than 20 meters -- and these days even 20 is questionable. This means you can probably make do with coaxial cable and a balun for operation on 2 or 3 bands but the general idea still holds.
>>
>> Al W6LX
>>
>>
>>> Yes, a center fed normal dipole with the middle (high current portion)
>>> higher off the ground (say 50 feet for 40m) and a common mode choke at
>>> the feedpoint would almost assuredly perform better.
>>>
>>> 73,
>>> Dave AB7E
>> ______________________________________________________________
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Phil Kane-2

Re: Center-fed antennas

In reply to this post by Wes Stewart-2

On 10/11/2019 5:32 AM, Wes wrote:

> I don't suppose your callsign [ 4X6GP ] has anything to do with the success of
> your antennas.:-)

When I was 4X4UQ in the mid-1960s I had to beat off the Europeans while
running 75 watts into a tri-bander about 1 meter above the roof of a
4-story cinder-black building. Elecraft products weren't available yet
but the TX was a Hallicrafters HT32B, RX was a Hallicrafters SX101. I
still got 55 countries in almost 2 years with just casual QSOs.

Those were the days!--

73 de K2ASP - Phil Kane
Elecraft K2/100 s/n 5402

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
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Jim Brown-10

Re: Center-fed antennas

In reply to this post by Wes Stewart-2

On 10/11/2019 5:32 AM, Wes wrote:
> I don't suppose your callsign has anything to do with the success of
> your antennas.

Vic's original call was K2VCO. As kids, we worked on 40M traffic nets
before heading out to high school in the '50s. We reconnected about 15
years ago after he and I had both moved to W6. Vic knows whereof he speaks.

73, Jim K9YC
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Edward R Cole

Re: Center-fed antennas

In reply to this post by alorona

A simple way to make a center-fed half-wave dipole multi-band is by
using alligator clips to disconnect outer section a dipole in order
to run on a higher freq band.

Simple make a dipole for the lowest freq of interest and then cut the
wires at the length for the higher band, attach an alligator clip on
the end of the shorter wires and connect the end wires to the shorter
wires by use of a small nylon cord.

We made 80/40m dipoles for use on the Iditarod Sled Dog Race in this
manner and its called an: "Iditarod Special".

Most of the remote checkpoint stations use this for an antenna
running 100w HF radios to provide race communications support back to
Anchorage HQ (Often distances of several hundred miles). Often the
temporary dipoles were hung pretty low to the ground so they operated NVIS.

Side Note: I just disconnected my old Drake MN-2000 tuner as the
auto-tuner in my KXPA100 does the job easily. I use either KX3 or K3 with it.

73, Ed - KL7UW
http://www.kl7uw.com
Dubus-NA Business mail:
[hidden email]

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Bill Frantz

Re: Center-fed antennas

In reply to this post by Don Wilhelm

In WVARA, we have very good success running several bands on the
same antenna at the same time using triplexers. We set up our
triband yagis parallel to each other so they are in each other's
low-gain area. We have been able to operate CW, SSB, and digital
on the same band at the same time.

The other things besides well-spaced antenna towers and the
triplexer that make this operation possible are using radios
with very good receivers and transmitters, currently only
Elecraft and Flex are used, and operating QRP. Since we have
scored in the top ten for the last 10 or so years, this is a
successful formula.

73 Bill AE6JV

On 10/10/19 at 4:44 PM, [hidden email] (Don Wilhelm) wrote:

>Bandpass filters at each station will help a lot, but they do
>not have infinite out of band rejection.
>There is still a huge benefit with single band antennas. My club uses both.
>
>Last Field Day (3F operation) one station got on the air with a
>multiband vertical, and all other operators jumped on that
>operator to shut him down quickly! The multi-band antenna
>radiated harmonics of the radio. Even though the transmitter
>met the -43 dB harmonic required by the FCC, the proximity of
>the multiband antenna to other antennas caused problems (that
>station was not using a bandpass filter).
>
>So for Field Day multi-station operation, single band antennas,
>bandpass filters and transmitters with low phase noise are
>important. We were not able to orient the antennas end to end
>due to space considerations at the EOC site, so we had to
>compromise on that, which makes the other factors very important.
>
>I need to point out that as an experiment, a 2nd station used
>an antenna on 20 meters separated from the main 20 meters, and
>we were able to operate one on CW (K3) at the same time as the
>other station (Icom) used digital and SSB modes. We had some
>mutual interference, but it was minimal. The K3 did not
>interfere much with the Icom due to the K3's low phase noise,
>but the Icom did raise the background noise level on the K3.

-----------------------------------------------------------------------
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(408)356-8506 | to C's continuing support of | 16345
Englewood Ave
www.pwpconsult.com | buffer overruns. | Los Gatos,
CA 95032

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123