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Portable Antennas (Is there an "easy" button?)

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va3bxg

Re: Portable Antennas (near end fed)

While agree with you about outdoor, the problem is that, at times one does not have choice. Either indoor or nothing.

I wish I, and am sure others feel this way, had the access to something outdoor, but many times that is not an option.

So if one does not have the opinion, what should one do?
Robert

a 'kosher' ham
Sent from my BlackBerry device

-----Original Message-----
From: David Cutter <[hidden email]>
Sender: [hidden email]
Date: Fri, 11 May 2012 17:24:48
To: <[hidden email]>
Subject: Re: [Elecraft] Portable Antennas (near end fed)

I think you've hit the nail on the head: couple your K series to the
internet using a decent outdoor aerial at home. Spend your money for
effective communication and avoid all those nasty emc troubles in hotel
rooms, unless you can poke a wire out of the window. BTW, you probably
need permission from the hotel owner to do this.

Loops are good for receiving using an external amplifier if you need
to. You can get very good nulling of nearby noise sources. You only
need simple wire loops, no fancy hardware.

David
G3UNA

On 11/05/2012 16:09, Mike WA8BXN wrote:

>
> I too would like to hear the answers to this question! But I have an added
> question and thought. What are reasonable expectations to being able to work
> much with an in the motel room antenna? I would expect a lot of noise, a lot
> of shielding and need to use 40 or 80a meters at night which is rougher to
> do with short antennas. My approach would be Internet access to a rig at
> home.
>
> The thought is that one could test out indoor antennas in their own shack to
> see how various things work. Second thought, particularly with respect to
> small loops, I wonder if they would be useful to home use (primarily as a
> receive antenna assuming the presence of better outside antennas for
> transmitting) being easy to rotate by hand to try to null noise or QRM.
>
> 73 - Mike WA8BXN

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Jim Brown-10

Re: Portable Antennas (near end fed)

In reply to this post by va3bxg

On 5/11/2012 8:16 AM, [hidden email] wrote:
> I for one am in a quandary on what to get at dayton
>
> A buddipole, alex loop, or g4tph.

The LAST thing I would go for is any form of loaded antenna, because
they tend to have poor efficiency, limited bandwidth, and are
expensive. Small loops (small as a fraction of a wavelength) also have
generally poor efficiency.

What I would look for instead are various means of supporting a long
wire in a variety of situations. For example, there's a very nice,
non-conductive telescoping pole made by a German ham (DK?SQ) that
collapses to 1 meter and expands to 10m. I've seen various mounting
accessories and clamps to facilitate holding it either vertical or away
from a building on a railing. Tape a wire to that pole, lay out another
wire to act as a counterpoise,and you've got a very efficient TX
antenna! Wire as small as #22 makes an antenna that is much more
efficient than an inductively loaded antenna and also more broadband.

I used exactly this antenna at the annual QRP night of our local club
when I lived in Chicago. I set up my K2 with a battery on a picnic
table, taped a length of #22 to that pole, wedged the pole between the
tabletop and the seat so that it was about half-way vertical, and laid a
couple of wires out on the ground to act as a counterpoise. In a little
over an hour, running 5W, I had a half dozen QSOs on 30M and busted a
pileup into the Caribbean.

73, Jim K9YC
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Tom Azlin N4ZPT-2

Re: Portable Antennas (near end fed)

In reply to this post by Mike WA8BXN

My experience in a hotel room is they do not work well at all. Seems
like you are inside a cage with RFI emitters all around you. Even high
up in the hotel. Have had better luck outside on the grass with a dipole
or wire just hung up arm's length in the trees.

Get some wire outside and away from the building! or go outside. I have
not had any luck getting hotel rooms with real balcony options.

73, tom n4zpt

On 5/11/2012 12:09 PM, Mike WA8BXN wrote:

>
>
> I too would like to hear the answers to this question! But I have an added
> question and thought. What are reasonable expectations to being able to work
> much with an in the motel room antenna? I would expect a lot of noise, a lot
> of shielding and need to use 40 or 80a meters at night which is rougher to
> do with short antennas. My approach would be Internet access to a rig at
> home.
>
> The thought is that one could test out indoor antennas in their own shack to
> see how various things work. Second thought, particularly with respect to
> small loops, I wonder if they would be useful to home use (primarily as a
> receive antenna assuming the presence of better outside antennas for
> transmitting) being easy to rotate by hand to try to null noise or QRM.
>
> 73 - Mike WA8BXN
>
> -------Original Message-------
>
> From: [hidden email]
> Date: 5/11/2012 11:27:40 AM
> To: [hidden email]; [hidden email]
> Cc: Elecraft list
> Subject: Re: [Elecraft] Portable Antennas (near end fed)
>
> I for one am in a quandary on what to get at Dayton
>
> A buddipole, Alex loop, or g4tph. Being a road warrior, need a good working
> interior (most times hotel rooms are not accessible to the outside) portable
>
>
> And a partridge in a pear tree as well :-)
> Robert
>
> A 'kosher' ham
> Sent from my BlackBerry device
>
> -----Original Message-----
> From: Stephen Prior<[hidden email]>
> Sender: [hidden email]
> Date: Thu, 10 May 2012 08:55:54
> To: [hidden email]<[hidden email]>
> Cc: [hidden email]<[hidden email]>
> Subject: Re: [Elecraft] Portable Antennas (near end fed)
>
> Hi Fred
>
> I have been very tempted by the Alex-loop, but in the meantime have just
> Bought one of G4TPH's loops which I shall put through its paces when the
> Weather improves! I should imagine that the insensitivity to electric
> Fields in the near field would be an advantage in electrically noisy
> Environments. Even a campsite can be very noisy with the inverters from RVs
> And the like spewing out rf everywhere.
>
> I'm spoilt for choice of antennas to play with once the KX3 arrives!
>
> 73 Stephen G4SJP
>
> On Wednesday, 9 May 2012, Fred Jensen wrote:
>
>> I haven't been following this thread closely but has anyone mentioned a
>> small magnetic loop like the Alex-Loop? I've got a good SOTA friend who
>> uses one and loves it.
>>
>> 73,
>>
>> Fred K6DGW
>> - Northern California Contest Club
>> - CU in the 2012 Cal QSO Party 6-7 Oct 2012
>> - www.cqp.org
>>
>> On 5/9/2012 2:47 AM, David Cutter wrote:
>>> What I particularly like about the near end fed is that you are more in
>>> control of the local stray capacitances and such like and you only need
>>> one slender wire in the sky. I wrote a power point on the subject which
>>> needs a bit of massage but I can send it to you for interest.
>>
>> ______________________________________________________________
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>>
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>>
>
>

Bill Steffey NY9H

Re: Portable Antennas (near end fed)

In reply to this post by Jim Brown-10

about 4 years ago i successfully used a telescoping crappie fishing
pole or a folding shock-rope tent pole I forget which on a cruise
ship balcony with my k2. ....we were up maybe 80-100 feet above the water..

The #22 line went out to the end of the pole (12-??ft) then dropped
down another maybe 25 feet,,,,with a gnd to the railing.., worked the
EU from the Carib just fine

I tried to be stealthy about it ,,,, about the third day the folks
in the adjacent room were on their balcony and saw me ....
and she started hollering at me to get my attention....
SHE WANTED TO LET ME KNOW THE BAIT FELL OFF.......really....

bill ny9h/3

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Jim Brown-10

Re: Portable Antennas (near end fed)

In reply to this post by Tom Azlin N4ZPT-2

On 5/11/2012 10:46 AM, Tom Azlin N4ZPT wrote:
> My experience in a hotel room is they do not work well at all. Seems
> like you are inside a cage with RFI emitters all around you. Even high
> up in the hotel.

Right. Trying to operate on the HF bands with an antenna inside of a
metal frame building displays a complete ignorance of the Laws of
Physics. Get the antenna outside and it's a different story. Sometimes
that's possible, sometimes it is not. And it's also quite possible to
TX using indoor antennas in wood frame buildings. The problem is going
to be RX noise -- you're going to be lucky to hear anything but the
loudest signals on the band.

On the other hand, you can have some fun on VHF and UHF with a talkie in
a window on a high floor -- you can work pretty well for roughly 150
degrees of azimuth that the window provides, but the building will
shield you from signals arriving from other directions.

73, Jim K9YC
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Jim Dunstan

Re: Portable Antennas (near end fed)

In reply to this post by Stephen G4SJP

At 03:16 PM 5/11/2012 +0000, [hidden email] wrote:

>I for one am in a quandary on what to get at dayton
>
>A buddipole, alex loop, or g4tph. Being a road warrior, need a good
>working interior (most times hotel rooms are not accessible to the
>outside) portable.
>
>And a partridge in a pear tree as well :-)
>Robert
>
>a 'kosher' ham
>Sent from my BlackBerry device

Without doubt the best kind of antenna given the environment you describe
is a small tuned loop. How well it works will depend on how well it is
built (literally). The quality of the loop material and the tuning
capacitor will determine the overall efficiency (and effectiveness) of the
antenna. The buddipole in either the vertical or dipole arrangement will
only come into its own when outside and away (to some degree) from
interfering structures. I have had success with a tuned small loop indoors
but not so with center fed or end fed dipoles. However they (longer
dipoles) work well even a few feet outside the building ... eg. I used a
bent up wire dipole made of invisible fishing wire suspended a couple of
feed away from a balcony with thin bamboo poles ... it worked vy well on cw
and PSK.

73 Jim, VE3CI

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va3bxg

Re: Portable Antennas (near end fed)

In reply to this post by David Cutter

Thanks for the update. This answers the question about the buddipole. And somewhat along the same lines.

Now with KX3 I need to figure out which loop is the best (coverage etc)

Now where is that 'easy button'

-----------Original Message-----------
From: Jim Dunstan
To: [hidden email]
To: [hidden email]
To: [hidden email]
CC: Elecraft list
Date: May 11 16:15:27
Subject: Re: [Elecraft] Portable Antennas (near end fed)

At 03:16 PM 5/11/2012 +0000, [hidden email] wrote:

Without doubt the best kind of antenna given the environment you describe
is a small tuned loop. How well it works will depend on how well it is
built (literally). The quality of the loop material and the tuning
capacitor will determine the overall efficiency (and effectiveness) of the
antenna. The buddipole in either the vertical or dipole arrangement will
only come into its own when outside and away (to some degree) from
interfering structures. I have had success with a tuned small loop indoors
but not so with center fed or end fed dipoles. However they (longer
dipoles) work well even a few feet outside the building ... eg. I used a
bent up wire dipole made of invisible fishing wire suspended a couple of
feed away from a balcony with thin bamboo poles ... it worked vy well on cw
and PSK.

73 Jim, VE3CI

Robert

a 'kosher' ham
Sent from my BlackBerry device
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Phil Kane-2

Re: Portable Antennas (near end fed)

In reply to this post by Bill Steffey NY9H

On 5/11/2012 3:22 PM, Ron D'Eau Claire wrote:

> I'd not be surprised to see someone operating an HF rig without
> permission have their equipment confiscated until returning to port
> and possibly find themselves banned from future passages on the ships
> of that line.

Remember also that operation on a vessel on the high seas is subject to
the laws of the country in which the vessel is registered, and those may
give the master the authority to confiscate the equipment and not return
it. Scary.

--
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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w7aqk

Re: Portable Antennas (near end fed)

In reply to this post by David Cutter

David and All,

I have a Bravo 7K, and so far, I find it to be only a "fair" performer.
This assessment is based only on limited testing against my Sigma 40XK
vertical dipole, which is another N6BT design from his time as owner of
Force12. So far, I've only been able to run limited A/B tests on 40 meters,
and the Bravo 7K is down about 1 S unit or more. I had hoped it would be
much better than that, particularly based on the positive commentary from
N6BT himself, but I do need to try more variations of location and setup. I
just haven't had a chance to do much additional testing due to a number of
other tasks and projects which are eating up my free time.

On the positive side, I am quite impressed with the portability of the Bravo
7K. It sets up quickly and easily, and is very easy to break down and
transport. It's quite possible I haven't found the right combination of
settings and location for the Bravo 7K. For example, it may be adversely
affected by other nearby objects. I'd also like to elevate it a bit more
than what the basic system allows. As supplied, the Bravo 7K is only about
2 feet off the ground at the bottom. My Sigma 40XK is 5 or 6 feet off the
ground.

I will tell you that the Sigma 40XK has been a very good performer on 40
meters. At one time it was available for something similar in price to what
the Bravo 7K sells for now, but the current owners of Force 12 have jacked
up the price considerably.

Anyway, hopefully some day soon I can get back into the experimentation
process with the Bravo 7K. If I accomplish anything noteworthy, I will
report it here.

Dave W7AQK

-------------------------------------
David, G3UNA said:

I wouldn't buy a loop. IF you only have those 3 choices, I would go for
the Buddipole, but I'm sure there must be other choices out there, I
don't like spending a lot of money on antennas unless it offers
something really special. Have you seen the Bravo?

See http://n6bt.com/n6bt-Bravo-dayton-faq-1.htm

Not sure if it would fit inside your hotel bedroom.

David
G3UNA

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Jim Low man

Re: Portable Antennas (near end fed)

I have a Sigma-5 from Force 12 when Tom owned the company, and haven't
really tried it out. Being retired now and having more time to play with
antennas, and with the nice weather that we've been having, I'm having
all kinds of fun. Just put together the Alexloop Walkham late yesterday.

Hopefully, the Sigma-5 will perform similarly to your Sigma 40XK.

72/73 de Jim - AD6CW

On 5/11/2012 4:52 PM, Dyarnes wrote:

> David and All,
>
> I have a Bravo 7K, and so far, I find it to be only a "fair" performer.
> This assessment is based only on limited testing against my Sigma 40XK
> vertical dipole, which is another N6BT design from his time as owner of
> Force12. So far, I've only been able to run limited A/B tests on 40 meters,
> and the Bravo 7K is down about 1 S unit or more. I had hoped it would be
> much better than that, particularly based on the positive commentary from
> N6BT himself, but I do need to try more variations of location and setup. I
> just haven't had a chance to do much additional testing due to a number of
> other tasks and projects which are eating up my free time.
>
> On the positive side, I am quite impressed with the portability of the Bravo
> 7K. It sets up quickly and easily, and is very easy to break down and
> transport. It's quite possible I haven't found the right combination of
> settings and location for the Bravo 7K. For example, it may be adversely
> affected by other nearby objects. I'd also like to elevate it a bit more
> than what the basic system allows. As supplied, the Bravo 7K is only about
> 2 feet off the ground at the bottom. My Sigma 40XK is 5 or 6 feet off the
> ground.
>
> I will tell you that the Sigma 40XK has been a very good performer on 40
> meters. At one time it was available for something similar in price to what
> the Bravo 7K sells for now, but the current owners of Force 12 have jacked
> up the price considerably.
>
> Anyway, hopefully some day soon I can get back into the experimentation
> process with the Bravo 7K. If I accomplish anything noteworthy, I will
> report it here.
>
> Dave W7AQK
>

Tom McCulloch

An obvious K2 battery observation

In reply to this post by John Huggins, kx4o

My guess is that with Field Day approaching more than a few guys, like
myself, will find themselves with a faulty battery in there K2 due to
lack of proper charging. I wasn't surprised that t is was the case but
I was a bit stumped when my A&A Smart Charger was not able to properly
power my K2. It was getting the infamous "Lo Bat" message (and no, the
probe switch was the problem) until I realized that the arrangement with
the Smart Charger calls the battery into use and the recharges it --
which, of course is good for the battery life.

Connecting my Astron PS to the original power jack on the K2 removed all
of the issues (except for the dead battery, of course).

Just an obvious observation, FWIW.

Tom
WB2QDG
K2 #1103
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David Dietrich

Re: An obvious K2 battery observation

Tom et al,

That is why I use an external gel cell, and didn't opt for the internal
battery. As we all know, rechargable batteries have a finite life and
do lose their charge over time.

73,

David
KC9EHQ
K1-4 s/n 2051
K2/10 s/n 7164
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123