Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack loop antenna?

2019-01-24 Thread Gwen Patton 
>
> Jim Said: Cut a large double sided piece of double sided circuit board to
> fit the
> backpack. Etch the back side with a symmetric Hilbert curve split into 2
> columns fed
> at the bottom center and the two columns attached at the top.


 Just don't accidentally etch a Do-Nha curve, or you might wind up with a
summoning grid that attracts alien monstrosities from beyond spacetime
that'll eat your brain. hi hi

73,
Gwen, NG3P

(In reference to this:
http://radiopsychedelica.blogspot.com/2014/01/dho-na-curve-of-sleeper.html)

On Thu, Jan 24, 2019 at 1:37 AM Jim Shepherd  wrote:

> Cut a large double sided piece of double sided circuit board to fit the
> backpack.
> Etch the back side with a symmetric Hilbert curve split into 2 columns fed
> at the bottom center and the two columns attached at the top.  Leave the
> other side as a solid ground plane... It will take some work to make a
> matching network, but the length of the 'curve' can easily be a half wave
> on 20 meters. It will be directional to your rear as you walk along.
>
> Jim W6US
> __
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>


-- 

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Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack loop antenna?

2019-01-23 Thread Jim Shepherd 
Cut a large double sided piece of double sided circuit board to fit the
backpack.
Etch the back side with a symmetric Hilbert curve split into 2 columns fed
at the bottom center and the two columns attached at the top.  Leave the
other side as a solid ground plane... It will take some work to make a
matching network, but the length of the 'curve' can easily be a half wave
on 20 meters. It will be directional to your rear as you walk along.

Jim W6US
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Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack loop antenna?

2019-01-23 Thread Grant Youngman 
It might be useful to read W8JI’s take on the E/H antenna … 
https://www.w8ji.com/e-h_antenna.htm 

Grant NQ5T
K3 #2091 KX3 #8342

> On Jan 23, 2019, at 10:07 PM, Wayne Burdick  wrote:
> 
> That might fit. Maybe something a little shorter, say 18". 
> 
> Can it be used with just 2 feet of coax? What's the bandwidth? How does it 
> compare to a 3' loop or a 4' whip?
> 
> Wayne
> N6KR
> 
> 

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Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack loop antenna?

2019-01-23 Thread Wayne Burdick 
That might fit. Maybe something a little shorter, say 18". 

Can it be used with just 2 feet of coax? What's the bandwidth? How does it 
compare to a 3' loop or a 4' whip?

Wayne
N6KR


> On Jan 23, 2019, at 9:51 AM, Jeff Wagner  wrote:
> 
> See the picture of a 20 Meter EH antenna on my QRZ page 
> https://www.qrz.com/db/KK6CUG.
> 
> It would fit into a backpack but it's 20 M only. Beer bottle for scale only - 
> hi hi.
> 
> https://www.qrz.com/db/KK6CUG
> 
> Jeff, KK6CUG
> 
> On 1/23/2019 8:34, Wayne Burdick n...@elecraft.com [KX3] wrote:
>> The entire purpose of the exercise is to be able to operate while walking. 
>> If the field is a potential health risk, power would have to be dropped 
>> accordingly. 
>> 
>> Wayne
>> 
>> > On Jan 23, 2019, at 8:28 AM, Jim Miller  wrote:
>> > 
>> > I assume that this "backpack frame antenna" wouldn't be actually used when 
>> > being worn. The circulating currents in a Hi-Q loop result in strong RF 
>> > fields along the loop axis which should be avoided in use.
>> > 
>> > jim ab3cv
>> > 
>> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
>> > On Wed, Jan 23, 2019 at 11:21 AM Wayne Burdick  wrote:
>> > Wish I had time to build one of these myself! A few other things in the 
>> > queue
>> > 
>> > Wayne
>> > N6KR
>> > 
>> > 
>> > > On Jan 23, 2019, at 6:32 AM, 'Dale Parfitt' pari...@frontier.com [KX3] 
>> > >  wrote:
>> > > 
>> > > 
>> > > HI Wolf,
>> > > 
>> > > VK3YE could have done so much better from an efficiency standpoint 
>> > > without making the loop any larger.
>> > > 
>> > > 1. Flat metal stock is not as efficient as round stock (of the same 
>> > > circumference) because current crowding at the edges of the rectangular 
>> > > stock makes it appear smaller in surface area.
>> > > 
>> > > 2. A much lower D capacitor such as a dual gang air variable with the 
>> > > gangs in series (to avoid resistive losses in the bearings) or a 
>> > > butterfly would also have aided in higher efficiency.
>> > > 
>> > > 3. Copper would have helped efficiency somewhat with its lower RF 
>> > > resistance and ability to be soldered versus mechanical connections, but 
>> > > that is partially offset by aluminum’s larger skin depth. Of course 
>> > > copper is heavier and more expensive, but in tube form the weight issue 
>> > > could be minimized..
>> > > 
>> > > 
>> > > 
>> > > Just some thoughts. Again, the VK1OD calculator allows one to make 
>> > > precise efficiency measurements so even small improvements can be 
>> > > measured. As an example, the difference in efficiency between using 
>> > > braided coax as the loop radiator versus hardline or copper tubing is 
>> > > readily apparent. For the same diameter loop and same conductor 
>> > > diameter, a narrower bandwidth means higher efficiency.
>> > > 
>> > > 
>> > > 
>> > > Dale W4OP
>> > > 
>> > > 
>> > > 
>> > > From: k...@yahoogroups.com [mailto:k...@yahoogroups.com] On Behalf Of 
>> > > 'Wolf Hoeller, OE7FTJ' wolf.oe7...@gmail..com [KX3]
>> > > Sent: Wednesday, January 23, 2019 4:57 AM
>> > > To: k...@yahoogroups.com
>> > > Subject: Fwd: [KX3] Urban stealth HF: Inside-the-backpack loop antenna?
>> > > 
>> > > 
>> > > 
>> > > 
>> > > 
>> > > Wayne,
>> > > 
>> > > 
>> > > 
>> > > a really good idea. 
>> > > 
>> > > Have a look at VK3YE's youtube channel for his experiment to put a loop 
>> > > antenna in (frame of) a notebook bag. 
>> > > https://www.youtube.com/watch?v=BC5lFbLqaeg
>> > > 
>> > > 
>> > > 
>> > > Another good idea for a stealth antenna has the spain company Inac. Here 
>> > > is the suitcase with a loop inside the frame: 
>> > > https://www.inac-radio.com/MAK721PRO
>> > > 
>> > > 
>> > > 
>> > > I would like the idea, to sit in an urban park with my backpack or 
>> > > similar on my knees and make some contacts. 
>> > > 
>> > > 
>> > > 
>> > > 
>> > > Wolf, OE7FTJ
>> > > 
>> > > Emergency Communications via Winlink Global Radio Email ®️
>> > > 
>> > > 
>> > > 
>> > > 
>> > > 
>> > > 
>> > > 
>> > > Am Di., 22. Jan. 2019 um 21:57 Uhr schrieb Wayne Burdick 
>> > > n...@elecraft.com [KX3] :
>> > > 
>> > >> 
>> > >> 
>> > >> I’ve engaged in plenty of ultralight HF pack operation, with a KX2, AX1 
>> > >> antenna and a dragged counterpoise. In wide open spaces it’s a blast. 
>> > >> But urban settings with dogs, wire-eating cacti and overzealous 
>> > >> Neighborhood Watchers can distract from one’s radio experience. 
>> > >> 
>> > >> 
>> > >> 
>> > >> So, just for grins, I’d like to try something completely incognerdo: no 
>> > >> visible antenna. A small remotely tuned loop (say 12” diameter) would 
>> > >> seem to be the best choice, as it would fit entirely inside a small 
>> > >> backpack. It could have modest efficiency while not requiring a 
>> > >> counterpoise wire. Rigid 1” copper pipe formed in a square would be 
>> > >> convenient to deploy. 
>> > >> 
>> > >> 
>> > >> 
>> > >> The loop would be only 6 to 8” from soft tissue, so you’d want to run 
>> > >> QRP, of course. OTOH, we’re talking about HF. A

Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack loop antenna?

2019-01-23 Thread Mike Cox 
A proper shield of a KPA-1500/PS with battery and 240VAC inverter should 
be adequate protection if stuffed between the antenna and your backside ;-).


... Mike

On 1/23/2019 11:34 AM, Wayne Burdick wrote:

The entire purpose of the exercise is to be able to operate while walking. If 
the field is a potential health risk, power would have to be dropped 
accordingly.

Wayne



On Jan 23, 2019, at 8:28 AM, Jim Miller  wrote:

I assume that this "backpack frame antenna" wouldn't be actually used when 
being worn. The circulating currents in a Hi-Q loop result in strong RF fields along the 
loop axis which should be avoided in use.

jim ab3cv

On Wed, Jan 23, 2019 at 11:21 AM Wayne Burdick  wrote:
Wish I had time to build one of these myself! A few other things in the 
queue

Wayne
N6KR



On Jan 23, 2019, at 6:32 AM, 'Dale Parfitt' pari...@frontier.com [KX3] 
 wrote:


HI Wolf,

VK3YE could have done so much better from an efficiency standpoint without 
making the loop any larger.

1. Flat metal stock is not as efficient as round stock (of the same 
circumference) because current crowding at the edges of the rectangular stock 
makes it appear smaller in surface area.

2. A much lower D capacitor such as a dual gang air variable with the gangs in 
series (to avoid resistive losses in the bearings) or  a butterfly would also 
have aided in  higher efficiency.

3. Copper would have helped efficiency  somewhat with its lower RF resistance 
and ability to be soldered  versus mechanical connections, but that is 
partially offset by aluminum’s larger skin depth. Of course copper is heavier 
and more expensive, but in tube form the weight issue could be minimized..

  


Just some thoughts. Again, the VK1OD calculator allows one to make precise 
efficiency measurements so even small improvements can be measured.  As an 
example, the difference in efficiency between using  braided coax as the loop 
radiator versus hardline or copper tubing is readily apparent. For the same 
diameter loop and same conductor diameter, a narrower bandwidth  means higher 
efficiency.

  


Dale W4OP

  


From: k...@yahoogroups.com [mailto:k...@yahoogroups.com] On Behalf Of 'Wolf 
Hoeller, OE7FTJ' wolf.oe7...@gmail..com [KX3]
Sent: Wednesday, January 23, 2019 4:57 AM
To: k...@yahoogroups.com
Subject: Fwd: [KX3] Urban stealth HF: Inside-the-backpack loop antenna?

  

   


Wayne,

  


a really good idea.

Have a look at VK3YE's youtube channel for his experiment to put a loop antenna 
in (frame of) a notebook bag. https://www.youtube.com/watch?v=BC5lFbLqaeg

  


Another good idea for a stealth antenna has the spain company Inac. Here is the 
suitcase with a loop inside the frame: https://www.inac-radio.com/MAK721PRO

  


I would like the idea, to sit in an urban park with my backpack or similar on 
my knees and make some contacts.




Wolf, OE7FTJ

Emergency Communications via Winlink Global Radio Email ®️

  

  

  


Am Di., 22. Jan. 2019 um 21:57 Uhr schrieb Wayne Burdick n...@elecraft.com [KX3] 
:

   


I’ve engaged in plenty of ultralight HF pack operation, with a KX2, AX1 antenna 
and a dragged counterpoise. In wide open spaces it’s a blast. But urban 
settings with dogs, wire-eating cacti and overzealous Neighborhood Watchers can 
distract from one’s radio experience.

  


So, just for grins, I’d like to try something completely incognerdo: no visible 
antenna. A small remotely tuned loop (say 12” diameter) would seem to be the 
best choice, as it would fit entirely inside a small backpack. It could have  
modest efficiency while not requiring a counterpoise wire. Rigid 1” copper pipe 
formed in a square would be convenient to deploy.

  


The loop would be only 6 to 8” from soft tissue, so you’d want to run QRP, of 
course.  OTOH, we’re talking about HF. A cellphone by your ear is probably 
worse.

  


Any other antenna suggestions?

  


Wayne

N6KR

  

  



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Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack loop antenna?

2019-01-23 Thread Wayne Burdick 
The entire purpose of the exercise is to be able to operate while walking. If 
the field is a potential health risk, power would have to be dropped 
accordingly. 

Wayne


> On Jan 23, 2019, at 8:28 AM, Jim Miller  wrote:
> 
> I assume that this "backpack frame antenna" wouldn't be actually used when 
> being worn. The circulating currents in a Hi-Q loop result in strong RF 
> fields along the loop axis which should be avoided in use.
> 
> jim ab3cv
> 
> On Wed, Jan 23, 2019 at 11:21 AM Wayne Burdick  wrote:
> Wish I had time to build one of these myself! A few other things in the 
> queue
> 
> Wayne
> N6KR
> 
> 
> > On Jan 23, 2019, at 6:32 AM, 'Dale Parfitt' pari...@frontier.com [KX3] 
> >  wrote:
> > 
> > 
> > HI Wolf,
> > 
> > VK3YE could have done so much better from an efficiency standpoint without 
> > making the loop any larger.
> > 
> > 1. Flat metal stock is not as efficient as round stock (of the same 
> > circumference) because current crowding at the edges of the rectangular 
> > stock makes it appear smaller in surface area.
> > 
> > 2. A much lower D capacitor such as a dual gang air variable with the gangs 
> > in series (to avoid resistive losses in the bearings) or  a butterfly would 
> > also have aided in  higher efficiency.
> > 
> > 3. Copper would have helped efficiency  somewhat with its lower RF 
> > resistance and ability to be soldered  versus mechanical connections, but 
> > that is partially offset by aluminum’s larger skin depth. Of course copper 
> > is heavier and more expensive, but in tube form the weight issue could be 
> > minimized..
> > 
> >  
> > 
> > Just some thoughts. Again, the VK1OD calculator allows one to make precise 
> > efficiency measurements so even small improvements can be measured.  As an 
> > example, the difference in efficiency between using  braided coax as the 
> > loop radiator versus hardline or copper tubing is readily apparent. For the 
> > same diameter loop and same conductor diameter, a narrower bandwidth  means 
> > higher efficiency.
> > 
> >  
> > 
> > Dale W4OP
> > 
> >  
> > 
> > From: k...@yahoogroups.com [mailto:k...@yahoogroups.com] On Behalf Of 'Wolf 
> > Hoeller, OE7FTJ' wolf.oe7...@gmail..com [KX3]
> > Sent: Wednesday, January 23, 2019 4:57 AM
> > To: k...@yahoogroups.com
> > Subject: Fwd: [KX3] Urban stealth HF: Inside-the-backpack loop antenna?
> > 
> >  
> > 
> >   
> > 
> > Wayne,
> > 
> >  
> > 
> > a really good idea. 
> > 
> > Have a look at VK3YE's youtube channel for his experiment to put a loop 
> > antenna in (frame of) a notebook bag. 
> > https://www.youtube.com/watch?v=BC5lFbLqaeg
> > 
> >  
> > 
> > Another good idea for a stealth antenna has the spain company Inac. Here is 
> > the suitcase with a loop inside the frame: 
> > https://www.inac-radio.com/MAK721PRO
> > 
> >  
> > 
> > I would like the idea, to sit in an urban park with my backpack or similar 
> > on my knees and make some contacts. 
> > 
> > 
> > 
> > 
> > Wolf, OE7FTJ
> > 
> > Emergency Communications via Winlink Global Radio Email ®️
> > 
> >  
> > 
> >  
> > 
> >  
> > 
> > Am Di., 22. Jan. 2019 um 21:57 Uhr schrieb Wayne Burdick n...@elecraft.com 
> > [KX3] :
> > 
> >>   
> >> 
> >> I’ve engaged in plenty of ultralight HF pack operation, with a KX2, AX1 
> >> antenna and a dragged counterpoise. In wide open spaces it’s a blast. But 
> >> urban settings with dogs, wire-eating cacti and overzealous Neighborhood 
> >> Watchers can distract from one’s radio experience. 
> >> 
> >>  
> >> 
> >> So, just for grins, I’d like to try something completely incognerdo: no 
> >> visible antenna. A small remotely tuned loop (say 12” diameter) would seem 
> >> to be the best choice, as it would fit entirely inside a small backpack. 
> >> It could have  modest efficiency while not requiring a counterpoise wire. 
> >> Rigid 1” copper pipe formed in a square would be convenient to deploy. 
> >> 
> >>  
> >> 
> >> The loop would be only 6 to 8” from soft tissue, so you’d want to run QRP, 
> >> of course.  OTOH, we’re talking about HF. A cellphone by your ear is 
> >> probably worse. 
> >> 
> >>  
> >> 
> >> Any other antenna suggestions?
> >> 
> >>  
> >> 
> >> Wayne
> >> 
> >> N6KR
> >> 
> >>  
> >> 
> >>  
> >> 
> > 
> > 
> > __._,_.___
> > Posted by: "Dale Parfitt"  
> > Reply via web post•   Reply to sender •   Reply to 
> > group  •   Start a New Topic   •   Messages in this topic (2)
> >  
> > Have you tried the highest rated email app?
> > With 4.5 stars in iTunes, the Yahoo Mail app is the highest rated email app 
> > on the market. What are you waiting for? Now you can access all your 
> > inboxes (Gmail, Outlook, AOL and more) in one place. Never delete an email 
> > again with 1000GB of free cloud storage.
> > VISIT YOUR GROUP
> > • Privacy • Unsubscribe • Terms of Use
> > 
> > SPONSORED LINKS
> > 
> > 
> > 
> > .
> >  
> > 
> > __,_._,___
> 
> __
> Elecraft

Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack loop antenna?

2019-01-23 Thread Jim Miller 
I assume that this "backpack frame antenna" wouldn't be actually used when
being worn. The circulating currents in a Hi-Q loop result in strong RF
fields along the loop axis which should be avoided in use.

jim ab3cv

On Wed, Jan 23, 2019 at 11:21 AM Wayne Burdick  wrote:

> Wish I had time to build one of these myself! A few other things in the
> queue
>
> Wayne
> N6KR
>
>
> > On Jan 23, 2019, at 6:32 AM, 'Dale Parfitt' pari...@frontier.com [KX3] <
> kx3-nore...@yahoogroups.com> wrote:
> >
> >
> > HI Wolf,
> >
> > VK3YE could have done so much better from an efficiency standpoint
> without making the loop any larger.
> >
> > 1. Flat metal stock is not as efficient as round stock (of the same
> circumference) because current crowding at the edges of the rectangular
> stock makes it appear smaller in surface area.
> >
> > 2. A much lower D capacitor such as a dual gang air variable with the
> gangs in series (to avoid resistive losses in the bearings) or  a butterfly
> would also have aided in  higher efficiency.
> >
> > 3. Copper would have helped efficiency  somewhat with its lower RF
> resistance and ability to be soldered  versus mechanical connections, but
> that is partially offset by aluminum’s larger skin depth. Of course copper
> is heavier and more expensive, but in tube form the weight issue could be
> minimized..
> >
> >
> >
> > Just some thoughts. Again, the VK1OD calculator allows one to make
> precise efficiency measurements so even small improvements can be
> measured.  As an example, the difference in efficiency between using
> braided coax as the loop radiator versus hardline or copper tubing is
> readily apparent. For the same diameter loop and same conductor diameter, a
> narrower bandwidth  means higher efficiency.
> >
> >
> >
> > Dale W4OP
> >
> >
> >
> > From: k...@yahoogroups.com [mailto:k...@yahoogroups.com] On Behalf Of
> 'Wolf Hoeller, OE7FTJ' wolf.oe7...@gmail..com [KX3]
> > Sent: Wednesday, January 23, 2019 4:57 AM
> > To: k...@yahoogroups.com
> > Subject: Fwd: [KX3] Urban stealth HF: Inside-the-backpack loop antenna?
> >
> >
> >
> >
> >
> > Wayne,
> >
> >
> >
> > a really good idea.
> >
> > Have a look at VK3YE's youtube channel for his experiment to put a loop
> antenna in (frame of) a notebook bag.
> https://www.youtube.com/watch?v=BC5lFbLqaeg
> >
> >
> >
> > Another good idea for a stealth antenna has the spain company Inac. Here
> is the suitcase with a loop inside the frame:
> https://www.inac-radio.com/MAK721PRO
> >
> >
> >
> > I would like the idea, to sit in an urban park with my backpack or
> similar on my knees and make some contacts.
> >
> >
> >
> >
> > Wolf, OE7FTJ
> >
> > Emergency Communications via Winlink Global Radio Email ®️
> >
> >
> >
> >
> >
> >
> >
> > Am Di., 22. Jan. 2019 um 21:57 Uhr schrieb Wayne Burdick
> n...@elecraft.com [KX3] :
> >
> >>
> >>
> >> I’ve engaged in plenty of ultralight HF pack operation, with a KX2, AX1
> antenna and a dragged counterpoise. In wide open spaces it’s a blast. But
> urban settings with dogs, wire-eating cacti and overzealous Neighborhood
> Watchers can distract from one’s radio experience.
> >>
> >>
> >>
> >> So, just for grins, I’d like to try something completely incognerdo: no
> visible antenna. A small remotely tuned loop (say 12” diameter) would seem
> to be the best choice, as it would fit entirely inside a small backpack. It
> could have  modest efficiency while not requiring a counterpoise wire.
> Rigid 1” copper pipe formed in a square would be convenient to deploy.
> >>
> >>
> >>
> >> The loop would be only 6 to 8” from soft tissue, so you’d want to run
> QRP, of course.  OTOH, we’re talking about HF. A cellphone by your ear is
> probably worse.
> >>
> >>
> >>
> >> Any other antenna suggestions?
> >>
> >>
> >>
> >> Wayne
> >>
> >> N6KR
> >>
> >>
> >>
> >>
> >>
> >
> >
> > __._,_.___
> > Posted by: "Dale Parfitt" 
> > Reply via web post•   Reply to sender •   Reply to
> group  •   Start a New Topic   •   Messages in this topic (2)
> >
> > Have you tried the highest rated email app?
> > With 4.5 stars in iTunes, the Yahoo Mail app is the highest rated email
> app on the market. What are you waiting for? Now you can access all your
> inboxes (Gmail, Outlook, AOL and more) in one place. Never delete an email
> again with 1000GB of free cloud storage.
> > VISIT YOUR GROUP
> > • Privacy • Unsubscribe • Terms of Use
> >
> > SPONSORED LINKS
> >
> >
> >
> > .
> >
> >
> > __,_._,___
>
> __
> Elecraft mailing list
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> Help: http://mailman.qth.net/mmfaq.htm
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Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack loop antenna?

2019-01-23 Thread Wayne Burdick 
Wish I had time to build one of these myself! A few other things in the 
queue

Wayne
N6KR


> On Jan 23, 2019, at 6:32 AM, 'Dale Parfitt' pari...@frontier.com [KX3] 
>  wrote:
> 
> 
> HI Wolf,
> 
> VK3YE could have done so much better from an efficiency standpoint without 
> making the loop any larger.
> 
> 1. Flat metal stock is not as efficient as round stock (of the same 
> circumference) because current crowding at the edges of the rectangular stock 
> makes it appear smaller in surface area.
> 
> 2. A much lower D capacitor such as a dual gang air variable with the gangs 
> in series (to avoid resistive losses in the bearings) or  a butterfly would 
> also have aided in  higher efficiency.
> 
> 3. Copper would have helped efficiency  somewhat with its lower RF resistance 
> and ability to be soldered  versus mechanical connections, but that is 
> partially offset by aluminum’s larger skin depth. Of course copper is heavier 
> and more expensive, but in tube form the weight issue could be minimized..
> 
>  
> 
> Just some thoughts. Again, the VK1OD calculator allows one to make precise 
> efficiency measurements so even small improvements can be measured.  As an 
> example, the difference in efficiency between using  braided coax as the loop 
> radiator versus hardline or copper tubing is readily apparent. For the same 
> diameter loop and same conductor diameter, a narrower bandwidth  means higher 
> efficiency.
> 
>  
> 
> Dale W4OP
> 
>  
> 
> From: k...@yahoogroups.com [mailto:k...@yahoogroups.com] On Behalf Of 'Wolf 
> Hoeller, OE7FTJ' wolf.oe7...@gmail..com [KX3]
> Sent: Wednesday, January 23, 2019 4:57 AM
> To: k...@yahoogroups.com
> Subject: Fwd: [KX3] Urban stealth HF: Inside-the-backpack loop antenna?
> 
>  
> 
>   
> 
> Wayne,
> 
>  
> 
> a really good idea. 
> 
> Have a look at VK3YE's youtube channel for his experiment to put a loop 
> antenna in (frame of) a notebook bag. 
> https://www.youtube.com/watch?v=BC5lFbLqaeg
> 
>  
> 
> Another good idea for a stealth antenna has the spain company Inac. Here is 
> the suitcase with a loop inside the frame: 
> https://www.inac-radio.com/MAK721PRO
> 
>  
> 
> I would like the idea, to sit in an urban park with my backpack or similar on 
> my knees and make some contacts. 
> 
> 
> 
> 
> Wolf, OE7FTJ
> 
> Emergency Communications via Winlink Global Radio Email ®️
> 
>  
> 
>  
> 
>  
> 
> Am Di., 22. Jan. 2019 um 21:57 Uhr schrieb Wayne Burdick n...@elecraft.com 
> [KX3] :
> 
>>   
>> 
>> I’ve engaged in plenty of ultralight HF pack operation, with a KX2, AX1 
>> antenna and a dragged counterpoise. In wide open spaces it’s a blast. But 
>> urban settings with dogs, wire-eating cacti and overzealous Neighborhood 
>> Watchers can distract from one’s radio experience. 
>> 
>>  
>> 
>> So, just for grins, I’d like to try something completely incognerdo: no 
>> visible antenna. A small remotely tuned loop (say 12” diameter) would seem 
>> to be the best choice, as it would fit entirely inside a small backpack. It 
>> could have  modest efficiency while not requiring a counterpoise wire. Rigid 
>> 1” copper pipe formed in a square would be convenient to deploy. 
>> 
>>  
>> 
>> The loop would be only 6 to 8” from soft tissue, so you’d want to run QRP, 
>> of course.  OTOH, we’re talking about HF. A cellphone by your ear is 
>> probably worse. 
>> 
>>  
>> 
>> Any other antenna suggestions?
>> 
>>  
>> 
>> Wayne
>> 
>> N6KR
>> 
>>  
>> 
>>  
>> 
> 
> 
> __._,_.___
> Posted by: "Dale Parfitt"  
> Reply via web post•   Reply to sender •   Reply to group  
> •   Start a New Topic   •   Messages in this topic (2)
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Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack loop antenna?

2019-01-22 Thread Rich Arland 
Ref: Homless..let's not forget the ever present shopping cart! Get a BIG 
one. It can be used as a counter poise in place of a set of radials or a drag 
wire. One could also try loading the shopping cart and using it as an antenna 
since the wheels are composed of a non-conductive set of wheels so the cart 
would be above ground.

Just sayin'

Vy 73 es gud DX!

Rich Arland   K7SZ   WPE7BYR
Radio/electronics archaeologist
Author: The ARRL's Low Power Communicatoions
Bent Dipole Ranch, Dacula, GA
http://commobunker.blogspot.com/




From: elecraft-boun...@mailman.qth.net  on 
behalf of Michael Blake via Elecraft 
Sent: Tuesday, January 22, 2019 4:40 PM
To: Mark Goldberg
Cc: Elecraft Reflector; KX3
Subject: Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack loop 
antenna?

Mark (W7MLG),  It is scary how perfectly sane and normal your suggestions sound 
to me :)

Very 73 - Mike - K9JRI







> On Jan 22, 2019, at 4:32 PM, Mark Goldberg  wrote:
>
> I would expect any high Q antenna like a loop would be detuned by any
> movement or any metal you pass by. One more reason to support automatic
> mobile screwdriver / mag loop antenna tuning on the KX series.
> A flag on a backpack would be more or less ignored. Just put a flag on the
> top of the AX1. Counterpoise is an issue though. Maybe a short one down
> your leg?
>
> Now, if you dressed as a homeless or otherwise distressed person, lots of
> weird things are possible, tinfoil hat with a big flag, dragged wire
> disguised as one of those fake animals on a leash, etc. The weirder, the
> more people will ignore you.
>
> Hopefully taken in the spirit of which it is posted.
>
> 73,
>
> Mark
> W7MLG
>
>
> On Tue, Jan 22, 2019 at 1:57 PM Wayne Burdick n...@elecraft.com [KX3] <
> kx3-nore...@yahoogroups.com> wrote:
>

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Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack loop antenna?

2019-01-22 Thread Michael Blake via Elecraft 
Mark (W7MLG),  It is scary how perfectly sane and normal your suggestions sound 
to me :)

Very 73 - Mike - K9JRI







> On Jan 22, 2019, at 4:32 PM, Mark Goldberg  wrote:
> 
> I would expect any high Q antenna like a loop would be detuned by any
> movement or any metal you pass by. One more reason to support automatic
> mobile screwdriver / mag loop antenna tuning on the KX series.
> A flag on a backpack would be more or less ignored. Just put a flag on the
> top of the AX1. Counterpoise is an issue though. Maybe a short one down
> your leg?
> 
> Now, if you dressed as a homeless or otherwise distressed person, lots of
> weird things are possible, tinfoil hat with a big flag, dragged wire
> disguised as one of those fake animals on a leash, etc. The weirder, the
> more people will ignore you.
> 
> Hopefully taken in the spirit of which it is posted.
> 
> 73,
> 
> Mark
> W7MLG
> 
> 
> On Tue, Jan 22, 2019 at 1:57 PM Wayne Burdick n...@elecraft.com [KX3] <
> kx3-nore...@yahoogroups.com> wrote:
> 

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Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack loop antenna?

2019-01-22 Thread Mark Goldberg 
I would expect any high Q antenna like a loop would be detuned by any
movement or any metal you pass by. One more reason to support automatic
mobile screwdriver / mag loop antenna tuning on the KX series.
A flag on a backpack would be more or less ignored. Just put a flag on the
top of the AX1. Counterpoise is an issue though. Maybe a short one down
your leg?

Now, if you dressed as a homeless or otherwise distressed person, lots of
weird things are possible, tinfoil hat with a big flag, dragged wire
disguised as one of those fake animals on a leash, etc. The weirder, the
more people will ignore you.

Hopefully taken in the spirit of which it is posted.

73,

Mark
W7MLG


On Tue, Jan 22, 2019 at 1:57 PM Wayne Burdick n...@elecraft.com [KX3] <
kx3-nore...@yahoogroups.com> wrote:

>
>
> I’ve engaged in plenty of ultralight HF pack operation, with a KX2, AX1
> antenna and a dragged counterpoise. In wide open spaces it’s a blast. But
> urban settings with dogs, wire-eating cacti and overzealous Neighborhood
> Watchers can distract from one’s radio experience.
>
> So, just for grins, I’d like to try something completely incognerdo: no
> visible antenna. A small remotely tuned loop (say 12” diameter) would seem
> to be the best choice, as it would fit entirely inside a small backpack. It
> could have  modest efficiency while not requiring a counterpoise wire.
> Rigid 1” copper pipe formed in a square would be convenient to deploy.
>
> The loop would be only 6 to 8” from soft tissue, so you’d want to run QRP,
> of course.  OTOH, we’re talking about HF. A cellphone by your ear is
> probably worse.
>
> Any other antenna suggestions?
>
> Wayne
> N6KR
>
>
>
> 
> elecraft.com
>
> __._,_.___
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> Posted by: Wayne Burdick 
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