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

[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?

[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] Auto-spot, tuning aids, and the arcane history of CW pitch-matching

[Wes]

Of course I know that.  Mine was a rhetorical question.

On 1/23/2019 6:08 PM, ab2tc wrote:

Hi,

It doesn't "compound". A 10Hz drift at the antenna output of the K3, will be
reflected as a 10Hz drift at the output of any transverter, be it VHF, UHF
or microwave. At the higher frequencies even a transverter with an OCXO its
drift would probably dominate.

AB2TC - Knut


Wes Stewart-2 wrote

You should be subscribed to Timenuts.

But clearly one of us is confused. If you're using an OCXO in your
transverter
and up converting the K3, how does K3 drift/inaccuracy "compound" at UHF?

Can you read that watch to 50 ms?  What are you going to do when WWVB goes
QRT?

Wes  N7WS

On 1/23/2019 12:26 PM, Dave New, N8SBE wrote:

Wes,

Yes.  I'm a stickler for accuracy.  It always bothered me that the







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

[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] HF Stealth Loops

[Gwen Patton]

I'm working on a potentially collapsible and packable small transmitting
loop. The main loop support is a 27-inch bicycle inner tube.

On an earlier version, I made a single loop unit using a wooden support
system and plastic plumbers pipe support strap, with conductive-adhesive
backed copper foil as the conductor. It worked excellently well, getting
good signal reports on 30m FT8, running about 25 watts indoors. I got to
Fargo from Philadelphia with a good signal. The structure, however was too
big, and the loop insufficiently rigid.

The first test will be a hybrid of the inner tube as the loop support for
the flexible plastic strap with copper foil. If it works, that's a usable
solution as it stands. But the eventual design is the copper foil directly
on the inner tube. I plan for six strips around the circumference, and a
system of connections to lengthen the conductor by jumping them together
strategically, to keep the center of the loop stationary. That won't
require moving the coupling loop.

My hope is a loop that can be deflated and packed, then reinflated onsite
using a small pump. The durability of the foil conductors will be part of
my testing, to make sure the repeated inflation and deflation doesn't
destroy them.

If nothing else, the hybrid should work easily, allowing for a quickly
deployed loop without heavy supports, that will take more than QRP output.
I've run 100 watts through the present loop without significant heating
anywhere on the loop or in the variable capacitor.

73,
Gwen Patton, NG3P

On Wed, Jan 23, 2019, 6:44 PM W1GO (Joe) via Elecraft <
elecraft@mailman.qth.net wrote:

> Prefer the W4OP loop due to ruggedness and remote tune feature. Yes, its
> heavier but how many of us actually hike to the top of a big mountain?
>
> What would be great, however, would be a mag loop that the KX2 or KX3
> could remotely tuned from the rig.  I’d pay for that ...
>
> Joe W1GO
>
> > On Jan 23, 2019, at 18:28, eric norris via Elecraft <
> elecraft@mailman.qth.net> wrote:
> >
> > Anyone interested in magloops should visit www.alexloop.com  by Alex,
> PY1AHD.  He has really pioneered the popularity of small, portable loops
> and has built many  experimental loops.  There is a video of him setting up
> an AlexLoop in 90 seconds (not rushed) at www.alexloop.com
> > A magloop inside a backpack next to the human body probably won't work
> because the loop is detuned by the human, and that tuning varies with the
> distance.  If you are walking, tuning would be difficult because the pack
> will jiggle, varying the distance--unless you could glide motionless over
> the ground (or water).  I suspect Wayne could do this, but probably not in
> public.  Even when you use a magloop on a tripod, you have to tune it using
> an offset so it is in the right place when you step away.  This quickly
> becomes intuitive once you know how much, and which way, to turn the tuning
> capacitor.
> > However, a loop mounted above the backpack, say on a folding stick,
> works and has been done.  See www.alexloop.com
> > A small loop does work--I have made contacts on a 3ft diameter AlexLoop
> on 40m SSB with 5w.  On 20m, it could be smaller and still work, though
> obviously with less efficiency.
> > The advantage of magloops is their small size, quick setup, and needing
> neither a counterpoise nor more height above ground than one loop
> diameter.  If you go to a public park and want to talk to a ranger, setting
> up a magloop will materialize one as if by magic.  Magloops are terrific
> chick magnets, kid magnets, and will get you in heated arguments with
> people who have never used one.
> > I have no commercial relationship with Alex, PY1AHD, but I count him as
> a mentor and friend.  Really, look at the portable magloops on his
> website.  www.alexloop.com
> > 73 Eric WD6DBM
> >
> > Sent from Yahoo Mail on Android
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Re: [Elecraft] Urban stealth HF: Inside-the-backpack loop antenna?

[CUTTER DAVID via Elecraft]

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Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching

[Bob McGraw K4TAX]

I've never had a drift issue with any of my modern transceivers on 28MHz as the 
IF.  Now the TCXO drift in the transverters is real issue. 

Bob, K4TAX


Sent from my iPhone

> On Jan 23, 2019, at 7:08 PM, ab2tc  wrote:
> 
> Hi,
> 
> It doesn't "compound". A 10Hz drift at the antenna output of the K3, will be
> reflected as a 10Hz drift at the output of any transverter, be it VHF, UHF
> or microwave. At the higher frequencies even a transverter with an OCXO its
> drift would probably dominate.
> 
> AB2TC - Knut
> 
> 
> Wes Stewart-2 wrote
>> You should be subscribed to Timenuts.
>> 
>> But clearly one of us is confused. If you're using an OCXO in your
>> transverter 
>> and up converting the K3, how does K3 drift/inaccuracy "compound" at UHF?
>> 
>> Can you read that watch to 50 ms?  What are you going to do when WWVB goes
>> QRT?
>> 
>> Wes  N7WS
>> 
>>> On 1/23/2019 12:26 PM, Dave New, N8SBE wrote:
>>> 
>>> Wes,
>>> 
>>> Yes.  I'm a stickler for accuracy.  It always bothered me that the
>> 
> 
> 
> 
> 
> 
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
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Re: [Elecraft] Urban stealth HF: Inside-the-backpack loop antenna?

[CUTTER DAVID via Elecraft]

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Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching

[ab2tc]

Hi,

It doesn't "compound". A 10Hz drift at the antenna output of the K3, will be
reflected as a 10Hz drift at the output of any transverter, be it VHF, UHF
or microwave. At the higher frequencies even a transverter with an OCXO its
drift would probably dominate.

AB2TC - Knut


Wes Stewart-2 wrote
> You should be subscribed to Timenuts.
> 
> But clearly one of us is confused. If you're using an OCXO in your
> transverter 
> and up converting the K3, how does K3 drift/inaccuracy "compound" at UHF?
> 
> Can you read that watch to 50 ms?  What are you going to do when WWVB goes
> QRT?
> 
> Wes  N7WS
> 
> On 1/23/2019 12:26 PM, Dave New, N8SBE wrote:
>>
>> Wes,
>>
>> Yes.  I'm a stickler for accuracy.  It always bothered me that the
> 





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Re: [Elecraft] HF Stealth Loops

[W1GO (Joe) via Elecraft]

Prefer the W4OP loop due to ruggedness and remote tune feature. Yes, its 
heavier but how many of us actually hike to the top of a big mountain?  

What would be great, however, would be a mag loop that the KX2 or KX3 could 
remotely tuned from the rig.  I’d pay for that ...

Joe W1GO

> On Jan 23, 2019, at 18:28, eric norris via Elecraft 
>  wrote:
> 
> Anyone interested in magloops should visit www.alexloop.com  by Alex, PY1AHD. 
>  He has really pioneered the popularity of small, portable loops and has 
> built many  experimental loops.  There is a video of him setting up an 
> AlexLoop in 90 seconds (not rushed) at www.alexloop.com
> A magloop inside a backpack next to the human body probably won't work 
> because the loop is detuned by the human, and that tuning varies with the 
> distance.  If you are walking, tuning would be difficult because the pack 
> will jiggle, varying the distance--unless you could glide motionless over the 
> ground (or water).  I suspect Wayne could do this, but probably not in 
> public.  Even when you use a magloop on a tripod, you have to tune it using 
> an offset so it is in the right place when you step away.  This quickly 
> becomes intuitive once you know how much, and which way, to turn the tuning 
> capacitor.
> However, a loop mounted above the backpack, say on a folding stick, works and 
> has been done.  See www.alexloop.com
> A small loop does work--I have made contacts on a 3ft diameter AlexLoop on 
> 40m SSB with 5w.  On 20m, it could be smaller and still work, though 
> obviously with less efficiency.  
> The advantage of magloops is their small size, quick setup, and needing 
> neither a counterpoise nor more height above ground than one loop diameter.  
> If you go to a public park and want to talk to a ranger, setting up a magloop 
> will materialize one as if by magic.  Magloops are terrific chick magnets, 
> kid magnets, and will get you in heated arguments with people who have never 
> used one.
> I have no commercial relationship with Alex, PY1AHD, but I count him as a 
> mentor and friend.  Really, look at the portable magloops on his website.  
> www.alexloop.com 
> 73 Eric WD6DBM
> 
> Sent from Yahoo Mail on Android
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[Elecraft] HF Stealth Loops

[eric norris via Elecraft]

Anyone interested in magloops should visit www.alexloop.com  by Alex, PY1AHD.  
He has really pioneered the popularity of small, portable loops and has built 
many  experimental loops.  There is a video of him setting up an AlexLoop in 90 
seconds (not rushed) at www.alexloop.com
A magloop inside a backpack next to the human body probably won't work because 
the loop is detuned by the human, and that tuning varies with the distance.  If 
you are walking, tuning would be difficult because the pack will jiggle, 
varying the distance--unless you could glide motionless over the ground (or 
water).  I suspect Wayne could do this, but probably not in public.  Even when 
you use a magloop on a tripod, you have to tune it using an offset so it is in 
the right place when you step away.  This quickly becomes intuitive once you 
know how much, and which way, to turn the tuning capacitor.
However, a loop mounted above the backpack, say on a folding stick, works and 
has been done.  See www.alexloop.com
A small loop does work--I have made contacts on a 3ft diameter AlexLoop on 40m 
SSB with 5w.  On 20m, it could be smaller and still work, though obviously with 
less efficiency.  
The advantage of magloops is their small size, quick setup, and needing neither 
a counterpoise nor more height above ground than one loop diameter.  If you go 
to a public park and want to talk to a ranger, setting up a magloop will 
materialize one as if by magic.  Magloops are terrific chick magnets, kid 
magnets, and will get you in heated arguments with people who have never used 
one.
I have no commercial relationship with Alex, PY1AHD, but I count him as a 
mentor and friend.  Really, look at the portable magloops on his website.  
www.alexloop.com 
73 Eric WD6DBM

Sent from Yahoo Mail on Android
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Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching

[Don Wilhelm]

Dave,

Put the external reference oscillator input option on your K3 and avoid 
that situation with an external 10 MHz reference oscillator.


The K3 Reference Oscillator temperature steering is from the static 
temperature offsets.  If you have equipment to do better than the Data 
Sheet, you can determine your own values, but for those without that 
equipment, the data sheet provides a good index for various temperatures.


73,
Don W3FPR



Yes.  I'm a stickler for accuracy.  It always bothered me that the
so-called 'temperature compensated' LO in the K3 was not actively being
steered by temperature compensation (i.e. I could only put static
temperature offsets into the rig memory from the data sheet that came
with the oscillator). That was a 'feature' that was never released. At
HF frequencies, it was only an annoyance, but using UHF transverters,
the error compounds (I'm using a crystal oven in my UHF transverter, but
the lack of one in the K3 caused drifting).

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[Elecraft] Not built 40/20 K1 Kit

[Bob W7AVK]

.In 2000 I purchased for a high school friend a two band [40 and 20]  K1 
kit.  Idea was to kick start his interest in ham radio. Turned out he 
put the kit away and never returned to ham radio.


Anyone interested in a 40 and 20 meter original K1 kit in the original 
box and packaging?


73  Bob  W7AVK



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Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching

[Wes]

You should be subscribed to Timenuts.

But clearly one of us is confused. If you're using an OCXO in your transverter 
and up converting the K3, how does K3 drift/inaccuracy "compound" at UHF?


Can you read that watch to 50 ms?  What are you going to do when WWVB goes QRT?

Wes  N7WS

On 1/23/2019 12:26 PM, Dave New, N8SBE wrote:


Wes,

Yes.  I'm a stickler for accuracy.  It always bothered me that the
so-called 'temperature compensated' LO in the K3 was not actively being
steered by temperature compensation (i.e. I could only put static
temperature offsets into the rig memory from the data sheet that came
with the oscillator). That was a 'feature' that was never released. At
HF frequencies, it was only an annoyance, but using UHF transverters,
the error compounds (I'm using a crystal oven in my UHF transverter, but
the lack of one in the K3 caused drifting).

I use a Citizen watch with WWVB reception, so the time on my wrist is
never more than 50 ms off.

Anally yours,

-- Dave, N8SBE



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

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

[Paul Wilton]

10+ years ago, we built a HF loop inside a coat.  I can’t really tell you the 
application but the loop was made of copper braid and put between the liner and 
the outer shell of the coat.  It was tuned with a simple L match with a LED to 
indicate peak power.  We operated it on the 80, 60 and 40m bands.  The drive 
was an FT817 at 5w.

We weren’t trying for DX but it worked well for the short distances we needed 
it to work.  It was also pretty easy to tune up and and once tuned stayed there.

73


Paul
M1CNK





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Re: [Elecraft] K2 VCO Alignment T5 L30

[Jim KO5V]

Tom,

On my latest K2 build, I put a 1pf cap into the C68 (10pf) location. The 1pf 
cap was labelled "1D", which looked a lot like a "10" to my eyes. I think it 
took me about 4 hours to figure that one out. Once fixed, it all fell into 
place, and everything worked.

We all do it!

73, Jim KO5V


"Message: 3
Date: Tue, 22 Jan 2019 21:57:09 -0500
From: K2bew 
To: donw...@embarqmail.com
Cc: Elecraft Mail List 
Subject: Re: [Elecraft] K2 VCO Alignment T5 L30
Message-ID:

Content-Type: text/plain; charset="UTF-8"

Don Et Al,
So, It is with some embarrassment, and much relief, that I can report it
was operator error and my BFO is now working perfectly.
I got home from work and was getting ready to do some continuity checks to
all the circuits surrounding and including U11,  but decided I better check
all the components again in that section with the RF board disconnected and
out of the case.
I found much to my chagrin I had not installed D37 and D38! I had them
checked off in the manual as being installed, and I even wrote in pencil in
the margin on the next step where you put the rest of the V149's in the RF
board that I had 2 left over, but I failed to notice I had them left over
because I did not put them in the step before!, good grief.
Anyway I have a high BFO reading of 4917.60 and a low reading of 4911.98
with a difference of 5.62.
Thank you Don and to others that gave suggestions, and I do wish those
having similar problems well in their trouble shooting.

Upward and onward 73,
Tom Bewick, K2BEW"
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Re: [Elecraft] Auto-spot, tuning aids, and the arcane history of CW pitch-matching

[Dave New, N8SBE]

> Are you serious?

> Wes  N7WS

Wes,

Yes.  I'm a stickler for accuracy.  It always bothered me that the
so-called 'temperature compensated' LO in the K3 was not actively being
steered by temperature compensation (i.e. I could only put static
temperature offsets into the rig memory from the data sheet that came
with the oscillator). That was a 'feature' that was never released. At
HF frequencies, it was only an annoyance, but using UHF transverters,
the error compounds (I'm using a crystal oven in my UHF transverter, but
the lack of one in the K3 caused drifting).

I use a Citizen watch with WWVB reception, so the time on my wrist is
never more than 50 ms off.

Anally yours,

-- Dave, N8SBE

On 1/22/2019 1:45 PM, Dave New, N8SBE wrote:
> Don't know how i did without it all these years...
>
> 73,
>
> -- Dave, N8SBE
>

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Re: [Elecraft] K3 KAT3 High SWR Issue Solved

[Don Wilhelm]

Mark,

I am not certain when they stopped installing the trap in the KAT3, but 
I know it is not in the KAT3A.


If you pull your KAT3 out for any reason, eliminate the trap.

73,
Don W3FPR

On 1/23/2019 2:07 PM, Mark Musick wrote:

Don,
Is the trap in all KAT3s up through those installed in K3s with 9000 or just 
the early K3s below some serial number?

Mark, WB9CIF

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Don Wilhelm
Sent: Wednesday, January 23, 2019 18:48
To: K9MA ; elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 KAT3 High SWR Issue Solved

Scott,

It was added to the initial K3s, but later found not to be necessary, and if 
the trap broke down, it would cause trouble.  So the KAR3A does not have it.

73,
Don W3FPR

On 1/23/2019 10:49 AM, K9MA wrote:

On 1/23/2019 09:41, Ed G wrote:

A fair amount of digging in the email archives found a couple posts
which touched on an issue with the 8.215 MHz trap (C10 and L10) on
the
KAT3 tuner board.

Although my older K3 doesn't seem to have a problem, I wonder why that
trap was not required in the KAT3A. It was there, presumably to
improve IF rejection, so I'd expect removing it without some other
change to the
K3 would be unwise.


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Re: [Elecraft] K3 KAT3 High SWR Issue Solved

[Mark Musick]

Don,
Is the trap in all KAT3s up through those installed in K3s with 9000 or just 
the early K3s below some serial number?

Mark, WB9CIF

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Don Wilhelm
Sent: Wednesday, January 23, 2019 18:48
To: K9MA ; elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 KAT3 High SWR Issue Solved

Scott,

It was added to the initial K3s, but later found not to be necessary, and if 
the trap broke down, it would cause trouble.  So the KAR3A does not have it.

73,
Don W3FPR

On 1/23/2019 10:49 AM, K9MA wrote:
> On 1/23/2019 09:41, Ed G wrote:
>> A fair amount of digging in the email archives found a couple posts 
>> which touched on an issue with the 8.215 MHz trap (C10 and L10) on 
>> the
>> KAT3 tuner board.
> 
> Although my older K3 doesn't seem to have a problem, I wonder why that 
> trap was not required in the KAT3A. It was there, presumably to 
> improve IF rejection, so I'd expect removing it without some other 
> change to the
> K3 would be unwise.
> 
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Re: [Elecraft] Urban Stealth

[Walter Underwood]

A pack frame is just about right for a 2 m moxon beam, but that isn’t HF.

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/  (my blog)

> On Jan 22, 2019, at 7:22 PM, Norm Lee  > wrote:
> 
> Good thinking, Grant.   How about the metal frame for a backpack?   
> Unobtrusive, lightweight, and an intregal part of the backpack.   Brilliant!
> Cheers
> Norm vk5gi
> McLaren Vale
> South Australia

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

[Dave New, N8SBE]

> Here's another idea.
>
> Run a wire inside your shirt from one cuff across your back and down to
> the other cuff.  Wrap loading coils around each arm just above the
> elbow.  Feed the "dipole" in the center at the back of your neck.
>
> I did a quick model (assuming your arms are held straight out) with 5.5
> feet total length and 2200 inductive ohms for each coil, with each coil
> 30% from their respective ends of the wire.  It "resonates" at around
> 14.15 MHz, but with only about 0.4 ohms real feedpoint impedance.  I
> assume it would take some sort of extra matching network to bring that
> up enough that a KX2 with the internal tuner could drive it.
>
> Ignoring the effect of a person's arm, another quick calculation says
> that the arm coils would need to be roughly 11 turns of 10 gauge wire
> 3.5 inches in diameter ... unless I made a mistake, which is quite
> possible.
>
> It would bring new meaning to the term "compromise antenna", but I bet
> it would be more effective than a super small loop the size of backpack
> frame.
>
> 73,
> Dave  AB7E

Wouldn't that be a 'scarecrow' antenna?

73,

-- Dave, N8SBE


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

[Dave New, N8SBE]

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

Who was that guy at the HFPack get-together at HARA a few Daytons ago,
that was running A KILOWATT pedestrian mobile?  It he still on this
planet? :-)

73.

-- Dave, N8SBE
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Re: [Elecraft] K3 KAT3 High SWR Issue Solved

[Don Wilhelm]

Scott,

It was added to the initial K3s, but later found not to be necessary, 
and if the trap broke down, it would cause trouble.  So the KAR3A does 
not have it.


73,
Don W3FPR

On 1/23/2019 10:49 AM, K9MA wrote:

On 1/23/2019 09:41, Ed G wrote:
A fair amount of digging in the email archives found a couple posts 
which touched on an issue with the 8.215 MHz trap (C10 and L10) on the 
KAT3 tuner board.


Although my older K3 doesn't seem to have a problem, I wonder why that 
trap was not required in the KAT3A. It was there, presumably to improve 
IF rejection, so I'd expect removing it without some other change to the 
K3 would be unwise.



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Re: [Elecraft] K3 S-meter reading and coax input or antenna voltage ?

[Wes]

At the antenna spigot.

On 1/23/2019 10:00 AM, Phil Hystad via Elecraft wrote:

If I had an S-meter reading, S9 for example, on my K3, what could I infer about 
the voltage level of that signal at the Coax input to my K3?

A table I found on the Internet for singals below 30 MHz says that an S-9 meter 
reading is a signal of 50-microvolts but where in the system is that 
registering 50 microvolts.  At the input the K3 or some other circuit within 
the K3?

Thanks -- just mostly curious about this and the connection between S-meter 
reading and actual signals input to the receiver.

73, phil, K7PEH


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Re: [Elecraft] K3 S-meter reading and coax input or antenna voltage ?

[Lyle Johnson]

Phil,

With the original K3, S Meter "ABS" mode the S meter is referenced to 
the signal level at the antenna jack.  S9 = -73 dBm = 50 uV into 50 ohms.


In the other S Meter mode, the reading varies with ATT and PRE settings, 
as well as signal level.


73,

Lyle KK7P

On 1/23/19 10:00 AM, Phil Hystad via Elecraft wrote:

If I had an S-meter reading, S9 for example, on my K3, what could I infer about 
the voltage level of that signal at the Coax input to my K3?

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[Elecraft] K3 S-meter reading and coax input or antenna voltage ?

[Phil Hystad via Elecraft]

If I had an S-meter reading, S9 for example, on my K3, what could I infer about 
the voltage level of that signal at the Coax input to my K3?

A table I found on the Internet for singals below 30 MHz says that an S-9 meter 
reading is a signal of 50-microvolts but where in the system is that 
registering 50 microvolts.  At the input the K3 or some other circuit within 
the K3?

Thanks -- just mostly curious about this and the connection between S-meter 
reading and actual signals input to the receiver.

73, phil, K7PEH


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

[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?

[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
> >
> >
> >
> > .
> >
> >
> > __,_._,___
>
> __
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Home: 

[Elecraft] KPA1500 Operating Remotely

[Dennis Egan]

Can someone assist me- off the reflector- with the different settings
needed to operate the KPA1500 remotely?  I have it operating behind a VPN,
and I want to be able to operate it either via another computer at the
location or via Ethernet from my residence.

Thanks for your assistance.  I can't find any help files available.

Dennis W1UE
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Re: [Elecraft] [KX3] Urban stealth HF: Inside-the-backpack loop antenna?

[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)
>  
> 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
> 
> 
> 
> .
>  
> 
> __,_._,___

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

[K9FD]

Years back QST had an article that showed a home made 2 meter "filter" made
in a garbage can,   they ran low power and placed a hot dog inside,  
closed the lid

and applied RF,   the hot dog was BBQed in short order,
Perhaps with QRP one could put a sandwhich in one pocket and coffee in 
another

and while hiking to your destination you would have hot food and drink when
you arrived.
Not saying what may happen to the wienie of the person hiking. Your mileage
may vary as they say,  at least you wont have kids to tell the story to.

Merv K9FD

Up the power to 100 W and you’ve got a personal heating appliance. Awesome.

“Without RF, life itself would be impossible.”

Wayne



elecraft.com


On Jan 22, 2019, at 9:04 PM, David Gilbert  wrote:



Here's another idea.

Run a wire inside your shirt from one cuff across your back and down to the other cuff.  
Wrap loading coils around each arm just above the elbow.  Feed the "dipole" in 
the center at the back of your neck.

I did a quick model (assuming your arms are held straight out) with 5.5 feet total length 
and 2200 inductive ohms for each coil, with each coil 30% from their respective ends of 
the wire.  It "resonates" at around 14.15 MHz, but with only about 0.4 ohms 
real feedpoint impedance.  I assume it would take some sort of extra matching network to 
bring that up enough that a KX2 with the internal tuner could drive it.

Ignoring the effect of a person's arm, another quick calculation says that the 
arm coils would need to be roughly 11 turns of 10 gauge wire 3.5 inches in 
diameter ... unless I made a mistake, which is quite possible.

It would bring new meaning to the term "compromise antenna", but I bet it would 
be more effective than a super small loop the size of backpack frame.

73,
Dave  AB7E






On 1/22/19 12:57 PM, Wayne Burdick 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

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Re: [Elecraft] K3 KAT3 High SWR Issue Solved

[K9MA]

On 1/23/2019 09:41, Ed G wrote:

A fair amount of digging in the email archives found a couple posts which 
touched on an issue with the 8.215 MHz trap (C10 and L10) on the KAT3 tuner 
board.


Although my older K3 doesn't seem to have a problem, I wonder why that 
trap was not required in the KAT3A. It was there, presumably to improve 
IF rejection, so I'd expect removing it without some other change to the 
K3 would be unwise.


73,

Scott K9MA

--
Scott  K9MA

k...@sdellington.us

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[Elecraft] K3 KAT3 High SWR Issue Solved

[Ed G]

I recently posted about a K3 40 meter SWR anomaly, where the K3 SWR reading on 
the front panel meter tended to increase as I tuned up higher in the band. I 
first observed the problem while using my Steppir yagi, which retunes itself so 
that I should have seen a low SWR across the entire 40 meter band. I saw a 3:1 
SWR on the K3 meter at the high end of 40 meters, while at the same time I was 
reading a much lower SWR on my inline LP-100A. Further investigation showed 
that this situation also occurred when transmitting into a known-good dummy 
load. I was seeing about 1.1:1 at 7.001 MHz, and this rose to 3:1 at 7.299 MHz. 
When the high SWR was being sensed by the K3, output power was also being 
folded back. For example, I would have about 36 watts output when the K3 was 
set to 50 watts at 7.299 MHz. This anomaly also affected 40 meter operation 
with the KPA1500, as I observed what appeared to be power overshoot and 
experienced the need to frequently readjust drive power on 40 meters. 
A fair amount of digging in the email archives found a couple posts which 
touched on an issue with the 8.215 MHz trap (C10 and L10) on the KAT3 tuner 
board. Keith WE6R at Elecraft then suggested removing C10 and L10, and adding a 
shorting wire in place of L10. This mod does indeed appear to fix the false SWR 
issue – at least it did in my K3. I now have flat 1.1:1 SWR readings into a 
dummy load on 40 meters at all power levels. 
The trap is not included in the design of the KAT3A, so K3S rigs with the KAT3A 
should not see this SWR problem. Any K3 users who have retrofitted the KAT3A 
tuner into their K3 should not see this anomaly. The problematic trap, from 
comments by Keith, may be due to some lots of capacitors which for reasons 
unknown to me have a high failure rate. It may be prudent for K3 owners with 
the KAT3 tuner board (S/Ns under 10,000 or vicinity) to check SWR readings on 
40 meters using a dummy load to ascertain whether they need to apply the KAT3 
trap fix.
How to check your K3: Although I do not know how many KAT3 tuners are affected 
by the trap issue, I do feel it is the kind of problem that some users may have 
but just have not noticed. It is fairly easy to check for; just connect the K3 
to a dummy load and observe the SWR as shown on the K3 meter at several random 
frequencies across the 40 meter band. Of course (assuming a stable 50 ohm dummy 
load) you should see a fairly flat 1:1 or near to it. But if the SWR rises as 
you approach 7.3 MHz, and you are using the older KAT3 tuner board, you most 
likely have the trap problem. Upon visual inspection, you may see evidence of 
burning on the trap components. Although my trap components looked fine, I 
apparently had some internal failure in C10. The faulty trap may also exist in 
the older KANT3 module (the trap parts would have different part designations) 
but I don’t have a KANT3 and have not researched this enough to comment further.
Trap fix: As Keith suggested, remove C10 and L10 on the KAT3 board, and install 
a jumper where L10 was. I cut out C10, and also cut the leads on L10 while 
leaving enough length to strip some enamel coating and solder the leads 
together, thereby creating the jumper. To remove the KAT3 board, use proper 
wrist strap procedures. First remove the K3 top cover and one rear panel corner 
screw near the ANT connectors on the rear panel, and unplug the coax from ANT1 
and ANT 2 connectors going to the KAT3 board. The KAT3 board can then be 
carefully pulled out for the trap mod. I did not have to remove the subreceiver 
or the K3 side panel.
Results: For me, I now have a flat SWR reading across the 40 meter band when 
using the K3 internal SWR meter. Power output is now stable and fixed with no 
foldback, and I am not experiencing any KPA1500 drive faults.
Thanks to Keith at Elecraft for his assistance on this issue. Please correct me 
Keith if I have not documented this issue accurately.
--Ed, N3CW--

Sent from Mail for Windows 10




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

[kd4iz]

I love the AB7E concept... 

Looks an awful lot like birth of a new character for cosplay and a Comicon run 
to me: 
"EtherMan" - the RF belching steampunk simulacrum of an Isaac Asimov automaton! 
A little work with the 3D printer, an RPi with a 7" display, and some burnished 
10 gauge wire coil gauntlets, chest shield flip down mount for the KX2. Ah the 
possibilities! KA6LMS doesn't stand a chance. Anyone want to give it a go?

Seriously now, has anyone looked at the rf field issues - ie the effect created 
by the position of the person (a 70% water, protein gel matrix) with the 
backpack on?

KD4IZ
Jack Spitznagel
FM19oo




-Original Message-
From: David Gilbert  
Sent: Wednesday, January 23, 2019 00:04
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Urban stealth HF: Inside-the-backpack loop antenna?



Here's another idea.

Run a wire inside your shirt from one cuff across your back and down to the 
other cuff.  Wrap loading coils around each arm just above the elbow.  Feed the 
"dipole" in the center at the back of your neck.

I did a quick model (assuming your arms are held straight out) with 5.5 feet 
total length and 2200 inductive ohms for each coil, with each coil 30% from 
their respective ends of the wire.  It "resonates" at around
14.15 MHz, but with only about 0.4 ohms real feedpoint impedance.  I assume it 
would take some sort of extra matching network to bring that up enough that a 
KX2 with the internal tuner could drive it.

Ignoring the effect of a person's arm, another quick calculation says that the 
arm coils would need to be roughly 11 turns of 10 gauge wire
3.5 inches in diameter ... unless I made a mistake, which is quite possible.

It would bring new meaning to the term "compromise antenna", but I bet it would 
be more effective than a super small loop the size of backpack frame.

73,
Dave  AB7E



>
>
> On 1/22/19 12:57 PM, Wayne Burdick 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



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

[Bill Steffey]

how about code to run a screwdriver antenna that is.

I use my k2 /kxpa100 in my VW   screwdriver up on the roof rack,.
woeks great  but could be elecraftmatic 

On 1/22/2019 10:56 PM, Wayne Burdick wrote:

Thanks for the amazing response and great ideas.

If someone wants to build a backpack loop antenna for 20 m sooner than I can, I 
promise to extensively field test it for you. If it works, it could become an 
Elecraft product. (AL1? :)

The KXIO2 option for the KX2 includes two open-drain outputs that could be used 
to slew a C-tuning motor up and down with suitable buffering. I’ll write the 
code for that if/when it’s needed.

Wayne
N6KR


elecraft.com


On Jan 22, 2019, at 7:43 PM, Bill Johnson  wrote:

The back pack frame would be the antenna?  Low power is the game.  I am not 
concerned. In the Vietnam era, I was in a station where we had ~5 10KW 
transmitters using wave guide at ~1.9Ghz and while there were very large 
dishes, the exposure was there.  I would never worry about HF at 10 watts close 
to my body, but there may be studies that dispute that.  I am still alive after 
12 months constant exposure to agent orange.  No problem.  What was I writing 
about? :_)

(Emoji added in case the sarcasm was missed.)

73,
Bill
K9YEQ

https://wrj-tech.com/

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Wayne Burdick
Sent: Tuesday, January 22, 2019 2:57 PM
To: Elecraft 
Cc: KX3 
Subject: [Elecraft] Urban stealth HF: Inside-the-backpack loop antenna?

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

[W2xj]

The problem I see is Uncontrolled contents of backpack detuning the loop. 

Sent from my iPad

> On Jan 22, 2019, at 10:56 PM, Wayne Burdick n...@elecraft.com [KX3] 
>  wrote:
> 
> Thanks for the amazing response and great ideas. 
> 
> If someone wants to build a backpack loop antenna for 20 m sooner than I can, 
> I promise to extensively field test it for you. If it works, it could become 
> an Elecraft product. (AL1? :)
> 
> The KXIO2 option for the KX2 includes two open-drain outputs that could be 
> used to slew a C-tuning motor up and down with suitable buffering. I’ll write 
> the code for that if/when it’s needed. 
> 
> Wayne
> N6KR
> 
> 
> elecraft.com
> 
>> On Jan 22, 2019, at 7:43 PM, Bill Johnson  wrote:
>> 
>> The back pack frame would be the antenna?  Low power is the game.  I am not 
>> concerned. In the Vietnam era, I was in a station where we had ~5 10KW 
>> transmitters using wave guide at ~1.9Ghz and while there were very large 
>> dishes, the exposure was there.  I would never worry about HF at 10 watts 
>> close to my body, but there may be studies that dispute that.  I am still 
>> alive after 12 months constant exposure to agent orange.  No problem.  What 
>> was I writing about? :_)  
>> 
>> (Emoji added in case the sarcasm was missed.)
>> 
>> 73,
>> Bill
>> K9YEQ
>> 
>> https://wrj-tech.com/
>> 
>> -Original Message-
>> From: elecraft-boun...@mailman.qth.net  On 
>> Behalf Of Wayne Burdick
>> Sent: Tuesday, January 22, 2019 2:57 PM
>> To: Elecraft 
>> Cc: KX3 
>> Subject: [Elecraft] Urban stealth HF: Inside-the-backpack loop antenna?
>> 
>> 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
>> __
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>> Post: mailto:Elecraft@mailman.qth.net
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>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html Message 
>> delivered to k9...@live.com
> 
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