Re: [Elecraft] Subject: Waaay OT: A new kind of QRM to be aware of ... warning issued by FCC today

[Eric Swartz]

This thread has already been closed. Please post no more messages on this
topic.
73,
Eric  WA6HHQ
*elecraft.com *


On Tue, Jan 19, 2021 at 6:35 PM Chris Cox, N0UK  wrote:

> Spot on,Phil.
>
> Chris Cox, N0UK
> chr...@chris.org
>
>
>
> > On Jan 18, 2021, at 12:07 PM, Phil Kane  wrote:
> >
> > On 1/18/2021 6:10 AM, Steve Hall wrote:
> >
> >> During my hamming of over 50 years, the FCC has never felt it necessary
> to
> >> threaten hams not to break the law, that is not until we have this new
> >> administration coming into control.  My concern is what they will
> define in
> >> the future as criminal acts.
> >
> > That's because up to now it was unthinkable that licensed hams would use
> amateur radio in the commission of crimes.  The law and the enforcement
> apparatus always was there, though, and was used without any publicity.
> We're going through violent times now and it's sad that such a notice had
> to be issued.  Violators can't say that they weren't warned.
> >
> > 73 de K2ASP - Phil Kane
> > Elecraft K2/100   s/n 5402
> > (30 year veteran of FCC Field Enforcement)
> >
> > __
> > Elecraft mailing list
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> > Post: mailto:Elecraft@mailman.qth.net
> >
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> > Message delivered to chr...@chris.org
>
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Re: [Elecraft] Absurd remarks about FCC and ARRL notices.

[Eric Swartz]

This thread has already been closed. Please post no more messages on this
topic.
73,
Eric  WA6HHQ
Moderator etc.
*elecraft.com *


On Tue, Jan 19, 2021 at 5:45 AM Robert Sands  wrote:

> Serious thinkers need to quietly look at the meaning of "incite",
> "promote", "instigate", "enable", "direct", "instruct", "Plan" and you will
> realize there was a plan (by someone) but no evidence of "incite" unless we
> are disconnected from meaning in language to achieve power. The disconnect
> of thought (inability to see contradictions) cannot be resolved through
> partisan rhetoric because there is no desire for analysis, truth and reason
> to a partisan, only power.  Emotion prevents clear thought. That's why, for
> the most part, ham radio is a pleasure as it encourages reason and clear
> thought (although not always). If the standard of logic is that Trump
> incited at the capitol (the group moved in before he spoke) then all the
> democrats who promoted violence for 9 months as redress should be
> impeached or in jail. Target the wrong doers or every protest from here on
> out will be "incitement" and blamed for the deeds of individuals. Dangerous
> thought error.
> Bob
> K7VO
>
> On Tue, Jan 19, 2021 at 4:27 AM  wrote:
>
> > Shame on you for bring politics into the Elecraft rmail list.  Democrats
> > and Republicans and
> > Independents please keep political factionalism off this email list.  Ham
> > radio is fraternity of
> > people interested in radio communications and its art.   This kind of
> post
> > just  makes more
> > work for the email administrators who will have to moderate all emails to
> > keep the list on
> > topic.
> >
> >
> > __
> > Elecraft mailing list
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> > Post: mailto:Elecraft@mailman.qth.net
> >
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> > Message delivered to k7vora...@gmail.com
> >
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Re: [Elecraft] Efficiency of MFJ remotely-tuned loop antennas

[Andy Durbin]

A couple of people expressed an interest so here is a link to a presentation on 
my mag loop.   It's a while since the presentation was given but the loop is 
still in service in the gamma match configuration.

https://www.dropbox.com/s/5va4ygzbd410le4/Prototype%20Magnetic%20Loop%20rev%20-.pdf?dl=0

Andy, k3wyc


From: Andy Durbin
Sent: Tuesday, January 19, 2021 5:39 PM
To: elecraft@mailman.qth.net 
Subject: Efficiency of MFJ remotely-tuned loop antennas

"although I saw a design not long ago that used two coaxial copper pipes with a 
PVC pipe as the insulator.  The inside conductor was mounted to a long threaded 
rod moving it in and out of the outer conductor."

Not my original idea but that's what I have on my loop (PEX insulator not PVC). 
 Works fine up to 100 W on 30 m but has SWR runaway at 150 W.   Capacitor is 
driven by a geared DC motor and is tuned from the shack.  Home brew is far more 
fun than buying commercial.

I'll post a link to a presentation if there is any interest.

Andy, k3wyc
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Re: [Elecraft] Efficiency of MFJ remotely-tuned loop antennas

[Fred Jensen]

1 vote for interest!

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 1/19/2021 4:39 PM, Andy Durbin wrote:

"although I saw a design not long ago that used two coaxial copper pipes with a PVC 
pipe as the insulator.  The inside conductor was mounted to a long threaded rod moving it 
in and out of the outer conductor."

Not my original idea but that's what I have on my loop (PEX insulator not PVC). 
 Works fine up to 100 W on 30 m but has SWR runaway at 150 W.   Capacitor is 
driven by a geared DC motor and is tuned from the shack.  Home brew is far more 
fun than buying commercial.

I'll post a link to a presentation if there is any interest.

Andy, k3wyc



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Re: [Elecraft] Subject: Waaay OT: A new kind of QRM to be aware of ... warning issued by FCC today

[Chris Cox, N0UK]

Spot on,Phil.

Chris Cox, N0UK
chr...@chris.org



> On Jan 18, 2021, at 12:07 PM, Phil Kane  wrote:
> 
> On 1/18/2021 6:10 AM, Steve Hall wrote:
> 
>> During my hamming of over 50 years, the FCC has never felt it necessary to
>> threaten hams not to break the law, that is not until we have this new
>> administration coming into control.  My concern is what they will define in
>> the future as criminal acts.
> 
> That's because up to now it was unthinkable that licensed hams would use 
> amateur radio in the commission of crimes.  The law and the enforcement 
> apparatus always was there, though, and was used without any publicity. We're 
> going through violent times now and it's sad that such a notice had to be 
> issued.  Violators can't say that they weren't warned.
> 
> 73 de K2ASP - Phil Kane
> Elecraft K2/100   s/n 5402
> (30 year veteran of FCC Field Enforcement)
> 
> __
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Re: [Elecraft] Mag Loop from MFJ

[Chris Cox, N0UK]

FWIW - I invested in an MFJ-1786 when we moved into our apartment 6 1/2 years 
ago.  Since then, kit has been out on our 5th floor balcony in central 
Minneapolis year round, easily standing up to both Minnesotan Winters and 
Summers with aplomb.

It has not ceased to work in that time and has netted me ~150 DXCC’s on all 
bands from 30 through 10 metres.  Most of my work is CW by preference although 
I did break a pile-up a couple of years back to work VP8 on 20m SSB from an 
ATNO.

To say I am pleased with its performance and capability may be understatement 
of the decade!  I am absolutely gobsmacked at how well such a physically small 
antenna plays on HF and am willing to stand up for MFJ (at least in this 
particular case).

YMMV, of course…

Chris Cox, N0UK
chr...@chris.org

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Re: [Elecraft] K4 Receive Filter question

[Bill Frantz]

Not to pick on Bruce, but there have been many posts to this 
thread with essentially the same thought.


However, none of them talk about what I see as one of the most 
important performance characteristics, which is the user 
interface (UI). How easy it the radio to use?


For me, I do a lot of digital modes. Here I want to monitor all 
of the power output, SWR, and ALC. On my K3, I have to switch 
between them. On the K4 I can have them all on the screen.


How easy is it to tune to a signal I see on the panadapter? On 
the P3, I need to move the cursor (via a knob) to be on top of 
the signal and press a button. Honestly, it's easier to turn the 
big knob. On the K4 I touch the touch screen. (I hope this 
screen is better at detecting my touch than my iPhone.)


There are probably a bunch of other examples too.

And, since I'm interested in remote operation, I think that will 
be a lot easier with a K4.


And I haven't even mentioned TX or RX performance. But it's an 
Elecraft, so I'm not worried.


73 Bill AE6JV

On 1/19/21 at 1:40 PM, wa8...@gmail.com (BRUCE WW8II) wrote:


If and when I spend my
cash I am not looking for the pretty blinkie colored lights and a fancy
screen, I want performance.


---
Bill Frantz| Truth and love must prevail  | Periwinkle
(408)348-7900  | over lies and hate.  | 150 
Rivermead Rd #235
www.pwpconsult.com |   - Vaclav Havel | 
Peterborough, NH 03458


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[Elecraft] Efficiency of MFJ remotely-tuned loop antennas

[Andy Durbin]

"although I saw a design not long ago that used two coaxial copper pipes with a 
PVC pipe as the insulator.  The inside conductor was mounted to a long threaded 
rod moving it in and out of the outer conductor."

Not my original idea but that's what I have on my loop (PEX insulator not PVC). 
 Works fine up to 100 W on 30 m but has SWR runaway at 150 W.   Capacitor is 
driven by a geared DC motor and is tuned from the shack.  Home brew is far more 
fun than buying commercial.

I'll post a link to a presentation if there is any interest.

Andy, k3wyc
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Re: [Elecraft] Absurd remarks about FCC and ARRL notices.

[Dave]

When will this end?
Please! Enough!

Dave wo2x

Sent from my waxed string and tin cans. 

> On Jan 19, 2021, at 7:03 PM, Al London  wrote:
> 
> There seems to be a misunderstanding of my thanking jim not geoffrey. I had
> no intention of thanking or condoning political diatribe in this forum.  So
> Geoff your response to my "thanks" is not warranted.
> 
> Al
> N4diy
> 
>> On Tue, Jan 19, 2021, 6:49 PM Barry  wrote:
>> 
>> There's no place for anonymous posting, either.  How hard is it to include
>> your name and/or call?
>> 
>> Barry W2UP
>> 
>> 
>> Elecraft mailing list wrote
>>> Listen.
>>> This is no place for political BS. I don’t care if you are right, left,
>> or
>>> in the f’ing middle. This is a place to discuss Elecraft equipment, uses,
>>> procedures, and other at least semi- related information. NOT POLITICS.
>>> There are plenty of sites out there on the never ending internet where
>> you
>>> can put down this or the next president and administration.
>>> 
>>> Sent from my iPhone
>> 
>> 
>> 
>> 
>> 
>> --
>> Sent from: http://elecraft.365791.n2.nabble.com/
>> __
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>> Message delivered to london...@gmail.com
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Re: [Elecraft] Absurd remarks about FCC and ARRL notices.

[Al London]

There seems to be a misunderstanding of my thanking jim not geoffrey. I had
no intention of thanking or condoning political diatribe in this forum.  So
Geoff your response to my "thanks" is not warranted.

Al
N4diy

On Tue, Jan 19, 2021, 6:49 PM Barry  wrote:

> There's no place for anonymous posting, either.  How hard is it to include
> your name and/or call?
>
> Barry W2UP
>
>
> Elecraft mailing list wrote
> > Listen.
> > This is no place for political BS. I don’t care if you are right, left,
> or
> > in the f’ing middle. This is a place to discuss Elecraft equipment, uses,
> > procedures, and other at least semi- related information. NOT POLITICS.
> > There are plenty of sites out there on the never ending internet where
> you
> > can put down this or the next president and administration.
> >
> > Sent from my iPhone
>
>
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> __
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Re: [Elecraft] Efficiency of MFJ remotely-tuned loop antennas

[Eric Garner]

Here's an interior shot of the tuning capacitor

https://imgur.com/a/sYdvgzF

-Eric KI7LTT

On Mon, Jan 18, 2021 at 10:59 PM Alan Bloom  wrote:

>  > That doesn't sound like they are welded, and given the cost
> difference for welded air variables I doubt MFJ used them.
>
> As I said, I don't have one so I can't say for sure.  I got my
> information from the MFJ web site:  "All welded construction, no
> mechanical joints, welded butterfly capacitor with no rotating contacts
> ... Each plate in MFJ's tuning capacitor is welded for low loss and
> polished to prevent high voltage arcing, welded to the radiator ...".
> https://mfjenterprises.com/products/mfj-1786
>
> Also, for what it's worth, some of the reviews on eham.com and qrz.com
> mention that it has a welded tuning capacitor.
>
> I got the impression that one reason people often receive units with
> bent capacitor plates is that they got bent in the welding process.
>
> It would be interesting to look at one and see what they actually mean
> by "welded".
>
> Alan N1AL
>
>
>
> On 1/18/2021 10:10 PM, David Gilbert wrote:
> >
> > According to another ham who recently posted here, he had to "tighten"
> > the plates on the MFJ capacitor to get it to work properly.  That
> > doesn't sound like they are welded, and given the cost difference for
> > welded air variables I doubt MFJ used them.
> >
> > I sincerely doubt that an actual practical small loop is only down 3
> > dB from a full size antenna.  That makes no sense to me at all. If
> > that were the case everyone would be using one, because they are not
> > that difficult to make ... at least for manually tuned ones.
> >
> > But you seem determined to believe differently, and it's not my place
> > to convince you otherwise.  You asked for inputs and I have made
> > mine.  Hopefully you are right and I am wrong.
> >
> > 73,
> > Dave   AB7E
> >
> >
> >
> > On 1/18/2021 9:54 PM, Alan Bloom wrote:
> >> > There is a reason why top quality variable capacitors often use
> >> welded plates.
> >>
> >> I believe they do weld the capacitor plates and also weld the loop to
> >> the capacitor.  (I don't have one, but that's what I've read.)
> >>
> >> > Yours is a limited theoretical analysis ... not a practical one.
> >>
> >> A number of reviews I have read (including the QST review of August
> >> 1994) have reported comparable performance to full-sized wire
> >> antennas located on the same site.  If the loop is down by, say, 3
> >> dB, that's only half an S unit, which would hardly  be noticeable in
> >> the QSB of a typical amateur band.
> >>
> >>
> >> As I see it, the advantages of the MFJ-1786 10-30 MHz loop are:
> >>
> >> - Continuous coverage on 6 amateur bands.  A convenient way to cover
> >> all the WARC bands.
> >> - Small and light.
> >> - Omni-directional (when mounted horizontally)  so does not need a
> >> rotor.
> >> - No control cable required - control voltage is fed through the coax.
> >> - Narrow bandwidth provides excellent RF selectivity.  Might be good
> >> on Field Day to reduce inter-station QRM.
> >> - Users have reported lower receiver noise compared to wire
> >> antennas.  No doubt that is because the isolated pickup loop prevents
> >> feedline radiation/pickup.
> >>
> >> And the disadvantages:
> >>
> >> - Expensive ($500 list price)
> >> - Less gain than a simple dipole (although you would theoretically
> >> need 6 of them).
> >> - Fiddly to tune.  If you QSY too far you have to re-tune.
> >> - MFJ quality control leaves something to be desired.  (You may have
> >> to open it up when you get it and  make minor repairs.)
> >> - You have to pay attention to the problem of entry of water and/or
> >> bugs into the housing.
> >> - The controller can be damaged by a DC short in the coax e.g. from
> >> an shorting-type antenna switch.  (I don't understand why MFJ didn't
> >> include a fuse or some other way to protect the controller.)
> >>
> >> I probably wouldn't buy the 7-21 MHz MFJ-1788 because of the poor
> >> efficiency at 7 MHz.  I think you'd have a better signal just using
> >> the coax as a random end-fed wire (with a tuner).
> >>
> >> Alan N1AL
> >>
> >>
> >> On 1/18/2021 8:17 PM, David Gilbert wrote:
> >>>
> >>> You are neglecting the losses in various connections in the system
> >>> ... including possibly the construction of the capacitor itself. I
> >>> don't believe that they are insignificant.  There is a reason why
> >>> top quality variable capacitors often use welded plates.
> >>>
> >>> I would also guess that contact resistance is worse for dissimilar
> >>> materials, such as a copper wire to an aluminum tube.
> >>>
> >>> Yours is a limited theoretical analysis ... not a practical one.
> >>>
> >>> Dave   AB7E
> >>>
> >>>
> >>>
> >>> On 1/18/2021 5:38 PM, Alan Bloom wrote:
>  Well let's see...
> 
>  Radiation resistance of a small loop is 31,171 * (Area /
>  wavelength^2)^2
> 
>  For a loop with a 91cm diameter at 14 MHz, I believe that comes out
>  

Re: [Elecraft] Absurd remarks about FCC and ARRL notices.

[Barry]

There's no place for anonymous posting, either.  How hard is it to include
your name and/or call?

Barry W2UP


Elecraft mailing list wrote
> Listen. 
> This is no place for political BS. I don’t care if you are right, left, or
> in the f’ing middle. This is a place to discuss Elecraft equipment, uses,
> procedures, and other at least semi- related information. NOT POLITICS.
> There are plenty of sites out there on the never ending internet where you
> can put down this or the next president and administration. 
> 
> Sent from my iPhone





--
Sent from: http://elecraft.365791.n2.nabble.com/
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Re: [Elecraft] Efficiency of MFJ remotely-tuned loop antennas

[Louandzip via Elecraft]

 Certainly don't want to throw away power in wasted heat, but when I turn down 
my 200W rig to 5W for QRP, it's still useful and that's 16 dB down. 

With ant restrictions, I'm looking at building a small horizontal loop for 6m.  
It'd be a little more than 4' in circumference, 16" dia,  and the capacitor 
could be be two 4 cm diameter plates ~2mm apart. That should be reasonably easy 
to make relatively efficent as there are not a lot of plates that need to be 
connected with very low resistance.  I calculate ~85% with 1/2" copper.  Should 
be good for 200W.  I'd orient it horizontally for horizontal polarization (weak 
sigs) and local noise rejection. 

I have a squalo made from a lawn chair, but technically that's not a small loop 
and a little big to be stealth. 

On Tuesday, January 19, 2021, 3:58:09 PM MST, Alan Bloom  
wrote:  
 
 I've been convinced that AEA's specification of 72% efficiency for the 
Isoloop at 14 MHz is too high, certainly too high for the MFJ antennas.  
So I re-did the calculations using the 59% efficiency figure calculated 
below.  The new results can be downloaded here:

https://www.dropbox.com/s/ve1v49b3gjvmt64/MFJ-1786-1788_2.pdf?dl=0

If you don't want to download the (1-page) document with the pretty 
graph, here's a synopsis of the results:

Freq      Eff. Gain with respect to a 1/2-wavelength dipole
MHz      dB  dBd
7.0         -9.5    -9.9
10.1       -5.1    -5.5
14.0       -2.3    -2.7
18.068   -1.1    -1.5
21.0   -0.7    -1.1
24.89 -0.4    -.8
28.0   -0.26  -0.65

My basic conclusions still stand.  With almost minus 10 dBd of gain on 7 
MHz, the 40 meter coverage of the MFJ-1788 doesn't seem very useful.  
That is confirmed by some of the reviews I have seen.  I think you'd get 
better results by just loading up the coax feedline as a random-wire 
antenna with a tuner.

The 10 MHz performance is a little better.  Good enough to at least 
allow you to get on the 30 meter band.

On the higher bands, the gain is within less than 3 dB of a full-sized 
dipole, which seems a useful trade-off for its small size and wide-band 
continuous coverage.

Disclaimer:  Again, I have never seen one of these things so this is all 
based on theory and on the many reviews I have read.  Even if my figures 
are off a bit, at least this gives an idea of the relative performance 
on the various bands.

Alan N1AL



On 1/18/2021 5:38 PM, Alan Bloom wrote:
> Well let's see...
>
> Radiation resistance of a small loop is 31,171 * (Area / wavelength^2)^2
>
> For a loop with a 91cm diameter at 14 MHz, I believe that comes out to 
> 0.064 ohms.
>
> Assuming the loss is due to the RF resistance of the loop:
>
> From the internet I get the volume resistivity and skin depth for 6063 
> aluminum is 0.03 microohms-meter and 23.3 micrometers respectively, so 
> the surface resistivity is 0.03/23.3 = 0.0013 ohms per square.  The 
> outside circumference of the tubing is PI * 1.05" = 3.3" and the loop 
> length is PI * 36" = 113" so the loss resistance is .0013 * 113/3.3 = 
> 0.045 ohms.
>
> So I calculate an efficiency of 0.064 / (0.064 + 0.045) = 59%
>
> So worse than AEA claimed, but in the ballpark.
>
> Alan N1AL
>
>
>
>
> On 1/18/2021 3:39 PM, Wayne Burdick wrote:
>> Hi Alan,
>>
>> 72% sounds a bit high. Is this number based on loop size alone ("in 
>> theory")? Or are they taking conductor geometry and other losses into 
>> account?
>>
>> Wayne
>> N6KR
>>
>>
>>> On Jan 18, 2021, at 2:05 PM, Alan Bloom  wrote:
>>>
>>> MFJ makes a pair of small, remotely-tuned loop antennas, the 
>>> MFJ-1786 that covers 10-30 MHz and the MFJ-1788 that covers 7 to 21+ 
>>> MHz.  As far as I can tell, the two antennas are identical except 
>>> for the size of the tuning capacitor.  Each consists of a 3 foot (91 
>>> cm) diameter loop made of aluminum tubing and a plastic housing that 
>>> contains the tuning capacitor, motor, and coupling loop.  No control 
>>> cable is required since the control voltage is sent from the control 
>>> box in the shack to the motor in the antenna via the coaxial cable.
>>>
>>> Before I purchase one of these I wanted to get an idea of the 
>>> efficiency of such a small loop.  MFJ is silent on the subject so I 
>>> did my own calculations.  The calculations and results are on a 
>>> 1-page document that I uploaded to Dropbox and can be downloaded here:
>>>
>>> https://www.dropbox.com/s/l8mv67cjrck2ssn/MFJ-1786-1788.pdf?dl=0
>>>
>>> My calculations are based on the assumption that the efficiency of 
>>> the MFJ antennas is similar to the (no longer manufactured) AEA 
>>> Isoloop (my reasoning for that is in the document) and that AEA's 
>>> specification of 72% efficiency at 14 MHz is correct.  From that 
>>> number I can calculate the efficiency and gain on all the other bands.
>>>
>>> If you don't want to download the document, here is a summary of the 
>>> results:
>>>
>>> Freq  Eff  Gain with respect to a half-wave dipole
>>> MHz  dB  dBd
>>> 7.0 

Re: [Elecraft] Efficiency of MFJ remotely-tuned loop antennas

[Alan Bloom]

I've been convinced that AEA's specification of 72% efficiency for the 
Isoloop at 14 MHz is too high, certainly too high for the MFJ antennas.  
So I re-did the calculations using the 59% efficiency figure calculated 
below.  The new results can be downloaded here:


https://www.dropbox.com/s/ve1v49b3gjvmt64/MFJ-1786-1788_2.pdf?dl=0

If you don't want to download the (1-page) document with the pretty 
graph, here's a synopsis of the results:


Freq      Eff. Gain with respect to a 1/2-wavelength dipole
MHz      dB  dBd
7.0         -9.5    -9.9
10.1       -5.1    -5.5
14.0       -2.3    -2.7
18.068   -1.1    -1.5
21.0   -0.7    -1.1
24.89 -0.4    -.8
28.0   -0.26  -0.65

My basic conclusions still stand.  With almost minus 10 dBd of gain on 7 
MHz, the 40 meter coverage of the MFJ-1788 doesn't seem very useful.  
That is confirmed by some of the reviews I have seen.  I think you'd get 
better results by just loading up the coax feedline as a random-wire 
antenna with a tuner.


The 10 MHz performance is a little better.  Good enough to at least 
allow you to get on the 30 meter band.


On the higher bands, the gain is within less than 3 dB of a full-sized 
dipole, which seems a useful trade-off for its small size and wide-band 
continuous coverage.


Disclaimer:  Again, I have never seen one of these things so this is all 
based on theory and on the many reviews I have read.  Even if my figures 
are off a bit, at least this gives an idea of the relative performance 
on the various bands.


Alan N1AL



On 1/18/2021 5:38 PM, Alan Bloom wrote:

Well let's see...

Radiation resistance of a small loop is 31,171 * (Area / wavelength^2)^2

For a loop with a 91cm diameter at 14 MHz, I believe that comes out to 
0.064 ohms.


Assuming the loss is due to the RF resistance of the loop:

From the internet I get the volume resistivity and skin depth for 6063 
aluminum is 0.03 microohms-meter and 23.3 micrometers respectively, so 
the surface resistivity is 0.03/23.3 = 0.0013 ohms per square.  The 
outside circumference of the tubing is PI * 1.05" = 3.3" and the loop 
length is PI * 36" = 113" so the loss resistance is .0013 * 113/3.3 = 
0.045 ohms.


So I calculate an efficiency of 0.064 / (0.064 + 0.045) = 59%

So worse than AEA claimed, but in the ballpark.

Alan N1AL




On 1/18/2021 3:39 PM, Wayne Burdick wrote:

Hi Alan,

72% sounds a bit high. Is this number based on loop size alone ("in 
theory")? Or are they taking conductor geometry and other losses into 
account?


Wayne
N6KR



On Jan 18, 2021, at 2:05 PM, Alan Bloom  wrote:

MFJ makes a pair of small, remotely-tuned loop antennas, the 
MFJ-1786 that covers 10-30 MHz and the MFJ-1788 that covers 7 to 21+ 
MHz.  As far as I can tell, the two antennas are identical except 
for the size of the tuning capacitor.  Each consists of a 3 foot (91 
cm) diameter loop made of aluminum tubing and a plastic housing that 
contains the tuning capacitor, motor, and coupling loop.  No control 
cable is required since the control voltage is sent from the control 
box in the shack to the motor in the antenna via the coaxial cable.


Before I purchase one of these I wanted to get an idea of the 
efficiency of such a small loop.  MFJ is silent on the subject so I 
did my own calculations.  The calculations and results are on a 
1-page document that I uploaded to Dropbox and can be downloaded here:


https://www.dropbox.com/s/l8mv67cjrck2ssn/MFJ-1786-1788.pdf?dl=0

My calculations are based on the assumption that the efficiency of 
the MFJ antennas is similar to the (no longer manufactured) AEA 
Isoloop (my reasoning for that is in the document) and that AEA's 
specification of 72% efficiency at 14 MHz is correct.  From that 
number I can calculate the efficiency and gain on all the other bands.


If you don't want to download the document, here is a summary of the 
results:


Freq  Eff  Gain with respect to a half-wave dipole
MHz  dB  dBd
7.0    -7.3    -7.7
10.1      -3.5    -3.9
14.0      -1.4    -1.8
18.068  -0.6    -1.0
21.0      -0.4    -0.8
24.89    -0.2    -0.6
28.0  -0.15  -0.5

I'd be interested in any comments people may have on the accuracy of
my assumptions and calculations in the document.

Alan N1AL


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Re: [Elecraft] Absurd remarks about FCC and ARRL notices.

[K4HYJ via Elecraft]

Thanks for posting this originally - I wouldn't have seen it otherwise.

The problem with political discussions - especially in the world of 24/7
news coverage and op eds - we all show how uneducated we are on the topics
and are willing to believe what we are told without doing the research.

The rhetoric is all too often divisive.  We can all agree on how fun and
fulfilling ham radio is to each of us in its own special way - let's stick
to that.

Hank
K4HYJ

-Original Message-
From: elecraft-boun...@mailman.qth.net  On
Behalf Of Wayne Burdick
Sent: Tuesday, January 19, 2021 5:00 PM
To: Elecraft Reflector 
Subject: Re: [Elecraft] Absurd remarks about FCC and ARRL notices.

My overworked business partner (WA6HHQ) is rightly trying to shut down this
thread. We certainly don't want red and blue Elecraft forums. 

Before he does, I'd like to slip in a final comment.

The intent of my posting (yes, I started this) was to call attention to a
highly unusual FCC announcement that was assumed to be of general interest.
Similar postings were made to many other ham forums in the same time frame.

It's clear that the message has been received loud and clear.
Interpretations are hereby officially left to the reader as a [private]
exercise. 

Thanks,

Wayne
N6KR

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Re: [Elecraft] Something different, old memories and using the KX3

[Dave Sublette]

Well done, Paul.  It is a joy to read your account and I know you have had
some great adventures.  You are right about we older folks who cherish the
memories of our adventures through the years.

73,

Dave, K4TO

On Tue, Jan 19, 2021 at 5:06 PM Paul GACEK via Elecraft <
elecraft@mailman.qth.net> wrote:

> I’ve been sorting out some of my LoTW records which inevitably covered the
> 2016 NPOTA event.
>
> I did a lot of low power phone activations in the Western USA using my KX3
> for NPOTA many in the San Francisco Bay Area when I was living in that fine
> city.
>
> Loved the event, love my KX3 and just wanted to jot down a few memories
> for me to re-read over a glass of whisky sometime in the future and not
> surprisingly thinking about the past is almost as good as going out now
> which clearly isn’t so easy.
>
> No technical insights nor stellar Q counts here…..just old fashioned
> memories of a more human kind.
>
> Delete if not interested or peruse at
> https://nomadic.blog/2021/01/19/camaraderie-in-the-age-of-national-parks-on-the-air/
> <
> https://nomadic.blog/2021/01/19/camaraderie-in-the-age-of-national-parks-on-the-air/
> >
>
> Paul
> W6PNG/M0SNA
> www.nomadic.blog 
>
> __
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[Elecraft] Something different, old memories and using the KX3

[Paul GACEK via Elecraft]

I’ve been sorting out some of my LoTW records which inevitably covered the 2016 
NPOTA event.

I did a lot of low power phone activations in the Western USA using my KX3 for 
NPOTA many in the San Francisco Bay Area when I was living in that fine city. 

Loved the event, love my KX3 and just wanted to jot down a few memories for me 
to re-read over a glass of whisky sometime in the future and not surprisingly 
thinking about the past is almost as good as going out now which clearly isn’t 
so easy.

No technical insights nor stellar Q counts here…..just old fashioned memories 
of a more human kind.

Delete if not interested or peruse at 
https://nomadic.blog/2021/01/19/camaraderie-in-the-age-of-national-parks-on-the-air/
 


Paul
W6PNG/M0SNA
www.nomadic.blog 

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Re: [Elecraft] Absurd remarks about FCC and ARRL notices.

[Wayne Burdick]

My overworked business partner (WA6HHQ) is rightly trying to shut down this 
thread. We certainly don't want red and blue Elecraft forums. 

Before he does, I'd like to slip in a final comment.

The intent of my posting (yes, I started this) was to call attention to a 
highly unusual FCC announcement that was assumed to be of general interest. 
Similar postings were made to many other ham forums in the same time frame.

It's clear that the message has been received loud and clear. Interpretations 
are hereby officially left to the reader as a [private] exercise. 

Thanks,

Wayne
N6KR

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Re: [Elecraft] Absurd remarks about FCC and ARRL notices.

[Al London]

Jim

Thank you for your concise comments. Greatly appreciated. The last thing we 
need is more politics.

Al
N4DIY

Sent from my Verizon, Samsung Note20 smartphone


From: elecraft-boun...@mailman.qth.net  on 
behalf of kennedyjp 
Sent: Tuesday, January 19, 2021 4:37:15 PM
To: Geoffrey Feldman ; elecraft@mailman.qth.net 
; elecraft-ow...@mailman.qth.net 

Subject: Re: [Elecraft] Absurd remarks about FCC and ARRL notices.

Enough already. Keep your political views and beliefs off this forum.  Not 
needed, not wanted. JimW7OUU Sent via the Samsung Galaxy S9+, an AT 5G 
Evolution capable smartphone
 Original message From: Geoffrey Feldman 
 Date: 1/18/21  19:06  (GMT-07:00) To: 
elecraft@mailman.qth.net, elecraft-ow...@mailman.qth.net Subject: [Elecraft] 
Absurd remarks about FCC and ARRL notices. The letters to this list regarding 
FCC and ARRL notices  were factuallyfalse and have absolutely nothing to do 
with Elecraft products exceptperhaps as some might choose to use such radio 
transmitting products tocommit unjustified criminal acts.  Those who have false 
pride in theircomments can read what I write here and readily determine their 
factualmistakes for themselves.   The reason for the FCC and ARRL Notices is 
factually not because of the nextadministration but the present one which 
incited a riot. IN THAT  CRIMINALOFFENSE, Radios were used unlawfully to commit 
Federal offenses againstdemocracy and the Constitution.   I also see the FCC 
notice as one askingcivilians to report criminal use of Amateur and other 
civiliancommunications g
 ear - This I will do as well as working with other lawabiding hams to find, 
locate and document criminal use, especially againstthe Constitution and US 
Government.   The reason why Washington D.C. is anarmed camp is that on 1/6 We 
had a president incite insurrection. ThatPresident is the only one with two 
impeachments, both of which are morelegally substantive than the two which 
preceded them.  Those personscriminally acted to disrupt lawful congressional 
preceding.  Many claim tohave done this on behalf of the current President, 
failing to understandnobody is above the law and any apparent direction to 
violate theconstitution is illegal no matter the source. That entire event 
wasunprecedented in the USA and the responses are and will be as well.  
Theelection was not fraudulent.  It was certified in each of the states, inmost 
cases by Republican elected authorities.  Over 60 cases whose lawyersclaimed 
fraud, were thrown out by Federal judges, many of whom appointed bythe cur
 rent President.  In several cases these judges noted there was noevidence at 
all and in the rest, no evidence that would show a change in theend result for 
that state.  The Supreme Court also spoke on this matter -against the 
Presidents false claims.  There are over 60 case transcripts,public oral 
opinions by the judges and supreme court, as well as the remarksof AG Barr who 
quit in disgust with his own administration.Frankly to blame the next 
administration for the FCC and ARRL notice isidiotic - they are not in power 
yet.  That assault on the Capitol wasunprecedented and THAT is what has led to 
the other unprecedented things.The reason is that under our constitution, 
nobody is above the law,including the President and those who stormed the 
capitol.  Acting toenforce the law should not be offensive to anyone who claims 
to be a patriotor writing in the traditions of Amateur Radio or the ARRL.   
Interesting  toknow the false sympathies of some of you though. I encourage you 
t
 o spendthe reasonable efforts of citizens to go and learn what you didn't. 
Geoffrey 
FeldmanW1GCF__Elecraft
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Re: [Elecraft] Absurd remarks about FCC and ARRL notices.

[kennedyjp]

Enough already. Keep your political views and beliefs off this forum.  Not 
needed, not wanted. JimW7OUU Sent via the Samsung Galaxy S9+, an AT 5G 
Evolution capable smartphone
 Original message From: Geoffrey Feldman 
 Date: 1/18/21  19:06  (GMT-07:00) To: 
elecraft@mailman.qth.net, elecraft-ow...@mailman.qth.net Subject: [Elecraft] 
Absurd remarks about FCC and ARRL notices. The letters to this list regarding 
FCC and ARRL notices  were factuallyfalse and have absolutely nothing to do 
with Elecraft products exceptperhaps as some might choose to use such radio 
transmitting products tocommit unjustified criminal acts.  Those who have false 
pride in theircomments can read what I write here and readily determine their 
factualmistakes for themselves.   The reason for the FCC and ARRL Notices is 
factually not because of the nextadministration but the present one which 
incited a riot. IN THAT  CRIMINALOFFENSE, Radios were used unlawfully to commit 
Federal offenses againstdemocracy and the Constitution.   I also see the FCC 
notice as one askingcivilians to report criminal use of Amateur and other 
civiliancommunications gear - This I will do as well as working with other 
lawabiding hams to find, locate and document criminal use, especially 
againstthe Constitution and US Government.   The reason why Washington D.C. is 
anarmed camp is that on 1/6 We had a president incite insurrection. 
ThatPresident is the only one with two impeachments, both of which are 
morelegally substantive than the two which preceded them.  Those 
personscriminally acted to disrupt lawful congressional preceding.  Many claim 
tohave done this on behalf of the current President, failing to 
understandnobody is above the law and any apparent direction to violate 
theconstitution is illegal no matter the source. That entire event 
wasunprecedented in the USA and the responses are and will be as well.  
Theelection was not fraudulent.  It was certified in each of the states, inmost 
cases by Republican elected authorities.  Over 60 cases whose lawyersclaimed 
fraud, were thrown out by Federal judges, many of whom appointed bythe current 
President.  In several cases these judges noted there was noevidence at all and 
in the rest, no evidence that would show a change in theend result for that 
state.  The Supreme Court also spoke on this matter -against the Presidents 
false claims.  There are over 60 case transcripts,public oral opinions by the 
judges and supreme court, as well as the remarksof AG Barr who quit in disgust 
with his own administration.Frankly to blame the next administration for the 
FCC and ARRL notice isidiotic - they are not in power yet.  That assault on the 
Capitol wasunprecedented and THAT is what has led to the other unprecedented 
things.The reason is that under our constitution, nobody is above the 
law,including the President and those who stormed the capitol.  Acting 
toenforce the law should not be offensive to anyone who claims to be a 
patriotor writing in the traditions of Amateur Radio or the ARRL.   Interesting 
 toknow the false sympathies of some of you though. I encourage you to spendthe 
reasonable efforts of citizens to go and learn what you didn't. Geoffrey 
FeldmanW1GCF__Elecraft
 mailing listHome: http://mailman.qth.net/mailman/listinfo/elecraftHelp: 
http://mailman.qth.net/mmfaq.htmPost: mailto:elecr...@mailman.qth.netThis list 
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[Elecraft] Absurd remarks about FCC and ARRL notices.

[Joseph Shuman via Elecraft]

This new OT topic and the preceding old OT topic combined has been one of the 
greatest examples of free speech I have ever seen on-line.  Kudos to this forum 
for open and honest participation, it fills me with hope to see such a 
wonderful exchange of contrasting viewpoints without digital censorship.  It 
may be “OT” but the unprecedented notice by the FCC and the ARRL should be 
openly discussed by all licensees.  After all, our hobby is an advancement of 
free speech that pre-dates the digital age, and in my view free speech is NEVER 
“absurd.”

Keeping Watch -
shu

Joe Shuman, NZ8P 
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Re: [Elecraft] Efficiency of MFJ remotely-tuned loop antennas

[Fred Jensen]

The plates in the two air variables in the [now ancient] ARC-5 command 
TX from WW2 were very securely welded in place to the rotor axle.  We'd 
remove many of the rotor plates and re-pad it with a fixed capacitor to 
spread out the ham band on the dial.  It took a lot of bending back and 
forth to break the welds.  Lower power loops often use butterfly caps 
since there is no resistive loss through the rotor connection.  Higher 
powered loops often use vacuum variables because of the high voltages, 
although I saw a design not long ago that used two coaxial copper pipes 
with a PVC pipe as the insulator.  The inside conductor was mounted to a 
long threaded rod moving it in and out of the outer conductor.


In your list of pros, you might note that while the bi-directional 
primary lobes of the loop when mounted vertically are very broad, the 
null perpendicular to the plane of the loop is extremely narrow and 
deep.  You can use it to null out noise or even another signal without 
sacrificing much of anything in the forward direction.


My Alexloop works ok on 30, poorly on 40, and really seems to come into 
its own on 20 and up.


73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 1/18/2021 8:54 PM, Alan Bloom wrote:
> There is a reason why top quality variable capacitors often use 
welded plates.


I believe they do weld the capacitor plates and also weld the loop to 
the capacitor.  (I don't have one, but that's what I've read.)


> Yours is a limited theoretical analysis ... not a practical one.

A number of reviews I have read (including the QST review of August 
1994) have reported comparable performance to full-sized wire antennas 
located on the same site.  If the loop is down by, say, 3 dB, that's 
only half an S unit, which would hardly  be noticeable in the QSB of a 
typical amateur band.



As I see it, the advantages of the MFJ-1786 10-30 MHz loop are:

- Continuous coverage on 6 amateur bands.  A convenient way to cover 
all the WARC bands.

- Small and light.
- Omni-directional (when mounted horizontally)  so does not need a rotor.
- No control cable required - control voltage is fed through the coax.
- Narrow bandwidth provides excellent RF selectivity.  Might be good 
on Field Day to reduce inter-station QRM.
- Users have reported lower receiver noise compared to wire antennas.  
No doubt that is because the isolated pickup loop prevents feedline 
radiation/pickup.


And the disadvantages:

- Expensive ($500 list price)
- Less gain than a simple dipole (although you would theoretically 
need 6 of them).

- Fiddly to tune.  If you QSY too far you have to re-tune.
- MFJ quality control leaves something to be desired.  (You may have 
to open it up when you get it and  make minor repairs.)
- You have to pay attention to the problem of entry of water and/or 
bugs into the housing.
- The controller can be damaged by a DC short in the coax e.g. from an 
shorting-type antenna switch.  (I don't understand why MFJ didn't 
include a fuse or some other way to protect the controller.)


I probably wouldn't buy the 7-21 MHz MFJ-1788 because of the poor 
efficiency at 7 MHz.  I think you'd have a better signal just using 
the coax as a random end-fed wire (with a tuner).


Alan N1AL


On 1/18/2021 8:17 PM, David Gilbert wrote:


You are neglecting the losses in various connections in the system 
... including possibly the construction of the capacitor itself. I 
don't believe that they are insignificant.  There is a reason why top 
quality variable capacitors often use welded plates.


I would also guess that contact resistance is worse for dissimilar 
materials, such as a copper wire to an aluminum tube.


Yours is a limited theoretical analysis ... not a practical one.

Dave   AB7E



On 1/18/2021 5:38 PM, Alan Bloom wrote:

Well let's see...

Radiation resistance of a small loop is 31,171 * (Area / 
wavelength^2)^2


For a loop with a 91cm diameter at 14 MHz, I believe that comes out 
to 0.064 ohms.


Assuming the loss is due to the RF resistance of the loop:

From the internet I get the volume resistivity and skin depth for 
6063 aluminum is 0.03 microohms-meter and 23.3 micrometers 
respectively, so the surface resistivity is 0.03/23.3 = 0.0013 ohms 
per square.  The outside circumference of the tubing is PI * 1.05" = 
3.3" and the loop length is PI * 36" = 113" so the loss resistance 
is .0013 * 113/3.3 = 0.045 ohms.


So I calculate an efficiency of 0.064 / (0.064 + 0.045) = 59%

So worse than AEA claimed, but in the ballpark.

Alan N1AL




On 1/18/2021 3:39 PM, Wayne Burdick wrote:

Hi Alan,

72% sounds a bit high. Is this number based on loop size alone ("in 
theory")? Or are they taking conductor geometry and other losses 
into account?


Wayne
N6KR



On Jan 18, 2021, at 2:05 PM, Alan Bloom  wrote:

MFJ makes a pair of small, remotely-tuned loop antennas, the 
MFJ-1786 that covers 10-30 MHz and the MFJ-1788 that covers 7 to 
21+ MHz.  As far as I can tell, the two antennas are 

Re: [Elecraft] K4 Receive Filter question

[Wes]

I happen to own the K3S that is #5 or Rob's list.  I also got tired of waiting 
on the K4 and having a burning desire for a new radio I have a month-old TS-890, 
which is now my primary radio.  The K3S is set up in a receive-only state, 
sharing the RX antenna out of the '890.


A few mornings ago I was tuning 160 near sunrise and copied a fishing buoy 60 Hz 
above one of the commonly used frequencies (forget which one).  My friend, and 
local ham, N7DD began calling CQ 60 Hz below the buoy.  Larry runs an Icom 7851, 
which is very clean and a BIG amplifier.  He is at least S9+40 db.  On the 
TS-890, cranked down to 80 Hz BW,  I could still copy the buoy which was S6 or 
so.  On the K3S I heard N7DD calling CQ.


Without QRM the rigs are comparable at hearing signals in the noise but the 
Kenwood sounds better.


Wes  N7WS

On 1/19/2021 12:38 PM, Louandzip via Elecraft wrote:

  I own a radio that's currently #1 on Sherwood's list. My 20 year old K2 is 
essentially equal at digging weak CW out of the noise (always dominated by band 
noise and not the noise floor of the rig) in virtually all situations I've run 
into. The K2 has no KSSB so I don't compare it on SSB. If I was up against a 
lot of really strong close-by sigs, presumably the new rig would win, but I 
haven't yet run into a situation with the two rigs side by side where big 
nearby sigs have actually caused a discernible difference.
Comparing SSB with other rigs, the new rig can beat the others on readability 
of weak sigs in noise, but I don't think it's due to the fundamental 
performance numbers in these cases but rather the DSP algorithm which makes the 
difference, and I don't believe this is quantified in the testing done by 
Sherwood or ARRL, except perhaps in subjective comments in the text of a QST 
review. .

 On Tuesday, January 19, 2021, 12:13:20 PM MST, George Thornton 
 wrote:
  
  I have followed the Sherwood Receiver test data over the years and I know Elecraft has always been in or near the top spot.


I also would be reluctant to upgrade to a K4 if my K3 is the same or pretty 
close to the same in the key performance characteristics.

I wonder whether we are nearing the theoretical limit of what can be gained in 
receiver performance.

The difference among the top eight to ten on the Sherwood list is not likely to 
be practically significant.


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Re: [Elecraft] K4 Receive Filter question

[Louandzip via Elecraft]

 I own a radio that's currently #1 on Sherwood's list. My 20 year old K2 is 
essentially equal at digging weak CW out of the noise (always dominated by band 
noise and not the noise floor of the rig) in virtually all situations I've run 
into. The K2 has no KSSB so I don't compare it on SSB. If I was up against a 
lot of really strong close-by sigs, presumably the new rig would win, but I 
haven't yet run into a situation with the two rigs side by side where big 
nearby sigs have actually caused a discernible difference.
Comparing SSB with other rigs, the new rig can beat the others on readability 
of weak sigs in noise, but I don't think it's due to the fundamental 
performance numbers in these cases but rather the DSP algorithm which makes the 
difference, and I don't believe this is quantified in the testing done by 
Sherwood or ARRL, except perhaps in subjective comments in the text of a QST 
review. . 

On Tuesday, January 19, 2021, 12:13:20 PM MST, George Thornton 
 wrote:  
 
 I have followed the Sherwood Receiver test data over the years and I know 
Elecraft has always been in or near the top spot.

I also would be reluctant to upgrade to a K4 if my K3 is the same or pretty 
close to the same in the key performance characteristics.

I wonder whether we are nearing the theoretical limit of what can be gained in 
receiver performance.

The difference among the top eight to ten on the Sherwood list is not likely to 
be practically significant.

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of BRUCE WW8II
Sent: Tuesday, January 19, 2021 10:40 AM
To: Louandzip 
Cc: elecraft 
Subject: Re: [Elecraft] K4 Receive Filter question

I work in the 2 to 3 db above the noise floor CW, and 6 to 10 db above the 
noise floor on SSB now, (that is why I presently own a K3s and a P3VGA)  so I 
guess I will have to wait for the real answer. I really cannot believe that 
Elecraft did not run their own test. If and when I spend my cash I am not 
looking for the pretty blinkie colored lights and a fancy screen, I want 
performance.  My really big issue is: receiver noise floor, sensitivity and DSP 
that does not distort or degrade the incoming signal.
 But thank all of you for your input  and I truly appreciate all the comments.

Bruce
WW8II



On Tue, Jan 19, 2021 at 10:43 AM Louandzip via Elecraft < 
elecraft@mailman.qth.net> wrote:

>  That's not a simple or easy question to answer, especially since 
> there's been no independent test of a K4, and there are many different 
> criteria that go into it.  That said,  I'll go out on a limb and say 
> that in most all practical situations on the air, it won't be. I say 
> that because I've listened to and half-assedly compared a number of 
> very good radios and some less good radios on the air. They might 
> sound different, and take some tweaking of the controls to make them 
> sound a similar as possible, but in the end I couldn't copy sigs 
> better on one than the other. The K3 is really good in the tests, and 
> I'm confident the K4 will surpass it, but that's at level that will 
> only matter in what I consider to be exceptional circumstances.
>
> I'll add that I'm not the radio connoisseur that some are, and what I 
> feel is largely the same, others may find hugely different. That 
> doesn't stop me from wanting the best, even if I believe it won't make 
> a practical difference in my operating.
>
>
>
>
>    On Tuesday, January 19, 2021, 12:47:17 AM MST, BRUCE WW8II < 
> wa8...@gmail.com> wrote:
>
>  I also would appreciate a real answer to the question.  The question 
> is will the K4 or K4D be as good or better on receive than my K3s with 
> the 2.1kHz and the 200Hz filters.
>
> Bruce WW8II
>
> On Tue, Jan 19, 2021 at 12:56 AM RVZ via Elecraft < 
> elecraft@mailman.qth.net>
> wrote:
>
> > I believe there are no crystal Roofing Filters in the standard K4 model.
> > Yet the manual talks about "one set of receive filters".  Please 
> > advise
> the
> > type and bandwidth of these filters?  (DSP?)
> >
> > From the K4 Manual:  There are three models: the basic K4, with one 
> > set
> of
> > receive filters and one analog-to-digital converter (ADC); the K4D, 
> > with
> a
> > second set of receive filters and a second ADC; and the K4HD, which 
> > adds
> a
> > superheterodyne front end that can be enabled as needed to provide 
> > even greater dynamic range. The superhet module uses 
> > high-performance, narrow-band crystal filters such as those used in the 
> > Elecraft K3S.
> Thanks
> > & 73, Dick- K9OM
> > __
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:Elecraft@mailman.qth.net
> >
> > This list hosted by: http://www.qsl.net Please help support this 
> > email list: http://www.qsl.net/donate.html Message delivered to 
> > wa8...@gmail.com
> 

Re: [Elecraft] K4 Receive Filter question

[George Thornton]

I have followed the Sherwood Receiver test data over the years and I know 
Elecraft has always been in or near the top spot.

I also would be reluctant to upgrade to a K4 if my K3 is the same or pretty 
close to the same in the key performance characteristics.

I wonder whether we are nearing the theoretical limit of what can be gained in 
receiver performance.

The difference among the top eight to ten on the Sherwood list is not likely to 
be practically significant.

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of BRUCE WW8II
Sent: Tuesday, January 19, 2021 10:40 AM
To: Louandzip 
Cc: elecraft 
Subject: Re: [Elecraft] K4 Receive Filter question

I work in the 2 to 3 db above the noise floor CW, and 6 to 10 db above the 
noise floor on SSB now, (that is why I presently own a K3s and a P3VGA)  so I 
guess I will have to wait for the real answer. I really cannot believe that 
Elecraft did not run their own test. If and when I spend my cash I am not 
looking for the pretty blinkie colored lights and a fancy screen, I want 
performance.  My really big issue is: receiver noise floor, sensitivity and DSP 
that does not distort or degrade the incoming signal.
 But thank all of you for your input  and I truly appreciate all the comments.

Bruce
WW8II



On Tue, Jan 19, 2021 at 10:43 AM Louandzip via Elecraft < 
elecraft@mailman.qth.net> wrote:

>  That's not a simple or easy question to answer, especially since 
> there's been no independent test of a K4, and there are many different 
> criteria that go into it.  That said,  I'll go out on a limb and say 
> that in most all practical situations on the air, it won't be. I say 
> that because I've listened to and half-assedly compared a number of 
> very good radios and some less good radios on the air. They might 
> sound different, and take some tweaking of the controls to make them 
> sound a similar as possible, but in the end I couldn't copy sigs 
> better on one than the other. The K3 is really good in the tests, and 
> I'm confident the K4 will surpass it, but that's at level that will 
> only matter in what I consider to be exceptional circumstances.
>
> I'll add that I'm not the radio connoisseur that some are, and what I 
> feel is largely the same, others may find hugely different. That 
> doesn't stop me from wanting the best, even if I believe it won't make 
> a practical difference in my operating.
>
>
>
>
> On Tuesday, January 19, 2021, 12:47:17 AM MST, BRUCE WW8II < 
> wa8...@gmail.com> wrote:
>
>  I also would appreciate a real answer to the question.  The question 
> is will the K4 or K4D be as good or better on receive than my K3s with 
> the 2.1kHz and the 200Hz filters.
>
> Bruce WW8II
>
> On Tue, Jan 19, 2021 at 12:56 AM RVZ via Elecraft < 
> elecraft@mailman.qth.net>
> wrote:
>
> > I believe there are no crystal Roofing Filters in the standard K4 model.
> > Yet the manual talks about "one set of receive filters".  Please 
> > advise
> the
> > type and bandwidth of these filters?  (DSP?)
> >
> > From the K4 Manual:  There are three models: the basic K4, with one 
> > set
> of
> > receive filters and one analog-to-digital converter (ADC); the K4D, 
> > with
> a
> > second set of receive filters and a second ADC; and the K4HD, which 
> > adds
> a
> > superheterodyne front end that can be enabled as needed to provide 
> > even greater dynamic range. The superhet module uses 
> > high-performance, narrow-band crystal filters such as those used in the 
> > Elecraft K3S.
> Thanks
> > & 73, Dick- K9OM
> > __
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:Elecraft@mailman.qth.net
> >
> > This list hosted by: http://www.qsl.net Please help support this 
> > email list: http://www.qsl.net/donate.html Message delivered to 
> > wa8...@gmail.com
> __
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>
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>
> __
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Please 

Re: [Elecraft] K4 Receive Filter question

[David Box]

Bruce,

Below are the receiver sensitivity specs from page 42 of the recently 
updated manual



Sensitivity    (MDS)

(Typical    values;    main    or
sub    RX,    BW    =    500    Hz)

0.1-1.5    MHz*:                Preamp    OFF/1/2: -120/-130/-135        
dBm
1.5-23    MHz:                            Preamp    OFF/1/2:     
-120/-132/-137    dBm
23-54    MHz:                                Preamp    OFF/1/2:         
-120/-132/-141    dBm

*0.1-1.5    MHz    MDS    measured    at    RX    antenna inputs.    When
using    shared    RX/TX    antenna,    sensitivity decreases    
below    1.5
MHz    due    to    intentional    high-pass    response    of T-R    
switch.



de Dave K5MWR

On 1/19/2021 12:40, BRUCE WW8II wrote:

I work in the 2 to 3 db above the noise floor CW, and 6 to 10 db above the
noise floor on SSB now, (that is why I presently own a K3s and a P3VGA)  so
I guess I will have to wait for the real answer. I really cannot
believe that Elecraft did not run their own test. If and when I spend my
cash I am not looking for the pretty blinkie colored lights and a fancy
screen, I want performance.  My really big issue is: receiver noise floor,
sensitivity and DSP that does not distort or degrade the incoming signal.
  But thank all of you for your input  and I truly appreciate all the
comments.

Bruce
WW8II



On Tue, Jan 19, 2021 at 10:43 AM Louandzip via Elecraft <
elecraft@mailman.qth.net> wrote:


  That's not a simple or easy question to answer, especially since there's
been no independent test of a K4, and there are many different criteria
that go into it.  That said,  I'll go out on a limb and say that in most
all practical situations on the air, it won't be. I say that because I've
listened to and half-assedly compared a number of very good radios and some
less good radios on the air. They might sound different, and take some
tweaking of the controls to make them sound a similar as possible, but in
the end I couldn't copy sigs better on one than the other. The K3 is really
good in the tests, and I'm confident the K4 will surpass it, but that's at
level that will only matter in what I consider to be exceptional
circumstances.

I'll add that I'm not the radio connoisseur that some are, and what I feel
is largely the same, others may find hugely different. That doesn't stop me
from wanting the best, even if I believe it won't make a practical
difference in my operating.




 On Tuesday, January 19, 2021, 12:47:17 AM MST, BRUCE WW8II <
wa8...@gmail.com> wrote:

  I also would appreciate a real answer to the question.  The question is
will the K4 or K4D be as good or better on receive than my K3s with the
2.1kHz and the 200Hz filters.

Bruce WW8II

On Tue, Jan 19, 2021 at 12:56 AM RVZ via Elecraft <
elecraft@mailman.qth.net>
wrote:


I believe there are no crystal Roofing Filters in the standard K4 model.
Yet the manual talks about "one set of receive filters".  Please advise

the

type and bandwidth of these filters?  (DSP?)

 From the K4 Manual:  There are three models: the basic K4, with one set

of

receive filters and one analog-to-digital converter (ADC); the K4D, with

a

second set of receive filters and a second ADC; and the K4HD, which adds

a

superheterodyne front end that can be enabled as needed to provide even
greater dynamic range. The superhet module uses high-performance,
narrow-band crystal filters such as those used in the Elecraft K3S.

Thanks

& 73, Dick- K9OM
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Re: [Elecraft] K4 Receive Filter question

[BRUCE WW8II]

I work in the 2 to 3 db above the noise floor CW, and 6 to 10 db above the
noise floor on SSB now, (that is why I presently own a K3s and a P3VGA)  so
I guess I will have to wait for the real answer. I really cannot
believe that Elecraft did not run their own test. If and when I spend my
cash I am not looking for the pretty blinkie colored lights and a fancy
screen, I want performance.  My really big issue is: receiver noise floor,
sensitivity and DSP that does not distort or degrade the incoming signal.
 But thank all of you for your input  and I truly appreciate all the
comments.

Bruce
WW8II



On Tue, Jan 19, 2021 at 10:43 AM Louandzip via Elecraft <
elecraft@mailman.qth.net> wrote:

>  That's not a simple or easy question to answer, especially since there's
> been no independent test of a K4, and there are many different criteria
> that go into it.  That said,  I'll go out on a limb and say that in most
> all practical situations on the air, it won't be. I say that because I've
> listened to and half-assedly compared a number of very good radios and some
> less good radios on the air. They might sound different, and take some
> tweaking of the controls to make them sound a similar as possible, but in
> the end I couldn't copy sigs better on one than the other. The K3 is really
> good in the tests, and I'm confident the K4 will surpass it, but that's at
> level that will only matter in what I consider to be exceptional
> circumstances.
>
> I'll add that I'm not the radio connoisseur that some are, and what I feel
> is largely the same, others may find hugely different. That doesn't stop me
> from wanting the best, even if I believe it won't make a practical
> difference in my operating.
>
>
>
>
> On Tuesday, January 19, 2021, 12:47:17 AM MST, BRUCE WW8II <
> wa8...@gmail.com> wrote:
>
>  I also would appreciate a real answer to the question.  The question is
> will the K4 or K4D be as good or better on receive than my K3s with the
> 2.1kHz and the 200Hz filters.
>
> Bruce WW8II
>
> On Tue, Jan 19, 2021 at 12:56 AM RVZ via Elecraft <
> elecraft@mailman.qth.net>
> wrote:
>
> > I believe there are no crystal Roofing Filters in the standard K4 model.
> > Yet the manual talks about "one set of receive filters".  Please advise
> the
> > type and bandwidth of these filters?  (DSP?)
> >
> > From the K4 Manual:  There are three models: the basic K4, with one set
> of
> > receive filters and one analog-to-digital converter (ADC); the K4D, with
> a
> > second set of receive filters and a second ADC; and the K4HD, which adds
> a
> > superheterodyne front end that can be enabled as needed to provide even
> > greater dynamic range. The superhet module uses high-performance,
> > narrow-band crystal filters such as those used in the Elecraft K3S.
> Thanks
> > & 73, Dick- K9OM
> > __
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:Elecraft@mailman.qth.net
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> > Message delivered to wa8...@gmail.com
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[Elecraft] Explained: K4/K4D receive performance vs. K3S

[Wayne Burdick]

> BRUCE WW8II  wrote:
> 
> The question is will the K4 or K4D be as good or better on receive than my 
> K3s with the
> 2.1kHz and the 200Hz filters.
> 
> Bruce WW8II


Bruce,

First, a bit of background would help since they're two different 
architectures. 

The K4/K4D are "pure" SDRs, meaning they're more agile in frequency, operating 
modes, modulation and demodulation, features in general, and extensibility. A 
lot of the flexibility of the design is in service of the built-in and external 
displays as well as remote control. The K4/K4D also have a lot more digital and 
RF I/O, satisfying the demand for a modern, integrated station. For example you 
can directly attach a keyboard, mouse, HDMI monitor, and flash storage drives 
or other USB devices.

By contrast, the K3S is a superhet, with emphasis primarily on receive close-in 
dynamic range performance rather than integration, agility, extensibility. The 
use of crystal filters is an advantage in raw performance, at the expense of 
passband flatness, available bandwidths, and group delay.

The K4HD will be a hybrid of the two: When the extra dynamic range is needed, 
you can turn on the HDR module, which is essentially two superhet 
downconverters, one for the main receiver and the other for the sub. But the 
HDR module is, in practice, rarely needed unless you have high-power 
transmitters in close proximity. Examples of this situation include 
multi-transmitter contest or DXpedition stations, those living in the shadow of 
a broadcast station, and those with very nearby ham neighbors.

With this context we can now talk about receiver performance.

- The K4/K4D are very similar to competing pure SDRs using 16 bit, wide-band 
A-to-D converters: signal handling is excellent by any measure, and there's 
plenty of headroom in all but the most heavily impacted RF environments.

- Compared to *any* pure SDR, the K3S (and a few other superhets) will have a 
few dB higher third-order intercept point. (Note that Sherwood's chart still 
shows the Flex 6700, a pure SDR, at 108 dB. He corrected this later to a much 
lower number -- see the '6700 footnotes in the far right column.)

- The K4HD will be in the same ballpark as the K3S, though we're still refining 
the design and our goal is for it to be higher. (The limitation with any 
superhet is the crystal filters, and we carefully control the quality of our 
suppliers.) 

73,
Wayne
N6KR



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Re: [Elecraft] KPA1500 Remote Operation

[Rajiv Dewan]

You do not need a computer - just use a usb to ethernet server such as Silex 
DS-510 (USB2 to Gigabit) or DS-600 (USB3 to Gigabit).  I am using them and I 
can remotely access the KPA500 and KAT500 without using a computer in the 
shack.  You may need a RS232 to USB adapter in addition for the KPA500 that has 
a serial port.  

My setup: 
K3 Twin setup using Remoterig RRC1258
ICOM IC-9700 with RS-BA1 software for remoting

KAT500 —> KXUSB cable —> USB Hub 
KPA500 —> Serial cable —> Prolific 4 serial port adapter —> USB Hub
KXPA100 —> home made KXSER —> Prolific 4 serial port adapter —> USB Hub 
IC9700 —> CI-V USB adapter —> USB Hub
Wavenode watt meter —> USB Hub
Green Heron RT21 —> USB Hub

USB Hub —> Silex DS-600 
LP Pan —> EMU USB Sound adapter —> Silex DS-600

The DS-600 has two USB ports, one ethernet port, and a power port.

You run a utility supplied by Silex in the remote operating computer that 
brings all the USB ports as if they were directly connected.  Everything just 
works including sound cards, serial ports, etc.

Raj, N2RD


> On Jan 19, 2021, at 11:15 AM, Paul DeFelice  wrote:
> 
> Just curious. Not being very knowledgeable about networking, I'd like to
> know why the KPA1500 does not have internal server capability. It sure would
> be nice to operate the amplifier without having to have a computer running
> in the home shack and running the Elecraft remote software (which does work
> quite well).
> 
> 73,
> 
> Paul K9NU
> 
> 
> 
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Re: [Elecraft] Automatic lightning protection for radios, an off the wall idea

[Bill Frantz]

I also received a link to:

 which is also an 
antenna disconnect. Note that the web page is in German, but you 
can download an English version of the manual.


A device that only disconnects the antenna fixes only part of 
the problem. What I would really like is a box that covers all 
the radio's connections.


It may not be necessary to cover all the connections. Elecraft 
support probably has a good idea of what in the radio survives 
nearby lightning strikes and what dies.


73 Bill AE6JV

On 1/19/21 at 10:35 AM, joe_a...@yahoo.com (Joe Pugliano) wrote:


Check out this Paradan antenna disconnect.
Paradan Radio Antenna Disconnect Actuators P-ADA-1


---
Bill Frantz|"Web security is like medicine - trying to 
do good for

408-348-7900   |an evolved body of kludges" - Mark Miller
www.pwpconsult.com |

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[Elecraft] KPA1500 Remote Operation

[Paul DeFelice]

Just curious. Not being very knowledgeable about networking, I'd like to
know why the KPA1500 does not have internal server capability. It sure would
be nice to operate the amplifier without having to have a computer running
in the home shack and running the Elecraft remote software (which does work
quite well).

73,

Paul K9NU

 

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Re: [Elecraft] Efficiency of MFJ remotely-tuned loop antennas

[Brian D]

I got a MFJ 10-30m loop at a SK sale. The original owner had never got it to
work. The rotor vanes had fallen apart. The fixed vanes were welded to the
loop. After re-assembly it worked well, but was difficult to tune as I
couldn't hear the buzzer for finding the tune point, it was too high in
audio frequency for my old ears, cured by adding a capacitor to the circuit.




David Gilbert  wrote:

> According to another ham who recently posted here, he had to "tighten" the
> plates on the MFJ capacitor to get it to work properly.  That doesn't
> sound like they are welded, and given the cost difference for welded air
> variables I doubt MFJ used them.
> 


-- 
Brian D
G3VGZ  YarmEngland
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Re: [Elecraft] K4 Receive Filter question

[Louandzip via Elecraft]

 That's not a simple or easy question to answer, especially since there's been 
no independent test of a K4, and there are many different criteria that go into 
it.  That said,  I'll go out on a limb and say that in most all practical 
situations on the air, it won't be. I say that because I've listened to and 
half-assedly compared a number of very good radios and some less good radios on 
the air. They might sound different, and take some tweaking of the controls to 
make them sound a similar as possible, but in the end I couldn't copy sigs 
better on one than the other. The K3 is really good in the tests, and I'm 
confident the K4 will surpass it, but that's at level that will only matter in 
what I consider to be exceptional circumstances.  

I'll add that I'm not the radio connoisseur that some are, and what I feel is 
largely the same, others may find hugely different. That doesn't stop me from 
wanting the best, even if I believe it won't make a practical difference in my 
operating. 




On Tuesday, January 19, 2021, 12:47:17 AM MST, BRUCE WW8II 
 wrote:  
 
 I also would appreciate a real answer to the question.  The question is
will the K4 or K4D be as good or better on receive than my K3s with the
2.1kHz and the 200Hz filters.

Bruce WW8II

On Tue, Jan 19, 2021 at 12:56 AM RVZ via Elecraft 
wrote:

> I believe there are no crystal Roofing Filters in the standard K4 model.
> Yet the manual talks about "one set of receive filters".  Please advise the
> type and bandwidth of these filters?  (DSP?)
>
> From the K4 Manual:  There are three models: the basic K4, with one set of
> receive filters and one analog-to-digital converter (ADC); the K4D, with a
> second set of receive filters and a second ADC; and the K4HD, which adds a
> superheterodyne front end that can be enabled as needed to provide even
> greater dynamic range. The superhet module uses high-performance,
> narrow-band crystal filters such as those used in the Elecraft K3S.  Thanks
> & 73, Dick- K9OM
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Re: [Elecraft] Automatic lightning protection for radios, .... an off the wall idea

[Louandzip via Elecraft]

 It's been quite a while since I worked in the biz, but IIRC, UL is a NRTL, 
"Nationally Recognized Testing Laboratory."  They don't approve devices per se, 
but rather certify a device passed statutory safety standard testing.  A 
certification only means samples and manufacturing process passed the specific 
tests. Other NRTLs can do the same, and there are quite a few. A manufacturer 
needs to have their products certified by an NRTL if fed, state, or local 
regulations require it, or customers (often large entities) require it.  At the 
time I was in the biz, "harmonization" was going on, that was bringing all the 
disparate standards of various entities into alignment.  IDK what the current 
situation is. 

I'm sure there are more knowledgeable and current guys on this reflector. 
On Tuesday, January 19, 2021, 5:03:58 AM MST, Rich NE1EE 
 wrote:  
 
 On 2021-01-18 20:23:-0600, Jim Borowski wrote:
>Did I read this right regulation connector?If the clamps on the ground rod, or 
>water pipe, it is not UL stamped, it's not approved.Jim K9TFSent from my 
>T-Mobile 4G LTE Device

Unfortunately,
the email footnotes don't include a link to the archive thread, and
there is no context, so I don't know to whom you reply...

but I am part of the thread, so I'll clarify for my part.
the loose connectors are UL listed. Two were loose, and 1 was incorrectly 
installed. I actually saw a web page that showed //an incorrect installation// 
as part of a "help page". I sent them a note, but didn't follow up.

Ah! Had not used nabble in the past, and I now see that this is in response to 
Bob McGraw - K4TAX, but the context is not clear.

~R~
72/73 de Rich NE1EE
The Dusty Key
On the banks of the Piscataqua

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Re: [Elecraft] Efficiency of MFJ remotely-tuned loop antennas

[Warren Merkel]

Resistive Losses around the loop are the biggest factor limiting 
efficiency.


My friend, Paul Casper, K4HKX has done very extensive investigation and 
documentation of Mag Loop performance.  His loops exhibit excellence in 
both Art and Science.   I'd recommend taking in his findings posted on 
his QRZ page.


https://www.qrz.com/db/k4hkx

You might get distracted looking at his other antenna creations.  I 
wrote the code running in the custom antenna control head.


The Mag Loops start way down at Section 7.   The progression of loop 
designs is staggering.  You might find his HF mobile loop quite 
interesting too.  He uses a KX3 + KXPA100 with his mobile loop.



Warren Merkel, KD4Z


On 1/19/2021 12:17 AM, elecraft-requ...@mailman.qth.net wrote:

Date: Mon, 18 Jan 2021 20:17:38 -0700
From: David Gilbert
To:elecraft@mailman.qth.net
Subject: Re: [Elecraft] Efficiency of MFJ remotely-tuned loop antennas
Message-ID:<2cd662a2-5959-f155-547c-815e6b242...@gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed


You are neglecting the losses in various connections in the system ...
including possibly the construction of the capacitor itself.? I don't
believe that they are insignificant.? There is a reason why top quality
variable capacitors often use welded plates.

I would also guess that contact resistance is worse for dissimilar
materials, such as a copper wire to an aluminum tube.

Yours is a limited theoretical analysis ... not a practical one.

Dave?? AB7E


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Re: [Elecraft] Absurd remarks about FCC and ARRL notices.

[Robert Sands]

Serious thinkers need to quietly look at the meaning of "incite",
"promote", "instigate", "enable", "direct", "instruct", "Plan" and you will
realize there was a plan (by someone) but no evidence of "incite" unless we
are disconnected from meaning in language to achieve power. The disconnect
of thought (inability to see contradictions) cannot be resolved through
partisan rhetoric because there is no desire for analysis, truth and reason
to a partisan, only power.  Emotion prevents clear thought. That's why, for
the most part, ham radio is a pleasure as it encourages reason and clear
thought (although not always). If the standard of logic is that Trump
incited at the capitol (the group moved in before he spoke) then all the
democrats who promoted violence for 9 months as redress should be
impeached or in jail. Target the wrong doers or every protest from here on
out will be "incitement" and blamed for the deeds of individuals. Dangerous
thought error.
Bob
K7VO

On Tue, Jan 19, 2021 at 4:27 AM  wrote:

> Shame on you for bring politics into the Elecraft rmail list.  Democrats
> and Republicans and
> Independents please keep political factionalism off this email list.  Ham
> radio is fraternity of
> people interested in radio communications and its art.   This kind of post
> just  makes more
> work for the email administrators who will have to moderate all emails to
> keep the list on
> topic.
>
>
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Re: [Elecraft] Automatic lightning protection for radios, .... an off the wall idea

[Rich NE1EE]

On 2021-01-18 20:23:-0600, Jim Borowski wrote:
>Did I read this right regulation connector?If the clamps on the ground rod, or 
>water pipe, it is not UL stamped, it's not approved.Jim K9TFSent from my 
>T-Mobile 4G LTE Device

Unfortunately,
the email footnotes don't include a link to the archive thread, and
there is no context, so I don't know to whom you reply...

but I am part of the thread, so I'll clarify for my part.
the loose connectors are UL listed. Two were loose, and 1 was incorrectly 
installed. I actually saw a web page that showed //an incorrect installation// 
as part of a "help page". I sent them a note, but didn't follow up.

Ah! Had not used nabble in the past, and I now see that this is in response to 
Bob McGraw - K4TAX, but the context is not clear.

~R~
72/73 de Rich NE1EE
The Dusty Key
On the banks of the Piscataqua

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Re: [Elecraft] Absurd remarks about FCC and ARRL notices.

[ron]

Shame on you for bring politics into the Elecraft rmail list.  Democrats and 
Republicans and 
Independents please keep political factionalism off this email list.  Ham radio 
is fraternity of 
people interested in radio communications and its art.   This kind of post just 
 makes more 
work for the email administrators who will have to moderate all emails to keep 
the list on 
topic.


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Re: [Elecraft] Mag Loop from MFJ

[turnbull]

Dear OMs,      I have had much success using the Brazilian Alexloop.   It is 
convenient, unobtrusive, easily packed and does a far better job than I would 
dream.   I use it travelling with KX2 or KX3.   ITt has been used indoors in a 
WPX contest for 233 Qs, from inside my sister's Connecticut house.   A third of 
the Qs were with EU.     Yes an end fed half wave will do better.    I can not 
always deploy such an antenna.    For me the AlexLoop is easy to use and does 
the impossible while on my travels.   A QRP antenna for sure.73 Doug EI2CNSent 
from my Galaxy
 Original message From: Morgan Bailey  
Date: 18/01/2021  23:42  (GMT+00:00) To: n...@sonic.net, 
Elecraft@mailman.qth.net Subject: [Elecraft] Mag Loop from MFJ They are 
unreliable pieces of junk. The housing does not protect thecapacitors that are 
in house made and bugs can crawl into the housing andshort them out. Secondly, 
the plastic housing in Kansas will be destroyedby the sun. The best thing about 
the loop is the loop itself. It is builtwell. The caps are cheap. Tuning the 
bastard is not consistent, not fast,and highly touchy. The only loop worth 
purchasing is the Ciro Mazzoni loopfrom Italy sold by DX engineering. It will 
take abuse and has an excellenttuning feature that will follow your radio. Each 
time you change freq withthe MFJ it is a task to get it to tune again. A friend 
of mine bought oneand it was soon offered to me for $100. Then he became so 
frustrated withit that he wanted me to take it for free if I would dig the post 
out of theground he mounted it on. I Passed knowing that any dipole would blow 
itaway. Even an end fed random wire will beat it in performance if put upright. 
In the end there are many cheaper options that work far better thanthe MFJ mag 
loop.73,Morgan NJ8MBS + MS + $2.98 = COFFEEReal Life Experience = Priceless, 
says the man who set his back yard onfire with a breadboard tuner loading a 160 
meter inverted L with 1000watts. 
LOL__Elecraft 
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