Re: [Elecraft] OT: The day I found out I was going to be an engineer

[John Magliacane via Elecraft]

 On Friday, September 15, 2023 at 08:35:40 PM EDT, Wayne Burdick 
 wrote:

> I was 8 years old. My dad had bought me a Radio Shack Science Fair 8-Note 
> Electronic Organ kit for Christmas, along with a soldering iron.

Sounds like one of their P-Box kits. When I was around the same age, my Father 
bought the 3-transistor regenerative Short-Wave Radio Kit. A listing of the 
P-Box kits can be found here: http://my.core.com/~sparktron/pbox.html

My Father was a Fireman, so there was no way he would trust me with a soldering 
iron at such a young age. Instead, he ended up building the kit himself while I 
watched with great interest.

He wound several coils so the receiver could receive several ham bands as he 
was trying to spark an interest in Amateur Radio, but I don't ever recall 
hearing any hams with the receiver, just the typical short-wave broadcasts of 
the time.

Several years later, he ended up taking the receiver away from me because the 
radiated broadband noise interfered with his Swan 500CX. :-)

It didn't matter much to me anyway as I never heard much with it. But it was 
every educational in the sense that the frequency range of the receiver was 
dictated by the size of the coil wound by the builder. Eventually he gave me 
his old Hammarlund HQ-140-X, so I hardly ever missed that old Radio Shack regen.

Interestingly enough, there's a modernized version of the receiver that employs 
silicon transistors (2N3904 and 2N3906s) instead of the original germanium 
jobs. Details can be found here: 
http://www.netzener.net/images/swradio/swradio.pdf

And that old Hammarlund lives on to this day after I "solid-stated it" not long 
after becoming a ham 40 years ago.


73 de John, KD2BD
  
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Re: [Elecraft] K2: Filter Aliginment software for Apple MACs.

[John Magliacane via Elecraft]

 Francis,

I use Baudline under Linux for various audio spectrum analysis tasks. There's a 
Mac version as well:

https://baudline.com/what_is_baudline.html

https://baudline.com/download.html


73 de John, KD2BD
  
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Re: [Elecraft] Muting the K2

[John Magliacane via Elecraft]

 Ray,

For what it's worth, I've been running a homebrew solid-state QSK CW 
transmitter for the past 4 years. My T/R relay is an AXICOM V23105A5303A201. It 
is a dual SPDT relay where each SPDT section is tied in parallel for greater 
power handling capability. The receiver is connected to the antenna through the 
relay on receive, and is allowed to "float" as an open-circuit on transmit.

The relay is controlled through timing and logic circuitry so that it becomes 
energized before any RF is produced, and de-energized after the RF envelope has 
decayed to zero. While I own a K2/100, I have been using this transmitter with 
either a Drake 2C or R4C receiver until I homebrew my own.

I just ran an experiment where I terminated the RCVE port with a 50 ohm load 
and measured the RF voltage across the load with a scope. On 40 meters where my 
transmitter produces 64 watts, I measured about 0.8v p-p across the terminated 
RCVE port, or about 1.6 mW (2 dBm) of RF. That equates to 46 dB of isolation at 
7 MHz. This seems consistent with the isolation specs on the relay that can be 
found here: https://www.farnell.com/datasheets/1918250.pdf.

The Drake receivers handle this signal level with ease, but I haven't tried the 
K2.

Incidentally, Jim, W6PQL has additional information on using inexpensive relays 
in RF circuits at his website: 
https://www.w6pql.com/using_inexpensive_relays.htm


73 de John, KD2BD
  
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Re: [Elecraft] [OT] WWVB Time Transmissions

[John Magliacane via Elecraft]

 > Bill,
> WWVB added a new modulation format starting around 2012/13 that includes a 
> phase shift that some older clocks can
> no longer resolve.

Gary,

The 2012 addition of BPSK modulation doesn't affect WWVB-controlled clocks -- 
only older carrier phase tracking receivers that use WWVB as a frequency 
reference that were designed prior to the October 29, 2012 modulation format 
change.

NIST has several receivers scattered around the country that monitor WWVB 
signal levels, 24 hours a day. You can check the status any time by going here:

 https://tf.nist.gov/tf-cgi/wwvbmonitor_e.cgi

Occasionally, WWVB is taken off the air for brief periods of time. Information 
on outages can be found here:

 
https://www.nist.gov/pml/time-and-frequency-division/radio-stations/wwvb/wwvb-station-outages

NIST Special Publication 250-67 provides technical details regarding the 
transmitters, feedlines, antenna systems, and routine maintenance procedures 
employed at WWV, WWVB, and WWVH.


73 de John, KD2BD
  
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Re: [Elecraft] Antenna tuners

[John Magliacane via Elecraft]

 On Friday, July 17, 2020, 10:03:24 PM EDT, Fred Jensen  
wrote:

> No antenna has, at any time, anywhere in any of our lifetimes, been
> "tuned" by an "antenna tuner."

Unless the "tuner" is simply a broadband transformer, I might agree.

But if the "tuner" is an LC network, like an adjustable L network, T network, 
Pi network, or a linked-coupled network, then I strongly disagree.

A tuner is a 2-port network. A transmission line is also a 2-port network. Both 
networks obey reciprocity, meaning that what you do to one port of the network 
will have a direct influence on the opposite end.

That being said, if an antenna exhibits a complex impedance at our frequency of 
interest, and that behavior can be corrected (brought to resonance) by the 
application of a particular value of reactance at the antenna's feedpoint, then 
that application of reactance can, for reasons of convenience, be made at the 
"shack end" of the transmission line. As such, the "tuner" in the shack is 
really "tuning" the antenna!

There's no "magic" involved here -- just a simple understanding that things 
that are connected together actually behave like they're connected together. A 
transmission line doesn't isolate the shack from the antenna: It couples them 
together with the highest degree of efficiency we can muster/afford. Therefore, 
what happens at one end of a transmission line DIRECTLY affects the other, and 
vice versa.

And so, properly applying an adjustable LC impedance matching network in the 
shack CAN (and often does) modify the resonant frequency of an antenna.


73 de John, KD2BD
  
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Re: [Elecraft] Antenna tuners

[John Magliacane via Elecraft]

 On Friday, July 17, 2020, 7:10:32 PM CDT, Kurt Pawlikowski  
wrote: 
 
> Ken: In some respects, a "matching device" at the base of the antenna is a 
> tuner! {'-) It accomplishes the same function... {'-) k
> WB9FMC

On Friday, July 17, 2020, 08:21:54 PM EDT, Ken Roberson via Elecraft 
 wrote:

> Kurt,
> We are not tuning the antenna , we are matching the antenna to the coax at 
> the base of the antenna.
> 73 Ken K5DNL

Kurt's correct. A low-loss (non-resistive) matching network connected directly 
at the feedpoint of an antenna will modify its resonant frequency.

A matching network connected to the feedpoint of an antenna through 1 inch 
(25.4mm) of transmission line will also modify the resonant frequency of the 
antenna.

A matching network connected through 1 meter of transmission line will also 
modify the resonant frequency of the antenna.

A matching network connected through 10 meters of transmission line will also 
modify the resonant frequency of the antenna.

And so on, and so forth... all the way back to the shack! ;-)

Why? Because transmission lines obey reciprocity. As such they cannot (aside 
from the effects of losses) separate what's on their source end from what's on 
their load end. What you do to one end directly affects the other, and vice 
versa.

Show me a transmission line that disobeys this property, and I'll show you a 
line that is either opened or shorted.

So, yes, a non-resistive matching network in the shack will bring your antenna 
SYSTEM (antenna + transmission line) into resonance at your operating 
frequency. In the process, the resonant frequency of the antenna is modified, 
as well.


73 de John, KD2BD
  
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Re: [Elecraft] Matching resonant antennas

[John Magliacane via Elecraft]

 On 15/07/2020 20:30, Ken WA8JXM wrote:

> Conversely, a non-resonant antenna can have a 1:1 SWR.

On Thursday, July 16, 2020, 03:33:12 AM EDT, David Woolley 
 wrote:

> You can only have a 1:1 SWR at a single impedance. If the design
> impedance is purely resistive, that means you can only have 1:1 for a
> resistive and therefore on-resonance load (or one that can be treated as
> having no reactive behaviour at the frequencies of interest - e.g. an
> ideal dummy load).

I agree completely, but there's a "catch".

Traveling-wave antennas, such as Rhombics, or Beverages, or leaky transmission 
lines, are, technically, non-resonant. However, they can each present a 50 ohm 
feedpoint impedance that is purely resistive, and produce a 1:1 VSWR as a 
result. ;-)

So, whether an antenna is resonant or non-resonant isn't the issue. The issue 
is whether or not a load impedance contains a reactive component. If it DOES, 
then it can never produce a 1:1 VSWR.

 
73 de John, KD2BD
  
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Re: [Elecraft] Conditions, shmonditions: DXing anyway

[John Magliacane via Elecraft]

On Fri, 9/21/18, Drew AF2Z  wrote:

> I generally use 440 Hz for sidetone/pitch, thinking that it is a familiar 
> standard musical note and perhaps is more recognizable to the
> brain in some way.  I don't know if that has any validity or not...

I've been using a sidetone pitch of 800 Hz on my K2/100 for years, but more 
recently thought I might prefer something a bit lower.

Running alongside a Drake R4C receiver, I've been experimenting with a homebrew 
CW transmitter over the past month that includes a sidetone oscillator.  I 
adjusted the pitch of the sidetone for something that "sounded about right" to 
my ears and left it at that.

Last weekend I decided to measure the frequency of the sidetone and found it 
was within 1 Hz of 800!

I suppose I've been listening to CW at 800 Hz for so long, I just committed the 
pitch it to memory.  :-)


73 de John, KD2BD
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Re: [Elecraft] Magnetic Loop question

[John Magliacane via Elecraft]

On Thu, 10/20/16, Steven Dick  wrote:

> The vertical loop can be horizontally polarized by feeding it in the middle 
> of the top or bottom edges.   It can be vertically polarized by feeding it in
> the middle of the vertical edges.

That's true for a loop having a full-wave circumference, but "Magnetic Loops" 
have circumferences that are typically only a fraction of a wavelength, and as 
such operate under a much different mechanism.

A vertically oriented magnetic loop, regardless of where it is fed, will 
achieve the highest degree of coupling to a vertically polarized signal, and 
have a bi-directional (half-wave dipole-like) radiation pattern.

A horizontally oriented magnetic loop, regardless of where it is fed, will 
achieve the highest degree of coupling to a horizontally polarized signal, and 
have an omni-directional radiation pattern.

This is because a magnetic loop is most responsive to the magnetic component of 
the RF wave.

When we speak of RF polarization, we are speaking of the polarization of the 
electric field.  A vertically polarized signal will have a horizontally 
polarized magnetic field, and vice-versa.  It is the horizontally polarized 
magnetic field from a vertically polarized wave front that will cut through the 
center of a vertically oriented magnetic loop and induce a voltage across its 
terminals.


73, de John, KD2BD
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Re: [Elecraft] Elecraft's linux utilities - somewhat OT, or maybe not

[John Magliacane via Elecraft]

On Tue, 5/27/14, Bill W2BLC w2...@nycap.rr.com wrote:

 I am not trolling, I really would like an honest answer as
 to why Linux is chosen over Windows for similar operations.

Bill,

In a similar way, I'm often asked why I spend so much effort with radio 
equipment, antennas, sunspots, etc. in such a cellphone and Internet dominated 
world.

The reasons are many.  None are simple to explain.

I started dabbling with Linux 20 years ago because it gave me the opportunity 
to run the equivalent of Unix on low-cost, non-proprietary hardware (a PC) that 
I already had in my possession.  I had previous experience with Unix, 
recognized it as a very serious and powerful OS, and wanted to learn more about 
it.  At the same time, I saw Microsoft products as being very poor in quality 
and being targeted toward individuals who knew very little about computers and 
(even worse) didn't want to know anything about computers.  I wasn't one of 
those people.

Slackware was my Linux distribution of choice in 1994, and it still remains so 
today.  I find many of the flashy all singing / all dancing Linux 
distributions difficult to use when doing anything out of the ordinary because 
they often try to think for the user (in their effort to make things easy), 
and more often than not, get things wrong in the process.  To me, these 
distributions aim for a Microsoft-like audience (individuals who know very 
little about computers and want to stay that way).

Having computer experience that dates back to the late 1970s, maybe you find 
yourself in a similar situation for a similar set of reasons.

I also think that the growing do-it-yourself, build-your-own (Linux) 
mentality that Doug (K0DXV) pointed out is also what Elecraft is all about as 
well, so it should come as no surprise that many Linux fans are Elecraft fans, 
too.


73, de John, KD2BD

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Re: [Elecraft] linux K3 utility

[John Magliacane via Elecraft]

On Wed, 5/21/14, Doug Person via Elecraft elecraft@mailman.qth.net wrote:

 I opened a terminal in the directory and
 entered ./k3util and got no such file or directory from
 bash. Huh?  I can see it, the permissions are correct,
 it is executable...  What am I doing wrong?
 
 Doug -- K0DXV

Hi Doug.

You're not doing anything wrong.  It sounds like you downloaded a pre-compiled 
binary that was linked to a library that is not present on your machine.  
That's what the no such file or directory error is referring to.

To see a list of libraries to which your executable file has been linked, type:

ldd k3util

After that, you'll have to determine what libraries you have, which ones you 
need, etc.


73, de John, KD2BD

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