PA3CLQ's Leuke Linken Nr. 477


Balun question

I want to make a 9:1 balun for an end-fed antenna.

The plans call for nine turns of three wires around a toroid core.

The wire and toroid I have can only fit seven turns.

Should I leave it at that or overlap the last two turns?

How will it effect its characteristics?
Dick. k2rfp
Just built one using a T200 20 and it took 10 turns no problem.

You can try using 0.8 mm copper varnished wire provided the power is circa 100W
And try and get the 9 turns as per design.
73 and 44 Roger 9H1UG

This balun info might help at the below link--

I picked up several baluns from them and they are the best designed I've ever come across.

Frank W7is

I didn't see anything on the internet that addresses this issue and some on this group say it is okay to overlap a turn or two and some say not to.

Of course the solution is to get a bigger toroid or use smaller wire but I want to use what I have.

I usually run 25 watts CW but this may be used with club activities when 100 watts SSB are used.
So for now I'm going to put this project on hold until I get a big enough shopping list to make $3 shipping for only a $2 toroid not so ridiculous.
Dick. k2rfp

Dick, the simple answer is if you don't use 9 turns, you will not have a 9:1 balun.
This cowboy hat wearing fellow has a fairly good YouTube on building the balun.

Chuck - K8HU

Just an observation coming in late on this thread where a few of the intermediate posts seem to be gone.....The impedance ratio is the square of the turns ratio.For example, a 9:1 balun for matching 450 ohms to 50 ohms will have a turns ratio of 3:1.
73 Mark K3MSB


Maritime Radio Histrical Society at:



Morse Instruments on an N&W CTC Machine

Attached (editor....below) is a photo from the Union Switch & Signal Co. files.

It shows a Morse relay and sounder hidden away inside the cabinet of a CTC machine, obviously put there for emergency purposes.

The photo was made February 25, 1946, before the machine was shipped.

I have cropped the scan so that the date and US&S file number appear on the image.

    Unfortunately the print was not made on G-surface glossy paper, but rather on that old N-surface "illustrator's paper," which was used so that engineering pen and pencil markings could be made on the print's surface.

The result is that the print is not as sharp as it could be, due to the somewhat rough surface of the paper.

    Under magnification, the relay appears to be labeled as a 100 Ohm, Model 4-D, but the "D" could be a "C."

Markings on the designation plate affixed to the sounder are illegible in this photograph.

    This CTC machine was built to handle the 106-miles of N&W single track between Walton (near Radford, Va) and Bristol, Va.

This territory was called "the Bristol Line" and was part of the original 1856-1857 Virginia & Tennessee RR construction.

Before CTC, the line was operated on a Time Table/Train Order basis, supplemented by an automatic block signal system installed in the late 19-teens, consisting semaphores set up on the APB (Absolute Permissive Block) principle.

Track circuits and semaphore motors were AC.

Traffic was extremely heavy (10+ passenger trains a day plus numerous freights, plus locals.)

The semaphores were converted to standard Position Light signals around the time CTC was installed.

The CTC machine handled 24 passing sidings in 102 miles.

The Bristol Line was known for some heavy (but mercifully short) grades.

Tonnage rating for the massive 2-8-8-2 Class Y-6 Mallets was only 2900 tons slow freight and 2600 tons fast freight.

The much smaller 4-8-0 Mastodons and old 2-8-0 Consolidations struggled along at 700 tons slow freight and 600 tons fast freight.

    The CTC machine was U-shaped and was located in R Office, the Radford Division Train Dispatcher's Office in Roanoke's General Office Building. My Grandfather began working the Bristol Line territory as a Brakeman in 1906, and I began working there as a Brakeman in 1964.

    I will also attach a second photo which shows R Office in 1958.

The Bristol Line machine is in the background, worked by Lucian Durham, a 1920s hire telegrapher.

The machine at right is the Roanoke-Bluefield machine, worked by Melvin Ramsey, a late-1930s hire telegrapher.

I was looking through old copies of "Dots & Dashes" ,,,,,,,,,

for something else and tripped across this image on the cover of the Spring 1999 issue.

It brought a smile to my face and so I went looking on-line and found the image.

I've attached it for your amusement.


73, Chris Hausler SlowSpeedWireGroup


Why kids should not try to hop freight trains! Old DL&W photo.


Duffy Littlejohn - "Hopping Freight Trains in America" ISBN 0-944627-34-X

Zephyr Rhoades Press


I am selling my Buzza 100 bug.

Anyone SERIOUSLY interested please email me at:

Photos and price via email.

Video on You Tube, Case included.

73, Pete W5PEH


Headphones advice

At the moment I am using a set of stereo Beyer Dynamic headphones.
However if I use them too long I get a headache, this I gather it down to the very wide frequency response.
So my question is can the group recommend some headphones designed for radio mainly Morse code use.
Or if not is there a way to modify these headphones to narrow the frequency response.
Oh I am not wishing to spend a fortune acheiving my goal.
Many thanks Mark G0NMY

I recently purchased a Heil Pro Set 3,

exactly for the same reasons you stated.

This is earphone headset only (no boom mic), is very light weight, soft ear cushions also very light weight, and great sound quality.

Has phase reversal switch which offers enhanced audio pleasure.

I am quite pleased.

Good luck Mike, K5MP,

I have a pair of heil pro 7 that I find comfortable and have great sound

I have the radiosport RS-20 headset.

Great sound, very comfortable and indestructible.
73 de kd0q

Well, you don't want hifi cans....
I have Heil ProSet, and use them when I need the mic and foot switch.
Just listening, or on CW, the best I've found are Kenwood HS5's
By a large margin!

I'll go in a little different direction responding to this one.

Having been an SWBC and MW DX'er for about 50 years, am very much concerned with my phone delivering maximum recovered audio.

Like many, I have a couple of flavors of Heil Pro-sets and a set of JRC's and find they work reasonably well but not impressively so.

That said, the Audio Technica ATH-7 noise cancelling headphone recovers more audio and is more listenable that any other phone I have tried.

The ATH-7 is the headphone of choice for those of us who are up before the sun trying to catch Chinese MW outlets coming over the pole at grayline.
They are a little hard to find having been out of production for a few years (Bose sued AT claiming their patent had been infringed) but you can find them on

E-Bay for about 40 quid.

There is a new, current model, the ATH-7B which now takes the place of the ATH-7 however I have not tried those as yet.
When switching on the active, ambient noise cancelling feature, the microphone in the headset also picks up some of the noise in the ear chamber of the headset.

The result, the intended audio virtually leaps from the headphone into your ear.
I have 2 pair, one rides with my Elecraft KX-3 and the other stays in the shack for use with the R390A, WinRadio G33DDC, FT-1000, etc...
Chuck, K8HU
I have a big head and can't wear the Heil earphones

(or others) for very long without getting headaches and/or ear lobe pain.

I went to a good pair of ear buds.
I have a rx/monitor control on my radio and I vary the pitch ever so often in contests or long QSOs.
Bill, N5IR
Are headphones the root cause leading to your question?
Or is your radio really the root cause (and not the headphones)?
Try this:
Turn your radio off.
Turn the volume control off.
Plug any set of headphones in and put them on.
Take note of what you hear... or rather don't hear.
Turn the radio on (leave the volume off) and note what you hear.
I normally hear hi frequency hiss/fizz/noise whatever you want to call it and it's always there regardless of volume setting.

I find this extremely fatiguing and annoying.
I assert this is due to poor audio circuit design in the radio.

I've experienced this in high end Yaesu, Kenwood, Elecraft and Flex radios.

Radio Mfg do so much on the RF side and then forget that the AF side is what interfaces to the human!
If this is the case, a simple low pass audio filter could be the ticket for you (it is for me)... a simple r/c circuit will do.

Good luck finding one commercially but they are really easy to build.

I normally use a 2 stage/pole filter.

No need for active filters or DSP (delay and other artifacts).
If this is not the case, please ignore and move on to other solutions.

However, if you find yourself trying all kinds of headphones and that doesn't solve your topic... give this a try.

It's one of three things...

1) The radio produces sound/noise.

2) The headphones convey the sound/noise to you.

3) You
Links you may find useful:

73, Tim K9TM
I have tried many of the suggested headphones

and while some are comfortable to wear they all have the same problem - to broad a frequency response.

What ever happened to CW only headphone that limited the audio range to that of CW signals?
73, Art, W2NRA

For CW, I rely on an old fashioned pair of high impedance magnetic phones.
I have a couple of pair of the old "Trimm Dependable" cans in the shack, but any of this older design would likely do well..
I find them to be less fatiguing for either voice or CW.

I believe it has much to do with the lack of bass response to background noise and static crashes, to which modern phones seem to respond to well.
73, JW (WB8SIW)
I too have the RadioSport RS-20.

They replaced a Kenwood set which gave me headaches after 90 minutes or so.

I can use the radioSport for hours on end and never the faintest headache.

I'm a CW only operator and am delighted with their performance.

Ralph, KØRO

Any reason you could not use an audio filter to filter out everything but the CW tone?
I have a Kenwood HS5, but it is uncomfortable for long use.
So I bought 2 years ago a Sennheiser HDR160.

It's cordless, not affect by any RFI, and very pleasant to wear.
I use the base without batteries (directly on the power via the provided power supply), and the headset last 2 or 3 days before charging (4/5 hours a day).
I find the cordless very useful, and now I would not change.

When you need something in the shack, bend down to get a fallen pen (or go to the toilet!!) you don't lose a piece of the QSO.

Also, the cord would always be messed-up in the ar of you chair, in a keyer on the now, no cord.
This is my little contribution!!
Good luck.
73 de Gerard, F6EEQ
What is the range for the headset?

30 meters?

How do walls affect that range?

I used to have a Sharper Image wireless headset but range was only about 10 meters through wooden walls so it was mostly useless as the shack was about that far away from the house.
Thank you. Jim Pruitt

I have two Philips wireless headpfones one FM Type SHC5100 and the other infrared type SHC1300

As Gerard wrote with the first everywhere you can watch the broadcast.

With the second that i prefer, no one can listen.


For a narrow freq response you will probably need to get a pair of old surplus or NOS headphones like the HS-16A:

I have a pair of these and they are noticeably "peaky", i.e., non linear and pretty narrow response.

The only thing I don't like is they are rather high for my choice of CW tone. I prefer 400 to 500 Hz but these are up near 700 Hz.

But if you're bothered by too much excess noise in hi-fi phones, these definitely will cut that.
They do look like they are torture to wear but if adjusted correctly they are fine.

The thumbscrews should be adjusted so that the earpieces swivel easily but not completely loose.

Also, spread the headband so they don't clamp your head tightly.

These phones are actually more comfortable than some newer modern phones that are very light but can't be adjusted for head pressure or rotated forward and back on your head.

73, Drew AF2Z

Frank Scheer's 1975 Photos of NKP Morse

Frank Scheer, Ph.D., is Curator of the Railway Mail Service Library, housed in the old N&W depot at Boyce, Va.

(His work at the Library, which he founded, is purely pro bono; he also teaches at the University of Maryland and is Logistics Officer for the USPS.)

Frank started his working career as a towerman/operator on the C&O and then on the RF&P, and later was Asst. Train Master on the N&W's Nickel Plate Road. It was while he was on the NKP in 1975 that he took the attached photos, as slides.

Unfortunately, the names of the men and the locations of the offices have been lost, but we can determine the dates from the wall calendars.

Frank has GENEROUSLY given me permission to post the images for the SlowSpeedWire List.

So, enjoy the fruit of his lensmanship !

I might add that Frank is a real patron of the telegraph.

He has working Morse in the restored bay window at Boyce depot (office call DK) and a MoseKOB Internet connection, and has "the telegraphers" in for the Library's annual Open House for the community.

73 SW & (abram burnett) SlowSpeedWireGroup


*** K3Y 2018 QSL Card Design Contest *** #K3Y

The 2018 K3Y QSL card design page has been updated with the latest submissions.

You can see them here:

Have an idea for a card design?

Please submit it.

The deadline is Dec. 14th at which time SKCC members will vote for the winning design.

Twelve other designs will appear in the SKCC 2018 print calendar.

More info at the above link.
73, Drew - AF2Z
K3Y Planning Group SKCCGroup


73, from the town at the rivers "De Bergsche Maas" and "De Dongen" Geertruidenberg (800+ years city rights) at: 51.702211N 4.853854E

Editor Jan Pieter Oelp PA3CLQ



My simple website about Gigantic DF-Antennas

Part 1 "DF-Antenna Wullenweber Array"

Part 2 "DF-Antenna USSR Variants"

Part 3 "DF-Antenna USA Variant"

Next Part 4 "USSR OTHRA DUGA 1,2 & 3" at: