PA3CLQ's Leuke Linken Nr. 453
Resonant CW Speaker
The resonant CW Speaker is featured in the February 2017 issue of QST.
A simple and inexpensive thing to build, and the author said that after listening to CW with the Resonant CW Speaker, a regular speaker will be unacceptable. That hook got me, and I built one.
The author is absolutely right!
It performs better than an active audio filter!
I love this little thing!
One of the best gadgets I've ever added to my shack.
The price tag for parts is minimal, under $15, and an hour to build using a Dremel tool and a soldering iron.
I have a loss of hearing and set the CW tone to 600 HZ so to get the speaker to resonate that low I added 2" PVC coupling between the speaker base and the street elbow, and just turned the elbow around.
I used two 1/8" mono jacks instead of the author's RCA jacks since my radio takes the 1/8" mono plug for the external speaker output.
Works like a dream!
I recommend you should give it a try, I think you'll love it too!
Rich-W4RQ
REM :
Hello Rich,
Thank
you.
I went out an cut some PVC pipe to start building mine after our QSO.
I
hope, my build of the "CW speaker" will make a great addition to my
2B.
72/73 and TU, Jeff K9JP
REM :
That was the Skytec product of the '70s.
I have a few...they work very well!
Dave
REM :
I made something similar, many years ago, with stiff cardboard shipping tubing for 750 Hz notes.
Maybe I will make one next, with the PVC pipe, but maybe several inches longer since I have my radios set for 400 HZ notes.
CW is Real Radio 73, John...K8JD
REM :
A few years ago, I built one of these, based on an article in QST... but wanting to do a quick and dirty version first, as a proof of concept, I built it out of a piece of scrap Foam-core, held together with duct tape... with cotton balls around the back side of the speaker.
It worked great, and still sits on my rig....
Good luck with yours.
73 de NC4RT
REM :
I'm currently building one.
One thing I did was to get a small sheet of plexiglass (about 6" square) from the local hardware store rather than use CD covers -- it isn't nearly as brittle and is easier to work with.
I'm
just waiting for the electronics to arrive so that I can finish it -- hopefully
before the weekend.
Andy, k2oo
REM :
Its in the February QST.
You can find it at :
and
read it if you're a member.
Andy,
k2oo
REM :
Any speaker will do.
The
magic comes from the cavity.
You tune in a note you like then slide the plunger in or out to peak it.
Or if an interfering tone tune it to notch the un wanted tone too.
Joe WB9SBD
REM :
Any ideas about making a lower frequency one?
I
assume the enclosure would need to be proportionately larger; or can you just
use use a longer straight section with the 2" pvc elbow?
73, Drew AF2Z
REM :
Yup that's all it takes.
A larger tuned chamber.
BUT also look for the "Natural Resonant" frequency of the speaker.
Choose
one that is closest to your freq of choice and it's even more effective.
Every speaker has a natural resonant freq.
Joe WB9SBD
REM :
LIKE A PIPE ORGAN NOTE, THE LONGER PIPE RESONATES ON A LOWER FREQ.
Same as a dipole or vertical antenna too, longer for lower freq> It's just physicics.
CW is Real Radio 73, John...K8JD
REM :
Luis,
Try this link...
https://www.amazon.com/MAGFLD-LO-PROFILE-ROUND-REPLACEMENT-SPEAKER/dp/B00H0L8SJW/ref=pd_sbs_23_1?_encoding=UTF8&psc=1&refRID=GNWW522X12W6E18KXPBN
73, Ed - ad7gr
REM :
I
guess I should have added the link to K5LN's article:
http://www.wcarc.com/images/elmer-files/CW%20Resonant%20Speaker.pdf
Dave - W3NP
REM :
See attachment pse
Editor
REM :
Hello,
This email message is a notification to let you know that a file has been
uploaded to the Files area of the skcc group.
File : /Tuned Speaker Calc.xls
Description : Simple spreadsheet to calculate frequency of a tuned speaker when
the length and diameter of the tube is known.
ad7gr
REM :
see attachment pse
Editor
REM :
Resonant Speaker: Another Design
http://kd1jv.qrpradio.com/resonatespkr/CWSPKR.HTM
What is a resonate CW speaker?
reillyjf
REM :
Dave,
According to the math... Using the formula F=122.4/(L=(0.3*D)) where F is
frequency, L is length of the tube and D is diameter of the tube, as you
decrease the length of the horn the resonant frequency will increase.
So, if you decrease the length to 5.73" the frequency should be 759 Hz.
If you were to have a length of 5.73" and increased the tube
diameter to 2.25" you would have 750.5 Hz. I've uploaded a simple
spreadsheet for this to the Files Folder..
73, Ed - ad7gr
REM :
If you have a top-firing speaker on your rig, simply buying a 4" PVC elbow and setting it on the speaker produces a resonance in the 650-750 Hz range.
I call this the "Passive Vocal Clarifier" speaker accessory, or "PVC" for short (grin).
If you want to lower the pitch. try setting the elbow on a ring of styrofoam, or just spacers.
To raise the pitch by 50-75 Hz, cut off about 1/2 inch from the
lip of the elbow.
Dana Browne AD5VC
REM :
I made the speaker (twice!) and got the following results:
1. The frequency response is very narrow. (Good!)
2. The audio output was extremely low -- too low to be of practical value in my
shack.
Have others gotten the same results?
Anyone better?
I'd love to improve the results and would welcome any suggestions
if they are out there.
73 Andy, k2oo
REM :
Sounds like you don't have enough power goint to the speaker.
Did you use headphone output or speaker output to drive it?
Headphone output usually has a resistor in siries inside the rig to keep you from blowing out your eardrums when you use efficient headphones !
Measure the AV volts with a tone going to the speaker, should get good, loud volume with anything over 1 V AC across the speaker. .
CW is Real Radio 73, John...K8JDREM :
Hello Andy,
I had the same results as you.
Where on your radio did you connect the audio input (Audio out of
your radio) side of the speaker?
I have a PROIII and first used the front "phone jack" for my audio
input to the resonate speaker.
I also had the very low audio output with my radio volume control turned all the way up.
Then, I took another look at the ICOM PROIII manual.
The phone jack on the front of that radio is rated at 5 milliwatts output max. which makes sense so you do not hurt your ears.
The speaker connection on the on the back of the radio has a full 2 watts of audio output.
Hope this helps, Jeff K9JP
REM :
Thanks to suggestions here, my problem is solved.
I had the speaker connected to the audio jack on the rear of my Flex 6300 and the audio was too low.
I tried the audio jack on the front of the Flex and the audio was excellent!
I found that by adding an additional inch of pipe, the response
was even better..
Again, thanks to all who tried to help.
Andy, k2oo
REM :
As shown in the photo in QST, the speaker has a resonant frequency of about 900 hz.
By adding an extension, you can vary the resonant frequency.
My results are as follows:
1 inch extension resonates at about 750 hz
1.5 inch extension resonates at about 650 hz
2.0 inch extension resonates at about 600 hz.
Personally, I find the 650 hz to be the most comfortable.
73 Andy, k2oo
REM :Hi Hi 1
I've really enjoyed my CALF CW audio filter.
You can choose the width all the way down to 80hz. And I've used 80hz but mostly use 500hz and 200hz.
http://kc9on.com/store/cw-kits/calf-the-cw-audio-limiter-filter/
73s & Enjoy! N4IVE - David Gale
REM :
Resonant (tuned) CW Speaker Build by John W2IU
https://www.youtube.com/watch?v=4iNELueaU6M
https://www.youtube.com/watch?v=4iNELueaU6M&t=2s
Building a Resonant CW Speaker by Steve Ellington
They sound beautiful and much better than an electronic filter because they do not ring - Very mellow sounding.
Also they allow you to use fast AGC and QSK without all the usual unwanted noises.
https://www.youtube.com/watch?v=MF8bk6958Hg
Texas Tumbler - Acoustic Resonance CW Speaker by NG9D
https://www.youtube.com/watch?v=2_giOx8SNnY
https://www.youtube.com/watch?v=mKQxQ2S_uB4
This clip illustrates sound resonance in tubes with one open end and one closed end
where the even numbered harmonics are missing in such instruments as flute and clarinet.
https://www.youtube.com/watch?v=i98D_RhaXt0
How
to find the frequency at which an object vibrates the most.
By hitting a solid object this will vibrate at its own resonant frequency. The
emitted sound was recorded using a photo camera's video recording function and
once more by the pc headset's
https://www.youtube.com/watch?v=W4HVqHaa_uk
REM : Hi Hi 2
Water's oxygen hydrogen bonds can be broken in many ways resulting in high energy outputs that are stored in water.
Since
water contains an enormous amount of energy, the potentials are endless.
This video demonstrates a single method of water bond breaking using radio
frequency.
https://www.youtube.com/watch?v=p8xYUDiSGDk
IS ANYONE ELSE EXCITED?
Novice Rig Roundup FINALLY made it into QST's Contest Corral after 3 years of trying!
Not only that but we somehow got TWO LINES (LOL.)
See Page 97 of February 2017 QST.
We are also on Page 154 and 3/4 of the way down the right hand column! NRR is GETTING ON THE MAP!!
ANNOUNCING NOVICE RIG ROUNDUP 2017!!! The dates are 0000 UTC on FEB 18 through 2359 UTC on FEB 26, 2017 - that is 9 full days (UTC.)
GOOD NEWS: THIS WILL COVER two ...
Bry Carling AF4K
Not all of me will die - - - The good I do will live forever.
Palm single lever paddle as cootie key.
Has anyone tried the Palm single lever paddle which can be switched to cootie mode?
Carl j mannle N6TVN.
Hello,
The Palm paddle - and all paddles can be used as sideswipers.
People say the Palm paddles are way too light.
Take a look at:
2bradioparts.com
as they have paddle fingerpieces - those are the ones that are flat, that you can use to convert a single or dual lever Vibroplex to a sideswiper.
73, David N1EA
REM :
See:
https://www.mtechnologies.com/palm/
Editor
Terminated Coaxial Cage Monopole by Martin Ehrenfried G8JNJ
I took the G5 and went along with a G5RV in the QRN... but at least this mistake which led me to discover an unknown antenna to me and even another one @ http://www.tc2m.info/
where I learned a lot more today !!
73s & 77s, Jean J. LEWUILLON 5T0JL
REM :
See Attachment pse
Thanks fellows, have a nice weekend, BCNU.
http://www.sideswipernet.org/
73, Yann, F5LAW. SideSwiperNetGroup
73, from the town at the rivers "De Bergsche Maas" and "De Dongen" Geertruidenberg (800+ years city rights) at: 51.702211N 4.853854E
Your Editor Jan Pieter Oelp PA3CLQ
-30-
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: