Re: [Elecraft] (OT) CW Resonant Speaker

Knowing very little about the physics of sound, does using a thinner tube as opposed to a larger diameter one, make the tube have a narrower " bandwidth " ? See: http://www.fonema.se/qpipe/qpipe.htm Since the primary loss component of an "organ pipe" is friction along the wall, a larger

Re: [Elecraft] (OT) CW Resonant Speaker

This whole topic is very interesting to me. Very ironically, just before this topic got started, I was thinking about qrp hall of famer, Rick Littlefield's, Ham Radio magazine article Mar 89', featuring a resonant cw speaker. It was built using a solo 16 cup and a small 700hz transducer. I put it

Re: [Elecraft] (OT) CW Resonant Speaker

The confusion here is a common one, closed vs open ended resonators, especially if one looks at the poorly explained graphs in most physics texts. The speaker, attached to one end of the pipe, is not the closed end, it is open, since it drives the air particles at that end, and that makes it a

Re: [Elecraft] (OT) CW Resonant Speaker

On 2/17/2017 6:56 PM, stan levandowski wrote: > A cylinder with a closed end is a "closed cylinder" and requires the > formula that uses 2f instead of f. A cylinder with a speaker in one end and open in the other is an "open" cylinder (open pipe). It is a *half wave* in air which means the

[Elecraft] (OT) CW RESONANT SPEAKER

Here's a video of the Sky Tec and a few tips for building a copy: https://www.youtube.com/watch?v=MF8bk6958Hg John AE5X http://ae5x.blogspot.com/ __ In the late 70's, I used a Sky Tec CW-1 resonant speaker. $9.95 USD in 1977. It worked very well and had a

Re: [Elecraft] (OT) CW Resonant Speaker

A cylinder with a closed end is a "closed cylinder" and requires the formula that uses 2f instead of f. The "real" formula accounts for lots of variables, including diameter of the sphere. But a ballpark formula that works just fine for less complex designs is just Length (in feet or

Re: [Elecraft] (OT) CW Resonant Speaker

I think a pipe with a speaker in the end is considered a closed end cylinder, but I am not completely sure.  If so, resonant lengths are shorter.  Here is the page from one of my favorite websites if you are interested in experimenting with resonant speakers:

Re: [Elecraft] (OT) CW RESONANT SPEAKER

In the late 70's, I used a Sky Tec CW-1 resonant speaker.  $9.95 USD in 1977.   It worked very well and had a very sweet sound.  A sleeve in the top allowed pitch adjustment.  I still have it, somewhere around here... When I first got my KX3, I considered duplicating it (it is made primarily

Re: [Elecraft] (OT) CW Resonant Speaker

I have not but you certainly can do it. The length of the tube will determine the peak resonant frequency and you would have to experiment with the length to tune it to the pitch you like best to listen to. Remember the days you would blow across a bottle to make a tone? The more you drank out

Re: [Elecraft] (OT) CW Resonant Speaker

The wavelength and frequency of musical notes can be found here: http://www.phy.mtu.edu/~suits/notefreqs.html A closed end pipe as used in the resonant speaker is a half-wave (half the given dimension). Note also there will be some "end effect" because the sound continues to vibrate past

Re: [Elecraft] (OT) CW RESONANT SPEAKER

There was a commercial version available about 20 years ago and I used it for quite some time. really made CW signals pop out of the background. May build a new one of here. Mike, k5wmg Bella-Green Bed & Breakfast and Tiny Houses www.bella-green.com On Fri, Feb 17, 2017 at 1:25 PM, Robert

Re: [Elecraft] (OT) CW Resonant Speaker

Try Pipe organ design.  Gives  you the input to cut the tube to any audio frequency. Mel, K6KBE  From: P.J.Hicks <hickspj...@comcast.net> To: ELECRAFT <elecraft@mailman.qth.net> Sent: Friday, February 17, 2017 10:56 AM Subject: [Elecraft] (OT) CW Resonant Speaker Has

Re: [Elecraft] (OT) CW Resonant Speaker

length you want to make out of harder material. 73, Ron AC7AC -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of P.J.Hicks Sent: Friday, February 17, 2017 10:57 AM To: ELECRAFT Subject: [Elecraft] (OT) CW Resonant Speaker Has anyone built the

[Elecraft] (OT) CW RESONANT SPEAKER

KD1JV has this version on his web page. I built one several years ago from fibre board and cement. Works very good and still using it, RC KC5WA -- May You Live Long and Prosper what's life without a few dragons

Re: [Elecraft] (OT) CW Resonant Speaker

ary 17, 2017 10:56 AM Subject: [Elecraft] (OT) CW Resonant Speaker Has anyone built the resonator with a straight length of tube? Perhaps terminated with a 45 deg. cut? Might be an interesting experiment. The 45 deg long radius street elbow in 2" is an order only item in my are

[Elecraft] (OT) CW Resonant Speaker

Has anyone built the resonator with a straight length of tube? Perhaps terminated with a 45 deg. cut? Might be an interesting experiment. The 45 deg long radius street elbow in 2" is an order only item in my area so thought I'd substitute a straight length. PJH, N7PXY

Re: [Elecraft] (OT) CW Resonant Speaker

That is really an excellent video Stan. That's a pretty effective speaker, I will be digging thru my plumbing supplies tomorrow! Gary N7DXT On Thu, Feb 16, 2017 at 6:14 PM, stan levandowski wrote: > For those with interest I just put up a video comparison of a standard >

[Elecraft] (OT) CW Resonant Speaker

For those with interest I just put up a video comparison of a standard "communications speaker" vs. the "CW Resonant Speaker" detailed in the article of the same name in the February 2017 QST, page 43. Included for Elecraft KX product owners is the amp necessary to use the headphone jack