Re: [Elecraft] Microphones (was electronic product standards)
Thanks for posting your interesting comments Brendan. Within the context of SSB useage in ham radio I believe that the 'hype about audio' could lead to another related problem, if not already existing, which is poor use of the HF spectrum available to us. Given the proven fact that a SSB transmitter filter bandwidth of 2.1 kHz will result in the transmission of a very 'good quality' speech signal, provided that the carrier is positioned properly and that the mic - audio - modulator system characteristics suit human speech, I see no valid reason for using wider SSB filters. In addition to the increased amount of spectrum used, the use of wider filters followed by linear amplifiers whose IMD products might be only 30db or so below a test tone obviously results in a wider 'Interference Bandwidth', and should be discouraged IMHO. Adding Reverse ALC to the mix can further increase interference. Just an opinion. 73, Geoff GM4ESD Brendan Minish [EMAIL PROTECTED] wrote: snip These words (in ham radio use anyway) have become marketing speak and now mean nothing. As a former audio professional I cannot understand why all the hype about Audio in ham radio and to my ears there's a lot of money wasted on trying to make SSB into something it isn't. snip ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: Re: [Elecraft] Microphones (was electronic product standards)
I've heard it said that some contest stations deliberately transmit a wider-than-necessary signal to keep competitiors away from their channel. David G3UNA Within the context of SSB useage in ham radio I believe that the 'hype about audio' could lead to another related problem, if not already existing, which is poor use of the HF spectrum available to us. Given the proven fact that a SSB transmitter filter bandwidth of 2.1 kHz will result in the transmission of a very 'good quality' speech signal, provided that the carrier is positioned properly and that the mic - audio - modulator system characteristics suit human speech, I see no valid reason for using wider SSB filters. In addition to the increased amount of spectrum used, the use of wider filters followed by linear amplifiers whose IMD products might be only 30db or so below a test tone obviously results in a wider 'Interference Bandwidth', and should be discouraged IMHO. Adding Reverse ALC to the mix can further increase interference. Just an opinion. 73, Geoff GM4ESD - Email sent from www.virginmedia.com/email Virus-checked using McAfee(R) Software and scanned for spam ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: Re: [Elecraft] Microphones (was electronic product standards)
On Thu, 14 Feb 2008 [EMAIL PROTECTED] wrote: I've heard it said that some contest stations deliberately transmit a wider-than-necessary signal to keep competitiors away from their channel. Ahmust be one of those advance the technology things that justify contestsgood for everyone. 73 k3hrn Thom,EIEIO Email, Internet, Electronic Information Officer www.baltimorehon.com/Home of the Baltimore Lexicon www.tlchost.net/hosting/ Web Hosting as low as 3.49/month ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: Re: [Elecraft] Microphones (was electronic product standards)
I've heard it said that some contest stations deliberately transmit a wider-than-necessary signal to keep competitiors away from their channel. I personally would not intentionally transmit a wide signal during a contest. It would, imho, be counterproductive, apart from any other reasons. On the small 40m band in Europe, during large contests, you almost can not avoid stations sitting on top of each other and/or overlapping. Even if I assume that there were no BC stations between 7100kHz and 7200kHz and that a channel is only 2.5kHz wide, between 7040kHz and 7200kHz one only has space for 63 running stations without any conflicts arising, or using the older limits of 7040kHz to 7100kHz space for 23 SSB signals. Here there will always be a certain amount of elbowing going on. If one considers all the high powered phase noise being radiated and so on, then even a 9+20 signal can be a weak signal when compared to 40m contest noise levels. And finding gaps between stations can be a real art. This is why you want to have a signal with a very high average power level, but one which is also not wider than necessary. vy 73 de toby ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: Re: [Elecraft] Microphones (was electronic product standards)
At 08:28 AM 2/14/2008, [EMAIL PROTECTED] wrote... This is why you want to have a signal with a very high average power level, but one which is also not wider than necessary. That sounds like CW. :-) ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: Re: [Elecraft] Microphones (was electronic product standards)
Agreed... You only get so much area under the curve so why waste it with width when its height that gets you heard? -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Thursday, February 14, 2008 5:29 AM To: elecraft@mailman.qth.net Subject: Re: Re: [Elecraft] Microphones (was electronic product standards) I've heard it said that some contest stations deliberately transmit a wider-than-necessary signal to keep competitiors away from their channel. I personally would not intentionally transmit a wide signal during a contest. It would, imho, be counterproductive, apart from any other reasons. On the small 40m band in Europe, during large contests, you almost can not avoid stations sitting on top of each other and/or overlapping. Even if I assume that there were no BC stations between 7100kHz and 7200kHz and that a channel is only 2.5kHz wide, between 7040kHz and 7200kHz one only has space for 63 running stations without any conflicts arising, or using the older limits of 7040kHz to 7100kHz space for 23 SSB signals. Here there will always be a certain amount of elbowing going on. If one considers all the high powered phase noise being radiated and so on, then even a 9+20 signal can be a weak signal when compared to 40m contest noise levels. And finding gaps between stations can be a real art. This is why you want to have a signal with a very high average power level, but one which is also not wider than necessary. vy 73 de toby ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Microphones (was electronic product standards)
I read years ago that speech processors like pre-emphasized audio (louder highs, quieter lows). And the heavier the processing the more pre-emphasis is optimum. Does anyone know if the K3 speech processor does that automatically? Al N1AL On Thu, 2008-02-14 at 01:52, Brendan Minish wrote: On Wed, 2008-02-13 at 12:12 -0800, Ron D'Eau Claire wrote: There were some microphones produced for the communications market back then such as the famous Astatic D-104 which had a microphone element with a shaped response showing a distinct hump around 3 kHz, rolling off slowly at lower frequencies and somewhat faster at higher frequencies. That hump helped with articulation by emphasizing the mid-range speech frequencies. This is a presence peak. I don't know if anyone is doing that today for mainstream communications microphones. Today Paging Microphones are still specifically designed to have this pronounced mid range presence peak and also usually include Quite a bit of low frequency Roll off Shure have a range of dynamic elements available for this market, that have response curves that look remarkably similar to the HC4 and HC5 elements. take a look at the response curve of the Shure 450 http://www.shure.com/ProAudio/Products/WiredMicrophones/us_pro_450SeriesII_content a direct link to just the curve http://www.shure.com/groups/public/@gms_gmi_web_us/documents/web_resource/site_img_us_rc_450series2_larg.gif the 522 has a broader presence peak http://www.shure.com/ProAudio/Products/WiredMicrophones/us_pro_522_content Direct to curve http://www.shure.com/stellent/groups/public/@gms_gmi_web_us/documents/web_resource/site_img_us_rc_522_large.gif elements for these mics (and many others) are available at low cost as replacement parts. Heil sound plot their curves on a different log scale but after accounting for that the similarities are remarkable. http://www.heilsound.com/amateur/products/hc4/index.htm The needs of paging systems which include efficient use of limited power and maximum intelligibility in noisy environments are pretty much identical to our requirements for effective SSB modulation. Any well made paging/ Dispatch mic (or element..) is ideal for amateur radio use, most are far more durable and cost effective than 'the made for ham radio' stuff that is popular these days. Even the high end Ham mics only offer general and uninformative comments about shaping and clarity that say much and convey little. These words (in ham radio use anyway) have become marketing speak and now mean nothing. As a former audio professional I cannot understand why all the hype about Audio in ham radio and to my ears there's a lot of money wasted on trying to make SSB into something it isn't. Interestingly, one of the big exceptions is the inexpensive little Radio Shack electret element. It comes with a frequency response chart showing a very flat response across the audio spectrum. If you are looking for flat then these are a great place to start, however the design of the housing may have quite an impact on how things sound, this can be used to your advantage to create a presence peak or LF roll off. My own headset is based on a salvaged electret condenser mic with some audio tailoring done by means of a simple R/C filter, being lazy I copied the circuit of an Icom handmic. It works great and cost me almost nothing. 73's Brendan EI6IZ ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
