low MHz connector design consultant
in [Design]
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From: John Larkin on 30 Apr 2010 10:01 On Fri, 30 Apr 2010 06:54:29 -0500, "mook johnson" <mook(a)mook.net> wrote: > >"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >news:ql9kt5tg7s7e5q7pb460gcdig4r00jjmrj(a)4ax.com... >> On Thu, 29 Apr 2010 18:30:41 -0500, "mook johnson" <mook(a)mook.net> >> wrote: >> >>>Gents, >>> >>>I looking for a consultant that can assist in the design of a custom >>>military style connector with controlled characteristic impedance and >>>insertion loss between two terminals in the 1MHz - 20MHz frequency range. >>> >>>This connector is special because is the application so an off the shelf >>>component will not work. >>> >>>Any leads where I can start looking for such a consultant? >>> >>>thanks >>> >>> >> >> There are so many military connectors, including ones for wild >> environments, hermetic, etc, some standard part might work. >> >> 20 MHz isn't very demanding. Most any mil connector will be "matched" >> to any impedance at 20 MHz. Wavelength is 15 meters! >> >> John > > >The connector I need goes into environments that far exceed military >applications but the physical concept is similar. We have an in-house >connector company that makes these connectors for us but they have never had >to deal with never greater than >200KHz signals before. We tried using our >regular connectors for this application and the impedance mismatch and >insertion loss were extreme at 5 - 20MHz. The Zo mismatched by 50% and was >not stable above 1MHz and had several resonant modes. Insertion loss >something on the order is 6dB/connector and we'll have a couple dozen in >series on this line. The number of series connection is the is the rub and >it is unavoidable, non negotiable. Sounds like those were filter-pin connectors. No conventional connector would behave like that at such low frequencies. "Not stable above 1 MHz" sounds very weird. Wavelength is 300 meters! John
From: RST Engineering on 30 Apr 2010 12:41 On Fri, 30 Apr 2010 06:54:29 -0500, "mook johnson" <mook(a)mook.net> wrote: .. We tried using our >regular connectors for this application and the impedance mismatch and >insertion loss were extreme at 5 - 20MHz. The Zo mismatched by 50% and was >not stable above 1MHz and had several resonant modes. Insertion loss >something on the order is 6dB/connector and we'll have a couple dozen in >series on this line. The number of series connection is the is the rub and >it is unavoidable, non negotiable. A PL-259 will do that, y'know. Jim
From: RST Engineering on 30 Apr 2010 12:42 On Fri, 30 Apr 2010 07:01:43 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >Sounds like those were filter-pin connectors. No conventional >connector would behave like that at such low frequencies. > >"Not stable above 1 MHz" sounds very weird. Wavelength is 300 meters! > >John > Hell, alligator clips wouldn't be that bad at these frequencies. Jim
From: RST Engineering on 30 Apr 2010 12:43 On Thu, 29 Apr 2010 20:42:20 -0700, Robert Baer <robertbaer(a)localnet.com> wrote: > An RCA phono type connector is almost good enough, a BNC certainly fits. RCAs work quite well up to about 100 MHz. Jim
From: John Larkin on 30 Apr 2010 12:43
On Fri, 30 Apr 2010 09:41:13 -0700, RST Engineering <jweir43(a)gmail.com> wrote: >On Fri, 30 Apr 2010 06:54:29 -0500, "mook johnson" <mook(a)mook.net> >wrote: > >. We tried using our >>regular connectors for this application and the impedance mismatch and >>insertion loss were extreme at 5 - 20MHz. The Zo mismatched by 50% and was >>not stable above 1MHz and had several resonant modes. Insertion loss >>something on the order is 6dB/connector and we'll have a couple dozen in >>series on this line. The number of series connection is the is the rub and >>it is unavoidable, non negotiable. > >A PL-259 will do that, y'know. > >Jim At 1 MHz, an ordinary wall plug and outlet has excellent specs. John |