Actually it depends on the Density of the Liquid material... Coy Hilton wrote:
> It's like a 8 ounce glass, >it doesn't matter what liquid you put into it, it still holds 8 >ounces. >73 > AC0Y > > > >--- In Repeater-Builder@yahoogroups.com, "kerry" <[EMAIL PROTECTED]> wrote: > > >>If you are not using a pll exciter, it's hard to get the >> >> >isolation.......... > > >>Kerry >>----- Original Message ----- >>From: "Kevin Custer" <[EMAIL PROTECTED]> >>To: <Repeater-Builder@yahoogroups.com> >>Sent: Monday, May 31, 2004 12:07 PM >>Subject: Re: [Repeater-Builder] Wacom WP-641, correction on its >> >> >specs... > > >> >> >>>Neal Newman wrote: >>> >>> >>> >>>>I am Getting only 83 db Isolation usning My 641's.. >>>>funny thing. I cannot get it to work with my MastrII repeater. >>>> >>>> >But it > > >>>>works great with the Spectrum.. >>>> >>>> >>>> >>>The obvious question is, is it tuned properly? The Wacom 641 is >>> >>> >very > > >>>simple to get close with nothing more than a handheld and a >>> >>> >signal > > >>>generator. >>>I prefer to tune the pass under low power, like one watt from >>> >>> >the > > >>>handheld. It makes the pass more precise, as tuning it with a >>> >>> >spectrum > > >>>analyzer usually won't yield as good a loss. I have always been >>> >>> >able to > > >>>hit the 1.5 dB loss mark by using this method. PLEASE spare me >>> >>> >the > > >>>"Don't tune the duplexer under power BS" These cavities are >>> >>> >rated at 350 > > >>>watts intermittent, and 275 continuous and you won't be able to >>> >>> >arc the > > >>>fingerstock with a few watts of power, especially if you get it >>> >>> >close to > > >>>resonance with a signal generator first. After getting the pass >>>frequency 'correct' you will find that obtaining the stated >>> >>> >isolation is > > >>>easy. >>> >>>One thing that happens is if the cavity is not tuned correctly >>> >>> >on the > > >>>pass frequency, the reject amount will suffer. Why? As the >>> >>> >spacing > > >>>between pass and reject frequencies decrease, so does the >>> >>> >ability for > > >>>the cavity to provide the rejection response. With this cavity, >>> >>> >the > > >>>lowest loss and best return loss appear nearly on top of one >>> >>> >another, so > > >>>match is at its best when the cavity is properly tuned for >>> >>> >lowest > > >>>insertion loss. Here is more on pass and reject response with >>> >>> >one > > >>>cavity from a WP-641 duplexer: >>>http://www.repeater-builder.com/rbtip/wacombpbrnotes.html >>> >>>Another thing that happens commonly with a duplexer and a radio >>> >>> >set that > > >>>was converted from commercial service to amateur, is the actual >>> >>> >terminal > > >>>impedance will not be 50 ohms. A duplexer that has been >>> >>> >optimized on a > > >>>piece of 50 ohm test equipment *may* not perform very well in >>> >>> >practice. > > >>>There are a few things that can be done to help this problem, >>> >>> >like using > > >>>a matching device (Z matcher) on the transmitter. Some prefer >>> >>> >to match > > >>>the duplexer to the transmitter by adjusting cabling lengths. >>> >>> >Either > > >>>method can substantially improve the operation of the duplexer. >>> >>> >Sure, > > >>>it would be nice or best if the radio set presented a perfect 50 >>> >>> >ohm > > >>>match, but many we convert do not. >>> >>>Wacom had written a dissertation on optimizing the duplexer >>>interconnection cabling lengths. That information, as well as >>> >>> >duplexer > > >>>tuning, is available here: >>>http://www.repeater- >>> >>> >builder.com/pdf/wp6xxVHFtuninginstructions.pdf > > >>>Look on page 4 under the section "Cable length between >>> >>> >transmitter and > > >>>duplexer" >>> >>>Hope this helps... >>>Kevin Custer >>> >>> >>> >>> >>> >>> >>> >>> >>> >>>Yahoo! Groups Links >>> >>> >>> >>> >>> >>> >>> >>> >>> > > > > > > >Yahoo! Groups Links > > > > > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
