I readily agree that it IS possible, but darned if the commercial manufacturers are not using that DSP capability to discriminate between 120 degrees and 180 degrees of reverse-burst tone shift.
A case in point: The local PD has a Kenwood repeater, and the County SO has a Motorola repeater- on separate public-safety frequencies, of course. The PD has Kenwood TK-380 and TK-390 portables, and TK-890 mobiles. The SO has HT1000, MT2000, and HT1250 portables, and both Spectra and CDM mobiles. Since the HT1250 and CDM1550-LS+ radios have the CPS-selectable reverse-burst shift, the SO deputies with those radios can use the mutual-aid channel with the PD and have silent muting. The PD officers, on the other hand, always create and suffer annoying squelch crashes when using the mutual aid channel. I agree with Nate- suppliers of commercial radios should be REQUIRED to furnish radios that automatically select the phase shift to eliminate squelch crashes, not to ensure that they occur! Fans of the old "Highway Patrol" show with Broderick Crawford may recall that the obligatory squelch crash followed every radio communication. That gets really old after a few minutes! Curiously, there are some old-timers who declare that they really like to hear squelch crashes. Let's hope that these people never are permitted to select public-safety radio systems... 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of wd8chl Sent: Tuesday, February 03, 2009 1:40 PM To: [email protected] Subject: Re: [Repeater-Builder] Non-Standard Reverse Burst WAS: Kenwood TKR-850 question Nate Duehr wrote: > I was going to bring up TIA-603-C, but I figured it wasn't worth the > resulting religious battles that would result in the Gaza Strip here. > (GRIN) > > I've also seen at least one (clueless) agency switch radios instead of > simply demanding the manufacturer support their existing radios. Wasted of > taxpayer dollars. > > "Stupid is as stupid does!" They could have demanded proper support or > thrown the repeater manufacturer out. But there were other politics > involved... if someone high enough up is a "Brand X" fanatic, it just means > the taxpayers lose... > > What bugs me about the above, is that I'm just an Amateur and I can figure > out that there's two prevailing standards. Why can't some "professionals"? > Most get it, but there's still people out there who don't. > > Perhaps they shouldn't be working on Public Safety systems? Mmm? Just a > thought... > > Nate WY0X > Yeah- there sure is a lot of people who should NOT be doing commercial radio, let alone PS... And even stranger, most of the more recent Kenwoods I have played with seem to decode either just fine. My F6, my 705D and 805D, my wife's G71 and G707, as well as 830's, 840's, and 860's I've 'played' with. I haven't had much chance to play with -80 or -90 series, or the current stuff. But what I just listed all played well with either a stock Micor, MSF, TKR, MastrII (the ones that had STE), or MastrIII. It's going the other way (rx'ing with the M's) that doesn't always work, even within different vintage M radios. So it's not that hard to make a radio that will respond to either format, on the fly. No programming required...
