[App_rpt-users] Audio detection circuit to generate 'COR'

David McGough kb4fxc at inttek.net
Tue Oct 6 15:05:08 UTC 2015


BTW, I meant 1/2 mile coverage.

On Tue, 6 Oct 2015, David McGough wrote:

> 
> Hi guys,
> 
> Yes, I also can confirm that these modules have DIRTY transmitters and RF
> synthesizers...And, their -loud- 2nd harmonics fall squarely in the busy
> 800MHz business/public service band. So, be careful with them, or you may 
> have unwanted visitors knocking at your door!!! Without proper filtering, 
> even with a small antenna, I'm sure their 2nd harmonic can be heard for 
> miles!
> 
> Personally, I wouldn't put a lot of effort into building a repeater 
> with these--my experience has been that they're not really usable for more 
> than a "back yard" repeater (meaning perhaps 1/2 coverage), due to high 
> synthesizer noise--you'll never get the receiver to hear very well.
> 
> As with everything, you mileage may vary--have fun and experiment! That's
> what ham radio is about! The nice thing about this hardware is that it's
> dirt cheap!  BTW, I'm specifically referring to the Dorji DRA818U/DRA818V
> modules here, of which I've got several.
> 
> 73, David KB4FXC
> 
> 
> 
> On Tue, 6 Oct 2015, Steve Zingman wrote:
> 
> > Steve,
> > Be aware that those transmitters are dirty.
> > There is a note about a module using the same RF circuit on Doug's 
> > HAMVIOP site.
> > He suggests a filter. REQUIRED if you are going to drive a amp or even 
> > connect it to a antenna!
> > 
> > 73, Steve N4IRS
> > 
> > On 10/6/2015 9:13 AM, Steven Donegan wrote:
> > > Thanks. For my first full duplex repeater (for test/learning purposes) 
> > > I am going with 2 of those modules and a 6 cavity duplexor (likely of 
> > > the 'notch' variety). If it works out may put my Mirage BD-35 on the 
> > > TX side before the duplexor and get ~16 watts for giggles.
> > > Steven Donegan
> > > KK6IVC General Class FCC License
> > > Silver State Car #86
> > > www.sscc.us
> > >
> > > ------------------------------------------------------------------------
> > > *From:* Steve Zingman <szingman at msgstor.com>
> > > *To:* Steven Donegan <donegan at donegan.org>
> > > *Sent:* Tuesday, October 6, 2015 6:10 AM
> > > *Subject:* Re: Audio detection circuit to generate 'COR'
> > >
> > > I'll send you the info tonight when I get home. I have a couple of them.
> > >
> > >
> > >
> > > On 10/6/2015 9:10 AM, Steven Donegan wrote:
> > >> Thanks Steve! I'll look into that as well.
> > >> Steven Donegan
> > >> KK6IVC General Class FCC License
> > >> Silver State Car #86
> > >> www.sscc.us <http://www.sscc.us/>
> > >>
> > >> ------------------------------------------------------------------------
> > >> *From:* Steve Zingman <szingman at msgstor.com> 
> > >> <mailto:szingman at msgstor.com>
> > >> *To:* Steven Donegan <donegan at donegan.org> 
> > >> <mailto:donegan at donegan.org>; "app_rpt-users at ohnosec.org" 
> > >> <mailto:app_rpt-users at ohnosec.org> <app_rpt-users at ohnosec.org> 
> > >> <mailto:app_rpt-users at ohnosec.org>
> > >> *Cc:* "app_rpt-users at ohnosec.org" <mailto:app_rpt-users at ohnosec.org> 
> > >> <app_rpt-users at ohnosec.org> <mailto:app_rpt-users at ohnosec.org>
> > >> *Sent:* Tuesday, October 6, 2015 6:06 AM
> > >> *Subject:* Audio detection circuit to generate 'COR'
> > >>
> > >> Steve COR or actually RUS "Receiver Un Squelch" is available in that 
> > >> radio. You have to unsolder the shield to get to it.
> > >>
> > >> 73, Steve
> > >>
> > >>
> > >>
> > >> On 10/6/2015 8:56 AM, Steven Donegan wrote:
> > >>> Well, it is a generic question - any radio without COR. The specific 
> > >>> model in my case is a UHF radio module model # SA-828U: 
> > >>> http://www.alibaba.com/product-detail/1W-5km-distance-SA828-U-uhf_60092524887.html?spm=a2700.7724857.29.62.Xbg6c5
> > >>> Steven Donegan
> > >>> KK6IVC General Class FCC License
> > >>> Silver State Car #86
> > >>> www.sscc.us <http://www.sscc.us/>
> > >>>
> > >>> ------------------------------------------------------------------------
> > >>> *From:* Skyler Fennell <electricity440 at gmail.com> 
> > >>> <mailto:electricity440 at gmail.com>
> > >>> *To:* Steven Donegan <donegan at donegan.org> <mailto:donegan at donegan.org>
> > >>> *Cc:* app_rpt-users at ohnosec.org <mailto:app_rpt-users at ohnosec.org>
> > >>> *Sent:* Tuesday, October 6, 2015 5:47 AM
> > >>> *Subject:* Re: [App_rpt-users] Audio detection circuit to generate 'COR'
> > >>>
> > >>> http://www.aaroncake.net/circuits/vidswitch.asp
> > >>>
> > >>> That might work, I use it for packet.
> > >>>
> > >>> What radio are you on?
> > >>>
> > >>> Sent from my iPhone
> > >>>
> > >>>
> > >>>
> > >>> On Oct 6, 2015, at 6:29 AM, Steven Donegan <donegan at donegan.org 
> > >>> <mailto:donegan at donegan.org>> wrote:
> > >>>
> > >>>> Does anyone have a circuit that will take audio from a radio and 
> > >>>> generate a pseudo COR signal for the URI-x? If so would you share 
> > >>>> the circuit diagram?
> > >>>>
> > >>>> TIA
> > >>>> Steven Donegan
> > >>>> KK6IVC General Class FCC License
> > >>>> Silver State Car #86
> > >>>> www.sscc.us <http://www.sscc.us/>
> > >>>> _______________________________________________
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> > >
> > 
> > 
> 
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