[aprssig] Receiver overload issues with Kenwood TH-D72

Steve Noskowicz noskosteve at yahoo.com
Fri Feb 8 18:50:57 CST 2013



  Yes.  Dummy loads on both. 
 It is a common misconception that radios or dummy loads don’t let any RF out except by an antenna.  The plastic case of the D72 is an RF sieve and even the metal case of the Alinco (if it is metal) is pretty much just as "open' to RF and the D72.  
Those two radios will talk to each other with dummy loads (or no antennas at all if in low power). for quite long distances..  I'd guess 1/4 mile     ...   400-500 yards or meters easily.

  Not too long ago there was an article in QST by one ham who mounted a light bulb dummy load on a pole and operated that way and worked Dx.

-- 

73, Steve, K9DCI  USN (Vet)  MOT (Ret)  Ham (Yet)

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--- On Fri, 2/8/13, Andrew P. <andrewemt at hotmail.com> wrote:

> From: Andrew P. <andrewemt at hotmail.com>
> Subject: Re: [aprssig] Receiver overload issues with Kenwood TH-D72
> To: "aprssig at tapr.org " <aprssig at tapr.org>
> Date: Friday, February 8, 2013, 3:56 PM
> Seems that dummy loading is the
> consensus; I just received the shipping notice for the dummy
> loads I ordered to get around the problem.
> 
> Thanks for your advice, everyone. 
> 
> Andrew KA2DDO
> ------Original Message------
> From: Ray Wells
> To: aprssig at tapr.org
> Sent: Feb 8, 2013 4:38 PM
> Subject: Re: [aprssig] Receiver overload issues with Kenwood
> TH-D72
> 
> 
> On 09/02/13 03:05, Andrew P. wrote:
> > Greetings, all.
> >
> > I was conducting some software tests that required
> passing data between two stations to ensure the data would
> be transmitted and received correctly. So, I had my
> transmitting station (Alinco DR-135T mobile and Byonics
> TinyTrak 4) and receiving station (Kenwood TH-D72 HT)
> sitting on the bench, both tuned to the same idle simplex
> frequency (I picked a quiet frequency not used for anything
> in my area), with the Kenwood HT about 1 meter from the
> Alinco's antenna. When I transmitted packets from the Alinco
> to the Kenwood, I could see the transmit indicator on both
> the TinyTrak and the DR-135T, but the TH-D72 would only
> occasionally squawk and acknowledge receipt of the packet
> (about 15% success rate). Transmitting in the reverse
> direction had an even lower success rate (zero packet
> detections at the receiver).
> >
> > Could it be I was overloading the radios' front ends by
> being too close to the other radio's antenna? I made sure to
> use the factory "rubber duck" antenna on the Kenwood to
> minimize gain, and even turned the HT on its side to ruin
> polarization, but that didn't help.
> >
> > Any suggestions (other than getting help because my
> arms aren't long enough to reach both rigs further apart)?
> I'm considering replacing the Alinco's antenna with a dummy
> load and depending on leakage to conduct the test, but I'm
> not sure if that will help.
> >
> > Andrew Pavlin, KA2DDO
> > Sent from my Verizon Wireless BlackBerry
> > _______________________________________________
> > aprssig mailing list
> > aprssig at tapr.org
> > http://www.tapr.org/mailman/listinfo/aprssig
> >
> Andrew,
> 
> I think that if you use a dummy load on both radios your
> problem will 
> vanish. By using antennas on the radios you would have had
> RF getting 
> into everything.
> 
> Ray vk2tv
> _______________________________________________
> aprssig mailing list
> aprssig at tapr.org
> http://www.tapr.org/mailman/listinfo/aprssig
> 
> 
> Sent from my Verizon Wireless BlackBerry
> _______________________________________________
> aprssig mailing list
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> 


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