[aprssig] Baofeng radio for igate use (PACKET TONES!)

Robert Bruninga bruninga at usna.edu
Tue May 9 11:24:14 CDT 2017


AMEN!
Thanks for finding that page.  I have now added it right up top of the main
APRS page aprs.org.  Bob

-----Original Message-----
From: Greg Trasuk

>> Is there a guide somewhere on exactly what an APRS transmission
>> should look like on a spectrum analyzer/mod scope?

> I find this is a pretty good introduction to [what] Bob’s talking about.
> https://www.febo.com/packet/layer-one/transmit.html

----------original message ----------------

> May 9, 2017 10:47 AM, "Robert Bruninga" <bruninga at usna.edu> wrote:
> Considering that 90% of the packets being transmitted on the air are
> not properly set for deviation, level, emphasis, skew, clipping, and
> overdrive, it is not necessarily a problem with a given receiver.
> Kenwoods receive proper signals (flat) down to just a few dB above 10
> dB SINAD. Similarly they can not decode a full quieting ppacket with
> bad skew. Bob
>
> From: aprssig [mailto:aprssig-bounces at tapr.org] On Behalf Of Andrew
> Rich
> Sent: Tuesday, May 09, 2017 9:33 AM
> To: David Andrzejewski
> Cc: TAPR APRS Mailing List
> Subject: Re: [aprssig] Baofeng radio for igate use
>
> Read the direwolf sdr test results
>
> A ken wood d710a copied 60 % of packets
>
> A sound card modem copied 100 %
>
> And the ken wood is conspired miles ahead of a baofeng
>
> I am not sure why they wasted their time making them
>
>
>
> Sent from my iPhone
>
>
> On 9 May 2017, at 10:51 pm, David Andrzejewski
> <david at davidandrzejewski.com> wrote:
>
> I have tested baofeng receivers for selectivity. They are some of the
> worst I have ever seen in that regard.
>
> Because of that and because of the problems with their transmitters and
> spurious emissions, I no longer recommend baofengs for anything.
>
> Most of the people on the internet who say "well I have one and it works
> fine for me" have never actually tested their radios on real test
> equipment.
>
> They're just plain bad radios.
>
> If you want a good cheap receiver for an urban environment, try to find an
> old Motorola Maxar and crystal it up for 144.39. They made some models
> with 100db of selectivity(!). They're a rat's nest of wires inside, but
> excellent receivers.
>
> --
>
> David Andrzejewski
> E-mail/iMessage/Jabber: david at davidandrzejewski.com PGP Key ID:
> 5EBA8A72
>
> On May 4, 2017, at 02:18, Jess Haas <km6gvw at jesshaas.com> wrote:
>
> I had this idea that a cheap Baofeng UV-5R would make a good igate radio
> and allow me to use my other radios for other things. Well it turns out
> that these radios have a serious lack of filtering that raises the noise
> floor significantly when used in an urban environment. With the Baofeng I
> can clearly hear the two digipeaters that are within a couple of miles of
> me and with the squelch open I hear no other stations and just the usual
> FM static noise. Using either the Yaesu VX-1R or ICOM T-81a(both HTs) that
> I have I hear an almost constant flood of packets. Many are weak but there
> are some stations that come in very clearly on my other radios but I don't
> get anything from with the Baofeng. After researching the issue a bit it
> seems that in a lab the UV-5R actually has a rather sensitive receiver but
> it is so wide open that unless you are in the middle of nowhere far from
> any RF sources the radio is deaf to all but the strongest signals. I just
> wanted to share this as these radios are dirt cheap and seem to be
> everywhere so I am sure other people are using them so I wanted to make
> sure people have realistic expectations. I use mine with the local
> repeaters and it works fine but since I have switched radios on my igate I
> have heard 35 stations directly where as before I was really only hearing
> two.
>
> I also wanted to share that I have found it rather amazing what the
> direwolf soundcard modem can pull out of the noise. When listening on my
> Kenwood D710 I have gotten used to only strong clear packets being decoded
> but with direwolf everything that I hear gets decoded. It regularly
> decodes packets from a digipeater 79miles away that I can barely hear.
> Right now there seems to be a bit of a band opening as I am also decoding
> packets from stations down in mexico including a digipeater that is 185
> miles away! They don't sound great but it decodes them anyway.
>
> 73,
>
> Jess
>
> KM6GVW
>
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