[aprssig] Baofeng radio for igate use

David Andrzejewski david at davidandrzejewski.com
Tue May 9 09:50:27 CDT 2017


Is there a guide somewhere on exactly what an APRS transmission should look like on a spectrum analyzer/mod scope? I have radios, I have a service monitor... it would be interesting to know what to look for.

- Dave

May 9, 2017 10:47 AM, "Robert Bruninga"  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 (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  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 (mailto:david at davidandrzejewski.com)
PGP Key ID: 5EBA8A72
On May 4, 2017, at 02:18, Jess Haas  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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