[CRAPRS] FW: Radio Problems

Fri Feb 6 10:25:33 CST 2009

THANK YOU! I've spent hours messing with that 
radio, trying various things, and searching the 
net for similar problems.  Now I can recreate the 
problem and know what I'm dealing with! With a 
little wiggle of the cable,  I can even make it 
change channels on EVERY transmission!

When I ordered radio cables for my TNCs, I got 
one for the Kenwood too, "just in case." And 
that's what I need to do, I need to put that 
cable back on the shelf as a "just in case" cable 
with that radio.  The Kenwood was used on a whim 
one day when I realized I might be able to 
actually easily receive, display,and review APRS 
way points while mobile without a PC. Now that I 
realize just how easy it is to have mobile APRS 
for receiving and displaying way points with the 
OpenTracker2 and the Garmin GPSIII, I need to 
stop using the HT, and connect it to either a 
dedicated 5 watt HT, or better yet, a mobile dual 
bander.

OpenTracker:  $50.
Garmin GPSIII+ on Ebay: $30.
Cables:  $20.
HT on ebay: $30.

It's not as pretty as the ads in the ham 
magazines for the Kenwood D710 ($530) with the 
AvMapG5 ($629), (plus mounts and cables... 
probably another $100) but $130 is one order of 
magnitude less expensive than $1,259, for nearly 
the same level of APRS function.

On the Solar Tetroon testing front, it's ready to 
go.  There will be one more freezer test, as I 
compare a set of Energizer Advanced Lithium to 
the prior test of Energizer Ultimate Lithium 
batteries.  I already have the Ultimates 
purchased for the flight, but the Advanced 
Lithium batteries are about half the cost, and I 
want to do a comparison before my gear flies away 
so I can get an exact comparison between the two 
battery types.

-Jerry

>Posting from the CRAPRS mailing list:
>Ah, the joys of running the TH-F6A.  I suspect the following:
>
>The remote mike button functions are wired as 
>different resistances into the mike circuit.
>Like remote mike button 'A' is a 10k resistance, 
>remote mike button 'B' is a 15k resistance
>across the mike circuit, etc.  I don't remember 
>the exact values, but you get the idea.
>
>I've found that the after market plugs don't 
>quite fit into the jacks properly on the side
>of the radio.  The jacks are recessed slightly, 
>meaning the outer shell or cover for any
>external plug must be very thin.  This
>means the plugs are almost, but not quite, 
>seated into the radio jacks.  When this
>happens, the slightest movement outward on the 
>plugs will trigger a channel change,
>vfo mode switch, or some other strange behavior 
>in the radio, even if you lock the
>functions.  I think the lock only affects the 
>buttons on the radio, not the external
>mike functions. 
>
>
>Even if you bought the cable from the open 
>tracker folks, it may still just use more
>standard sized plugs.
>
>If you made your own plug, be aware that the 
>ground or return for the mike circuit is not
>the shell or shield on the (larger) mike jack; 
>it's the shell on the audio output jack.
>
>I have a cable I made from external parts, with 
>very narrow shells, that do seat properly
>into the jacks.  I can let you borrow it.
>
>Or maybe better yet, I have a known-good
>Radio Shack HTX-202 you could use. It uses the 
>more standard wiring for audio and mike:
>the larger 3.5 mm or 1/8 inch for external 
>speaker, 2.5 mm or 3/16 for the mike, with
>a 10K to ground to key the thing.  When powered 
>by 12 volts, it's rated to 5 watts out,
>and the usually measure pretty close to that. 
>BNC RF connector, standard barrel sleeve
>for input power. 
>
>Everything about the Kenwood is odd, as far as connectors are concerned.
>
>
>>  Date: Wed, 4 Feb 2009 16:35:58 -0600
>>  To: craprs at rf.org
>>  From: info at n-connect.net
>>  Subject: [CRAPRS] Radio Problems
>>
>>  Posting from the CRAPRS mailing list:
>>  I've got an Opentracker2 in my truck connected to a KenwoodTHF6A, and
>>  an external antenna. It's a "waste" of a tribander to use it on
>>  APRS, and I've got another HT on my list of radio gear to acquire,
>>  but for now, the Kenwood is all I've got.
>>
>>  The problem I'm having with it is that it changes channels.
>  > Completely randomly. Sometimes it's fine for weeks, and other times,
>>  it changes channels after only a minute of use. It's worse when I
>>  run it off it's internal battery, so I run it off 12 volt vehicle
>>  power. And it's random. It will randomly change to some memory
>>  channel.
>>
>>  I've got some snap on chokes, for the mic and audio cable, but they
>>  don't seem to have any effect. Running off the HT's antenna (crap for
>>  getting packets out, but I wanted to test it) or external roof top
>>  mag mount doesn't make any difference. Normal power is 5 watts.
>>  I've run it on .5 watts, and .05 watts, and have seen no difference.
>>  And yeah, you CAN actually get some APRS packets out on .05 watts.
>>  But not many, and not far from a digi. :-)
>>
>>  I've set it to one band use only, and always run it with the controls
>>  locked when I use it as an APRS radio. I also run it in VFO mode,
>>  since I do not have a memory setting for 144.390. So VFO, one band
>>  mode, controls locked, and it still manages to change to some random
>>  memory channel. Since I have a lot of channels in memory that I
>>  can't transmit on, (radio works well as a scanner too) I usually land
>>  on one of those channels, so it's no real harm. But one of these
>>  days, I'm going to land on a repeater channel, and blast it with APRS
>>  packets.
>>
>>  And that day was today, when I noticed it was on 444.225. (Dubuque?)
>>  I'm not sure if that is a working repeater, or not.
>>
>>  And it stays locked during the channel change. I have to unlock it,
>>  and change it back and relock it.
>>
>>  Anyone have any ideas?
>>
>>  _______________________________________________
>>  CRAPRS mailing list
>>  CRAPRS at rf.org
>>  http://rf.org/mailman/listinfo/craprs
>
>
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>
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