[OZAPRS] Setting up TT4 Tx on 2m and more! Problem Solved

Norm, VK3XCI vk3xci at aanet.com.au
Thu Feb 18 17:53:53 EST 2010 

Told you so :>





73 de Norm, VK3XCI
Mildura, Australia
The Wintersun City
QF15bt.

David and Justine Olsen wrote:
> When in doubt, check the baud rate <blush>
> 
> David
> 
> On 18 Feb 2010, at 12:29, David and Justine Olsen wrote:
> 
>> Too late for my hair Ray.
>>
>> I've moved on to the other part of my project now, and will go back 
>> over your email when I get back to the TT4 Tx issue.
>>
>> I've got a tracker to install in my aircraft an 8W unit from Byon. I 
>> want to set up a portable computer EEPC with TT4 and UIview at the 
>> gliding club, have a tracker in my glider and have its position shown 
>> on the EEPC.
>>
>> I'm running it now and it is being decoded by the TT4 via a Kenwood 
>> TM201A. I can see the decodes in Hyperterminal, of my tracker and 
>> other local APRS transmitters when TT4 is in text and when TT4 is in 
>> KISS mode. In KISS mode the first part of the transmission is 
>> gibberish in Hyperterminal - no problems.
>>
>> My problem is how to setup UIView in KISS mode to receive data from 
>> the TT4. The TT4 is setup in Alpha mode.
>>
>> As I said, Hyperterminal shows data received via the serial port, but 
>> I can;t get anything to appear in UIView.
>> Can anyone point me to UIview KISS setup for TT4?
>>
>> Thanks for the audio stuff....I'll file it away for when I get back to 
>> that part of the project.
>>
>> David
>>
>>
>>
>>
>> On 18 Feb 2010, at 12:14, Ray Wells wrote:
>>
>>> David/All,
>>>
>>> I'm not suggesting your problem is tone level related but failure to 
>>> grasp the following is arguably responsible for more TNC decode 
>>> issues than any other cause.
>>>
>>> The need for "twist" adjustment depends on the radio hardware 
>>> involved so a brief discussion is probably in order.
>>>
>>> The "norm" for an FM/PM radio is to apply 6dB (x2) per octave of 
>>> preemphasis in the transmitter. For packet, this results in the high 
>>> tone (2200Hz) having twice (near enough) the deviation as the low 
>>> tone (1200). In the receiver deemphasis is applied which restores the 
>>> audio to a "flat" condition, i.e. both tones going to the TNC have 
>>> the same level.
>>>
>>> If TNC audio is fed into the microphone socket you can depend on 6dB 
>>> per octave preemphasis. However, if the TNC audio is fed in further 
>>> down the tx audio chain, such as the audio injection point for tone 
>>> signalling, preemphasis will not be applied in the tx and should be 
>>> applied externally - with twist, in the case of the TT4.
>>>
>>> Going to the receiver again, if it receives a signal without 
>>> preemphasis, it will still apply deemphasis (assuming audio is taken 
>>> after deemphasis), resulting in the high tone being just half the 
>>> level of the low tone when fed to the TNC. FSK demodulators based on 
>>> the the  exar pair 2206/2211 will not decode if the high tone is 
>>> lower in amplitude than the low tone, by even a very small amount.
>>>
>>> If rx audio is taken from the demodulator in the radio, i.e. before 
>>> deemphasis, the preceding is not a problem because audio that is 
>>> transmitted "flat" will be decoded "flat".
>>>
>>> The exar chip set (found in genuine TNC2 TNC's)  is not disturbed by 
>>> high tone being considerably higher in amplitude than the low tone.
>>>
>>> In summary, every tx should employ preemphasis, regardless of it 
>>> being generated internally, or externally. That will eliminate any 
>>> decode problems in TNC's with finicky chip sets because high tone 
>>> will always be the same level as, or higher than, the low tone coming 
>>> out of the rx.
>>>
>>> David, is TXD 60 60mS or 600mS? Although TXD provides time for your 
>>> tx to stabilise before valid data is sent, it can also have an impact 
>>> on the remote rx in cases where muted audio is being used for the 
>>> TNC. There are some very sluggish receivers kicking about and TXD 
>>> needs to be long enough for that rx to unmute. My Icon handheld 
>>> scanner is pathetic in this regard, with the mute being so slow that 
>>> I can miss at least half of the digi beacon, even when I'm at the 
>>> digi site.
>>>
>>> Get that CRO working and save your hair, lest you should end up like 
>>> me :-)
>>>
>>> Ray vk2tv
>>>
>>>
>>>
>>> David and Justine Olsen wrote:
>>>> I am presently running TxD of 60 and TXTWIST of 50. I've tried a 
>>>> range of TXTWIST but none sound too different
>>>> David
>>>>
>>>> On 18 Feb 2010, at 00:36, Scott Evans wrote:
>>>>
>>>>>
>>>>> ABAUD is just the speed set for serial port 1 ... what TXDELAY are 
>>>>> you running? because depending on how quick you radio is you may 
>>>>> need to lengthen the delay a little, also check the TXTWIST setting 
>>>>> too, this controls the level between the 1200Hz & 2200Hz tones.
>>>>>
>>>>> On Wed, 2010-02-17 at 21:51 +1000, David and Justine Olsen wrote:
>>>>>> ABAUD is set to 19200
>>>>>>
>>>>>>
>>>>>> On 17 Feb 2010, at 21:37, Norm, VK3XCI wrote:
>>>>>>
>>>>>> > Sort of like 9600 baud?
>>>>>> >
>>>>>> >
>>>>>> >
>>>>>> >
>>>>>> >
>>>>>> >
>>>>>> >
>>>>>> > 73 de Norm, VK3XCI
>>>>>> > Mildura, Australia
>>>>>> > The Wintersun City
>>>>>> > QF15bt.
>>>>>> >
>>>>>> > David and Justine Olsen wrote:
>>>>>> >> I've gone through all of the TT4 audio adjustments as explained in
>>>>>> >> the help docs by listening on another set, but still no success being
>>>>>> >> received by any digis.
>>>>>> >>
>>>>>> >> One thing that has me curious, is the the squak from my Tx sounds
>>>>>> >> nothing like those from others. The others are a deehdaaah kind of
>>>>>> >> sound with two distinctly different tones ate the beginning and end
>>>>>> >> tone, whereas mine is a sqaaaark :-) of mixed tones at the same time.
>>>>>> >>
>>>>>> >> David
>>>>>> >>
>>>>>> >> VK4MDX
>>>>>> >>
>>>>>> >> _______________________________________________
>>>>>> >> OZAPRS mailing list
>>>>>> >> OZAPRS at aprs.net.au <mailto:OZAPRS at aprs.net.au>
>>>>>> >> http://lists.aprs.net.au/mailman/listinfo/ozaprs
>>>>>> >>
>>>>>> >>
>>>>>> >> --------------------------------------------------------------------- 
>>>>>> >> ---
>>>>>> >>
>>>>>> >>
>>>>>> >> No virus found in this incoming message.
>>>>>> >> Checked by AVG - www.avg.com <http://www.avg.com>
>>>>>> >> Version: 9.0.733 / Virus Database: 271.1.1/2692 - Release Date:  
>>>>>> >> 02/17/10 06:35:00
>>>>>> >>
>>>>>> > _______________________________________________
>>>>>> > OZAPRS mailing list
>>>>>> > OZAPRS at aprs.net.au <mailto:OZAPRS at aprs.net.au>
>>>>>> > http://lists.aprs.net.au/mailman/listinfo/ozaprs
>>>>>>
>>>>>> _______________________________________________
>>>>>> OZAPRS mailing list
>>>>>> OZAPRS at aprs.net.au <mailto:OZAPRS at aprs.net.au>
>>>>>> http://lists.aprs.net.au/mailman/listinfo/ozaprs
>>>>>>       
>>>>>
>>>>> -- 
>>>>> Scott Evans <scott at vk7hse.hobby-site.org 
>>>>> <mailto:scott at vk7hse.hobby-site.org>>
>>>>>
>>>>>
>>>>> -- This email and any files transmitted with it are confidential 
>>>>> and intended solely for the use of the individual or entity to whom 
>>>>> they are addressed. If you have received this email in error please 
>>>>> notify the system manager. This message contains confidential 
>>>>> information and is intended only for the individual named. If you 
>>>>> are not the named addressee you should not disseminate, distribute 
>>>>> or copy this e-mail. Please notify the sender immediately by e-mail 
>>>>> if you have received this e-mail by mistake and delete this e-mail 
>>>>> from your system. If you are not the intended recipient you are 
>>>>> notified that disclosing, copying, distributing or taking any 
>>>>> action in reliance on the contents of this information is strictly 
>>>>> prohibited.
>>>>> _______________________________________________
>>>>> OZAPRS mailing list
>>>>> OZAPRS at aprs.net.au <mailto:OZAPRS at aprs.net.au>
>>>>> http://lists.aprs.net.au/mailman/listinfo/ozaprs
>>>>
>>>> ------------------------------------------------------------------------
>>>>
>>>> _______________________________________________
>>>> OZAPRS mailing list
>>>> OZAPRS at aprs.net.au
>>>> http://lists.aprs.net.au/mailman/listinfo/ozaprs
>>>>   
>>>
>>> _______________________________________________
>>> OZAPRS mailing list
>>> OZAPRS at aprs.net.au <mailto:OZAPRS at aprs.net.au>
>>> http://lists.aprs.net.au/mailman/listinfo/ozaprs
>>
>> _______________________________________________
>> OZAPRS mailing list
>> OZAPRS at aprs.net.au <mailto:OZAPRS at aprs.net.au>
>> http://lists.aprs.net.au/mailman/listinfo/ozaprs
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> OZAPRS mailing list
> OZAPRS at aprs.net.au
> http://lists.aprs.net.au/mailman/listinfo/ozaprs
> 
> 
> ------------------------------------------------------------------------
> 
> 
> No virus found in this incoming message.
> Checked by AVG - www.avg.com 
> Version: 9.0.733 / Virus Database: 271.1.1/2693 - Release Date: 02/17/10 18:35:00
>

More information about the OZAPRS mailing list