OE3GBB I use an ATMEGA8 as I describe before. It has 6 ADC converters. I directly connect the VOut of LM35 to the ADC input of ATMEGA8. I use internal 2.56 V reference. I am not sure if I answer your question. If not please describe Gerhard.
Posts by SV1BDS
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OE3GBB LM35 TO92 for inside and outside environment temperature & LM35 TO220 for power supply and SSPA as TO220 permits thermal contact with heat sink. LM35 is very easy to implement in a microcontroller as it has Linear + 10-mV/°C Scale Factor. With 2.56 internal VREF you just strip the last 2 bits and you have C !!! Also is possible to just use a voltmeter !!!
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Hi,
A new sub project is under development. The requirement is telemetry for the WB uplink. An ATMEGA8 is used to read internal, external, power supply and SSPA temperatures , power output in Watts using the published RF probe, and current in A from ACS712 at 48V. The output is serial ASCII and will drive a Mikrotik router RS232 port. It will be available via WAN link via TCP/IP.
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Hi, I will try to create a new version with the option to measure the difference between the Tx and Rx. Maybe will be a standalone program. This program will be useful for some to eliminate frequency errors. Also as DVB-T usage to QO100 is only for experimentation and is not recommended as it is not as efficient as DVB-S2, a version with 1.2/2.4 GHz support for simplex or repeater usage is planned to created. Personal priority is to complete the WB station uplink. DVB-T development is second priority.
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I do not mean bw (lets assume 500 KHz) The difference between Tx and Rx frequency must not be greater than 2 KHz.
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SWL-Waleed if the receiving frequency is not within 2 KHz no constellation is possible for 500 KHz bw.
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SWL-Waleed it is critical the frequency differences. As I noted before for 500 KHz about 2 KHz is maximum.
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Hi,
Try to use DFU mode. Link
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Hi,
Just another Pluto in a shielded box.
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Hi,
A word around has be found. I increase the sweep time to 1 sec and the fatal error does not occur.
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Hi,
The HP8720C network analyser display this error and reboot when I enter full calibration menu. Any ideas? I have operation and service manual. Any one have calibration or hardware manual?
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Hi,
The version 6 of DVB-T Rx code. Now fixed sample rate 2M. Use with ratio 4 or bigger (4 for 500 KHz bw = default). RIT is immediate changing now. Spectrum is display now only after BPF. The hidden feature is that avoid receiving at center of spectrum (DC problem) that pilot tones exists. Expected performance improvement. F5OEO if anything can be done to help you improving your code please notify.
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Hi,
The Rx code.
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Hi,
Local DVB-T 64QAM Tx at UHF using only 25 KHz BW at 75 k using GNURADIO.
Important is that separate Tx (Pluto GPSDO)and Rx(RTL TCXO) units are used.
The required SNR is 30 dB (about S5). This mode permits to use video from 29 MHz and above.
The required accuracy is about 200 Hz.
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ON7NDR , ik1hgi Tony the rate for 500 KHz must be also 500. I hope soon to make a simplex QSO DVB-T between Greece and Italy.
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Hi,
Some photos from SV8RV transmitting via DATV Express and Pluto for Rx.
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Maybe my RF splitter has issue at 2.4Ghz...
Is it possible to provide the .grc to see blocks more clearly ?
For the moment I do not plan to give GRC. It is based on the examples provided with 3.7. My plans is to develop Python code and extend capabilities that GRC can not provide such as change at runtime ratio of sample rate or DVB T attributes.
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Yes I have noticed that your reception was not flat as the Tx signal is.
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Hi,
Some more notes: the +-2 KHz is for 500 KHz. Analogous for each bw. If you use the Pluto version may be there is interference from its own Tx. The Pluto version is still alpha version. Try 1st 500 KHz and then other speeds. 333 KHz seems not working (may be due that is really 333333). The time for constellation is analogous to the speed - bigger bw faster time to constellate.
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Hi Evariste,
First my compliments regarding your software !!!
Try to adjust RIT. It creates the 2nd constellation only +-2 KHz from the central frequency.
Keep me informed ...