ISRO developing TWTA for space-borne payloads

[Ryuzaki]

BENGALURU: The Indian Space Research Organisation is indigenously developing Traveling Wave Tube Amplifier (TWTA) for space borne payloads.

TWTA is commonly used in satellite communication links, earth observation payloads, scientific missions or probes and inter-spacecraft communications links. It consists of Electronic Power Conditioner (EPC) and Traveling Wave Tube (TWT)

TWT is a complex multidisciplinary technology involving controlled interaction of microwave with electron beam under ultra high vacuum.

ISRO said its Space Applications Centre has developed space qualified C-Band TWTA for space borne applications, jointly with the Central Electronics Engineering Research Institute (CEERI), Pilani.

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[ShankaraBharanam]

This is good news. What it tells us is that ISRO is looking at high speed satellite communication in K, ka, Ku band.

or it could be used for our lunar mission. Nice.

 

[mehboobkz]

TWTAs are generally used in communication satellite transponders, that relay & amplify radio telecommunications signals through it, to transform the weak (input) signal into a high (output) power one.

ISRO has come up with C Band TWT that go into direct broadcast TV, video and data transmission services via satellite, hitherto imported from Thales.


Thales produces up to maximum 125 watts output, whereas India has not specified the max wattage it has gone into production.

Now KU band in progress.

 

[ShankaraBharanam]

TWTAs are generally used in communication satellite transponders, that relay & amplify radio telecommunications signals through it, to transform the weak (input) signal into a high (output) power one.

ISRO has come up with C Band TWT that go into direct broadcast TV, video and data transmission services via satellite, hitherto imported from Thales.


Thales produces up to maximum 125 watts output, whereas India has not specified the max wattage it has gone into production.

Now KU band in progress.

All amplifiers uprate weak signal to strong signal. But TWTA have very low noise output. They are useful in the Ka band since solid state amplifiers are not efficient nor can they output much power beyond 15 GHz.

 

[mehboobkz]

All amplifiers uprate weak signal to strong signal. But TWTA have very low noise output. They are useful in the Ka band since solid state amplifiers are not efficient nor can they output much power beyond 15 GHz.

 

[ShankaraBharanam]

View attachment 303005

LOL..... Solid State power amplifiers have a frequency band limit genius. At higher freq. they have too much noise and their gain drops off as the freq. increases. For high power requirements TWT's are always chosen.

 

[mehboobkz]

LOL..... Solid State power amplifiers have a frequency band limit genius. At higher freq. they have too much noise and their gain drops off as the freq. increases. For high power requirements TWT's are always chosen.

Even for low power = 20-30 W
Because the typical dB gain is in the same range; that is 48-53 - Irrespective of low or high wattage.

 

[ShankaraBharanam]

Even for low power = 20-30 W
Because the typical dB gain is in the same range; that is 48-53 - Irrespective of low or high wattage.

What gave you the idea that 20-30 W is "low power" ? That is pretty high power on any scale.

The average cell phone tower output is less than 1 W. Its usually 500-600 mW.

dB gain is directly proportional to Wattage. What do you mean the gain is independent of wattage ? are you reinventing physics ? We are talking about signal amplifiers, not power amplifiers.

 

[mehboobkz]

What gave you the idea that 20-30 W is "low power" ? That is pretty high power on any scale.

The average cell phone tower output is less than 1 W. Its usually 500-600 mW.

dB gain is directly proportional to Wattage. What do you mean the gain is independent of wattage ? are you reinventing physics ? We are talking about signal amplifiers, not power amplifiers.

No company makes C band TWT amplifiers below 20 W....As for as Satellite Transponders are concerned. If you you use 5 W of power....Signals wont reach mother earth.

And do not compare cell towers, each of which cater to paltry 50 Km range.

This is from Thales.

 

[ShankaraBharanam]

No company makes C band TWT amplifiers below 20 W....As for as Satellite Transponders are concerned. If you you use 5 W of power....Signals wont reach mother earth.

And do not compare cell towers, each of which cater to paltry 50 Km range.

This is from Thales.
View attachment 303031

Where did C band TWT come into the picture ? we are talking about Ka band. Also a 5 W power would indeed reach earth, an generation ago that was the transmit power of satellites. You compensate for it by having sensitive receivers and fixed satellite service and lower antenna gain.

Satellite signal power requirements would depend upon the type of satellite, the frequency band, and data rate. For LEO 5 W would be sufficient since they are only 1000 km above earth.

Cell towers emit enough power to give your cancer. A Power line carries only 1 W.

GEO carries transponders of much higher frequency so their Power acquirements are much higher too since Power and frequency are directly proportional and the orbit being inversely proportional.

 

[mehboobkz]

Where did C band TWT come into the picture ? we are talking about Ka band. Also a 5 W power would indeed reach earth, an generation ago that was the transmit power of satellites. You compensate for it by having sensitive receivers and fixed satellite service and lower antenna gain.

Satellite signal power requirements would depend upon the type of satellite, the frequency band, and data rate. For LEO 5 W would be sufficient since they are only 1000 km above earth.

Cell towers emit enough power to give your cancer. A Power line carries only 1 W.

GEO carries transponders of much higher frequency so their Power acquirements are much higher too since Power and frequency are directly proportional and the orbit being inversely proportional.

Because of the topic:

ISRO developing TWTA for space-borne payloads

ISRO said its Space Applications Centre has developed space qualified C-Band TWTA for space borne applications, jointly with the Central Electronics Engineering Research Institute (CEERI), Pilan


Why you should maintain the luxury to talk of other bands and thereby go off topic?

 

[ShankaraBharanam]

Because of the topic:

ISRO developing TWTA for space-borne payloads

ISRO said its Space Applications Centre has developed space qualified C-Band TWTA for space borne applications, jointly with the Central Electronics Engineering Research Institute (CEERI), Pilan


Why you should maintain the luxury to talk of other bands and thereby go off topic?

My bad, I thought ISRO was working on TWTA for K Band. But I guess C Band is good too. Its good for high speed Mobile Satellite Service. Hopeful the next satellite will have a much higher data rate.