Max radar return range on VS mode?

[dresoccer4]

Wondering what the max radar return range on VS mode is? I am at FL32 with a 747 90nm in front of me. At what point should my VS radar pick it up and show me?

[_Hoss]

It depends on its Duty Cycle...........

Peak- and Average Power

The energy content of a continuous-wave radar transmission may be easily figured out because the transmitter operates continuously. However, pulsed radar transmitters are switched on and off to provide range timing information with each pulse. The amount of energy in this waveform is important because the maximum range is directly related to the transmitter output power. The more energy the radar system transmits, the greater the target detection range will be. The energy content of the pulse is equal to the peak (maximum) power level of the pulse multiplied by the pulse width. However, meters used to measure power in radar systems do so over a period that is longer than the pulse width. For this reason, pulse-repetition time is included in the power calculations for transmitters. Power measured over such a period is referred to as average power.

Duty cycle

D =

P

=

τ

where:

P = average power Pi = pulsed power τ = pulse width Τ = pulse-repetition time PRT

The product of pulse width (τ) and pulse-repetition frequency (PRF) as the reciprocal of the pulse period (Τ) in the above formula is called the duty cycle of the radar system. The duty cycle is the fraction of time that a system is in an “active” state. In particular, it is used in the following contexts: Duty cycle is the proportion of time during which a component, device, or system is operated. Suppose a transmitter operates for 1 microsecond and is shut off for 99 microseconds, then is run for 1 microsecond again, and so on. The transmitter runs for one out of 100 microseconds, or 1/100 of the time, and its duty cycle is therefore 1/100, or 1 percent. The duty cycle is used to calculate both the peak power and average power of the radar system.

For the performance of radar, an average power has more significance than the pulse power of the transmitter. Since the introduction of intrapulse modulation and pulse compression, there is no longer any proportionality between pulse power and maximum range.

The Interference Blanker Unit (IBU) in the Hornet is what controls the TX/RCV time for all RF systems in the Hornet, or their Duty Cycle.

 

Hoss

 

[dresoccer4]

17 minutes ago, _Hoss said:

It depends on its Duty Cycle...........

Peak- and Average Power

The energy content of a continuous-wave radar transmission may be easily figured out because the transmitter operates continuously. However, pulsed radar transmitters are switched on and off to provide range timing information with each pulse. The amount of energy in this waveform is important because the maximum range is directly related to the transmitter output power. The more energy the radar system transmits, the greater the target detection range will be. The energy content of the pulse is equal to the peak (maximum) power level of the pulse multiplied by the pulse width. However, meters used to measure power in radar systems do so over a period that is longer than the pulse width. For this reason, pulse-repetition time is included in the power calculations for transmitters. Power measured over such a period is referred to as average power.

Duty cycle

D =

P

=

τ

where:

P = average power Pi = pulsed power τ = pulse width Τ = pulse-repetition time PRT

The product of pulse width (τ) and pulse-repetition frequency (PRF) as the reciprocal of the pulse period (Τ) in the above formula is called the duty cycle of the radar system. The duty cycle is the fraction of time that a system is in an “active” state. In particular, it is used in the following contexts: Duty cycle is the proportion of time during which a component, device, or system is operated. Suppose a transmitter operates for 1 microsecond and is shut off for 99 microseconds, then is run for 1 microsecond again, and so on. The transmitter runs for one out of 100 microseconds, or 1/100 of the time, and its duty cycle is therefore 1/100, or 1 percent. The duty cycle is used to calculate both the peak power and average power of the radar system.

For the performance of radar, an average power has more significance than the pulse power of the transmitter. Since the introduction of intrapulse modulation and pulse compression, there is no longer any proportionality between pulse power and maximum range.

The Interference Blanker Unit (IBU) in the Hornet is what controls the TX/RCV time for all RF systems in the Hornet, or their Duty Cycle.

 

Hoss

 

thanks for the reply, although i probably understood 15% of what you said

[Mike_Romeo]

23 hours ago, dresoccer4 said:

At what point should my VS radar pick it up and show me?

It depends

[Napillo]

I've seen it get about 70nm range, for a target that large.

[dresoccer4]

16 hours ago, Napillo said:

I've seen it get about 70nm range, for a target that large.

thanks. my brain can't handle all the science behind it. i did get an 80nm ping but it worked in VS, TWS, and RWS. I didn't see VS as having further distance luck in my little experiment

[Tinchus2009]

The theroy is very nice and I think we all thank you for posting such knowledge, really. But that is not answering the question, I think the question is targeted to DCS, and that theory seems not be working in the last updates. VS is not picking any contact for F16, F18 at 50nm and it should. last night , head to head aprouch, I could peak any contact on VS for a F16 anf F18 and I was already hard locked.... nd I hardly clould take the contact on RWS with target still locking me at 42 NM
Have you n otice such downgrade on radar perfomance?