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New Sanwa MT-44 4-channel 2.4GHz radio system

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New Sanwa MT-44 4-channel 2.4GHz radio system

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Old 12-29-2016, 05:06 AM
  #46  
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Does it seem odd that Banzai has the radio and 481/2 reciever combo less than the 471/2? I thought it would be the other way since the 481/2 have telemetry.
Also it looks like DeSoto has the radio with 482 in stock on their website so they should be available for the domestic shops soon.
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Old 12-29-2016, 06:39 AM
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the receivers ending in 2 have telemetry,

the difference between 48x and 47x is the shape
the 48x series has build in antenna, the 47x is the classic design with antenna
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Old 12-29-2016, 10:35 AM
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Also pulled the trigger on this as well... anyone sells hard case for this yet? prob not since radio is not even available yet at some stores.. thought I ask
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Old 12-29-2016, 10:40 AM
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Thanks a lot haplm
Just bought one thar is comming slowly as a turtle. O just like to read it while i wait.
Don t worry about the scanner!
Have a happy 2017!
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Old 12-29-2016, 11:19 AM
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Thinking about getting the MT44 or Futaba 4PV. Leaning towards the MT44, but Amain says it won't be available until mid Jan. Have you guys had success buying it from Banzai Hobby if you live in the U.S. or would you just wait? The Futaba looks good as well. Decisions...decisions.

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Old 12-29-2016, 11:28 AM
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Originally Posted by 1shnot View Post
Also pulled the trigger on this as well... anyone sells hard case for this yet? prob not since radio is not even available yet at some stores.. thought I ask
I've just ordered Sanwa 40th Anniversary Bag - one of the shops here had last one in stock. Not exactly hard case, but it should work. I will let you guys know how the transmitter fits once I get it.
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Old 12-29-2016, 11:32 AM
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Originally Posted by gacbora View Post
Thinking about getting the MT44 or Futaba 4PV. Leaning towards the MT44, but Amain says it won't be available until mid Jan. Have you guys had success buying it from Banzai Hobby or would you just wait? The Futaba looks good as well. Decisions...decisions.
I have bought it from Schumacher Racing in the UK (they are one of the two official distributors there). However, it is not yet available through their webshop (it should be soon).
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Old 12-29-2016, 03:57 PM
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Originally Posted by gacbora View Post
Thinking about getting the MT44 or Futaba 4PV. Leaning towards the MT44, but Amain says it won't be available until mid Jan. Have you guys had success buying it from Banzai Hobby if you live in the U.S. or would you just wait? The Futaba looks good as well. Decisions...decisions.
I preordered mine from AMain and they shipped it today.
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Old 12-29-2016, 10:15 PM
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Originally Posted by RoyB View Post
I preordered mine from AMain and they shipped it today.
What?! I asked them today when it would be available and they said not till mid Jan.
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Old 12-29-2016, 10:42 PM
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Originally Posted by gacbora View Post
What?! I asked them today when it would be available and they said not till mid Jan.
I was surprised to see the email today. Hopefully it wasn't a mistake.
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Old 12-29-2016, 10:48 PM
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I ordered from Banzai Hobby over the Christmas period when they had a sale, the MT-44 wasn't that much off, I think around $245 + Shipping with an RX-481, but it arrived yesterday without issue.

I'll be using it to race tomorrow night, but spent a few minutes setting it up with my cars already and I like it so far.

I'm a little concerned about the battery life considering it's 3 x AAA. I typically use Eneloop NiMH batteries, which are 750mAh. That's only a nominal of 2.7Wh of capacity, compared to the traditional 4 x AA @ 2,000mAh, giving a nominal of 9.6Wh... I'd be surprised if the MT-44 really used 3.5 times less power than the MT-S!

A few other interesting points to note are:

- The base is slightly offset, which makes it a bit better balanced because the wheel obviously sticks out one side.
- There is a rubber cover on the left side of the base, which looks like it could be for a charging port, but it's basically just a hole if you use the AAA battery caddy.
- There is a 1.01.09 firmware available on the Sanwa Japan website; apparently this improves the battery level indicator, and a few other things. Mine came with 1.01.03 out of the box.
- Out of the box, the language was set to English for mine, despite it having come from Japan. The MT-S that I had previously, wasn't like that.

If anyone would like any photos, let me know, I'd be happy to post them up.
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Old 12-29-2016, 11:22 PM
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The other thing I did as soon as I got my MT-44, was to compare response time to some other radios. I've been compiling a spreadsheet of this, along with some other information, and the results are enlightening to say the least!

In order to do the tests, I've been using a SkyRC ProgBox, which includes a PPM monitor feature. An understanding of how RC radios work is needed if you want to know what PPM is, so I'll cover that briefly first:
The standard servo signal that's used by 90% of surface servos is based on an on-off pulse. The width of that pulse determines the position of the servo, with 1.5ms pulse width being the standard for centered position. The maximum and minimum pulse widths usually seen are 2.4ms and 0.6ms, but we usually use less than this range because we need less than 90 degrees of motion in either direction. This concept is called Pulse Position Modulation, or PPM.

In the days of analog servos, the rate at which these pulses were sent to a servo was at around 60 times per second. This rate limits the response of the servo, because there is a period of nearly 16.67ms between pulses (1/60 = 16.67ms), so the latency of the system could never be less than 16.67ms.

Digital signal processing used in digital servos allowed the pulse rate to be increased, reducing latency. It should be clear then, that the faster the rate the pulses are sent, the quicker the servo (or ESC) can react to a change. The fastest radio systems based on the 1.5ms neutral pulse width have a pulse frequency of around 384Hz, which means that pulses are being sent at 2.6ms. (1/384 = 2.6ms).

The limiting factor now becomes the 1.5ms neutral pulse width, because this standard allows the pulse to be up to 2.5ms wide, and if the pulse rate were to be faster than every 2.6ms, the width of the pulse could cause an overlap!

For this reason, a new 'Narrow Pulse' standard is available, where the pulse width is 0.3ms wide at neutral. If we assume a similar range as the 1.5ms pulse width, the largest pulse width for a narrow pulse system would be somewhere just under 0.5ms. Theoretically then, it should be possible to build a radio system with a less than 1ms response time. I've not seen that yet, but I have a big hole in my data because I've not yet measured the M12 and M12S... Hopefully tomorrow night I'll get a chance.

Before I get to my results, I should state that I'm measuring the lowest theoretical response time of the radio system. The actual radio transmission adds no measurable latency, but there could be some processing in the transmitter and receiver. I'm not able to measure that, and not making any claims about that either. I would think however, looking at the trends in the data, that at least of the Sanwa / Airtronics kit, the processing is what limits the PPM rate, so this is probably a very accurate way of measuring latency.
On to the results then:
  • Sanwa MX-V: 63Hz / 15.9ms
  • Sanwa MT-4 (Normal Mode): 90Hz / 11.1ms
  • Sanwa MT-4 (SHR Mode): 192Hz / 5.2ms
  • Sanwa MT-4 (SSR Mode - Narrow Pulse): 191Hz / 5.2ms
  • Sanwa MT-4S (Normal Mode): 93Hz / 10.8ms
  • Sanwa MT-4S (SHR Mode): 383Hz / 2.6ms
  • Sanwa MT-S (FH4T Normal Mode): 95Hz / 10.5ms
  • Sanwa MT-S (FH4T SHR Mode): 384Hz / 2.6ms
  • Sanwa MT-S (FH4T SSR Mode - Narrow Pulse): 191Hz / 5.2ms
  • Sanwa MT-S (FH3 Normal Mode): 83Hz / 12.0ms
  • Sanwa MT-S (FH3 SHR Mode): 332Hz / 3.0ms
  • Sanwa MT-44 (FH4T Normal Mode): 95Hz / 10.5ms
  • Sanwa MT-44 (FH4T SHR Mode): 383Hz / 2.6ms
  • Sanwa MT-44 (FH4T SSR Mode - Narrow Pulse): 383Hz / 2.6ms
  • Sanwa MT-44 (FH3 Normal Mode): 83Hz / 12.0ms
  • Sanwa MT-44 (FH3 SHR Mode): 332Hz / 3.0ms
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Old 12-29-2016, 11:32 PM
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I'm cautious to draw too many conclusions from the data, but I'll state what I think I can see:

- The MT4-S is indeed faster than the MT-4, across the board in fact, with a fast as you can get with 1.5ms neutral pulse width speed of 2.6ms
- The MT-S is basically the same performance as the MT-4S, and though it is the replacement of the MT-4, performance wise, it's the equal of the MT-4S
- Oddly, the SSR mode in the MT-S appears to be slower than SHR mode. I can understand the MT-4 result here, because the radio seems limited to ~191Hz for both SHR and SSR, but that isn't the case for the MT-S. I'll try to measure the MT-4S in SSR mode tomorrow and see if this has similar results. I wonder if this has been deliberately 'hobbled' to make the M12 more competitive!
- The MT-44 is only faster than the MT-S in SSR mode, which is un-usable for most servos (and ESCs). The MT-44 is undoubtedly a nicer radio than the MT-S, but just don't expect any performance benefit unless you're using a narrow pulse servo
- FH4T Mode is faster than FH3, which appears to be limited to 3.0ms in SHR mode

As I said, still a few holes in the data. I'm really hoping to see the M12 and M12S have faster pulse rate in SSR mode. There's room for improvement there, but I've not seen a compelling reason to use SSR mode in all the testing that I've done so far.
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Old 12-30-2016, 12:19 AM
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Originally Posted by Nezil View Post
I'm cautious to draw too many conclusions from the data, but I'll state what I think I can see:

- The MT4-S is indeed faster than the MT-4, across the board in fact, with a fast as you can get with 1.5ms neutral pulse width speed of 2.6ms
- The MT-S is basically the same performance as the MT-4S, and though it is the replacement of the MT-4, performance wise, it's the equal of the MT-4S
- Oddly, the SSR mode in the MT-S appears to be slower than SHR mode. I can understand the MT-4 result here, because the radio seems limited to ~191Hz for both SHR and SSR, but that isn't the case for the MT-S. I'll try to measure the MT-4S in SSR mode tomorrow and see if this has similar results. I wonder if this has been deliberately 'hobbled' to make the M12 more competitive!
- The MT-44 is only faster than the MT-S in SSR mode, which is un-usable for most servos (and ESCs). The MT-44 is undoubtedly a nicer radio than the MT-S, but just don't expect any performance benefit unless you're using a narrow pulse servo
- FH4T Mode is faster than FH3, which appears to be limited to 3.0ms in SHR mode

As I said, still a few holes in the data. I'm really hoping to see the M12 and M12S have faster pulse rate in SSR mode. There's room for improvement there, but I've not seen a compelling reason to use SSR mode in all the testing that I've done so far.
Excellent work! Your results confirm what I "felt" with the MX-V vs. MT-4S vs. MT-S that I've owned, but it's really nice to see the data rather than just guess off of feel.
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Old 12-30-2016, 07:23 AM
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Originally Posted by Nezil View Post
The other thing I did as soon as I got my MT-44, was to compare response time to some other radios. I've been compiling a spreadsheet of this, along with some other information, and the results are enlightening to say the least!

In order to do the tests, I've been using a SkyRC ProgBox, which includes a PPM monitor feature. An understanding of how RC radios work is needed if you want to know what PPM is, so I'll cover that briefly first:
The standard servo signal that's used by 90% of surface servos is based on an on-off pulse. The width of that pulse determines the position of the servo, with 1.5ms pulse width being the standard for centered position. The maximum and minimum pulse widths usually seen are 2.4ms and 0.6ms, but we usually use less than this range because we need less than 90 degrees of motion in either direction. This concept is called Pulse Position Modulation, or PPM.

In the days of analog servos, the rate at which these pulses were sent to a servo was at around 60 times per second. This rate limits the response of the servo, because there is a period of nearly 16.67ms between pulses (1/60 = 16.67ms), so the latency of the system could never be less than 16.67ms.

Digital signal processing used in digital servos allowed the pulse rate to be increased, reducing latency. It should be clear then, that the faster the rate the pulses are sent, the quicker the servo (or ESC) can react to a change. The fastest radio systems based on the 1.5ms neutral pulse width have a pulse frequency of around 384Hz, which means that pulses are being sent at 2.6ms. (1/384 = 2.6ms).

The limiting factor now becomes the 1.5ms neutral pulse width, because this standard allows the pulse to be up to 2.5ms wide, and if the pulse rate were to be faster than every 2.6ms, the width of the pulse could cause an overlap!

For this reason, a new 'Narrow Pulse' standard is available, where the pulse width is 0.3ms wide at neutral. If we assume a similar range as the 1.5ms pulse width, the largest pulse width for a narrow pulse system would be somewhere just under 0.5ms. Theoretically then, it should be possible to build a radio system with a less than 1ms response time. I've not seen that yet, but I have a big hole in my data because I've not yet measured the M12 and M12S... Hopefully tomorrow night I'll get a chance.

Before I get to my results, I should state that I'm measuring the lowest theoretical response time of the radio system. The actual radio transmission adds no measurable latency, but there could be some processing in the transmitter and receiver. I'm not able to measure that, and not making any claims about that either. I would think however, looking at the trends in the data, that at least of the Sanwa / Airtronics kit, the processing is what limits the PPM rate, so this is probably a very accurate way of measuring latency.
On to the results then:
  • Sanwa MX-V: 63Hz / 15.9ms
  • Sanwa MT-4 (Normal Mode): 90Hz / 11.1ms
  • Sanwa MT-4 (SHR Mode): 192Hz / 5.2ms
  • Sanwa MT-4 (SSR Mode - Narrow Pulse): 191Hz / 5.2ms
  • Sanwa MT-4S (Normal Mode): 93Hz / 10.8ms
  • Sanwa MT-4S (SHR Mode): 383Hz / 2.6ms
  • Sanwa MT-S (FH4T Normal Mode): 95Hz / 10.5ms
  • Sanwa MT-S (FH4T SHR Mode): 384Hz / 2.6ms
  • Sanwa MT-S (FH4T SSR Mode - Narrow Pulse): 191Hz / 5.2ms
  • Sanwa MT-S (FH3 Normal Mode): 83Hz / 12.0ms
  • Sanwa MT-S (FH3 SHR Mode): 332Hz / 3.0ms
  • Sanwa MT-44 (FH4T Normal Mode): 95Hz / 10.5ms
  • Sanwa MT-44 (FH4T SHR Mode): 383Hz / 2.6ms
  • Sanwa MT-44 (FH4T SSR Mode - Narrow Pulse): 383Hz / 2.6ms
  • Sanwa MT-44 (FH3 Normal Mode): 83Hz / 12.0ms
  • Sanwa MT-44 (FH3 SHR Mode): 332Hz / 3.0ms
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