jrcoxx

Arnold

Would you please provide some additional information that is not on your website?

1) What is the frequency used by the transmitter?
2) Can the frequency be changed by the user?
3) What it the rated power output of the transmitter?
4) What is the Receiver Sensitivity?
5) Is there a Security Coding or other method to prevent another unit or spurious transmission from activating my reciever?
6) How was the range capability of "Over 1 Mile Range" deterimined?
7) Is there a removeable safety interlock on the transmitter?

John

Art Upton

I saw this posted John:

General Specifications
Operating Temperature: -4° to +140° F (-20° to +60° C)
Receiver Type: Superheterodyne
Sensitivity: -118 dB (minimum)
Selectivity: 6 KHz
Carrier Frequency: 27,255 MHz
Number of Codes: 65,536
Code Setting Method: DIP switch programming
Antenna Impedance: 50 Ohms
Range Manufacturer specs 2 miles. SWT tested 1 mile city
Interlock Magnetic key

Steve_Shannon

Shouldn't that be a period in the carrier frequency? (Or are they using the comma as the decimal place holder like some other places do?)

jrcoxx

Thanks Art,
The information posted on the Space Warp website was after I posted my questions. The thing that concerns me the most is safety with any launch system. In this case, I did not see adequate information in the initial news article or the website. I still have many reservations considering the design.

1) The Magnetic interlock key is on the receiver. I readily agree that the reciever should have a safety shut off while any one is at the pad. However there should be an Interlock at the transmitting site as well.

2) The pad cables are 12' long. This is a remote system capable of launching High powered rockets (why else would I be interested in the posting on Rocketry Planet). This means that "as is" when a user arms the receiver with the Magnetic interlock, he is then 12' from what ever size HPR motor. (seems kind of wrong for a system that is $1499)

3) Why do many of the vendors in the hobby lead marketing statements "No Amateur Radio License Required". Ok if a Ham license is not required, then what is the FCC compliance of this system?

Say I wonder what the Booster Vision guys use for licensing or compliance? Oh wait there is a statement on the BoosterVision site that the receiver is a consumer use item and no license is required, FCC Certified. However the transmitters require a license. Well it would appear that BoosterVision is OK.

There are other Wireless launch systems available and I have similar "safety" concerns about their designs also. However this is a very expensive offering, the product quality and information should match the price. But you know, according to the manufacture this device is "Designed for the Serious Rocket Scientists" and "$h!t Happens"

John

Art Upton

Hi John,

I simply posted what I saw on the website, sorry; I was only posting as a public service

Our license free transmiters have an FCC-ID certification number.
We also sell license required units.

I have NO CONNECTION to Spacewarp.

My guess as of reading this again is 27.255 is one of the channels legal for use of remote control in the CB band, at least it was in the 70s when I fixed them as a kid with my FCC Radiotelephone permit.

I am assuming Spacewarp is using an FCC certified 27.255 transmiter since they make the license free claim.

As for other wireless systems, if you claim license free, you need an OEM unit that carries the certs along with it. Many OEMS have them for sale. One of my favorite for data circuits is Maxstream Radio moduals.

denverdoc

First I have no affiliation with any company involved or any potentially competing with the Space Warp unit. Since the range is intended to be up to a mile, one would assume it is intended for VERY LARGE motors/projects. Why wireless relay systems seem to be tricky is beyond me, but almost every time at Balls I've seen one tried, there have been issues. Presumably for 1500 bucks there are none with this one.

Not being a radio engineer, I don't have the kind of in depth knowledge required to properly critique the unit, but the technology does seem a bit long in tooth. For this kind of money, i would hope to see a DSS unit that is completely encrypted, like the state of the art staging and deployment devices offered by say Jim Amos at Missile Works.

Along with john coxx, i'm also a little leery of relying on a reed swich to prevent unplanned ignition. While the open circuit resistance of these are very high IIRC, they can be jostled and if a gust of wind were to take down the rocket, might it be possible to have a very large and fire breathing land shark on the loose? I don't know but I think its a fair question. I would rather see encrypted receivers both inside the rocket and at the battery site. But again details are a bit sparse. Maybe the manufacturer can comment.

rocketman28

where can I buy these?

denverdoc

What are "these"?

UncleVanya

Do you mean this: http://www.spacewarptechno...WT/SWTD1P4L/SWTD!P4L.htm

If so follow the link in the page to email them for more info.

Arnold Roquerre

The web page was not updated as quickly as I had hoped. It has now been updated. Hopefully, the update answers most questions. I have responded to some questions below:




1) The Magnetic interlock key is on the receiver. I readily agree that the receiver should have a safety shut off while any one is at the pad. However there should be an Interlock at the transmitting site as well.

===================================
The system comes with two interlocks: one on the transmitter and one on the receiver side.
===================================


2) The pad cables are 12' long. This is a remote system capable of launching High powered rockets (why else would I be interested in the posting on Rocketry Planet). This means that "as is" when a user arms the receiver with the Magnetic interlock, he is then 12' from what ever size HPR motor. (seems kind of wrong for a system that is $1499)


===================================
Actually no, system initialization requires all cables to be powered up and the piezo buzzer of each line activated to confirm each line and buzzer is working. After initialization of the entire system, the transmitter interlock is disconnected and the transmitter once more tested to verify the lines can not be activated. Again, all lines must have been verified to work and then silenced. The transmitter interlock has to be activated and verified to be dead. The timer power disconnect is to be activated before attaching the cables to anything. Once the timer has been set for 1 to 15 minutes, the user has that much time to attach the cables. The timer can be reset as often as necessary until done. Optionally, one can use the receiver's magnetic interlock to power off the receiver and then use the timer before powering the unit back up to ensure no accidental firing while near the launch site. Since standard extension cords are used, one can attach a longer extension cord to increase length. .
===================================


3) Why do many of the vendors in the hobby lead marketing statements "No Amateur Radio License Required". Ok if a Ham license is not required, then what is the FCC compliance of this system?

===================================
The transmitter and receiver are produced by another company. The unit is FCC compliant. The unit has a 10 mile plus advertised range with appropriate antennas which SWT does not sell or recommend. .
===================================

However this is a very expensive offering, the product quality and information should match the price. But you know, according to the manufacture this device is "Designed for the Serious Rocket Scientists" and "$h!t Happens"


===================================
A very nice and inexpensive system anyone can build is referenced on the web page. Yes $hit does happen which is why the unit has three safety systems to prevent accidental launching. In short, an accidental launch is not likely. What is more likely is a ladder falling on a launch control of a non-remote control launch system causing a premature launch of a very big rocket. I believed this type of situation happened last year. .
===================================

denverdoc

Arnold,

Thanks for the clarification. I think it goes a long way to satisfying the concerns expressed.

Arnold Roquerre

The SWTD1P4 has been designed to be simple to use, safe and reliable. Needless complexity guarantees problems which this unit has been designed to avoid. The timer shuts all power off for the duration the user selects 1 - 15 minutes. This features ensures the unit cannot activate, period. The piezo buzzers activate whenever the cable is powered up, to ensure they are never used while hot. The initialization procedure ensures that everything is operational and set correctly before the cables are attached to anything other than the SWTD1P4.

Not being a radio engineer, I don't have the kind of in depth knowledge required to properly critique the unit, but the technology does seem a bit long in tooth. For this kind of money, i would hope to see a DSS unit that is completely encrypted, like the state of the art staging and deployment devices offered by say Jim Amos at Missile Works.

The transmitter and receiver were picked for simplicity, reliability, robustness and range on the ground. The assumptions are that the unit will be in very hostile environments that are dirty, hot, cold and wet; dropped and banged often and subject to abuse.


Along with john coxx, i'm also a little leery of relying on a reed swich to prevent unplanned ignition. While the open circuit resistance of these are very high IIRC, they can be jostled and if a gust of wind were to take down the rocket, might it be possible to have a very large and fire breathing land shark on the loose? I don't know but I think its a fair question. I would rather see encrypted receivers both inside the rocket and at the battery site. But again details are a bit sparse. Maybe the manufacturer can comment.

Arnold Roquerre

Yes, there should be a period. The comma was a typo.

jrcoxx

Arnold

My comments were based on a lack of information provided in the initial press release and the accompaning link to the product website. Without the appropriate technical specifications and safety information we (the potiential customers) are left to make our own assumptions.

Having a multiple shut-off, interlocks, shunts or whatever are a great idea as long as they are utilized. I do not understand your description of the Timer shut off. What I'm understanding you to say is that when I arrive at the pad (Unit is set up and already initialized) I should set a timer for up to 15 minutes. Appereantly this is to turn off the power while I am at the pad setting up my rocket ("The timer shuts all power off for the duration the user selects 1 - 15 minutes").

If the power is off to everything great, but what if I exceed 15 minutes and forget to reset the timer while I'm prepping my rocket at remote pad? Does the remote launch system power itself back on and re-initialize? (Hopefully I remembered to remove the magnetic interlock at the pad, a second required step). This appears to be an added complexity that I would not want to be thinking about when I prepping a complex or large project at an away pad.

It would make sense to me that the Timer is only set prior to re-arming the reciever after everything (all rockets) are configured on all of the pads AND Ready to Launch. Then I (and others) have 15 minutes to move away before the pad area goes "Hot". Note: This may not make sense to many launch locations, but could be an idea to consider at locations such as Black Rock or Lucerne with very large, multi-stage/clustered projects.

Most of the other wireless launch controllers that I have reviewed are using 300mhz and higher bands, the idea to use 27.255mhz equipment may actually perform better at long ranges (5k to 6k feet) and various terrain conditions. The FCC regulations for remote control with this frequency allow for higher transmitter outputs (up to 25 watts) and external antennas.
(google 27.255 remote control for more information)

On your web page product statement, instead leading with "No Amateur Radio License Required", why not lead with a positive statement about your product? Example "Four Channel Wireless Launch Controller" Then later in your specifications, list that this is an FCC approved OEM device and licensing is not required. Sell the positive, not a negative. If you have a User Guide, setup information or documentation; post it where the customer is able to use the information. Why make us hunt and ask for it?

Last, the website ( http://www.spacewarptechno...WT/SWTD1P4L/SWTD!P4L.htm ) is extremely slow to open fully. I am assuming that this is due to the file size of the photos. While I do have a "low" bandwidth broadband connection, it takes almost 5 minutes for this website to load on my PC. I cannot image what it would be like if I had a 56k modem.

Good luck with your product
John

Arnold Roquerre

Thanks, I appreciate the input!

Having a multiple shut-off, interlocks, shunts or whatever are a great idea as long as they are utilized.

There is no choice. The interlocks have to be used to turn on the electronics.

I do not understand your description of the Timer shut off. What I'm understanding you to say is that when I arrive at the pad (Unit is set up and already initialized) I should set a timer for up to 15 minutes before arming the motor and/or NOX & LOX solenoids . Appereantly this is to turn off the power while I am at the pad setting up my rocket ("The timer shuts all power off for the duration the user selects 1 - 15 minutes").

If the power is off to everything great, but what if I exceed 15 minutes and forget to reset the timer while I'm prepping my rocket at remote pad? Does the remote launch system power itself back on and re-initialize? The initalization procedure insures everything is ready for a new launch. Electronics can break and still work, so the initialization procedure which takes the user a few minutes is requred. Sort of a "do not look into the barrell of a gun until you verify the chamber is empty and the clip is out and the trigger has been pulled while aiming at the floor - not your foot" routine.

How safe is safe? You set the timer, so you know how long you have. It can be reset. Even if it counts down to zero and powers up the relays, nothing will happen until the launch button is pressed. The magnetic key has to be inserted for that to happen. Since the initialization procedures were followed, everthing is technically off waiting for the relay activation from the control receiver.

(Hopefully I remembered to remove the magnetic interlock at the pad, a second required step). This why each line has an embedded piezo buzzer. You know the line is active simply because it is buzzing. You can hear the buzzer(s) up to 50' away.This appears to be an added complexity that I would not want to be thinking about when I prepping a complex or large project at an away pad.
It really isn't much complexity. It is simply one last layer of safety. A 30 minute timer was tried, but it seemed too long, so a 15 minute timer was used. Normally, attaching launch leads is the last step on engages in before leaving the area. You do not want to be next to an R motor and have it fired up. Perhaps in a Jackass 3 movie!

It would make sense to me that the Timer is only set prior to re-arming the reciever after everything (all rockets) are configured on all of the pads AND Ready to Launch.
The SWTD1P4L is really for large motors and is not a club launcher. A club version would have a 30 minute timer and come with 8 lines.There would be a warning siren that power up would begin in two minutes once the timer was at zero. Then I (and others) have 15 minutes to move away before the pad area goes "Hot". Note: This may not make sense to many launch locations, but could be an idea to consider at locations such as Black Rock or Lucerne with very large, multi-stage/clustered projects.

Most of the other wireless launch controllers that I have reviewed are using 300mhz and higher bands, the idea to use 27.255mhz equipment may actually perform better at long ranges (5k to 6k feet) and various terrain conditions. Long wave definetly out performs short wave at ground level. The FCC regulations for remote control with this frequency allow for higher transmitter outputs (up to 25 watts) and external antennas.
(google 27.255 remote control for more information)

On your web page product statement, instead leading with "No Amateur Radio License Required", why not lead with a positive statement about your product? Example "Four Channel Wireless Launch Controller" Good point! The reason I had done this was because most no amateur license system simply do not have ground range. I will have that wording changed.Then later in your specifications, list that this is an FCC approved OEM device and licensing is not required. Sell the positive, not a negative. If you have a User Guide, setup information or documentation; post it where the customer is able to use the information. Why make us hunt and ask for it? Good point! Honestly, the user manual will be short, but I will have it added.

Last, the website ( http://www.spacewarptechno...WT/SWTD1P4L/SWTD!P4L.htm ) is extremely slow to open fully. I am assuming that this is due to the file size of the photos. While I do have a "low" bandwidth broadband connection, it takes almost 5 minutes for this website to load on my PC. I cannot image what it would be like if I had a 56k modem. Yeah, bandwidth is a problem. Sort like when the old rotary phones were being phased out. Do you design you system to work with rotory are not. Maybe, I will have a page made for cell phones which should load faster on slow lines.

Good luck with your product
Appreciated

denverdoc

Arnold, I just wanted to thank you again--it is really a class act to step up as the designer/manufacturer and take the time to address questions/comments in detail as you have. I also wish you best of luck.

UhClem

Bad example. The phone system will still accept pulse dialing although if you encounter a machine on the other end that insists that you "press one now", you could have trouble.

Instead of shoehorning the full size version of the images into each tiny window, it would be far better to load just a 250X187 pixel thumbnail. Leaving the full size (2848X2136) image to be loaded only if requested.

jsdemar

Why is it so expensive?

Why do you need a timer? What is the vulnerability of the system you are protecting against?