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Dual Purpose: Mallincam AND Wireless - HOW?

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#26 Jack Huerkamp

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Posted 27 December 2007 - 08:18 AM

As pointed out by ccs_hello, the FCC licenses the use of wireless transmission devices and regulates their use. In checking with a representative of The VFM Store where I and several others have obtained high powered video transmission devices, the 1.2 GHz units do NOT have FCC approval. The 2.4 GHz units DO. However, operators of units that have power outputs equal to or exceeding 50mW need to secure an FCC license to operate them. All of the 2.4 GHz units sold by The VFM Store require FCC licensing for legal operation.

Jack

#27 jayscheuerle

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Posted 27 December 2007 - 09:59 AM

Unfortunately for our usage, most compression schemes (like MPEG2) show the most artifacts in areas of subtle contrast and gradation, which are the defining characteristics of most DSOs. These darker, softer areas are also the ones that are problematic for most lower end LCD displays (or older ones in general), which tend not to have the range of displayable values and colors that CRTs do.

#28 b1gred

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Posted 27 December 2007 - 10:22 AM

I'm going to chime in with ccs and Jack on this topic.

Operating these devices which require FCC licenses without being licensed is risking a lot of your hard earned cash and potentially even your freedom.

Can you get away with it? Maybe. Just like you can get away with speeding.

Will you get away with it? Maybe.

How would you get caught? IF the device you operate without a license on a frequency and at a power that requires one, chances are there's another entity who IS operating legally, with a licence - and possibly providing a service for which they are paid. If your operation interferes with them and they report you (which they probably would), you will probably get caught.

Think about it long and hard, is it worth the $10k (per offense) or even possible jail time? The FCC is not going to care why you're operating such a unit, or who you are, or that it's a hobby.

#29 Jack Huerkamp

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Posted 27 December 2007 - 11:10 AM

So this raises a new question. Is there a wireless video transmitter that:

1. Is FCC certified
2. Has less than 50 mW of power
3. Provides good quality video transmission
4. Provides it over an acceptable range?

Jack

#30 greg

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Posted 27 December 2007 - 01:33 PM

Is there anyone using the wireless units that have Antenna's that have to be aimed at each other? The antenna's look like small dishes??? The reason I ask is last night I found a few on-line that advertised S-Video connections. There was not very much info. on the format or if they used MPEG-2 or not, but they where less expensive leading me to believe that they may not be compressing the image like MPEG-2.
I will be trying my MPEG-2 system with my new 9" CRT and my 50" DLP TV, first with the wireless MPEG-2 and then hard wired with S-video, so I can compare the two.

Greg

#31 jayscheuerle

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Posted 27 December 2007 - 01:55 PM

Alternatively, you can find 100' of S-Video cable for under $60 (and up to $150) if you want to run a long-distance, wired connection.

#32 midway199

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Posted 27 December 2007 - 01:58 PM

I purchased a 5.8 GHz unit from B&H a while ago:

http://www.bhphotovi...z_Wireless.html


I was not impressed and ended up returning it. I had to work a lot harder than I thought I should to get them aimed at each other for a clean transmission. I literally tinkered with it off and on for hours. Perhaps something was interfering? Once I got it right, things seemed fine, but it took quite a bit of tinerking and they were only about 8 feet apart. Lots of static, crackling, and popping to get to that point. I was testing with digital video cameras and my XBox. And considering I will be setting things up and taking them apart for some time, I didn't think I'd care to go through this with each and every viewing session. Very time consuming.

That's been my experience. YMMV. I'm sure I'll revisit wireless someday, because I also want to do serial bluetooth to the hand controller (which I have had success with on my Meade LXD-55 mount), but am content with the simplicity and clean signal of a cable for now.

#33 jpniewski

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Posted 27 December 2007 - 06:43 PM

How about a laptop at the scope with a wireless router. S-video into the laptop's video card. 802.11g wireless routers/cards have huge data transfer rates, hundreds of feet of transfer range, no FCC issues. You get a screen at the scope, the ability to drive the scope mount with a planetarium program and wireless video. Used laptops are no more expensive than some of the wireless video equipment being talked about.

Joe

#34 CarolG

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Posted 27 December 2007 - 08:52 PM

I think that's the route I've decided to take. I've got a wireless router and plan to use the remote desktop feature on my indoor computer to run my laptop that's with the scope. I've tested the remote desktop feature a little, but have yet to use it to control my scope. Part of the problem is remotely adjusting camera settings and focusing. I did order a cable that works on the GSTAR-EX and is supposed to work on the Mallincam to control the camera settings via computer. I guess a motorized focuser is next on my wish list.

#35 ccs_hello

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Posted 27 December 2007 - 09:10 PM

How about a laptop at the scope with a wireless router. S-video into the laptop's video card. 802.11g wireless routers/cards have huge data transfer rates, hundreds of feet of transfer range, no FCC issues. You get a screen at the scope, the ability to drive the scope mount with a planetarium program and wireless video. Used laptops are no more expensive than some of the wireless video equipment being talked about.

Joe


Joe,

great idea! Thinking outside the box.

Actually, IMHO, I think in this situation under many constraints, there is no need to stick with (digitally) "streaming video" or (in analog method) "broadcast/RF-transmitting video" concept.

Note in the high-sensitive mode, it is very similar with "slow scan TV (SSTV)" where there are just frequent new image update (e.g., every 2.1 second) while the rest of time, it is repeating the same thing at video rate. In such case, one can program a laptop to do TWAIN VGA-resolution capture every 2.1 (or 1) second. This will be the best quality capture and consume little bandwidth. The local laptop screen will change at almost the same update frequency as teh camera. The rest laptop and home PC WiFi link-up is just as described as Joe had said (using Microsoft RDP) or using VNC.

Clear Skies!

ccs_hello

#36 JAT Observatory

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Posted 27 December 2007 - 10:18 PM

I did order a cable that works on the GSTAR-EX and is supposed to work on the Mallincam to control the camera settings via computer. I guess a motorized focuser is next on my wish list.



Carol,
Not sure where you ordered the Mallincam cable from but the cable I ordered also came with the RS-485 to RS-232 cn=onvertor which you are going to need, since the interface to the Mallincam is RS-485. The big issue with my converter is it would not work with the Mallincan (or the GStar-EX) until I supplied it with external power (5~12 vdc) The other thing to remember is the software to drive the camera will only work on com port 1.

Since I have 2 cameras I built my own cable and ordered my own converter for the 2nd unit but was still hampered by the need to use com port 1. The solution was to use a serial port switch. While that setup worked it required the use of null modems between the serial port output connectors and the RS-232 to RS-485 converters.

#37 CarolG

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Posted 28 December 2007 - 09:03 AM

Marcus, THIS is what I ordered. I haven't gotten it yet. Does it look like it might work? The reason I got this is because I read in another post that it would work with a mallincam. I've followed your posts about connections and work arounds. When I get the cable, I would appreciate your help in setting it up. Thanks in advance!

#38 Douglas

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Posted 28 December 2007 - 09:42 AM

I have used my laptop at the scope but the reason I wanted a wireless transmitter is that the laptop connects directly to the camera with a cable, you can use S-Video if you capture card supports it, but when you slew the scope to different targets, the cable will get wrapped around the scope and will tug on both the laptop and scope. If you aren't at the scope to tend to the wire as the scope slews you are sure to end up with a laptop falling to the ground or getting dragged by the wrapped up cable, or worse, the cable will tug on the MallinCam and you don't want to think about what can happen there.

www.marklessastronomics.com sells a PC stalk which attaches to the scopes rocker box (Newtonian Dob) and keeps the laptop moving around with the scope when it slews, but it presents balance issues for scopes under 18", with my 12.5" scope it was not possible to install the PC stalk so the laptop must sit to the side of the scope independently.

The biggest benefit to going with a wireless transmitter is that you don't have the cable wrapping around the scope as it slews around to various targets. A cable wrapped around the scope can do serious damage to equipment if your not careful, in the dark, it is hard to see when the cable is getting caught up and about to tug on equipment.

- Doug

#39 Jack Huerkamp

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Posted 28 December 2007 - 09:43 AM

Carol,

That is not the cable I ordered from GStar for use with my MallinCams. Mine is 10 meters in length and has an RS-232 connector to interface with the COM port on the laptop. It cost about $140 delivered to the US via global express mail. I just checked the GStar site and I could not fine the one I purchased.

The cable that I have does work with the MallinCam; however, you need to have the camera in 2.1 second mode when making menu changes via the software on your computer. So you will still need to have access to the camera to turn off the HYPER mode before you change the gain and other parameters.

If you want to control some of the HYPER functions via the GStar cable and software, that is a possibility. But you would loose the ability to use the "X4" function. This would limit you to a 14 second exposure. But you could chage from 2.1 seconds to 7 and to 14 using a computer. The camera would need to be sent back to Rock to have this conversion made.

When the wireless is released, all camera functions will be available through the remote.

Jack

#40 Douglas

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Posted 28 December 2007 - 09:52 AM

When Rock is ready to roll out the wireless functionality, I will send my Color MCHP back to him for a retro-fit.

- Doug

#41 CarolG

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Posted 28 December 2007 - 11:34 AM

You bring up a good point, Doug. I've thought about cable wrap, and it is a real concern. In fact, I've had several times when that happened, and I don't want to experience that kind of panic ever again! I'm always at my scope when I move to another target. I guess I'm just lazy and get tired of hopping up and down and going back and forth to make setting adjustments. Thanks for your input.

Jack, thanks too for your helpful info. I knew that Rock was planning on retrofitting our cameras with the wireless option when he is ready, but I thought this option of the cable might work in the meantime. I really want the wireless function, and hope it will be available soon.

#42 CarolG

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Posted 28 December 2007 - 12:12 PM

All this talk about wireless has made me wonder about something. This question will probably show how electronically challenged I am, but if one has a wireless camera, a wireless focuser, a wireless telescope control, etc, do all these signals interfere with one another? I am assuming that most of these devices use 2.4 Ghz.

#43 JAT Observatory

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Posted 28 December 2007 - 12:20 PM

Carol,
I can't say the cable won't work but I will say this:
The My Astro Shop guys have changed the cable they used to sell (the one I ordered from them was different));
AND they have either changed the interface that is used on the GStar-EX OR there is an error in their description of the cable on their website.

Here is part of the description for the cable you ordered:
"This 5 meter cable connects to GSTAR-EX cameras with RS232 interfaces and the RS-232 port D-Type of a computer."
Here is the description of the GStar interface from their current manual:
"Interface: 5 buttons for OSD control on back panel plus RS-485 interface for computer control"

Unless Rock has changed the interface, the Mallincam uses an RS-485 interface not a RS-232. Both my Mallincam and GStar-EX camera use a RS-485 interface not a RS-232 interface. As stated in another post these camera are based on other cameras. Those camera are available in RS-485, RS232 and RS422 flavors.

When I first got my Mallincam (model with only 7 and 14 sec integration switch) I contacted Rock and ask him about the serial interface because I wanted to control it remotely. He stated the interface was RS-232. Well after spending countless hours trying to make the camera work I figured out it was RS-485 not RS-232. I then ordered a cable from My Astro Shop that was used on their GStar-EX camera (which I also own) with a RS-485 interface. The cable worked on both.

I decided I wanted another cable but didn't want to spend the money for their 10meter cable which is all they sold then. So I built my own. The RS-485 converter which I mentioned in my earlier post was the same one that was used in the cable I purchased from My Astro Shop.

I am hoping that My Astro Shop didn't change the camera interface and just worded the cable description wrong. Because if they did switch, then unless Rock has switched to RS-232 interfaces that cable won't work.

#44 JAT Observatory

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Posted 28 December 2007 - 04:51 PM

As as wireless goes if they interfere with each other or not depends on the frequency and how the receivers are designed. In my case I have chosen to use 434 Mhz (same as UHF TV ch 59) for my wireless frequency.

I have had no issue with my devices in that frequency band and I don't have to worry about the devices operating near frequencies of microwave ovens. LOS operations on these devices at 100mw can be 800 to 1000 ft.

#45 b1gred

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Posted 28 December 2007 - 05:38 PM

Marcus.

434 MHz is in the middle of the 70CM amateur radio band. Unless you are a licensed amateur operator you are operating illegally. And that is NOT UHF TV CH 59, but Cable CH 59.

#46 JAT Observatory

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Posted 28 December 2007 - 08:56 PM

Cable TV 59, UHF TV 14.

With all due respect I suggest you go learn about the 434Mhz band before you publicly accuse me of operating illegally within it.

#47 b1gred

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Posted 28 December 2007 - 09:28 PM

Au contraire.

The Amateur Radio 70CM Band is: 420-450

[Code of Federal Regulations]
[Title 47, Volume 5]
[Revised as of October 1, 2006]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR97.301]

[Page 587-589]

TITLE 47--TELECOMMUNICATION

CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION (CONTINUED)

PART 97_AMATEUR RADIO SERVICE--Table of Contents

Subpart D_Technical Standards

Sec. 97.301 Authorized frequency bands.


The following transmitting frequency bands are available to an
amateur station located within 50 km of the Earth's surface, within the
specified ITU Region, and outside any area where the amateur service is
regulated by any authority other than the FCC.
(a) For a station having a control operator who has been granted a
Technician, Technician Plus, General, Advanced, or Amateur Extra Class
operator license or who holds a CEPT radio-amateur license or IARP of
any class:

----------------------------------------------------------------------------------------------------------------
Sharing requirements
Wavelength band ITU--Region 1 ITU--Region 2 ITU--Region 3 see Sec. 97.303
(Paragraph)

UHF MHz MHz MHz
----------------------------------------------------------------------------------------------------------------
70 cm......................... 430-440.......... 420-450.......... 420-450.......... (a), (b), (f).


And TV channel 14 is 470-476MHz. See this site.

You are operating in the amateur band - in an unauthorized manner - if you are on 434MHz.

434MHz is assigned to Amateur Radio Operators in all regions.



#48 Bob S.

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Posted 28 December 2007 - 10:22 PM

Randy, I %@ink I hav* my wirele&% working g@@d now. How's the rad&* w#rking? ;)

#49 b1gred

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Posted 28 December 2007 - 10:23 PM

Looks like a little QRM in your transmission...

#50 JAT Observatory

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Posted 28 December 2007 - 11:32 PM

Randy,
Read FCC part 15 on Radio Frequency Devices the exemptions are there. But if you think your correct I suggest you contact the FCC. I have already been down this road with another mis informed amateur radio operator in my neighborhood. He was a bit red faced when it was confirmed that my system in fact met one or more of the requirements in Part 15 and didn’t require a license to operate in the said frequency band.


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