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Dual Purpose: Mallincam AND Wireless - HOW?

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#51 b1gred

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Posted 29 December 2007 - 12:11 AM

I understand under Part 15, under "Intentional Radiators" you may operate such a device, HOWEVER it MUST be on a "non-interference basis" with the Primary Licensed Service and in no case may it emit signals which exceed the limits listed in the following:

Sorry this doesn't format well in the forums

§ 15.209 Radiated emission limits; general
requirements.
(a) Except as provided elsewhere in
this subpart, the emissions from an intentional
radiator shall not exceed the
field strength levels specified in the
following table:
Frequency (MHz) Field strength
(microvolts/meter)
Measurement
distance
(meters)
0.009–0.490 ................... 2400/F(kHz) 300
0.490–1.705 ................... 24000/F(kHz) 30
1.705–30.0 ..................... 30 30
30–88 ............................. 100 ** 3
88–216 ........................... 150 ** 3
216–960 ......................... 200 ** 3
Above 960 ...................... 500 3
** Except as provided in paragraph (g), fundamental emissions
from intentional radiators operating under this section
shall not be located in the frequency bands 54–72 MHz, 76–
88 MHz, 174–216 MHz or 470–806 MHz. However, operation
within these frequency bands is permItted under other sections
of this part, e.g., §§ 15.231 and 15.2


SO, if you can ensure that you don't exceed the limits of Part 15, and you don't cause interference with the primary service (in this case Amateur Radio) AND you can prove all that to the local FCC field office AND you're willing to risk the $10,000 per occurrence or per day if the complainant can prove harmful interference, you are free to proceed.

However, wouldn't it make sense to operate in a frequency band where there isn't a risk of causing interference to a licensed service.

The good news for your operation is that 434 is a frequency not commonly used for voice communications (the most common use of those bands), rather it is mostly restricted to use in "Amateur Television". As long as your "device doesn't CAUSE interference to such a device and is willing to accept interference from same" (according to Part 15), you're fine. I just wouldn't take the chance... But it's your choice, and your money.

The reason this is of great interest to me is that I'm one of the Interference Specialists (Technical Specialists) as a volunteer to the ARRL. This is an area in which I specialize my volunteer work.

#52 JAT Observatory

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Posted 29 December 2007 - 12:48 AM


<<The good news for your operation...>>

It's not good news to me Randy as I already knew my system is legal before I mentioned it here. But you chose to accused me of doing something illegal without knowing the details. I didn't and still don't appreciate that.

#53 ccs_hello

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Posted 29 December 2007 - 01:00 AM

I would say most of the CN forum members are not pro in RF field nor knowing how to use a tuned, highly directional antenna to confine the radiated power). I do know the simple analog based video transmission device (pro-grade VSB will take up at least 5.5 MHz B/W while cheapo AM will take at least 8.4 MHz or more, assuming the baseband is already bandwidth-limited). A product may "push" for high(er) power output (like 1 Watt) just to get the uneducated users feel the product is useful. But this is no different than setting up a "low power personal broadcast TV station", IMHO.

What am I trying to say here?
Some suggested approaches are well beyond the consumer plug-n-play devices and is not like a simple device only causing impact/interference just inside his/her own house. If not operated properly, it will get the user in trouble.
To help CN community, an end-user operating an intentional radiator, especially in the wide-band and high power need to either be able to have some write up to "avoid misunderstaning" or have a vendor willing to back the product up with the necessary FCC compliance documentation.

Look, even for unintential radiators, there are almost always have a label regarding FCC registered or a declaration in that aspect.

Clear Skies!

ccs_hello




#54 b1gred

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Posted 29 December 2007 - 04:56 PM

Like with many products that are "available for purchase" (high power Green Laser Pointers come to mind), just because they're available AND have an FCC Part 15 label on them, does NOT make them legal or appropriate for use.

Caveat emptor.

#55 Bowmoreman

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Posted 30 December 2007 - 12:48 AM

Lovely... I just got back from 4 days out of state to find out my brandy new VFM wireless transmitter/receiver are NOT FCC compliant?

Freaking lovely...

Well, I have the 1.2Ghz version (same as Jack). I am not sure what I'll do - haven't fired em up yet.

I *may* just look into making a HIGHLY directional antenna encapsulation for them to make them WICKED directional... I have the advantage of being pretty remote (for my general location) sharing well over 300 acres, and 1/2 mile + (through woods) from nearest roads, etc...

Or, maybe I'll contact VFM and check into return... sigh

I *am* glad I started this thread though, much useful information flowing (amidst some agita unfortunately)...

Jack, what are you going to do with your 1.2Ghz VFM setup?

I really don't want to go the computer in the observatory route, with wireless, etc. etc... so much CLUTTER! (not to mention wires)...

Oh well...

clear enough skies - they were tonight! :jump:

#56 Mike Harvey

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Posted 30 December 2007 - 01:59 AM

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


I'll be taking the latest prototype wireless hand controller (and modified MCH) with me to the upcoming Winter Star Party. *Note to everyone who has asked: this is NOT a production model!
Anyone planning to attend is invited to stop by and check it out.
Just look for the 28" StarStructure.

Mike

#57 Jack Huerkamp

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Posted 30 December 2007 - 07:49 AM

My unit is residing in my closet. I got mine over 2 years ago, so I am sure I can't return it. However, if you just got yours, I would contact VFM about returning it. If its any consolation, my TX/RX set cost almost twice the current price. :(

#58 Jack Huerkamp

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Posted 30 December 2007 - 08:36 AM

I tested an earlier version of a wireless MallinCam (Prototype 3) at the Deep South Regional Stargaze in November. It had 7, 14 and unlimited exposure times. I much preferred having the automatically refreshed 28 and 56 second exposures over the unlimited exposure. Plus going longer than 56 seconds on an Alt-Az scope was not practical nor was it close to "live" observing. It was turning into imaging. Based upon my experience at the stargaze, Rock initialed a poll on the Yahoo E-Group, and the functionality of the wireless was changed to the version that Mike will be testing. Mike's camera is the latest version of the wireless MallinCam prototype and it is first to incorporate the 7, 14, 28, and 56 second exposures along with FREEZE. Rock and I are looking forward to Mike's repots on the camera's performance at WSP 2008. This is another step in the perfection of the wireless system. Once Rock is satisfied with its performance, he will offer it as an upgrade to existing MallinCam owners.

Jack

#59 Douglas

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Posted 30 December 2007 - 09:20 AM

Mike, you lucky dog. Wireless menu changes with 7,14,28 and 56 and freeze! And I just finished building a freeze switch two days ago, oh well.

I am looking forward to the wireless menu setting changes. Looks like we're getting closer to a release date, it will be worth the wait.

- Doug

#60 Jack Huerkamp

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Posted 30 December 2007 - 10:09 AM

Doug,

I have built and use my FREEZE button with great success. The wireless will be a great addition to the camera, but I don't think it will be needed by all users. Someone like Mike with a 28" scope that requires a 5 step ladder to get to the focuser will benefit. Owners of smaller Dobs and SCTs will probably not need it unless they want remote operation of the camera. Then the key will be range. Hopefully Mike will get a chance to test the range on the unit at WSP to see if he finds its limitation.

Jack

#61 Bowmoreman

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Posted 30 December 2007 - 11:22 AM

I'll definitely be looking forwards to learning about the range, and abilities of the "wireless" version...

I had about 3 hours last night, and did NOT check out the VFM wireless transmitter (nor the 3.5" WATEC!)... just did some nice viewing of M42/43, Horsehead, M81/82, M1 instead...

Boy, M42 is a tough target due to its dynamic range, eh?

clear enough skies (mine won't be tonight - we're getting another 5-9" of snow, sigh)

#62 Douglas

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Posted 30 December 2007 - 11:41 AM

I can see where Mike would greatly benefit. I'm sure when you live on the ladder, making setting changes while looking at a monitor can be a whole different ball game than it is for us folks with our feet on the ground right next to our monitors.

I look forward to the wireless unit because I have trouble with the small buttons so close together on the camera. NY can get pretty frigid and I hate the cold, this time of year I wear thin gloves with rubberized dots so I can handle EPs and adjust the focuser but it's not possible to hit those small individual buttons so close together on the MCHP with the thin gloves on. I got a pair of fingerless gloves for the time being.

Wireless would also be great for me because I view on my 50" plasma in the house quite a bit and making those changes from inside the house would be a huge plus. I use Starry Night with Argo Navis and ServoCat with the wireless 232 system from Gary Myers to choose targets and slew the scope while I am inside the house. Starry Night will also allow me to control focusing with the ASCOM driver and I'm going for the new starlight motorized adapter for my Feathertouch.

When I make setting changes I like to study the image for fine differences between the settings. It is easier for me to do that inside the house comfortably, rather than dancing in the cold.

I'm hoping Mike gets an opportunity to test the range. I really look forward to the new wireless capability.

Doug

#63 Douglas

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Posted 30 December 2007 - 11:51 AM

Jack, I forgot to mention that I made the freeze switch with John Paladini and we tested it out, works great.

I was careful to test every pin with the ohm meter prior to use! My heart starting beating again once we tested on the camera and it worked and my camera wasn't fried. It will get alot of use when I do public outreach and have fun with friends over.

- Doug

#64 Bowmoreman

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Posted 01 January 2008 - 07:32 AM

Well, sorta back on the original thread... got out for about an hour last night (couldn't stay more due to family wanting my time for New Years!)...

I got the wireless (VFM) working; through the Observatory wall, about 75 feet across yard, through house wall, and another 10 feet to the receiver plugged into the 42" HDTV...

worked just fine... now I know it works, I have to research other users of this bandwidth in the vicinity, making it super directional to avoid bandwidth pollution, etc... Don't want to continue to use it unless I know it will be in a totally non-interfering manner!

I took the MCHP composite BNC output via provided harness over to my Proton 19" monitor, and then from the monitor video OUT into the VFM which is on top of the monitor... I used the S-video output, via S-video to RCA adapter from Radio Shack, to BNC to operated the Watec which I mounted piggyback on my refractor.

Got everything working and setup in less than an hour and also bagged/studied M31, M42, M81/82, and M33...

Here's a picture. It looks like a rats nest, but that is cause I also have 4 dew strips connected at the same time... I'm using cable guides to keep things semi-organized... but leaving sufficient slack to prevent cable wrap leaves a lot of looseness when pointed to the South East, as in this picture! :lol:

Wish I knew of a fully FCC compliant Wireless video adapter though!

clear enough skies

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