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Hey boys and girls, I just got my butt back in gear on my new diversity receiver design this evening. I haven't touched diversity since I made my first design 3 years ago that I sold through BWAV. I'm back at it though. I've been itching to make a couple different designs with different features.

Design 1: Super duper cheap

-I want to make a unit that I can sell for $149-$179. I know, sounds a little low but it is do-able. Especially with the new airwave modules I am playing with. So many people start messing with aerial video and shy away because of interference problems. I want this to be like the cheap 4-channel FM transmitter you get with the screw together ARF from Towerhobbies. Its not good for anything but a trainer but if it gets you hooked and you come back and buy a 9 channel PCM radio a year down the road, it did its job.

You buy it, use it and get hooked then advance from there.

Design 2: Modular

I thought about the universal, expandable, modular, stupendous diversity receiver last year. Its actually not to bad at all once you approach it from the right angle. I would love to make a unit that can take up to 4 units and another that could even take 8!! Impossible? Nah.

Design 3: OSD

-What all could we show on our video display with a quick, off the shelf OSD module? Shoot some GPS telemetry back down, always good. Which receiver is active and signal strengths of each receiver? Heck, there is all kinds of stuff there.

Design 4: Any channel, anytime.

-Found a 2.4ghz module that I can change the channel on anywhere between 2400 and 2480 mhz in 1 mhz steps. Therefore it would be a universal 2.4 video module, forget frequency set 1 & 2 & 20. It would do them all!

-----

I'll start with the super duper cheap model. My original design had a ton of hand building in it and after I sold it to Bill at BWAV and he took his cut the unit ended up costing a lot more then I wished it had. These new units should be super fast to build by hand especially with someone to CNC the cases for me. Next will be the modular.

My big question is what frills and thrills do we really need?

-Signal strength meter? (Overkill in my book, no plans for one on cheapy)

-Active receiver LED (absolutely)

-Channel indicator LEDs (maybe, maybe not. Depends on what switch I use for LEDs)

-Speaker that chirps on receiver switch (maybe, it doesn't cost much)

-Voltage range (theoretically the unit could run on 6 volts since everything inside is 5V. Definitly needs reverse polarity protection)

-Screw mount (I had a tripod mounting screw in bottom of my first units, think it would be handy? Or are most people putting these things on the ground)

We'll go from there, a production ready unit won't take long. The cases will be hand drilled for the first couple weeks until my CNC guy gets his stuff setup.

Matt Klarich

Klarich Electronics

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Sounds pretty cool! As far as the basic function (ie: switching inputs to best signal received), will they all use the same core technology? Meaning, will you get just as good signal reception with the "super duper cheap" unit as with the "any channel, any time" unit? Just curious if the difference between them was the added features.

As far as powering the unit, it would be really handy to power it from either a 2S or 3S lipo. I've got lots of those laying around that are no longer designated as "flight" packs.

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I'd like to make it so it can run anywhere from 6v to 12-15V so that covers the 3S lipo setup. If I use a cheap linear regulator it just means I'll need a lot of heatsink for the regulator.

The super duper cheap units receive sensitivity will be the same as the high end units, mostly the cost will go to features and expandibility. Would love to make it so you can have a main box that manages a couple 2.4ghz receivers as well as some 900 or 1.2ghz units.

Matt

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Hmm..Looks to me like you have been reading the posts from this forum Matt !

Terry

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"-Screw mount (I had a tripod mounting screw in bottom of my first units, think it would be handy? Or are most people putting these things on the ground)"

I bet for have that already fitted. its better to have the unit as high as you can and use long video wires than use longer aerial wiress to keep the antenas as high as possible due to the signal loss.

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Wow, this sounds exactly like what I was hoping somebody would do! As far as the super cheap one...I think it would be best to keep it that way. No chirp on reciever switch, no screw on bottom for tripod mount...just the bare minimum to keep cost as low as possible. That IS the intent with this one after all, right? But the upgraded ones should definitely have these features, as people love to upgrade and expect more when they do. Being able to power it off a 2S or 3S LiPo is an absolutle must, IMHO. Who doesn't have a couple of these laying around that is in this hobby nowadays? And they are so small and lightweight that they make a perfect portable power source for the field. Just my 02 cents! ;)

Edit: Would it be possible to make a LVC that is compatible with LiPo's in these recievers so beginners and absentminded people(like me!) don't ruin thier batteries if they leave the reciever turned on?

Edited by philthyy

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Terry, I developed and marketed the first hobby diversity receiver over 2 years ago. I've been wanted to improve upon its design ever since, unfortunately personal issues kept me from being able to do that.

About a year ago I came around and I was asking people what they wanted to see in a new design. Those ideas and a few more are what have been floating around and are now once again being compilied. These ideas are nothing new to me and I'm just trying to make sure I give the people what they want at a price that the average hobbyist can afford. If I want to make big money I'll beef the unit up, add more bling to it then you'll ever need and sell it to the government.

My electronics business is a "Hobby" business for me, I work as an electrical engineer/circuit board designer all day at a scoreboard company so this isn't my primary income. I love AP and want to do my part to get other people interested, I know, sounds corny but it is true.

Matt

Edited by mklarich

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Matt, its not corny, its great! People like you are who get things done in this hobby, and I can't even begin to explain how many people are so impressed with my FPV videos that they start asking how can they get into it! An entry level diversity is just what this hobby needs! (Heck, just what I need!) :D

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Nothing personal Matt, its just odd you should pop up with a lot of the same ideas talked about in this thread http://www.rc-cam.com/forum/index.php?showtopic=1324

Its a shame you didnt start a bit sooner, you could have saved me the trouble of building a 4 way diversity receiver and I could have got on with another project.

Im sure there will be a lot of takers for the cheap version as I said in the other thread. If you can supply it with cheap patch aerials then you have the ultimate starter pack as far as the RX side goes.

All the best, Terry

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Terry, didn't take it personally, just wrote that email in a hurry during lunch earlier. Unfortunately other things took priority over my hobby last year, wish they hadn't. Just think of all the knowledge you gained by building your own :D

Matt

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Nothing personal Matt, its just odd you should pop up with a lot of the same ideas talked about in this thread http://www.rc-cam.com/forum/index.php?showtopic=1324

Yeah, it looks like the market might be getting crowded soon. We've got possibly several head tracking systems in the works, several diversity receivers, several suppliers of video tx/rx equipment, etc. But this is only good news for the consumer. More choices equals good selection and great prices. :)

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Oh twin, did I mention I'm working on my headtracker as well? It doesn't use the buddy channels on the transmitter, costs a little more but well worth it when I detail the advantages. Shhhh...

Matt

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Yeah, I think I saw you post some info about it in RCU or rcgroups. There's another guy (or maybe it's you) that goes by the screen name MX that's working on one too I think.

I know you talked about building one many months ago, but there didn't seem to be any progress for a long time. I ended up getting one from Kilrah at RC-Tech. However, I'm always looking at the new technology coming out so I will be following the progress on these new head tracking units.

Edited by twinturbostang

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Hi Matt, any news on these new diversity systems of yours yet ?

Terry

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please dont use linary regulator, but switch mode !

ok they cost 3$ more, but no heat problems, and much wider supply range.

existing rx boxes run glowing when powered by a 14V lead acid accu.

SMA connectors for ant.

some sort of signal indicator, a few leds will do fine for most,

OSD in the diversity box could be cool, to indicate signals and the selected ant.

this OSD must be possible to on/off or even move, so it dont conflict with the OSD onboard the plane.

well the RSSI and OSD system can be made using two AVR chips, each 2$ and video switch 1$ and lm1881 2$ plus two receivers with rssi out.

the switching must also be done on the sound / data link channel at the same time.

we could work together if you need a super flexible OSD solution that is cheaper and much more avail compared to other OSD board or chips.

see here what kind of OSD I came up with:

http://www.webx.dk/rc/video-wireless/video-osd.htm

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I really have to question the usefulness of knowing which channel is selected, be it via LEDs, a buzzer, or an OSD.

In addition, knowing the signal strength isn't that critical

What is this based on?, over 100 flights using a DIY diversity receiver that had some of this information.

Basically I've never used it. When flying, I really don't care which antenna is selected, and for signal strength, near the range limits it becomes quite apparent by looking at the video signal itself.

Yeah, the other stuff has 'cool factor', but practically, its of close to zero value (in my humble opinion).

What I want from a diversity Rx is something that is reasonably priced (not much more than 2x a std. receiver), does its job well, and only bugs me when something bad is about to happen... and the only example that I have of that, is when the receiver battery is about to die.

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I have no interest in a cheap diversity. If I am buying a diversity receiver, I am trying to increase my performance, not lower it. Why buy something cheap that will not perform that well ? The receiver sensitivity is vastly important. Poeple want to see a good picture, and if the receivers used in the diversity are not sensitive enough, the results will be worse than a single lawmate receiver.

Why buy a diversity receiver that does not have the range of a single receiver ?

Most of us that want diversity receivers are to the point we are ready to put more money into our system, and want more performance. I like your idea of a system that will work on any frequency... Or even better the modular system that can have 2, 3, or 4 receivers, that could make a great system. I am willing to pay higher prices for good equipment, but not willing to spend anything on second rate gear.

JettPilot

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Jett, cheap doesn't necessarily == low performance.

Cheap could indicate 'contains only the stuff required to do its job, and nothing else'

Indeed !!! ;)

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Jett, cheap doesn't necessarily == low performance.

Cheap could indicate 'contains only the stuff required to do its job, and nothing else'

Once you start adding crud like led's to show which one is active, OSDs, signal strength displays, lcd's etc... that and the coding behind it is what your paying for. Just plain diversity wouldnt cost all that much to do.

Just like if you buy a new car, if you get all the optional extras it could cost you $15k+ more. However, a great deal of those features you probably couldnt give a rats ass about.

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Yep, the led to show which antenna it is using is nice for set - up and antenna testing purposes. Other than that, I could do without all the fancy stuff....

As long is it performs and is equal to or more sensitive my current receivers. I got the idea that the "CHEAP" diversity would use cheap receiver modules, which would suck. I dont want to pay extra for something that does not give me the range of my current receiver.

JetPilot

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Thats why I abandoned the airwave diversity receiver. I made a couple, they worked fine but the sensitivity varied so greatly from receiver to receiver it was ridiculous.

I'm back to a better quality consistent receiver with the intention of working anywhere from 2400 to 2483.

Matt

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Thats why I abandoned the airwave diversity receiver. I made a couple, they worked fine but the sensitivity varied so greatly from receiver to receiver it was ridiculous.

I'm back to a better quality consistent receiver with the intention of working anywhere from 2400 to 2483.

Matt

Which Airwave modules were you using?, I've worked with a lot of these modules and haven't seen much variation at all.

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