Re: Transmitter update

Josh Jensen
 

Jared,

I don't think you transmitting will be any problem at all. I think my biggest concern would be the GPS reception, but I don't think it interferes with your GPS, so it should be fine with mine. By the time my drone is finished, I'll have more, higher power transmitters on it directly. I would think it wouldn't even notice yours. 

If you're still concerned about interference, I can work in an autonomous flight plan, and have it take off, and fly up to altitude on its own. Have it hover at altitudes for a while, then come down and hover at 20 feet off the ground while you power down your stuff, then I take manual control for final landing. I'll need to see what I have for battery life. 

Josh

On Jun 10, 2017 11:49 PM, "Jared Smith" <jared@...> wrote:
Josh -

That would be cool! And I want to check out the drone anyway. I will need to do some testing to see how the antenna is going to work. It's VERY thin (like hair thin), 36 gauge magnet wire and I need to make sure it's not going to coil back onto itself - especially in turbulent conditions. The antenna's almost 35' long with the payload attached in the middle.

I now have all of the individual components working (except the solar stuff), so am now working on programming them all together. There are some interesting complexities in getting the sequencing and timing all right - and ensuring it's entirely autonomous. I'm planning on lots of testing, and an airborne test from your drone would be wonderful. I'm probably several weeks out from being to that point. 

We'll want to consider whether I should do a transmission test while hanging from your drone. I suspect not - I think the RF will likely interfere with your flight system.

Thanks,

Jared


On Sat, Jun 10, 2017 at 11:06 PM, Josh Jensen <kd7wrc@...> wrote:
Jared,

I was just thinking. If you want to give your payload an airborne test before you launch it, we could take it up suspended from my hexacopter. I made some good progress today, and could possibly take it on its first flight soon. 

Now I just need to work on some ham payloads. Probably my first will be a camera and transmitter, then a small digi to pick up APRS beacons from lost payloads, or relaying Bear 100 runner data.

Josh

On Jun 9, 2017 5:25 PM, "Jared Smith" <jared@...> wrote:
Tyler -

It's a single defined frequency per band - so no need to change based on regions like you have to with APRS or other VHF/UHF modes.

I do, however, have to add some logic so it won't transmit over certain countries where airborne transmissions are illegal. I'm not sure yet whether to do this geofencing based on lat/lon or grid square.

Mine will do 20 meters WSPR only. So it can be locked on the defined 20 meter frequency with a tuned dipole. The signal generator makes the slight changes in tones (4 of them total) to encode the almost 2-minute long WSPR transmission.

Some balloons are using 20 and 30 meter WSPR, but this makes the antenna configuration a bit more complex. And some are also using APRS with a separate transmitter. I may add APRS depending on what the weight comes to.

Jared


On Fri, Jun 9, 2017 at 3:41 PM, Tyler Griffiths <tyler.griffiths@...> wrote:
 I should say as it circles the earth. 


On Fri, Jun 9, 2017 at 3:40 PM Tyler Griffiths <tyler.griffiths@...> wrote:
So does it need to change  frequencies like a VHF or UHF  beacon. Or does HF work on a single frequency ?

Tyler
On Fri, Jun 9, 2017 at 9:17 AM Kevin Reeve <kevin.reeve@...> wrote:
And I think the whole Wisper thing is cool because it is on a worldwide recognized freq, and has a great chance of being heard even when across the ocean.

Kevin



From: <BARC-HAB@groups.io> on behalf of Main <kevin.reeve@...>
Reply-To: "BARC-HAB@groups.io" <BARC-HAB@groups.io>
Date: Friday, June 9, 2017 at 9:09 AM
To: "BARC-HAB@groups.io" <BARC-HAB@groups.io>
Subject: Re: [BARC-HAB] Transmitter update

I think your selling yourself short on the programming skills. If you have that much working as of last night, you have made great progress and accomplished much, especially converting lat and long to grid square.

Kevin



From: <BARC-HAB@groups.io> on behalf of Jared Smith <jared@...>
Reply-To: "BARC-HAB@groups.io" <BARC-HAB@groups.io>
Date: Thursday, June 8, 2017 at 11:29 PM
To: "BARC-HAB@groups.io" <BARC-HAB@groups.io>
Subject: [BARC-HAB] Transmitter update

I have a basic prototype up and running with the WSPR transmitter. A photo is attached.

It puts out only 10 milliwatts (much less than that by the time it gets to my antenna) and was heard in several places across the US tonight on 20 meter band well after sunset. I track reception reports using WSPRnet.org. A screen shot of those hearing me is attached.

The furthest was W0PAS in Eastern Ohio. That comes out to 155,590 miles per watt!!! Not bad for a radio the size of a matchbook.

Thanks Gary for helping me test it out.

The GPS receivers came today, so that's my next project. I've learned my programming skills leave a lot to be desired! I programmed up the telemetry module yesterday. It converts NMEA lat/lon to grid square, and encodes the altitude and temperature into the telemetry format.

Jared

--
Tyler, Sent from Gmail Mobile

--
Tyler, Sent from Gmail Mobile



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