GPSL@groups.io | Messages

TrackSoar

L. Paul Verhage KD4STH

#16950

I'm testing a TrackSoar APRS tracker before near space season begins in earnest. If you haven't seen one of these, it's a small board with GPS, GPS antenna, transmitter, Arduino, and two meter antenna. It runs from 2 'AA' cells. You program it's Audrino with your callsign and it's ready to go.

Anyhow, I wonder if anyone is using one as I'm having a problem with mine. I see that it has a GPS lock (the GPS LED illuminates once per second) and that it's trying to transmit ( the PTT LED illuminates for 30 seconds on and off). However, my Kenwood D72 doesn't hear anything. My D72 does decode packets from my other trackers, including a Strato Track.

So if you have any experience with the TrackSoar, could you let me know?

Thanks

Re: MAX-M8Q GPS lock problem

Leo Bodnar <leo@...>

#16949

You don't need RFI interference in GPS L1 band to disable GPS.

Ublox MAX-8Q and all other MAX series modules do not have *any* antenna input preselector filtering - just an impedance match. Their antenna input is attached to on-chip LNA followed by a mixer. Imagine bypassing all the bandpass filters in your HAM rig and trying to listen to DX station close to a powerful nearby broadband transmitter.

For complex payloads I would suggest using either module with internal filter - like NEO - or simply placing a GPS band SAW filter between the antenna and the module. Having only a few dB insertion loss It would not hurt the sensitivity but can help with nearby out of band EMI. If you really need these few extra dB back take it out and bypass it with a short piece of wire.

Cheers

Leo

Show quoted text

On 24 Mar 2019, at 02:55, Bill Brown via Groups.Io wrote:

Hi Zack,

Digital cameras are a huge source of EMI to desense GPS receivers. I always try to keep about 6 to 10 feet of isolation between GPS trackers and camera payloads. Aluminum shielding on the top or bottom of the camera payload is also a good idea.

By identical sister do you mean the other board also uses the MAX-8Q or does it use some other version of the MAX series? In the case of the MAX-8Q if you don't send it the command to only use the US GPS constellation, it will also use the Chinese and Russian GPS sytems and will access more satellites. That might help.

- Bill WB8ELK

I use the MAX-7Q and MAX-8Q almost exclusively now. However, for extreme EMI environments such as coexisting next to an ATV transmitter with digital cameras, then I use the Trimble Copernicus module as it is a lot more impervious to EMI effects. I still offer them every once in awhile for folks using ATV on gliders or RC aircraft as well as ATV payload on balloons.

-----Original Message-----
From: Michael <mw@...>
To: GPSL <GPSL@groups.io>
Sent: Sat, Mar 23, 2019 11:58 am
Subject: Re: [GPSL] MAX-M8Q GPS lock problem

Looks like you have an EMI issue, try wrapping the cameras with aluminum foil with just a small hole for the lens as small as you can get it without interfering with the view. Most likely your cameras are using a frequency that has a harmonic on the GPS frequency and with a GPS having say 165db of sensitivity, you pretty much can not get far enough away on a flight string to realize some impact, but more shielding and space will likely help.

--Michael Willett

K5NOT

On Mar 23, 2019, at 11:08 AM, Zack Clobes W0ZC <zclobes@...> wrote:

I'm looking for some ideas on troubleshooting some lock problems on a new board/capsule/camera design. The board has worked well during testing up until I started integration testing with the actual capsule with the cameras under it.

The capsule is about 6cm thick and is mostly two layers of foam. There are two cameras sandwiched in the middle and there is an aluminum bar holding them in place. The GPS antenna is as far away from that as I can get. Lid open or lid closed doesn't seem to make any difference.

During testing I noticed that this board would take a lot longer to get a lock than it's identical sister. Initially I thought it was a bad GPS or antenna, and eventually replaced both. Then I noticed if I unplug an external (optics) sensor, the GPS would lock up almost immediately.

So I nixed the sensor at the 11th hour and went flying. The GPS never locked on a single time during the whole flight. There's about 2m of separation to the next capsule.

This morning I plugged everything back in just like it flew, and it immediately got a lock. The only thing I noticed was that after powering up the cameras, the altitude was reading about 100 meters high. But I still had 5-9 sats.

I'm running low on ideas on what to try to isolate this problem.

Zack

<IMG_20190319_163333.jpg>

<IMG_20190319_163351.jpg>

Re: MAX-M8Q GPS lock problem

Bill Brown

#16948

Hi Zack,

Digital cameras are a huge source of EMI to desense GPS receivers. I always try to keep about 6 to 10 feet of isolation between GPS trackers and camera payloads. Aluminum shielding on the top or bottom of the camera payload is also a good idea.

By identical sister do you mean the other board also uses the MAX-8Q or does it use some other version of the MAX series? In the case of the MAX-8Q if you don't send it the command to only use the US GPS constellation, it will also use the Chinese and Russian GPS sytems and will access more satellites. That might help.

- Bill WB8ELK

I use the MAX-7Q and MAX-8Q almost exclusively now. However, for extreme EMI environments such as coexisting next to an ATV transmitter with digital cameras, then I use the Trimble Copernicus module as it is a lot more impervious to EMI effects. I still offer them every once in awhile for folks using ATV on gliders or RC aircraft as well as ATV payload on balloons.

Show quoted text

-----Original Message-----
From: Michael <mw@...>
To: GPSL <GPSL@groups.io>
Sent: Sat, Mar 23, 2019 11:58 am
Subject: Re: [GPSL] MAX-M8Q GPS lock problem

Looks like you have an EMI issue, try wrapping the cameras with aluminum foil with just a small hole for the lens as small as you can get it without interfering with the view. Most likely your cameras are using a frequency that has a harmonic on the GPS frequency and with a GPS having say 165db of sensitivity, you pretty much can not get far enough away on a flight string to realize some impact, but more shielding and space will likely help.

--Michael Willett

K5NOT

On Mar 23, 2019, at 11:08 AM, Zack Clobes W0ZC <zclobes@...> wrote:

I'm looking for some ideas on troubleshooting some lock problems on a new board/capsule/camera design. The board has worked well during testing up until I started integration testing with the actual capsule with the cameras under it.

The capsule is about 6cm thick and is mostly two layers of foam. There are two cameras sandwiched in the middle and there is an aluminum bar holding them in place. The GPS antenna is as far away from that as I can get. Lid open or lid closed doesn't seem to make any difference.

During testing I noticed that this board would take a lot longer to get a lock than it's identical sister. Initially I thought it was a bad GPS or antenna, and eventually replaced both. Then I noticed if I unplug an external (optics) sensor, the GPS would lock up almost immediately.

So I nixed the sensor at the 11th hour and went flying. The GPS never locked on a single time during the whole flight. There's about 2m of separation to the next capsule.

This morning I plugged everything back in just like it flew, and it immediately got a lock. The only thing I noticed was that after powering up the cameras, the altitude was reading about 100 meters high. But I still had 5-9 sats.

I'm running low on ideas on what to try to isolate this problem.

Zack

<IMG_20190319_163333.jpg>

<IMG_20190319_163351.jpg>

Re: MAX-M8Q GPS lock problem

Michael

#16947

Troubleshooting EMI can be fun... try doing this while at an FCC lab where the clock is ticking $$$ and you are calculating beat frequencies on almost unrelated things in a system to get a clue why/who is causing issues, and when you get the thing to pass it is not pretty but you have a clue and go back to the lab and implement changes that production can also implement and go back to the FCC lab with fingers crossed that you solved the issue. That is why they invented anti-anxiety drugs. :)

--Michael Willett

Show quoted text

On Mar 23, 2019, at 12:36 PM, Zack Clobes W0ZC <zclobes@...> wrote:

Most of my testing that I did was with the cameras powered down.

That's what is throwing me on this one - sensor seems to cause problems so I yank that, then it seems like the cameras are doing it, but I remind myself that I didn't have them turned in through most of the testing.

I do have E/H probes on their way for the spectrum analyzer.

I need to recharge the battery then I'll try the foil to see if it changes anything...

Zack

On Sat, Mar 23, 2019, 12:31 PM Jeff Ducklow <jeffducklow@...> wrote:

I second Micheal's advice. I once had an EMI issue with a GoPro camera not allowing a GPS lock. My solution involved the cover from an Altoids tin. Once I had enough metal between the GPS unit the GoPro I was back in business.

Jeff Ducklow
N0NQN

On March 23, 2019 at 11:58 AM Michael <mw@...> wrote:

Looks like you have an EMI issue, try wrapping the cameras with aluminum foil with just a small hole for the lens as small as you can get it without interfering with the view. Most likely your cameras are using a frequency that has a harmonic on the GPS frequency and with a GPS having say 165db of sensitivity, you pretty much can not get far enough away on a flight string to realize some impact, but more shielding and space will likely help.

--Michael Willett

K5NOT

On Mar 23, 2019, at 11:08 AM, Zack Clobes W0ZC < zclobes@...> wrote:

I'm looking for some ideas on troubleshooting some lock problems on a new board/capsule/camera design. The board has worked well during testing up until I started integration testing with the actual capsule with the cameras under it.

The capsule is about 6cm thick and is mostly two layers of foam. There are two cameras sandwiched in the middle and there is an aluminum bar holding them in place. The GPS antenna is as far away from that as I can get. Lid open or lid closed doesn't seem to make any difference.

During testing I noticed that this board would take a lot longer to get a lock than it's identical sister. Initially I thought it was a bad GPS or antenna, and eventually replaced both. Then I noticed if I unplug an external (optics) sensor, the GPS would lock up almost immediately.

So I nixed the sensor at the 11th hour and went flying. The GPS never locked on a single time during the whole flight. There's about 2m of separation to the next capsule.

This morning I plugged everything back in just like it flew, and it immediately got a lock. The only thing I noticed was that after powering up the cameras, the altitude was reading about 100 meters high. But I still had 5-9 sats.

I'm running low on ideas on what to try to isolate this problem.

Zack

<IMG_20190319_163333.jpg>

<IMG_20190319_163351.jpg>

Re: MAX-M8Q GPS lock problem

Zack Clobes W0ZC

#16946

Most of my testing that I did was with the cameras powered down.

That's what is throwing me on this one - sensor seems to cause problems so I yank that, then it seems like the cameras are doing it, but I remind myself that I didn't have them turned in through most of the testing.

I do have E/H probes on their way for the spectrum analyzer.

I need to recharge the battery then I'll try the foil to see if it changes anything...

Zack

Show quoted text

On Sat, Mar 23, 2019, 12:31 PM Jeff Ducklow <jeffducklow@...> wrote:

I second Micheal's advice. I once had an EMI issue with a GoPro camera not allowing a GPS lock. My solution involved the cover from an Altoids tin. Once I had enough metal between the GPS unit the GoPro I was back in business.

Jeff Ducklow
N0NQN

On March 23, 2019 at 11:58 AM Michael <mw@...> wrote:

Looks like you have an EMI issue, try wrapping the cameras with aluminum foil with just a small hole for the lens as small as you can get it without interfering with the view. Most likely your cameras are using a frequency that has a harmonic on the GPS frequency and with a GPS having say 165db of sensitivity, you pretty much can not get far enough away on a flight string to realize some impact, but more shielding and space will likely help.

--Michael Willett

K5NOT

On Mar 23, 2019, at 11:08 AM, Zack Clobes W0ZC < zclobes@...> wrote:

I'm looking for some ideas on troubleshooting some lock problems on a new board/capsule/camera design. The board has worked well during testing up until I started integration testing with the actual capsule with the cameras under it.

The capsule is about 6cm thick and is mostly two layers of foam. There are two cameras sandwiched in the middle and there is an aluminum bar holding them in place. The GPS antenna is as far away from that as I can get. Lid open or lid closed doesn't seem to make any difference.

During testing I noticed that this board would take a lot longer to get a lock than it's identical sister. Initially I thought it was a bad GPS or antenna, and eventually replaced both. Then I noticed if I unplug an external (optics) sensor, the GPS would lock up almost immediately.

So I nixed the sensor at the 11th hour and went flying. The GPS never locked on a single time during the whole flight. There's about 2m of separation to the next capsule.

This morning I plugged everything back in just like it flew, and it immediately got a lock. The only thing I noticed was that after powering up the cameras, the altitude was reading about 100 meters high. But I still had 5-9 sats.

I'm running low on ideas on what to try to isolate this problem.

Zack

<IMG_20190319_163333.jpg>

<IMG_20190319_163351.jpg>

Re: MAX-M8Q GPS lock problem

Jeff Ducklow

#16945

I second Micheal's advice. I once had an EMI issue with a GoPro camera not allowing a GPS lock. My solution involved the cover from an Altoids tin. Once I had enough metal between the GPS unit the GoPro I was back in business.

Jeff Ducklow
N0NQN

Show quoted text

On March 23, 2019 at 11:58 AM Michael <mw@...> wrote:

Looks like you have an EMI issue, try wrapping the cameras with aluminum foil with just a small hole for the lens as small as you can get it without interfering with the view. Most likely your cameras are using a frequency that has a harmonic on the GPS frequency and with a GPS having say 165db of sensitivity, you pretty much can not get far enough away on a flight string to realize some impact, but more shielding and space will likely help.

--Michael Willett

K5NOT

On Mar 23, 2019, at 11:08 AM, Zack Clobes W0ZC < zclobes@...> wrote:

I'm looking for some ideas on troubleshooting some lock problems on a new board/capsule/camera design. The board has worked well during testing up until I started integration testing with the actual capsule with the cameras under it.

The capsule is about 6cm thick and is mostly two layers of foam. There are two cameras sandwiched in the middle and there is an aluminum bar holding them in place. The GPS antenna is as far away from that as I can get. Lid open or lid closed doesn't seem to make any difference.

During testing I noticed that this board would take a lot longer to get a lock than it's identical sister. Initially I thought it was a bad GPS or antenna, and eventually replaced both. Then I noticed if I unplug an external (optics) sensor, the GPS would lock up almost immediately.

So I nixed the sensor at the 11th hour and went flying. The GPS never locked on a single time during the whole flight. There's about 2m of separation to the next capsule.

This morning I plugged everything back in just like it flew, and it immediately got a lock. The only thing I noticed was that after powering up the cameras, the altitude was reading about 100 meters high. But I still had 5-9 sats.

I'm running low on ideas on what to try to isolate this problem.

Zack

<IMG_20190319_163333.jpg>

<IMG_20190319_163351.jpg>

Re: MAX-M8Q GPS lock problem

Michael

#16944

Looks like you have an EMI issue, try wrapping the cameras with aluminum foil with just a small hole for the lens as small as you can get it without interfering with the view. Most likely your cameras are using a frequency that has a harmonic on the GPS frequency and with a GPS having say 165db of sensitivity, you pretty much can not get far enough away on a flight string to realize some impact, but more shielding and space will likely help.

--Michael Willett

K5NOT

Show quoted text

On Mar 23, 2019, at 11:08 AM, Zack Clobes W0ZC <zclobes@...> wrote:

I'm looking for some ideas on troubleshooting some lock problems on a new board/capsule/camera design. The board has worked well during testing up until I started integration testing with the actual capsule with the cameras under it.

The capsule is about 6cm thick and is mostly two layers of foam. There are two cameras sandwiched in the middle and there is an aluminum bar holding them in place. The GPS antenna is as far away from that as I can get. Lid open or lid closed doesn't seem to make any difference.

During testing I noticed that this board would take a lot longer to get a lock than it's identical sister. Initially I thought it was a bad GPS or antenna, and eventually replaced both. Then I noticed if I unplug an external (optics) sensor, the GPS would lock up almost immediately.

So I nixed the sensor at the 11th hour and went flying. The GPS never locked on a single time during the whole flight. There's about 2m of separation to the next capsule.

This morning I plugged everything back in just like it flew, and it immediately got a lock. The only thing I noticed was that after powering up the cameras, the altitude was reading about 100 meters high. But I still had 5-9 sats.

I'm running low on ideas on what to try to isolate this problem.

Zack

<IMG_20190319_163333.jpg>

<IMG_20190319_163351.jpg>

MAX-M8Q GPS lock problem

Zack Clobes W0ZC

#16943

I'm looking for some ideas on troubleshooting some lock problems on a new board/capsule/camera design. The board has worked well during testing up until I started integration testing with the actual capsule with the cameras under it.

The capsule is about 6cm thick and is mostly two layers of foam. There are two cameras sandwiched in the middle and there is an aluminum bar holding them in place. The GPS antenna is as far away from that as I can get. Lid open or lid closed doesn't seem to make any difference.

During testing I noticed that this board would take a lot longer to get a lock than it's identical sister. Initially I thought it was a bad GPS or antenna, and eventually replaced both. Then I noticed if I unplug an external (optics) sensor, the GPS would lock up almost immediately.

So I nixed the sensor at the 11th hour and went flying. The GPS never locked on a single time during the whole flight. There's about 2m of separation to the next capsule.

This morning I plugged everything back in just like it flew, and it immediately got a lock. The only thing I noticed was that after powering up the cameras, the altitude was reading about 100 meters high. But I still had 5-9 sats.

I'm running low on ideas on what to try to isolate this problem.

Zack

Re: GPSL Registration

Bruce Coates

#16942

Hi Mike

Leigh (VE5LEE) and I (VE5BNC) had hoped to attend but, in a fit of wander lust, ended up booking a trip around Europe in June. GPSL is a ton of fun but Amsterdam, Prague, Vienna, Venice and Paris won out this time.

Have fun everyone!

Bruce - SABRE

Show quoted text

------ Original message------

From: Mike, n0mpm

Date: Thu, Mar 21, 2019 4:26 PM

To: GPSL@groups.io;

Cc:

Subject:[GPSL] GPSL Registration

GPSL 2019 registration is now open and available. Please go to “superlaunch.org” for details on hotels, registration fees, and group dinners. Hope to see you all in Pella, IA on June 13, 14 and 15 !!!!

Mike, n0mpm

GPSL Registration

Mike, n0mpm

#16941

GPSL 2019 registration is now open and available. Please go to “superlaunch.org” for details on hotels, registration fees, and group dinners. Hope to see you all in Pella, IA on June 13, 14 and 15 !!!!

Mike, n0mpm

GPS Rollover

Harry M

#16940

https://www.energy.gov/oe/articles/april-2019-global-positioning-system-gps-week-number-rollover

LightAPRS Tracker

Mustafa Tan

#16939

Hi,

Three years ago I was googling about high altitude balloons and I ended up with pico (floater) balloon projects. I was really impressed with some amateur radio operators efforts to circumnavigate around the world with party balloons and track them.

Six months later I got my amateur radio license and started flights with heavy APRS trackers. Since payload is very heavy, balloons maximum altitude never exceeded 9.000 meters and modules I used was not frequency agile.

So we (TA2MUN and TA9OHC) decided to develop a lightweight, extendable, affordable and open source APRS tracker. Since our tracker is very light and frequency agile, it's very convenient for pico (floater) balloon and HAB (High Altitude Balloon) projects. LightAPRS Tracker has been developed for nearly two years now and has been proven on many flights.

You can check out our tracker using following links:

Github page : https://github.com/lightaprs/LightAPRS-1.0
Shop : http://www.qrp-labs.com/lightaprs.html

Please do not hesitate to share if you have questions or comments about our tracker

TA2MUN

Re: Frequency selection for airborne cross band repeaters

Carlton Corbitt

#16938

One thing i think works well, if you are part of a ham club that has a working repeater. Is to put your balloon repeater output frequency the same as your clubs repeater output frequency. That way everyone has the output frequency already programmed into the mobile radios to listen while tracking.

And you should be able to know if your own clubs repeater is planning to be in use or not.

Carlton

KI4NHK

Re: Frequency selection for airborne crossband repeaters

Joe WB9SBD

#16937

Also since you are running ATV, if you are flying a GPS unit, try to separate it as far as possible from the ATV system, I have had both the transmitters and even just the video cameras desence the GPS so much it was useless.

Joe WB9SBD

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

Show quoted text

On 2/27/2019 12:52 PM, Bill Brown via Groups.Io wrote:

I would go with the 500 mW setting since it will likely have a high duty cycle and could overheat, even at 500 mW it could still overheat so try to mount the module on a good heatsink. Since you are running ATV on 70cm, you will want to transmit the crossband repeater on 70cm as well otherwise the receiver will be desensed by ATV EMI hash. But be aware to keep good separation between the ATV payload and the crossband repeater since you could see interference from the ATV transmitter getting into the 2m receiver as well. Perhaps a low-pass filter or bandpass filter in front of the receiver module would be a good idea. Also be aware that the ATV transmitter and camera could desense GPS receivers so also keep separation between the ATV payload and your balloon trackers.

- Bill WB8ELK

I would agree with other posts on this topic that it is best to stay with simplex frequencies. That's why I always fly with 446.025 out and 144.340 input or vice versa. The 446.025 frequency is not used a lot as compared to 446.000...although 445.975 and 446.300 are good alternates. Same for 144.340. It is primarily used nation-wide as an ATV talk frequency and occasionally for APRS links for balloon flights. The ATV folks don't mind and love to follow balloon flights and particularly appropriate in this case since you are flying an ATV transmitter. Even if someone is using 144.340 and not following your balloon, it won't matter since you won't interfere with them. I did fly a crossband repeater years ago from 73 Magazine headquarters in NH with 446.000 as the input and a 25 milliwatt 10m FM transmitter as the output during the VHF/UHF contest. It was a blast hearing all the mountaintop rover stations from well beyond typical line-of-sight ranges. Yes, that's right I used 10m as the output. It is legal to do so in the FM portion of 10m.

-----Original Message-----
From: Michael Hojnowski <kd2eat@...>
To: GPSL <GPSL@groups.io>
Sent: Wed, Feb 27, 2019 12:12 pm
Subject: Re: [GPSL] Frequency selection for airborne crossband repeaters

Well, I pulled the spreadsheet kept by the Upstate New York Repeater coordinators, and found a few frequencies that seem clear - 144.580 input, 447.025 output.

I'm going to try a few NiceRF SA828 Walkie Talkie modules. Not sure if I'll run them at 500mW or 1W. Since it'll be transmitting on 70cm, I'm inclined to use the lower power, since it'll have lower free space path loss. That would also reduce battery drain.

This is going to be an ambitious flight, including analog TV video on 70cm, the repeater, a payload drop initiated via DTMF tones, and with luck, the entire thing livestreamed onto youtube. We hope to have a ground station with a high gain beam tracking based on APRS beacons, and feeding into the youtube stream.

Bill / WB8ELK has me on the agenda to talk about the successes (or spectacular "lessons learned") at the Balloon Sat session at Dayton.

As the flight draws near, and we're confident we can livestream, I'll post URLs for those who would like to watch at home. Tentative flight date is Sunday, April 28 with a rain date on May 5.

Mike / KD2EAT
Advisor, Amateur Radio Club at Cornell

On 2/27/2019 12:23 PM, Joe wrote:

I agree with Bill on that Pairing.

FORGET repeater co-coordinators. We used them on the very first repeater flight ever.Way back in like 1989 or so. And They just do not understand the coverages we can get with these flights. And one of the UHF freqs we were suggested to use as being safe, ended up being a UHF link from a repeater system, satellite receivers. So in the middle of our flight, suddenly on the balloon was a swapnet happening.

But if you want quiet great freq the pair Bill stated below we have used probably a dozen times and have worked great every time.

Now if you really want to have FUN! Many will make me now to put on my Flame suit. But we have done it probably 4 times? But the biggest fun was this pair
146.52/446.000 Yup! It was crazy easily worked well over 300+ stations!

Mike what do you plan on usi9ng for equipment?

Will the repeater go both ways, think HT in crossband repeat but both directions.

Joe WB9SBD
KB9KHO
Near Space Sciences

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

On 2/27/2019 9:59 AM, Bill Brown via Groups.Io wrote:

I typically use 446.025 and 144.340. Both are simplex. For a simplex repeater i use 144.340. -Bill WB8ELK

On Feb 27, 2019, at 8:39 AM, Michael Hojnowski <kd2eat@...> wrote: Hey Gang, I'm intending to fly a cross-band repeater with a HAB in April. It occurs to me that I don't have a good idea of how to select frequencies. Should I be using one from the repeater input range on one band, and output on another? Should I be selecting simplex frequencies for this short term use? Should I attempt any kind of coordination with our regional frequency coordination groups? What have people done? Thanks for any advice, Mike / KD2EAT

Re: Frequency selection for airborne crossband repeaters

Joe WB9SBD

#16936

Mike,
As I and others have stated forget about the repeater co-oridinators. You say up state NY. how about 600 miles away? or at least 3 to 4 hundred because that is what your balloon will be hearing.

Get on line and look for a old Wyman Research ATV transmitter. I got two, (and no I will not ever let them go)

Reason is his transmitters are two for the price of 1 and battery budget because while he has the typical ATV signal AM on say 439.250 MHz, and the audio sub carrier. at 3 watts or so.

BUT he does magic! He FM Modulates the AM carrier also, so not only do you have the ATV signal. but a 3 watt 5 KHz FM signal for your cross band repeater transmitter!

Joe WB9SBD

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

Show quoted text

On 2/27/2019 12:11 PM, Michael Hojnowski wrote:

Well, I pulled the spreadsheet kept by the Upstate New York Repeater coordinators, and found a few frequencies that seem clear - 144.580 input, 447.025 output.

I'm going to try a few NiceRF SA828 Walkie Talkie modules. Not sure if I'll run them at 500mW or 1W. Since it'll be transmitting on 70cm, I'm inclined to use the lower power, since it'll have lower free space path loss. That would also reduce battery drain.

This is going to be an ambitious flight, including analog TV video on 70cm, the repeater, a payload drop initiated via DTMF tones, and with luck, the entire thing livestreamed onto youtube. We hope to have a ground station with a high gain beam tracking based on APRS beacons, and feeding into the youtube stream.

Bill / WB8ELK has me on the agenda to talk about the successes (or spectacular "lessons learned") at the Balloon Sat session at Dayton.

As the flight draws near, and we're confident we can livestream, I'll post URLs for those who would like to watch at home. Tentative flight date is Sunday, April 28 with a rain date on May 5.

Mike / KD2EAT
Advisor, Amateur Radio Club at Cornell

On 2/27/2019 12:23 PM, Joe wrote:
I agree with Bill on that Pairing.

FORGET repeater co-coordinators. We used them on the very first repeater flight ever.Way back in like 1989 or so. And They just do not understand the coverages we can get with these flights. And one of the UHF freqs we were suggested to use as being safe, ended up being a UHF link from a repeater system, satellite receivers. So in the middle of our flight, suddenly on the balloon was a swapnet happening.

But if you want quiet great freq the pair Bill stated below we have used probably a dozen times and have worked great every time.

Now if you really want to have FUN! Many will make me now to put on my Flame suit. But we have done it probably 4 times? But the biggest fun was this pair
146.52/446.000 Yup! It was crazy easily worked well over 300+ stations!

Mike what do you plan on usi9ng for equipment?

Will the repeater go both ways, think HT in crossband repeat but both directions.

Joe WB9SBD
KB9KHO
Near Space Sciences

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

On 2/27/2019 9:59 AM, Bill Brown via Groups.Io wrote:
I typically use 446.025 and 144.340. Both are simplex. For a simplex repeater i use 144.340. 
-Bill WB8ELK
On Feb 27, 2019, at 8:39 AM, Michael Hojnowski <kd2eat@...> wrote:

Hey Gang,

I'm intending to fly a cross-band repeater with a HAB in April.  It occurs to me that I don't have a good idea of how to select frequencies.  Should I be using one from the repeater input range on one band, and output on another?  Should I be selecting simplex frequencies for this short term use?  Should I attempt any kind of coordination with our regional frequency coordination groups?

What have people done?

Thanks for any advice,
Mike / KD2EAT

Re: Frequency selection for airborne crossband repeaters

Bill Brown

#16935

I would go with the 500 mW setting since it will likely have a high duty cycle and could overheat, even at 500 mW it could still overheat so try to mount the module on a good heatsink. Since you are running ATV on 70cm, you will want to transmit the crossband repeater on 70cm as well otherwise the receiver will be desensed by ATV EMI hash. But be aware to keep good separation between the ATV payload and the crossband repeater since you could see interference from the ATV transmitter getting into the 2m receiver as well. Perhaps a low-pass filter or bandpass filter in front of the receiver module would be a good idea. Also be aware that the ATV transmitter and camera could desense GPS receivers so also keep separation between the ATV payload and your balloon trackers.

- Bill WB8ELK

I would agree with other posts on this topic that it is best to stay with simplex frequencies. That's why I always fly with 446.025 out and 144.340 input or vice versa. The 446.025 frequency is not used a lot as compared to 446.000...although 445.975 and 446.300 are good alternates. Same for 144.340. It is primarily used nation-wide as an ATV talk frequency and occasionally for APRS links for balloon flights. The ATV folks don't mind and love to follow balloon flights and particularly appropriate in this case since you are flying an ATV transmitter. Even if someone is using 144.340 and not following your balloon, it won't matter since you won't interfere with them. I did fly a crossband repeater years ago from 73 Magazine headquarters in NH with 446.000 as the input and a 25 milliwatt 10m FM transmitter as the output during the VHF/UHF contest. It was a blast hearing all the mountaintop rover stations from well beyond typical line-of-sight ranges. Yes, that's right I used 10m as the output. It is legal to do so in the FM portion of 10m.

Show quoted text

-----Original Message-----
From: Michael Hojnowski <kd2eat@...>
To: GPSL <GPSL@groups.io>
Sent: Wed, Feb 27, 2019 12:12 pm
Subject: Re: [GPSL] Frequency selection for airborne crossband repeaters

Well, I pulled the spreadsheet kept by the Upstate New York Repeater coordinators, and found a few frequencies that seem clear - 144.580 input, 447.025 output.

I'm going to try a few NiceRF SA828 Walkie Talkie modules. Not sure if I'll run them at 500mW or 1W. Since it'll be transmitting on 70cm, I'm inclined to use the lower power, since it'll have lower free space path loss. That would also reduce battery drain.

This is going to be an ambitious flight, including analog TV video on 70cm, the repeater, a payload drop initiated via DTMF tones, and with luck, the entire thing livestreamed onto youtube. We hope to have a ground station with a high gain beam tracking based on APRS beacons, and feeding into the youtube stream.

Bill / WB8ELK has me on the agenda to talk about the successes (or spectacular "lessons learned") at the Balloon Sat session at Dayton.

As the flight draws near, and we're confident we can livestream, I'll post URLs for those who would like to watch at home. Tentative flight date is Sunday, April 28 with a rain date on May 5.

Mike / KD2EAT
Advisor, Amateur Radio Club at Cornell

On 2/27/2019 12:23 PM, Joe wrote:

I agree with Bill on that Pairing.

FORGET repeater co-coordinators. We used them on the very first repeater flight ever.Way back in like 1989 or so. And They just do not understand the coverages we can get with these flights. And one of the UHF freqs we were suggested to use as being safe, ended up being a UHF link from a repeater system, satellite receivers. So in the middle of our flight, suddenly on the balloon was a swapnet happening.

But if you want quiet great freq the pair Bill stated below we have used probably a dozen times and have worked great every time.

Now if you really want to have FUN! Many will make me now to put on my Flame suit. But we have done it probably 4 times? But the biggest fun was this pair
146.52/446.000 Yup! It was crazy easily worked well over 300+ stations!

Mike what do you plan on usi9ng for equipment?

Will the repeater go both ways, think HT in crossband repeat but both directions.

Joe WB9SBD
KB9KHO
Near Space Sciences

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

On 2/27/2019 9:59 AM, Bill Brown via Groups.Io wrote:

I typically use 446.025 and 144.340. Both are simplex. For a simplex repeater i use 144.340. 
-Bill WB8ELK

On Feb 27, 2019, at 8:39 AM, Michael Hojnowski <kd2eat@...> wrote:

Hey Gang,

I'm intending to fly a cross-band repeater with a HAB in April.  It occurs to me that I don't have a good idea of how to select frequencies.  Should I be using one from the repeater input range on one band, and output on another?  Should I be selecting simplex frequencies for this short term use?  Should I attempt any kind of coordination with our regional frequency coordination groups?

What have people done?

Thanks for any advice,
Mike / KD2EAT

Re: Frequency selection for airborne crossband repeaters

Michael Hojnowski

#16934

Well, I pulled the spreadsheet kept by the Upstate New York Repeater coordinators, and found a few frequencies that seem clear - 144.580 input, 447.025 output.

I'm going to try a few NiceRF SA828 Walkie Talkie modules. Not sure if I'll run them at 500mW or 1W. Since it'll be transmitting on 70cm, I'm inclined to use the lower power, since it'll have lower free space path loss. That would also reduce battery drain.

This is going to be an ambitious flight, including analog TV video on 70cm, the repeater, a payload drop initiated via DTMF tones, and with luck, the entire thing livestreamed onto youtube. We hope to have a ground station with a high gain beam tracking based on APRS beacons, and feeding into the youtube stream.

Bill / WB8ELK has me on the agenda to talk about the successes (or spectacular "lessons learned") at the Balloon Sat session at Dayton.

As the flight draws near, and we're confident we can livestream, I'll post URLs for those who would like to watch at home. Tentative flight date is Sunday, April 28 with a rain date on May 5.

Mike / KD2EAT
Advisor, Amateur Radio Club at Cornell

Show quoted text

On 2/27/2019 12:23 PM, Joe wrote:

I agree with Bill on that Pairing.

FORGET repeater co-coordinators. We used them on the very first repeater flight ever.Way back in like 1989 or so. And They just do not understand the coverages we can get with these flights. And one of the UHF freqs we were suggested to use as being safe, ended up being a UHF link from a repeater system, satellite receivers. So in the middle of our flight, suddenly on the balloon was a swapnet happening.

But if you want quiet great freq the pair Bill stated below we have used probably a dozen times and have worked great every time.

Now if you really want to have FUN! Many will make me now to put on my Flame suit. But we have done it probably 4 times? But the biggest fun was this pair
146.52/446.000 Yup! It was crazy easily worked well over 300+ stations!

Mike what do you plan on usi9ng for equipment?

Will the repeater go both ways, think HT in crossband repeat but both directions.

Joe WB9SBD
KB9KHO
Near Space Sciences

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

On 2/27/2019 9:59 AM, Bill Brown via Groups.Io wrote:
I typically use 446.025 and 144.340. Both are simplex. For a simplex repeater i use 144.340. 
-Bill WB8ELK
On Feb 27, 2019, at 8:39 AM, Michael Hojnowski <kd2eat@...> wrote:

Hey Gang,

I'm intending to fly a cross-band repeater with a HAB in April.  It occurs to me that I don't have a good idea of how to select frequencies.  Should I be using one from the repeater input range on one band, and output on another?  Should I be selecting simplex frequencies for this short term use?  Should I attempt any kind of coordination with our regional frequency coordination groups?

What have people done?

Thanks for any advice,
Mike / KD2EAT

Re: Frequency selection for airborne cross band repeaters

Barry

#16933

A couple of things come to mind. 

The most important choice is the input freq as, not long after you launch, you'll be receiving any/all transmissions within hundreds of miles with no easy way to contact those making the transmissions to explain the situation and ask them to move to a different freq which means the cross-band repeater will basically become useless. Therefore I would stay away from using a repeater freq unless you are 100% sure there aren't any using your chosen input freq as either an input or output freq. For the same reason you should avoid using the simplex calling freq or any other simplex freq that some group may have chosen to use for their simplex conversations. This may be hard to determine and you'll have to simply ask around and hope for the best. Anyway, in the past we have always used a UHF simplex freq several channels away from the calling freq as UHF basically eliminated the chance of having a problem with our APRS VHF transmissions affecting the cross band receiver plus we would have much less UHF simplex activity to worry about. Therefore our cross band transmissions had to be VHF which was preferred as many more amateurs have VHF transceivers than UHF and allowed more to participate (even though simply by listening). 

The output freg is not nearly as important as anyone that may be on the freq can/will simply move to a free channel. Most are quite forgiving (or should be) and after hearing a few cross band transmissions will likely realize what's going on, especially if there's a control operator, like we had, that regularly explains the situation and the input freq being used for anyone listening that may want to join in on the fun. (I believe we reached about 100,000ft and our furthest contact was from about 600 miles away. I'm pretty sure there aren't any unused VHF repeater freq's that could have been used and guessing the situation is most likely the same just about anywhere in the US.).

Barry - VE6SBS

Show quoted text

-----Original Message-----
From: GPSL@groups.io [mailto:GPSL@groups.io] On Behalf Of Michael Hojnowski
Sent: Wednesday, February 27, 2019 7:40 AM
To: GPSL list
Subject: [GPSL] Frequency selection for airborne crossband repeaters

Hey Gang,

I'm intending to fly a cross-band repeater with a HAB in April.  It
occurs to me that I don't have a good idea of how to select
frequencies.  Should I be using one from the repeater input range on one
band, and output on another?  Should I be selecting simplex frequencies
for this short term use?  Should I attempt any kind of coordination with
our regional frequency coordination groups?

What have people done?

Thanks for any advice,
Mike / KD2EAT

Re: Frequency selection for airborne crossband repeaters

Joe WB9SBD

#16932

I agree with Bill on that Pairing.

FORGET repeater co-coordinators. We used them on the very first repeater flight ever.Way back in like 1989 or so. And They just do not understand the coverages we can get with these flights. And one of the UHF freqs we were suggested to use as being safe, ended up being a UHF link from a repeater system, satellite receivers. So in the middle of our flight, suddenly on the balloon was a swapnet happening.

But if you want quiet great freq the pair Bill stated below we have used probably a dozen times and have worked great every time.

Now if you really want to have FUN! Many will make me now to put on my Flame suit. But we have done it probably 4 times? But the biggest fun was this pair
146.52/446.000 Yup! It was crazy easily worked well over 300+ stations!

Mike what do you plan on usi9ng for equipment?

Will the repeater go both ways, think HT in crossband repeat but both directions.

Joe WB9SBD
KB9KHO
Near Space Sciences

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

Show quoted text

On 2/27/2019 9:59 AM, Bill Brown via Groups.Io wrote:

I typically use 446.025 and 144.340. Both are simplex. For a simplex repeater i use 144.340. 
-Bill WB8ELK

On Feb 27, 2019, at 8:39 AM, Michael Hojnowski <kd2eat@...> wrote:

Hey Gang,

I'm intending to fly a cross-band repeater with a HAB in April.  It occurs to me that I don't have a good idea of how to select frequencies.  Should I be using one from the repeater input range on one band, and output on another?  Should I be selecting simplex frequencies for this short term use?  Should I attempt any kind of coordination with our regional frequency coordination groups?

What have people done?

Thanks for any advice,
Mike / KD2EAT

Re: Frequency selection for airborne crossband repeaters

Bill Brown

#16931

I typically use 446.025 and 144.340. Both are simplex. For a simplex repeater i use 144.340. 
-Bill WB8ELK

Show quoted text

On Feb 27, 2019, at 8:39 AM, Michael Hojnowski <kd2eat@gmail.com> wrote:

Hey Gang,

I'm intending to fly a cross-band repeater with a HAB in April.  It occurs to me that I don't have a good idea of how to select frequencies.  Should I be using one from the repeater input range on one band, and output on another?  Should I be selecting simplex frequencies for this short term use?  Should I attempt any kind of coordination with our regional frequency coordination groups?

What have people done?

Thanks for any advice,
Mike / KD2EAT