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uscjones

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Sorry if this flags as a redundant thread (no pun intended), but the only other thread I found on this didn't answer my questions, so I decided to start my own. Anyway...

For my L3 project, I'm planning to build a 75 mm MD and stick an M2245 in it, which by all accounts and sims looks like I'll easily be over 40k ft, so obviously some tracking is required. I've already got a Telemetrum V2.0 that's worked well for me in the past and will serve as my primary ejection altimeter and tracker, but I was worried about signal strength and wanted to add some redundancy to my tracking, so I was thinking of putting a BRB or other brand of higher-powered RDF Beacon in there....both units would be mounted in a nosecone avbay, about 2 inches apart, with the antennas parallel, but slightly staggered -- the base of one is a couple inches above the base of the other, and correspondingly sticks up a little higher, too. Neither can be moved for better spacing, bc that's the only radio-transparent part of the rocket. For receiving, currently I'm using a 3-element Arrow yagi with the TeleBT, and if I added a 70 cm RDF I'd likely buy a 5-element and hook it up to my HT, then build a boom to keep the two antennae well-separated but still able to be held and monitored by one person. All that said, my questions are:

- First off, is this even worth it? Has anybody taken a Telemetrum V2.0 to 40-50k and has some feedback to offer on their signal transmission reliability at those altitudes? Also a bit worried about line-of-sight distance after it's on the ground...Every time I've used the TM2.0 for tracking it's only been able to give me a "last GPS fix" rather than live tracking all the way to recovery, and a windy playa might take it and run.
- If I'm running them both at 70 cm, I assume that even on different frequencies I'll get at least some level of interference, but how much? Too much to make the redundancy worth it?
- Would it help to run one of them in 915 MHz (BRB is also available in this band)? If so, can someone recommend a good handheld antenna for that band? Maybe Arrow's Fox Hunt Loop, then I'll just null-line it?

Thanks for your help.
 

ksaves2

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Are you going to 40 to 50k on an L3 flight? If you use two trackers on the same band, be certain there is some separation in their frequencies. The TeleMetrum V2 is 40mW output so with a 5 to 7 element Yagi you improve your chances of decoding packets. I don't know if it would be good for 40 to 50k. Perhaps someone who's gone there can comment. You could get a higher powered Beeline RDF tracker at 100mW and that should perform well as a backup tracker at those heights.

I don't think an EggFinder would perform all that well at that altitude. If the rocket doesn't go that far downrange, you could pick up the location as it gets lower. A patch antenna on 900Mhzantennastick.jpg is what you really need on the 900Mhz band. I have mine attached to a pole to get it off the ground. Do not attempt to use a 900Mhz Yagi for in-flight tracking as the beamwidth of the antenna is too narrow to reliably point at the rocket. Especially since a flight at those levels could end up totally sight unseen. Once the rocket is down, one can use a 900Mhz Yagi to increase the ground footprint of the tracker as the rocket isn't generally moving that fast.

If you want to be foolproof with a GPS tracker one could do a 100mW 70cm Beeline GPS tracker. That altitude should be possible to easily track at 40 to 50k. Another cheaper option that would be good at altitude for positioning
but not so good with altitude reporting is a Sainsonic AP510. It's on the 2meter band, tunable and don't have to have it on the national 144.390 frequency. Learning curve is high for that one but 1.1 watts is plenty of output.
Only drawback is the size. On a 4 inch 5:1 or 6:1 nosecone it would carry a nice antenna and could likely hit 100k without a problem. The Sirf4 chipset is allegedly not so accurate with altitudes although some balloon guys
told me they flew an AP510 as backup to a Beeline GPS and in the low dynamic state of a high altitude balloon the AP510 recorded altitudes that corresponded well with the Beeline GPS. This was close to 100k altitude as I recall.

Byonics has a 1 watt and 2 watt 2meter tunable trackers but one has to get their own batteries and be comfortable wiring in their own GPS. One can use a Ublox chipset if they desire. https://www.byonics.com/mt-2000

A fellow posted a link to the 300mW Tracksoar but I'm concerned about the tiny chip GPS antenna being reliable for a high dynamic rocket flight. https://www.tracksoar.com/
Plus you have to buy your own Radiometrix chip. I'd consider 144.800 so not to have to worry about congestion. That device would cost as much as an HP BeelineGPS on 70cm after getting the programming shield
and the Rf chip. Actually, I'm waiting to see a rocket person fly one and report back as to how it performs. A couple of folks have them. Would be a nice addition if it works out but I have my
reservation with that dinky GPS receive antenna. The Tracksoar is enticing with its small size and 300mW power output.

I recommend if you get a 2 meter band tracker get one that is tunable so you don't have to use 144.390. If you're in a high traffic area, your receiver may get clogged with positions from other APRS stations.
That would interfere with your collection of positions from your rocket.

With 33cm (900Mhz) Missileworks has a 250mW tracker as does Beeline. These might be more serviceable with the higher power output. Be aware that the ground foot print with comparable
antenna systems is 33cm<70cm<1.25m<2meters.

With adjacent frequencies one wants to avoid harmonics. Check in a Ham radio manual. Plus if you run the lower powered tracker in the ebay and the higher powered one in the NC you should be ok. Many folks duct tape
a "contained" Beeline RDF on the harness while a GPS tracker runs in another part of the rocket. Always, always, always do a ground range test in an open area if possible of your system(s)
operating in their intended bays.

You take your pick. Size? Power output? Battery requirements? Ease of using "right out of the box" vs. having to cobble bits to a "base tracking unit" to get it to work?

Oh, if you are flying on the playa, getting the last known packet at altitude is all you are going to get. Once your rocket is down, the playa sucks up Rf like a sponge. It is a well known observation and it's said
that dissolved salts in the subsurface attenuates Rf close to ground level. One is O.K. with the rocket at altitude but once down, the ground footprint is very small.
I posted this observation on TRF before and a few people pooh-poohed it. I did admit I never flew there but reported what was said to me in correspondence. I was fortunate that an experienced flier who has flown
there spoke up, posted and essentially stated it was true. RDF guys have a very hard time tracking once the rocket is down because they can't hold a bearing once the rocket is down. With GPS, propagation is fine in the air and can
get that "last known fix" to get you to the location where the rocket likely resides.

If your project is going to go a good distance downrange on the playa, a GPS tracker is a must if you want to have a chance to find the rocket quickly. In the Midwest, GPS is fine with RDF backup but we don't have the
propagation issues of the playa. Your best bet is the highest powered GPS tracker you can carry on the rocket. RDF backup in that case would only help insure the ground footprint if the GPS tracker fails close to or after
touchdown. If your GPS tracker fails early in the flight for whatever reason, unless you can hold a bearing with the tracking Yagi until after touchdown, you are SOL.

Now you could invest in a Garmin Mapping GPS that has a "Sight n' Go" feature: https://www.manualslib.com/manual/56166/Garmin-Etrex-Vista-Cx.html?page=62 for an explanation.

One would have the device ready to lock a bearing and hold it parallel to the Yagi beam antenna. When the maximum signal is detected, the bearing can be "locked" in the mapping GPS
and one would just have to start following the bearing on the Etrex Vista HcX (in this example) I love this feature with modrocs and wear one around my neck whenever I fly. Great to lock a bearing on a rocket you have
a visual on. I once lost an HPR rocket and went out to search for it. I was quite a distance "short" of the rocket when I espied it across a 15' deep drainage ditch. It was still quite a distance away stuck in the corn stubble.
I caught glimpses of the parachute blowing "up" in the wind. The rocket was stationary as it was stuck. I shot a line to it with the the Etrex Vista HcX and had to walk about 1/2 mile to the west to be able cross over the ditch.
The Vista kept track of the point and I followed the bearing from this new position and walked right up to the rocket. Shooting a bearing of course doesn't give a distance but if pointed accurately one will eventually get to
the general area. Good luck on your choice and whoa, doing a 40 to 50k L3 attempt is mighty aggressive. Kurt
 
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Viperfixr

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Oh, if you are flying on the playa, getting the last known packet at altitude is all you are going to get. Once your rocket is down, the playa sucks up Rf like a sponge. It is a well known observation and it's said
that dissolved salts in the subsurface attenuates Rf close to ground level. One is O.K. with the rocket at altitude but once down, the ground footprint is very small.
I posted this observation on TRF before and a few people pooh-poohed it.
I've experienced this many times as well. It's actually useful for knowing when the rocket lands when you cannot see it. Not to get too far off track, but I have been wondering about using quadcopters to help locate lost or unseen landing rockets (I have a Parrot Bebop 2, but looking at a DJI Mavic). I wonder if a antenna & receiver/transmitter could be easily added to a quad and relay the signal even if on the ground. Just a thought...
 

ksaves2

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I've experienced this many times as well. It's actually useful for knowing when the rocket lands when you cannot see it. Not to get too far off track, but I have been wondering about using quadcopters to help locate lost or unseen landing rockets (I have a Parrot Bebop 2, but looking at a DJI Mavic). I wonder if a antenna & receiver/transmitter could be easily added to a quad and relay the signal even if on the ground. Just a thought...
With one of those fancy, pricey copters, one could tell it to "go to" the last known GPS position to start a visual search. Now that would be getting
really lazy. Kurt
 

uscjones

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Thanks for the reply, Kurt....

Hmm....I was trying to get away from GPS tracking, as I wasn't keen on spending another $200-300 on a tracker I'll likely only use again on flights like this....I'm going to Black Rock to do this flight, my normal launch site (ROC, in Southern California) only has a waiver of 14.5k, so the Telemetrum is sufficient for pretty much anything I'd be doing on a regular basis. But it seems like the RF interference of flying on a playa is going to screw me into buying another one or abandoning the idea altogether. My normal launch site is also a playa, and I know a bunch of guys there use RDF trackers, but the lower waiver (and shorter drift distances, accordingly) probably means they're still inside the footprint even when the signal gets attenuated by the playa. ROC or AEROPAC guys, if you read this, would you care to weigh in?

Also, there is a thread I've seen where a couple guys flew a rocket to 60k at BALLS using a Telemetrum, and they said it worked great for their tracking purposes....so I think this really would just be a backup, and likely only to give me something extra to lock onto as I get closer to it after using the last known GPS position to get in the ballpark. You mentioned that as long as I had plenty of spread on my frequencies, I could run both in the 70 cm band and not get a ton of interference, especially if I switched to a 5 or 7-element yagi? Unfortunately, as I said, I don't really have the option to put a ton of space between them, as, for one thing, it's a 3", not 4", my total length (including nose cone) is only 73" (including 3" for a gopro bay and 42" just for the motor and retainer/bulkhead), and I don't have a midship avbay (single break, reefing the main), everything's in the nose cone, along with a dual CO2 system for the apogee charges, so space is really at a premium. I could look at taping it to my shock cord, but I'd really rather not, as my chute bay is also going to be packed pretty tight, so the odds of it getting ripped off on the way out are pretty good.

And yeah, I know doing a high-speed, high-altitude launch like that on a cert flight goes against the conventional wisdom of cert flights, but I figure I won't be buying a ton of M, N, or O motors, and likely not more than one at a time unless I'm doing a crazy staged project, and there's no cert past L3, so I figured shoot for the moon (or at least the upper end of Class A airspace :p), and if I fail, it's really not keeping me from anything.
 

FMarvinS

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I agree with Kurt-I have 2 BRB 70 cm trackers and it should work fine at 40,000 feet if appropriate antennas are utilized. I'd ground test your GPS and tracking transmitters fully to ascertain optimal performance on antenna placement and frequency choice. The BRB 100 mw 70cm band tracker frequency is programmable. Also, you may want to consider mounting one antenna on the NC bulkhead externally and attached to the bulkhead via an SMA connector whose cable runs internally to the transmitter. When your chute is deployed, this enable the antenna to be propagating in the open air. I prefer the latter to taping the tracker to the shroud lines and risk losing the tracker if the tape doesn't hold. Good luck, I'd be interested in knowing both the results of your ground testing & the actual performance during flight.

Fred, L2
KG4YGP
 

tfish

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In my 3" rockets I usually fly both GPS and Tx. Just ground test them to make sure they are both compatible to each other and to your electronics. Here's how. Do a rough mock up, turn on the Tx and go for a walk and see how far you get a signal. Remember that spot. Go back and turn on your GPS, go for another walk. Same? Different? Better? Now go back and turn off your Tx. Go for a walk. How far for the GPS? Go back and turn on the TX and check the GPS Distance. Now put ematches only on your electronics. Turn on both GPS and Tx and go check your distances again? Did any ematches fire? How was the GPS and Tx distances do? You will have better distances in the air.
I like tracking with Tx. Probably because it's more interactive. Never talk to a guy using a Yagi. I hate it when people come up and want to talk. Actively track the TX. I constantly scrub a line in the playa with my foot as I'm tracking. Keep a mental idea of the center of your side to side swings. Also track the elevation so you know about when your going to loose the signal. If your buddies are standing around talk to them.."the signal is strongest just to the right of the far away pad on the left. It seems to e moving to the right" etc. Take a photo of a landmark off in the distance where you last had a signal.
You do lose signal once the rocket lands. I set my main chutes on all my rockets at 3000'. Gives me a bit more time to dial in the general area. Check the jet stream before you fly. which way is it blowing. How fast? How long are you going to be in it? Where have other rockets been landing? Out on the playa, where are other guys driving out too?
A couple years ago I had the main come out at apogee. My last GPS packet was a tad over 6K and on the edge of the playa. That one took some hunting to recover. I never could re-aquire GPS or Tx. The rocket landed in a gulley. But I did find it in a gulley at the base of a mountain, which is better then in a gulley on top of a mountain, found that one too!

sorry for rambling...

Tony
 

uscjones

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Hmm, that's a thought to calm my antenna separation anxiety. Is there such a thing as a 1/8th wave antenna? My NC bulkhead will be recessed into the nose cone by a few inches to "cheat" some volume out of the airframe, so I'd be a little worried about the shock cord scraping the antenna across the coupler edge and damaging it, but if I could use a 3.5" antenna rather than a 7" one, that would be my ideal solution...if not, do you think a simple wire rather than a semi-rigid whip would be better?
 

FMarvinS

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I've used "shortened rubber ducky" 70 cm band antennas without shock cord problems. Also, you can use a helical antenna which is shorter than 3.5 inches in height for the 70 cm band. You could easily make one or alternatively, BRB sells them for SMA connections and they are maybe an inch tall. The only caveat is that propagation from a helical antenna won't be as effective as a vertical style antenna.
 

uscjones

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Thanks Tony, I was definitely going to do some testing like that, just to verify the setup (and I will be doing it on my home playa to simulate RF loss to the playa, before anyone asks), but I haven't actually bought the Tx or built the avbay/NC yet, so I wanted to make sure I wouldn't be spending $$ on a BRB Tx and an extra receiving antenna and taking the time to design mounts for both just for nothing. It seems from everyone's responses (including yours, thanks!) that I should be at least okay with putting both devices in one bay, and it's given me some ideas on how I can mount them for the best separation, so at least I can move forward with that. Just out of curiosity, how do you handle the two antennas for your two trackers? Do you still use a yagi for your GPS one, then have some kind of bracket to be able to hold them both, or do you just have a simple vertical antenna for the GPS? That was another thing I was considering to make my setup easier, but couldn't find any data or recommendations about people using the Telemetrum with a vertical antenna as their receiver....

And thank you, Fred, I'll look into getting a little rubber ducky, I think that's the ticket....didn't think of that, but now that you mention it, I could probably just pull the one off my HT and use that, since I'll have a yagi hooked up to that anyways for RDF.
 

ksaves2

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Thanks for the reply, Kurt....

Hmm....I was trying to get away from GPS tracking, as I wasn't keen on spending another $200-300 on a tracker I'll likely only use again on flights like this....I'm going to Black Rock to do this flight, my normal launch site (ROC, in Southern California) only has a waiver of 14.5k, so the Telemetrum is sufficient for pretty much anything I'd be doing on a regular basis. But it seems like the RF interference of flying on a playa is going to screw me into buying another one or abandoning the idea altogether. My normal launch site is also a playa, and I know a bunch of guys there use RDF trackers, but the lower waiver (and shorter drift distances, accordingly) probably means they're still inside the footprint even when the signal gets attenuated by the playa. ROC or AEROPAC guys, if you read this, would you care to weigh in?

Also, there is a thread I've seen where a couple guys flew a rocket to 60k at BALLS using a Telemetrum, and they said it worked great for their tracking purposes....so I think this really would just be a backup, and likely only to give me something extra to lock onto as I get closer to it after using the last known GPS position to get in the ballpark. You mentioned that as long as I had plenty of spread on my frequencies, I could run both in the 70 cm band and not get a ton of interference, especially if I switched to a 5 or 7-element yagi? Unfortunately, as I said, I don't really have the option to put a ton of space between them, as, for one thing, it's a 3", not 4", my total length (including nose cone) is only 73" (including 3" for a gopro bay and 42" just for the motor and retainer/bulkhead), and I don't have a midship avbay (single break, reefing the main), everything's in the nose cone, along with a dual CO2 system for the apogee charges, so space is really at a premium. I could look at taping it to my shock cord, but I'd really rather not, as my chute bay is also going to be packed pretty tight, so the odds of it getting ripped off on the way out are pretty good.

And yeah, I know doing a high-speed, high-altitude launch like that on a cert flight goes against the conventional wisdom of cert flights, but I figure I won't be buying a ton of M, N, or O motors, and likely not more than one at a time unless I'm doing a crazy staged project, and there's no cert past L3, so I figured shoot for the moon (or at least the upper end of Class A airspace :p), and if I fail, it's really not keeping me from anything.
Remember. It's not a problem with the rocket at altitude. It's after it's down. You run the Telemetrum you'll likely get some positions while it is close to touchdown. Just proceed where the GPS tracker said it was and you'll likely be close enough to see it. Kurt
 

ksaves2

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In my 3" rockets I usually fly both GPS and Tx. Just ground test them to make sure they are both compatible to each other and to your electronics. Here's how. Do a rough mock up, turn on the Tx and go for a walk and see how far you get a signal. Remember that spot. Go back and turn on your GPS, go for another walk. Same? Different? Better? Now go back and turn off your Tx. Go for a walk. How far for the GPS? Go back and turn on the TX and check the GPS Distance. Now put ematches only on your electronics. Turn on both GPS and Tx and go check your distances again? Did any ematches fire? How was the GPS and Tx distances do? You will have better distances in the air.
I like tracking with Tx. Probably because it's more interactive. Never talk to a guy using a Yagi. I hate it when people come up and want to talk. Actively track the TX. I constantly scrub a line in the playa with my foot as I'm tracking. Keep a mental idea of the center of your side to side swings. Also track the elevation so you know about when your going to loose the signal. If your buddies are standing around talk to them.."the signal is strongest just to the right of the far away pad on the left. It seems to e moving to the right" etc. Take a photo of a landmark off in the distance where you last had a signal.
You do lose signal once the rocket lands. I set my main chutes on all my rockets at 3000'. Gives me a bit more time to dial in the general area. Check the jet stream before you fly. which way is it blowing. How fast? How long are you going to be in it? Where have other rockets been landing? Out on the playa, where are other guys driving out too?
A couple years ago I had the main come out at apogee. My last GPS packet was a tad over 6K and on the edge of the playa. That one took some hunting to recover. I never could re-aquire GPS or Tx. The rocket landed in a gulley. But I did find it in a gulley at the base of a mountain, which is better then in a gulley on top of a mountain, found that one too!

sorry for rambling...

Tony
This is good advice except I'm stuck in the Midwest and want to fly as many rockets per session as I can get up. Folks who have more opportunities to fly, RDF can be rewarding but I don't want to be messing with it with high fliers because of the potential of being able to find a totally sight unseen flight more quickly and getting back to fly the next one. Setting the main chute deployment high (and geez which devices allow that? Ravens?) allows for better "at altitude" propagation and as Tony mentions, more time to get a good fix for RDF. Of course the bearing can be changing quickly with wind until just before touchdown. I've been setting my mains at 1000' or above in the Midwest just to get more "hang time" for EggFinder testing. I haven't lost a rocket but more positions are recorded with a patch antenna on the receive end. Simple duck antennas miss more on the receive end but they'll be enough positions coming through to get one within the ground footprint of most sport rockets. I do the same thing with my Ham APRS trackers although Yagis are ok there. The altitude readouts are more accurate with anything but the Sirf "brand"
based terrestrial trackers. They're fine for position though.

Oh, one other bit of advice for uscjones. If you are running two trackers, at least on the certification flight, Have two people doing the tracking. One on the GPS receive station and if possible an experienced RDF person
on that station. It's too much for you to keep track of while the flight is in progress. If you're on the GPS station, you can yell out the positions and that can cue the RDF person as to the direction of the maximum to point
the Yagi or Patch antenna as the case may be. One thing on antennas: Use the best antenna on your transmitter you can properly fit in your installation. Short and stubby might not be advisable for a 40 to 50k flight.
Also we all know carbon fiber attenuates Rf and need to avoid that for a tracker bay....... But, do you know that the "black" non-CF nosecones use lampblack (er, um another form of carbon) as a colorant? Also a fellow posted
there was something like a 1dB attenuation (not much) with the tracker inside the nosecone with testing as opposed to the antenna in free air. Food for thought. Perhaps avoid a 16mW Beeline GPS in a "black" nosecone that is
travelling to a 5 figure altitude level with the potential to drift a long ways on the playa. Pick the tracker power to fit the venue, antenna and installation. Kurt
 
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Adrian A

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Oh, if you are flying on the playa, getting the last known packet at altitude is all you are going to get. Once your rocket is down, the playa sucks up Rf like a sponge. It is a well known observation and it's said
that dissolved salts in the subsurface attenuates Rf close to ground level. One is O.K. with the rocket at altitude but once down, the ground footprint is very small.
I posted this observation on TRF before and a few people pooh-poohed it. I did admit I never flew there but reported what was said to me in correspondence. I was fortunate that an experienced flier who has flown
there spoke up, posted and essentially stated it was true. RDF guys have a very hard time tracking once the rocket is down because they can't hold a bearing once the rocket is down. With GPS, propagation is fine in the air and can
get that "last known fix" to get you to the location where the rocket likely resides.
I have experienced this myself, and can quantify it somewhat.

I have range-tested the Telemetrum 1.0 and gotten over 10 miles with a clear line of sight across town (across a valley). I went to the playa and did a range check of the same unit, and had less than 1 mile range, even with the transmitter suspended from an EZ-up 6 feet up and my receiving antenna over my head. I don't know the physics of this, but it really does suck up the RF like nobody's business when trying to transmit horizontally.
 

ksaves2

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Great confirmation Adrian. Reinforces the technique of opening the main up high to get as many positions as possible to get one close to the "smaller" ground footprint of a tracker. Kurt
 

Titan II

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Setting the main chute deployment high (and geez which devices allow that? Ravens?)
RRC3 3,000'

StratoLoggerCF 9,999'
 

uscjones

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Yikes, thanks Adrian. I guess I'm opening my main high up, then....maybe around 3k? I was planning to do at least 1500 ft anyways, as I'm using a deployment bag and want to give the main enough time to deploy. I'm also using a main that's slightly oversized (Iris Ultra 60", FC claims 20 fps @ 19 lbs, my rocket models at around 13 lbs post-burn), so that should give me some extra time to zero in on it if I lose my GPS, too. And thanks, Kurt, those are all good points....unfortunately I don't know anyone who's experienced with RDF that will for sure be there with me, but I should have some willing-to-learn help. As far as antenna location, I don't have much choice with my Telemetrum bc it's got the basic soldered-on wire whip, and I don't really want to mess with re-soldering an SMA connector on, but I will definitely take your advice on getting the RDF antenna out of the NC...I think if I place it properly, a 7" whip can be okay with my setup.
 

ksaves2

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Yikes, thanks Adrian. I guess I'm opening my main high up, then....maybe around 3k? I was planning to do at least 1500 ft anyways, as I'm using a deployment bag and want to give the main enough time to deploy. I'm also using a main that's slightly oversized (Iris Ultra 60", FC claims 20 fps @ 19 lbs, my rocket models at around 13 lbs post-burn), so that should give me some extra time to zero in on it if I lose my GPS, too. And thanks, Kurt, those are all good points....unfortunately I don't know anyone who's experienced with RDF that will for sure be there with me, but I should have some willing-to-learn help. As far as antenna location, I don't have much choice with my Telemetrum bc it's got the basic soldered-on wire whip, and I don't really want to mess with re-soldering an SMA connector on, but I will definitely take your advice on getting the RDF antenna out of the NC...I think if I place it properly, a 7" whip can be okay with my setup.
If faced with the fixed wire then you try to improve the receive end which would be a 70cm Yagi. Keith and B'dale did a lot of work on their antenna wire lengths
and I remember Keith saying something like the wire worked better than anything screwed in a socket with their units.

If you know how to RDF, put the less experience person on to monitor the GPS receiver to call out directions and altitude and you can do the RDF stuff!:wink:

A "non-black" FG nosecone is fine. A NC with a non-metallic paint is fine. CF is a no-no.

I put the lower powered BeelineGPS (16mW) in the same ebay as a Raven II altimeter in a Wildman Jr rocket. The BLGPS rides on top of the Raven with the wire antenna projecting up into the main chute bay through a very tight tolerance hole in the bulkhead.
I use the cardboard tube that AT wired igniters come in as a stent for the antenna and use a grout or clay to help seal the base of the antenna wire where it comes through the bulkhead. The cardboard tube keeps the main chute from squishing the antenna wire and if the tube falls out after ejection, no big deal. Have had 12 out of 13 sight unseen flights with the one flight I just caught a glimpse of the rocket under the main.. Flights were 5 to 9k feet and the tracker worked great. I used a Garmin 60CsX for the map and had the Kenwood D72A set to display the telemetered altitude. It's weird staring at the place where the tracker tells one where the
rocket is at and not seeing the main chute deploy because the rocket is too far away to be seen. The sudden slowing of the rate of descent tells one the chute is out and it certainly looks that way when one comes up to the rocket. Kurt
 
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