The Big Red Bee 70cm

[Onebadhawk]

Every time I think about URRF I smile.
I finally got my mile high.
I never would have gone for it if I didn't have a tracker in the nose cone.
I've had the Big Red Bee since the spring.
I played around with it a bit, to try to get a feel for it.
I didn't get it that well,,,,,,,Till URRF.
Every time I'd listen for the transmitter, I was too close.......
The signal was too strong.......
Particularly if the rocket was in the air.......
But when the rocket landed at URRF after the 6500 ft flight, and was on the ground,,,, along way off.......
The signal faded,,,, as you swing the yagi antenna back and forth the sound of the morse beeps
would fade in and out,,,,,, it brought me right too it.......
I was never so impressed..........

Customer service from Greg at Big Red Bee is the absolute tops..........

I'm very glad this is the method I chose for tracking.......

My transmitter goes in the nosecone, so it's easily transferable, from rocket to rocket........

Thanks again Greg,,,,,,,,,,,,,,,Teddy

 

[Jmhepworth]

I'll add to the kudos on the 70cm BRB tracker. It's a tough SOB. I had a lawn dart with a 2.6" fiberglass rocket. The BRB was stuffed in the nose cone surrounded with bubble wrap. When it hit the desert floor, the nose cone collapsed 8" into the fiberglass tube. The threaded rod in the nose cone was bent, but probably saved the BRB. I had to cut the threaded rod to get the beat up fiberglass bulkhead off. The antenna was crushed into a pretzel. But the BRB kept chirping away. I almost wanted it to stop because I needed to take it home to get a hacksaw to cut the threaded rod, and I was worried about causing harmful interference (along with my call sign every 10 minutes) on the hour drive home. Greg's support can't be beat.

I use an Arrow 7 element Yagi. Up close, the signal overpowers the radio. I'm going to get an attenuator to see if that helps.

Joe

 

[azzie]

I use an Arrow 7 element Yagi. Up close, the signal overpowers the radio. I'm going to get an attenuator to see if that helps.

It definitely does. Get an offset attenuator like this one. I can tell BRB's signal direction from as close as 10ft.

-Alex

 

[ksaves2]

It definitely does. Get an offset attenuator like this one. I can tell BRB's signal direction from as close as 10ft.

-Alex

Here's another attenuator for a DIY. Mount in box and screw on to the Yagi. https://www.west.net/~marvin/k0ov.htm

 

[JimZNJ]

Indeed, an offset attenuator really helps as you get closer to the rocket. I fly a BRB tracker in most every rocket I fly, except for small model rockets. Armed with it, and an offset attenuator on the receiving end, I have found rockets solely based on the beacon signal, in rows of crops. Literally able to discern location within feet as azzie alluded to.

The BRB saved my bacon again yesterday flying my Madcow Piranha on a high flight. Lost sight of it but quickly homed in on it with the tracker and recovered it.

Jim Z

 

[Greg Young]

Here's another attenuator for a DIY. Mount in box and screw on to the Yagi. https://www.west.net/~marvin/k0ov.htm

It makes for a quick assembly, and uses an inexpensive 9 volt battery to boot! Go with the 4 Mhz offset. You will need to supply a case, but R Shack has some nice small ones. Also for 440 Mhz tracking work a 5 element beam will be sufficient. All HPRs should have a tracker (or GPS if you want to go that route). You never know when it will come in handy, especially with neighboring corn fields, etc....

 

[1tree]

Another idea is to get or make a TDOF unit. These switch between two antennas rapidly. When one antenna is closer then the other a tone appears in the audio of the radio. You can use these beauties right up on top of the transmitter.

 

[Derek]

Another idea is to get or make a TDOF unit. These switch between two antennas rapidly. When one antenna is closer then the other a tone appears in the audio of the radio. You can use these beauties right up on top of the transmitter.

I had to google this one. I didn't find any references to TDOF, but I did find TDOA in relation to fox hunting. So, what is TDOF?

https://webhome.idirect.com/~griffith/tdoa.htm

 

[1tree]

TDOF is a typo. Sorry, I meant TDOA. I am hoping to build one myself in the next few weeks. No need to worry about adjusting an attenuator it wouldn't have the range of a yagi, but I suspect the range isn't that big of a deal.

 

[Onebadhawk]

TDOF is a typo. Sorry, I meant TDOA. I am hoping to build one myself in the next few weeks. No need to worry about adjusting an attenuator it wouldn't have the range of a yagi, but I suspect the range isn't that big of a deal.

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[Greg Young]

TDOF is a typo. Sorry, I meant TDOA. I am hoping to build one myself in the next few weeks. No need to worry about adjusting an attenuator it wouldn't have the range of a yagi, but I suspect the range isn't that big of a deal.

TDOA= Time Difference of Arrival. If you couple more than one antenna on a given receiver, and then check signal on each antenna in rapid sequence, you wind up with a Doppler RDF (radio direction finder). It's great for tracking down errant signals, using usually 4 antennas spaced at 1/4 wave lengths apart in a 90 degree pattern. For our rocketry finding, an simple 5 element yagi will do the job. An attenuator simplifies it when you get in close, although using your body as a shield, and disconnecting the hand held's antenna are other proven ways to help attenuate the signal when close...

 

[Derek]

TDOF is a typo. Sorry, I meant TDOA. I am hoping to build one myself in the next few weeks. No need to worry about adjusting an attenuator it wouldn't have the range of a yagi, but I suspect the range isn't that big of a deal.

no problem. thanks for the clarification!

 

[1tree]

If you search TDOF you will find it typically uses only two antennas. The simplest can be built with less then $5.00 in parts. When either antenna is closer to the source a tone appears in the audio (created by switching antennas). The simplest circuit leaves you with an ambiguity on that the transmitter can be behind you. This can be overcome with a relatively simple sense circuit to tell which antenna is closer to the source.

The advantages to this are:
1) No need to adjust an attenuator as you get closer.
2) The unit is smaller then most yagis.

The disadvantages are:
1) The sense may reverse when changing radios.
2) The range isn't as far.

Personally, I am making both a TDOA unit and a yagi. The cost isn't that much. I used to have both years ago when I participated in transmitter hunts. Parted with them to reduce clutter.

 

[Onebadhawk]

Re: Apogee Aspire
Unread postby Jim Z » Sun Aug 11, 2013 12:50 am

My newest 29mm performance build has been a LOC Aura. My poor Aspire has been neglected as I poured all of my attention to the Aura. Fortunately I packed the Aspire today for our launch. Many thanks to KC! He provided me with a couple of the Apogee Medalist F10-8 motors. This is the motor that Apogee claims can take the Aspire to over a mile in the air!!

Our launch was winding down, the high power window had closed, but conditions were still very nice for flying. We needed one epic flight to end the day. With a little coaxing from my rocketry buds, I loaded one of the F10-8's into my Aspire. I also loaded my Altimeter Two. What good is flying real high if you can't prove it? And since we were going to be flying out of sight high, I put my BRB tracker in the nose of the Aspire. A large silver mylar streamer was used for recovery with the hopes it would catch our eyes on the way down.

The rocket was loaded on the 1/4inch rod. After a countdown, Jenna at LCO hit the button, the motor lit, and the rocket started its long climb to altitude. With an 8 second burn, this is a very long burn motor. The Psssssst sound of the boost seemed to go on forever as the rocket vanished into the cloud speckled blue sky. After another 8 seconds of delay, the subtlest of ejection events was heard. We all looked, and looked, but never saw even a glint of her on the way down. Foolishly, though worried about the light breeze blowing it too far downrange, I tried to compensate by slightly angling the launch rod. The result was that it flew waaaaaay upwind! Fortunately there is a lot of open farmland up that direction so there was a prayer she might be found.

Remember kids, trackers save lives! Ok, maybe not lives, but they do save rockets! After none of us saw the rocket returning to earth, the next logical step was to grab the tracking gear and see if we had a signal from the rocket. Indeed we did, but where the heck was it to lead us?! Realizing that it seemed to be from WAY across the farm and WAY upwind, Jenna and I hopped in my car and headed out to track it down. KC followed in the chase vehicle, eager to see how the tracker would work. We all arrived on the far side of the farm, at the junction we used to fly from by the weeds. We headed out on foot, surrounded by fully planted fields. The signal first led us into rows of tomatoes. Difficult to navigate but we seemed hot on the trail. My heart sunk a bit at first as we were being tracked towards a 6foot+ high dense field of corn! Confident that as long as I had a signal, and indeed I had a signal that indicated to my ear that we were very close, I started my way through the corn, it towering above me! Deeper and deeper... and then I stopped to get a bearing on the signal from the rocket. It led me back towards the edge of the corn. Not 3 rows ahead of me I found it!! I let out the biggest yahoo yelp this side of Saskatoon! There is absolutely NO WAY anyone could have found this rocket without the tracker. I had walked by it on the way into the corn and only after refining my track, came upon it. Nestled on the ground between the towering corn plants! WOW! All were impressed, even me! THANK YOU Big Red Bee!! LOL!

2013-08-10 17.14.33.jpg
Hidden in the corn


2013-08-10 17.14.08.jpg
Where's Waldo?


So the flight stats for this first flight of my Aspire on an F10-8:

Altitude: 3516 feet (no doubt hurt by the angle I launched it with and the ensuing arc)
Top Speed: 466 MPH
Burn duration: reported as 5.6 seconds (versus the spec for this motor of 7.8 seconds)
Flight duration: 97.6 seconds

I promised KC that we'll try this again another perfect day. This time we'll aim the rocket straight up and perhaps I can polish the finish a bit to reduce the drag. I would love to break a mile on what looks like an inexpensive Estes rocket. Its that F10 motor that makes it all happen!

To be continued...
Jim Z
NAR 91938 L2
Jim Z

Posts: 691
Joined: Mon Sep 17, 2012 12:32 am
Location: Jersey City, NJ