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Spektrum / Boomerang Sprint Experts - Radio Help Needed!

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Spektrum / Boomerang Sprint Experts - Radio Help Needed!

Old 08-26-2021, 05:43 PM
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Default Spektrum / Boomerang Sprint Experts - Radio Help Needed!

Hello all,

I'm looking for some advice on my setup in a Boomerang Sprint. Currently using an AR12310T receiver with 3 satellites and an iX12 transmitter. My concerns is with the amount of frame losses (Fades / F) and individual antenna fades I am experiencing. I'm wondering where everyone is placing their satellites for best radio reception and to minimize antenna fades. I am also struggling to understand what to do with telemetry as I'm seeing a significant amount of losses on that.

Current Satellite Positioning:
Left Satellite is shown in the picture with the radio deck mounted.
Right Satellite is Shown in the picture with the radio deck removed.
Satellite B is located on the fuel tank.

Image attached below of Frame Losses over a 5 minute flight including taxi.

What changes in position should I consider? What is the expected normal that most are seeing in terms of frame losses and antenna fades?

Thank You

Old 08-26-2021, 08:52 PM
Dave Wilshere
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Change the orientation so there is less chance od the aerials pointing at you/Tx. The one on the tank as you taxi/fly past will be racking up fades. It’s only the tip of the aerial that receives, so turn that say 45 degrees in a plastic tube.
since the tip hatch is hollow. Put the vertical aerials above the split line, so they are into the hatch void. Get the telemetry aerial away from all that wire!

Then try again.
Old 08-27-2021, 01:11 PM
Len Todd
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First off, the telemetry antenna is blocked by all the wiring near it. But the plane will still fly even with no telemetry data making it back to the Txer. However, if there are spurious emissions going on in the adjacent wiring, the telemetry antenna can also pick that up causing other RF issues.

The two remotes that are out in the clear look OK and those are probably giving you an appropriate # of fades. You did not tell us the ID letters (in the Pics) for the various remotes. So it is impossible for us to figure out which one has what # of fades. But I have a couple remotes just like that in my Sprint. However, they have the old antenna design.

Lately, it is NOT unusual to see 400-800 fades in a 6 minute flight. The one on the tank is probably not working well. We typically do not put them on the tanks. However unless there is Kevlar or carbon fiber embedded in the tank this location is typically not a problem. But, as previous stated, it should not be pointing at the Txer. But on the top of the tank is a great place to put a mount and get the remote up in the clear under the canopy. I probably would not have it horizontally polarized as you already have that covered with one of the other remotes. I would get it at a 45 degree angle up and not have the end pointing at the side.

I am wondering if you may be flying to far out or if the transmitter is operating correctly. Or if you have the transmitter's antenna pointing directly at the plane, most of its signal is lost into the ground or not radiating toward the plane. Typically, these potential issues are not a problem, but can be. For me, a frame loss tells me something is not right (i.e. all Rxers missed a frame) Others accept several (e.g. < 10) frame losses because a frame is only a 22 ms signal disruption and there are a lot of frames sent in a second. So basically if you have under 800 or so fades you are just "fine tuning." I tend to dabble with fine tuning the remotes because I have been working with RF devices for over 50 years and I am not used to seeing frame losses.

On another note, I have noticed that since the remotes now only have one antenna, I have been seeing more frame losses when we troubleshoot at our events. It used to be I very seldom saw frame losses, once we had the remotes in the best places. Now, ... it seems like I am seeing more frame losses, even though it looks like the remotes are positioned OK. From an RF perspective, it makes sense. Going from a dipole arrangement to a quarter wave may still work. But, going from a dipole to a quarter wave antenna reduces antenna gain. Also, a quarter wave is typically more sensitive to its surrounding environment. For me, the jury is still out on the current remote design. The current design may still work, But is an optimal solution? There is only so much you can do with the electronics to compensate for a less than optimum antenna.

Good Luck. Have fun with the Sprint. After several years and hundreds of flights, I still love mine.
Old 08-27-2021, 01:26 PM
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I don't fly Spektrum any longer but as I recall from when I did, one of the remotes MUST be connected to A. You said you're using 3 and mentions B Left and Right but I saw no mention of A. Perhaps things have changed over the past couple of years but in the past, connecting remote A was required..

Also I don't like to mount antennas close to other electronics (I like >3" away) and one of your pictures showed a remote right next to a GPS unit. I'd keep a bit farther away from that too..
Old 08-30-2021, 04:52 PM
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Hi All, thanks for the replies.

Dave Wilshere, I will try and change the positioning of the antenna on the tank. I do believe that being this close to the tank is causing issues as well and as a result I'd like to see how I can get it further away. I don't have any room to get the antenna much higher as the tank is near max height. Is there a better spot for a remote receiver in the rear of the fuselage? Do you have pics where you mounted yours?
As far as getting the vertical Left satellite antenna in the image higher or above the parting line, this may be difficult too as the cockpit is right in this area only leaving me with about 3/4in to play with. I'll take aa looks and see what I can do.
I'll move the bottom telemetry antenna, just not sure where to. The fuel tank is huge and the antenna is not long enough to get around it. Keep in mind the deck is off and the wire seen in the image for the top/upper telemetry/antenna would be under the deck when it's fastened.

Len Todd. I'll move the telemetry antenna, just not sure where to. Antenna ID's were in original post. The tank is kevlar and I did not know kevlar was an issue. Maybe I can make a bracket to get the satellite further rearward from the tank?

field0455, I only mentioned B, L and R as the A antenna is the telemetry signal only. I've shown where these are within the pictures. Will see if I can move the antenna further away from the GPS.

Does anyone have pictures of their Spektrum install in to a Sprint?

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