My Spektrum DX5C mods

[Kraton83]

Hey all,

Just wanted to make a post about some of the mods I've done to my Spektrum DX5c. I picked this up initially for a Limitless/Infraction build because I wanted to try the spektrum AVC and telemetry (mainly mph and pack voltage). After I got it I found out that the range is not great for speed running and it there wasn't a factory option for powering it with a 2s lipo like I thought. So I decided to see what I could do about both.

Despite there being nothing in the manual or anywhere else online confirming of the DX5c could handle more than 6 volts I found 1 video on youtube showing someone adding a 2s lipo so that's the first mod I did. Remove 2 screws and the battery tray comes out and you can snip the wires to solder on whatever power lead you want. I took it a step further and took apart the transmitter, desoldered the battery tray leads from the voltage regulator, and soldered in a JST plug that disconnects from an XT60 plug. The 2s lipos I have to use were originally for my fpv goggles and a tad too big so I had to trim some plastic in the battery tray but all said and done it now runs on a 3000mah 5c 2s lipo.
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When I had the DX5c apart I noticed that the radio module actually had a second unused IPX antenna connection. This would indicate that the radio was capable of diversity but again found nothing online to confirm that.
View attachment 84798

To test I set up an esc, motor, servo, and spektrum receiver on the bench. Before changing anything I confirmed that the signal was good all the way across my house. I then disconnected the factory antenna completely and without any antennas connected the range was only about 5 feet then stopped. I then plugged the factory antenna into Antenna B and the signal reached all the way across my house again. This confirmed that Antenna B actually did something.

So I took a IPX to SMA antenna cable and drilled a hole next to the stock antenna and reassembled. I now have the ability to add a second antenna for better range which I will be testing later on. In addition I've ordered a 2MW booster that can be powered by 5v and conveniently the DX5c has a data port that can supply the 5 volts already on the side under a panel and is easily connected by a normal servo plug or JST plug.

Anyways I think it came out really clean and hopefully everything tests well. If so then this eliminates one of the biggest shortcomings of the spektrum compared to other radios in its class.
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Is there any range improvement with the extra antenna intall with out the Range Booster???

I having issues with my DX5C/SR515 setup at 200ft/60meters loosing range

 

[Primarrma]

Is there any range improvement with the extra antenna intall with out the Range Booster???

I having issues with my DX5C/SR515 setup at 200ft/60meters loosing range

That definitely doesn't sound right, I've easily had double that with a stock transmitter and avc receivers. Can you confirm the last portion of the receiver antenna is intact and not damaged? Is it sticking up in the body?

 

[suchtragedy]

Is there any range improvement with the extra antenna intall with out the Range Booster???

I having issues with my DX5C/SR515 setup at 200ft/60meters loosing range

Yeah I'm with @Primarrma on this one and it sounds like your antenna might have some issues on the SR315, either damage wise or it's placement is not optimal, or you have some environmental factors affecting signal.

 

[Kraton83]

That definitely doesn't sound right, I've easily had double that with a stock transmitter and avc receivers. Can you confirm the last portion of the receiver antenna is intact and not damaged? Is it sticking up in the body?

Yeah I'm with @Primarrma on this one and it sounds like your antenna might have some issues on the SR315, either damage wise or it's placement is not optimal, or you have some environmental factors affecting signal.

Yes, the antenna is intact, it is a brand new receiver taken by myself out of the package...the car is a non-arrma, it is a hpi baja 5b Gas... and the antenna is stick out of the body with a antenna tube and also when is at 200ft(60meters) the latency is notable... also I have to set the frame rate at 22ms because if I set it to 11ms the throttle servo get stuck when a quickly try to response at throttle input

I have a SRS6000 receiver but I cannot use it to tested because of the analog servo that have the baja

 

[Primarrma]

Have you set your endpoints on the throttle servo?

Does the steering have noticeable latency, too?

Is the steering servo a digital servo?

This might seem silly, but have you got multiple receiver battery packs? If the servos are driving very hard and you have a week pack your receiver voltage might be dipping below spec? This is why I'm also asking about your endpoints, if the servo is over driving it might be starting to fail or drags the system down. Is there a reason you have to use an analogue servo? Just remember to bind into the gas mode of the receiver for the fail-safe if you make any changes.

 

[Kraton83]

Have you set your endpoints on the throttle servo?

Does the steering have noticeable latency, too?

Is the steering servo a digital servo?

This might seem silly, but have you got multiple receiver battery packs? If the servos are driving very hard and you have a week pack your receiver voltage might be dipping below spec? This is why I'm also asking about your endpoints, if the servo is over driving it might be starting to fail or drags the system down. Is there a reason you have to use an analogue servo? Just remember to bind into the gas mode of the receiver for the fail-safe if you make any changes.

- Yes I set the endpoints

- Yes the steering also have latency too

- No, the steering servo is analog too, is the original HPI SFL-10MG 1/5 Steering servo

- No I don't have multiple battery packs

- I have analog servo because that I have been using since I got the car for a few year now, and have been using Futaba with same servos and I have got any issue with futaba

- That step binding into gas mode I haven't done...

Yeah I'm with @Primarrma on this one and it sounds like your antenna might have some issues on the SR315, either damage wise or it's placement is not optimal, or you have some environmental factors affecting signal.

The antenna!

 

[slick2500]

You can use the SRS6000 but you have to set the rx to blinky mode disabling avc.

 

[Kraton83]

I'll

You can use the SRS6000 but you have to set the rx to blinky mode disabling avc.

I have try and no luck

 

[Primarrma]

- Yes I set the endpoints

- Yes the steering also have latency too

- No, the steering servo is analog too, is the original HPI SFL-10MG 1/5 Steering servo

- No I don't have multiple battery packs

- I have analog servo because that I have been using since I got the car for a few year now, and have been using Futaba with same servos and I have got any issue with futaba

- That step binding into gas mode I haven't done...


The antenna!

If you try steering with the break on and the car near you does it struggle at all? Any signs the servos are slow or not powerful?

 

[Kraton83]

If you try steering with the break on and the car near you does it struggle at all? Any signs the servos are slow or not powerful?

No, it does not struggle at all and the servo does not show any sigb of slow or underpower

 

[Primarrma]

No, it does not struggle at all and the servo does not show any sigb of slow or underpower

Well I am all out of ideas, sorry.

 

[olds97_lss]

You've tried a different receiver?

I had issues back in the day with the single wire antenna receivers. Range was 100 feet max. Then I found the knock off orange receivers for $8 a piece that had a coaxial antenna. All the sudden, my range went to 300+ yards. Then after about 5-6 months, the range would drop again, something in the receivers was dying. Replaced it and my range came back. I've since started swapping out the receivers with spektrum ones that have coaxial antenna's. The SR210 was what I was buying. They seemed to last much longer.

I haven't used the newer shaped ones like the SR315.

 

[Kraton83]

You've tried a different receiver?

I had issues back in the day with the single wire antenna receivers. Range was 100 feet max. Then I found the knock off orange receivers for $8 a piece that had a coaxial antenna. All the sudden, my range went to 300+ yards. Then after about 5-6 months, the range would drop again, something in the receivers was dying. Replaced it and my range came back. I've since started swapping out the receivers with spektrum ones that have coaxial antenna's. The SR210 was what I was buying. They seemed to last much longer.

I haven't used the newer shaped ones like the SR315.

I am going to try the sr515 (the one that have issue with) on another rc to tested and see if it does the same thing

 

[IRONWORKER]

I’m having a similar issue with my sr315, it has very limited range compared with my old sr210...

 

[Kraton83]

I’m having a similar issue with my sr315, it has very limited range compared with my old sr210...

I contact Horryzon Hobby they send me a replacement... hope that it will fix my problem

 

[olds97_lss]

I just bought a 2S 2000mah lipo and installed it in DX5C. Probably did a "no no" though as I wired a receiver plug up to the charge port I installed to charge the 2S lipo without removing it. I have a small 20W charger that charges via the balance cable and another USB powered one that came with my axial scx24 that I can take with me when I go bash. I couldn't find a good "socket" type plug for 3S charging, so I just wired it to a standard servo/receiver plug using all 3 pins then made a 2S->receiver plug adapter for the charger.

My AA's life were getting shorter and shorter, so figured instead of shelling out $24 for a good set of LSD AA's, I'd give this a try. Would be nice if the alarm would allow you to adjust the voltage so something more than 6V though.

 

[olds97_lss]

Kind of blowing my mind how long it lasts on a charge... have had it on my desk all day and writing down the voltage every time the timer reaches 99 minutes.

Started at 8.3V
99 - 1: 8.1v
99 - 2: 8.0v
99 - 3: 7.7v
99 - 4: 7.5v

That's over 6.5 hours and it's barely below storage voltage. I was worried it would run out while out bashing... the duracell recharge lsd's were dropping down to low 5v after a couple hours.

Anyway, just thought it was mildly interesting.

 

[elschizo]

What i thought is that an 3D printed adapter/battery tray from 4AA to 5AAA could work? Then it would be 6V as in standard 4AA.

 

[olds97_lss]

aaa's aren't that high of capacity though.

 

[elschizo]

Forgot about that . damn ;-)