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Old Feb 24, 2013, 10:33 AM
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WL V911 Transmitter Antenna Module * this is the pcb antenna module of my transmitter used for WL v911 it might have similarity with the V959 controller. I can experiment with it first before doing it with the v959 controller. it has a wire antenna with the shield and signal soldered separately- it can easily be replaced by sma, but you are using rp-sma?

there is a print on the board that says 20dbm, but i don't know about how much power it throws.

will the A7105-500m be of any help since it is only rated at 17dBm output.

here is a bigger picture is the top one doesn't work.
WL V911 Transmitter Antenna Module
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Old Feb 24, 2013, 06:05 PM
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Hi R3npogi,

Yes, the WLToys v929 uses the same RF module you pictured. It states 20dBm (100mW) but is no where near that, as actual range is more like 550ft. I soldered an RP-SMA pigtail directly to the WLToys Tx antenna, attached it to the Sunhans and it worked great.

The tricky part is soldering the pigtail signal wire to the side of the surface mount capacitor without knocking off or damaging it.
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Old Feb 24, 2013, 07:33 PM
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Patrick, You are obviously very knowledgeable in range boosting. Thank you for the information shared. It was very interesting read.

I have a WL-V949, a Hubsan X4, and a Syma X1. For the time being, I'm not doing FPV, just LOS flying. Therefore, I am not looking for incredible range. I found that the range of the stock V949 is adequate for my needs.

However, I wish I could say the same for the Syma X1. While it is a fun little flyer, its range has been very short and unreliable. Sometimes, I get signal drop as close as 50-75 feet. If I could get the 550 feet like you said about the V929, I'd be very happy.

Shy of adding a signal boosting module on the back of the Tx, is there anything you could suggest that could improve the range? The Syma X1 uses the exact same protocol as WL-V949. I would use the Tx interchangeably. In my experience, the V949 Tx gives much better range on the X1 than the X1 stock Tx itself.

I know that the V949 has a simple coaxial wire as the antenna of the Tx. The X1 has a PCB trace. Here is a picture of the X1 Tx:



Is there any simple thing I could try to improve the dismal range of the stock X1 Tx?
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Old Feb 25, 2013, 04:12 AM
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Hi Heli Pad,

Your Syma X1 RF module uses the 1mW A7105 module without any 2nd stage, so I'd expect range would be pretty anemic like the Hubsan. Look on the back of the PCB to see if the solder pads are labeled with SCS, SCK, SDIO, GPIO, GND and 3.3v. If so you can likely use the RF module out of a WLToys v929 Tx. If the connections aren't labeled then it looks easy enough to trace the connections back to the A7105 IC. Here's it's datasheet.

A consideration is that the WLToys Tx uses 6 AA batteries to supply higher current to the RF module. If your X1 uses smaller AAA's then they won't be enough unless you use something like NiZn or high current disposable batteries.

Also check to see if the WLToys v929 or v202 Tx by chance works as is with the Syma X1.
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Old Feb 25, 2013, 10:19 AM
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i was never a big fan of power boosters but that may change in view of recent experiments with super cheap rf amp chips. ive just succeeded in building a 1w booster that costs less than $5 and will start a how-to thread soon.

anyway i found a better way to extend range is with simple and cheap antenna modifications. for example the range on my v929 was quadrupled just by replacing the stock cheapo whips with cheapo dipoles. total cost about 10 cents. heres a pic of the tx mod:



similar deal for the rx. then almost doubled range again (over 1km now w/stock v929 rf module) by adding a piece of wire for 2 element yagi.
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Old Feb 25, 2013, 11:18 AM
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Quote:
Originally Posted by patricklupo View Post
Hi Heli Pad,

Your Syma X1 RF module uses the 1mW A7105 module without any 2nd stage, so I'd expect range would be pretty anemic like the Hubsan. Look on the back of the PCB to see if the solder pads are labeled with SCS, SCK, SDIO, GPIO, GND and 3.3v. If so you can likely use the RF module out of a WLToys v929 Tx. If the connections aren't labeled then it looks easy enough to trace the connections back to the A7105 IC. Here's it's datasheet.

A consideration is that the WLToys Tx uses 6 AA batteries to supply higher current to the RF module. If your X1 uses smaller AAA's then they won't be enough unless you use something like NiZn or high current disposable batteries.

Also check to see if the WLToys v929 or v202 Tx by chance works as is with the Syma X1.
Your expert observation means a lot to me. So, some Tx has 2 stages, the X1 has just one. When you have the time and patience, please educate me about this stage 1, stage 2, construction a bit more.

The X1 Tx uses only 4 AA batteries. That could be part of the problem, I'm not sure.

AFAIK, X1 works with V949 Tx, and therefore, it should work with the V929 Tx as well. The V202 is a different and incompatible one, I think.

@Dave, Would your dipole antenna help? I look forward to reading more of your mod, too. I like the sound of inexpensive mod. I love the signal boosting modules, but they cost substantially more.

There is a little bit more to the X1 antenna story. If you want to read about the experiment, I made a post in the X1 thread. In essence, my friend helped me soldered in an antenna taken from another radio. But the result was very puzzling, inconsistent, and inclusive. We are still scratching our heads on that. Perhaps, you signal experts here could tell us why.
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Old Feb 25, 2013, 11:26 AM
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One more question. There is a PCB trace antenna on the Hubsan x4 Receiver. Unlike the simple trace shown in the X1 Tx picture above, it has many more turns and substantially longer length. How long is that trace, and is it aiming at 1/2, 3/4, or full wavelength?

In that sense, I tend to think that the receiver is not the weak link on the X4, is it? It the Tx, missing stage 2, the culprit of the problem and thus, when signal is boosted in the Tx, then we have good range?

I'm hoping that one day, I could figure out a way to use my T9x with the Hubsan X4. In fact, I think someone has already demonstrated something like that, except he wouldn't share how he achieved it.
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Old Feb 25, 2013, 02:55 PM
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Originally Posted by Heli Pad View Post
I'm hoping that one day, I could figure out a way to use my T9x with the Hubsan X4. In fact, I think someone has already demonstrated something like that, except he wouldn't share how he achieved it.
Just to put it simple - if is isn't able to share and make it reproduceable - he is a liar.
Going the Deviation way the Hubsan protocol already is implemented and works without issues.
-mike-
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Old Feb 25, 2013, 03:08 PM
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Well, I wouldn't put it pass anyone who has the smart to mod his T9x to control the X4. If he wants to share the knowledge, many of us will be grateful. It is within his rights to keep it as a trade secret. Perhaps he wants to do it as a money making service. Who knows? He owes it to no one to share the knowledge. That doesn't make him a liar or a bad person. So, I won't go there.

Deviation X is great. However, I'm not there either. I have my T9x, which I'm happy with, and it meets most of my needs. Would I like to have Deviation? Absolutely! The money is not there, yet.
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Old Feb 25, 2013, 03:28 PM
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Originally Posted by Heli Pad View Post
Well, I wouldn't put it pass anyone who has the smart to mod his T9x to control the X4. If he wants to share the knowledge, many of us will be grateful. It is within his rights to keep it as a trade secret. Perhaps he wants to do it as a money making service. Who knows? He owes it to no one to share the knowledge. That doesn't make him a liar or a bad person. So, I won't go there.

Deviation X is great. However, I'm not there either. I have my T9x, which I'm happy with, and it meets most of my needs. Would I like to have Deviation? Absolutely! The money is not there, yet.
The video "proof" I've seen makes it highly doubtful that it is working as said.
I had a good laugh reading his words "One rule: No questions!"
If he is not willing to PROVE via third parties - common procedure in scientific work anyway - he is a liar. HE is stating something - so HE has to prove it.
I will not spend any further thought about it.

Back to topic:
The 9X way isn't really cheaper than going Deviation - just made my mind yesterday and was adding some numbers.
I did NOT include any costs for modules I bought that has to be used for both variations (HT-8, FrSky). For 28 USD more (even less if I add money for module cases, minor parts and components) I'll get a high quality TX system (ball beared gimbals, etc) without any module to change.

-mike-
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Old Feb 25, 2013, 07:03 PM
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Dave, Would your dipole antenna help? I look forward to reading more of your mod, too. I like the sound of inexpensive mod. I love the signal boosting modules, but they cost substantially more.
i know one person with x1 radio and agree it is by far the shortest range of any similar tx. his stock v911 tx goes 8-10 times farther when we did a range test. he didnt want to open it up but seeing your picture its obvious why. in addition to the lack of 10mw booster like the v911 have there is no matching network. you can see an example of matching stub in this photo of a flysky compatible diy rx thierry from electronics forum sent me. the module is mine:



the stub is that trace in the gold antenna circuit that looks like a short circuit to ground (actually thats exactly what it is). its purpose is to match impedance (swr ratio) so more power is transferred. i had a problem with too much rf overloading my bench setup and cut that trace which also cut range in half. normally we want more power radiated but since my rx were less than a foot away i needed to reduce effectivess.

idk if adding a matching stub to the x1 module will fix your problem because microwave rf is funny stuff but pretty sure replacing that module wth one from v911-v959 with its power amp and matching network will increase range big time.

as far as antenna mods like i say that gave me about 8x range increase on my v911 radios. last year i bought a huge quantity of these radios for myself and my school when they were on sale for $8 at tmart. the whip antenna was bent back on itself instead of sticking out straight so fixing that almost doubled range. idk if thats why they were sold cheap but it was a simple way to increase range. i use these for flying planes so needed even more range. thats when i tried changing the simple stripped coax whip into a real dipole like in my photo. while i was at it i tilted the wires so it was vertical when holding the radio at 45 deg. the result was douple again, so now 4x the range. 500m, 1500'.

recently i added another piece of wire as a yagi reflector and testing couple weeks ago with my diy rx showed close to 1km. not sure if youd get the same improvement because like i say microwave is tricky but may be worth a try if your current setup just aint doing the job.
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Old Feb 25, 2013, 10:59 PM
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HMMMMMMMMMM, I very interesting read and some great ideas! With all of these great mods, its easy to get fully distracted. O'well.
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Old Feb 26, 2013, 01:11 AM
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Originally Posted by Heli Pad View Post
Your expert observation means a lot to me. So, some Tx has 2 stages, the X1 has just one. When you have the time and patience, please educate me about this stage 1, stage 2, construction a bit more.

The X1 Tx uses only 4 AA batteries. That could be part of the problem, I'm not sure.

AFAIK, X1 works with V949 Tx, and therefore, it should work with the V929 Tx as well. The V202 is a different and incompatible one, I think.

@Dave, Would your dipole antenna help? I look forward to reading more of your mod, too. I like the sound of inexpensive mod. I love the signal boosting modules, but they cost substantially more.

There is a little bit more to the X1 antenna story. If you want to read about the experiment, I made a post in the X1 thread. In essence, my friend helped me soldered in an antenna taken from another radio. But the result was very puzzling, inconsistent, and inclusive. We are still scratching our heads on that. Perhaps, you signal experts here could tell us why.
Hi Heli Pad,

Simply put, if you see an additional small IC next to the A7105 on the transceiver board then it's a 2nd stage amp.

4 AA batteries are fine. It doesn't matter whether the Tx uses 4 or 6 or 8 batteries becuase the A7105 runs off 3.3v either way. It's about current output (i.e. C rating). AAA alkaline batteries don't deal well with drawing 100mA from them, while AA can manage it. On that note, if you upgrade the RF module in your Syma Tx, be aware that the radio's built-in 3.3v regulator isn't going to supply enough current to power the WLToys RF module. You'd need to power the WLToys PCB from an LM1117T 3.3v regulator, similar to the Hubsan A7105-500 mod.

A dipole on the Tx may help, but bear in mind that these aren't Futaba, JR or FRsky electronics. They're built around a $40 retail price point with probably $12 of component's, inlcuding packaging, motors, frame, LCD display and electronics. Not only does the basic A7105 only put out 1mW (of probably not all that clean) RF...the sensitivity on the receiving end is likely pretty poor as well. I cut the PCB antenna traces on both my Hubsan Tx & Rx, and replaced them with a better antenna but range didn't improve very much for me.
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Old Mar 02, 2013, 10:10 PM
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So has anyone tried the booster off the stock tx of the hubsan.I was down at Aeromicro today and saw one flying and figured I wanted one for a micro fpv setup.Perry showed me a pic of Patricks setup and it looked pretty good.
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Old Mar 03, 2013, 12:53 PM
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This thread has got me all confused.
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