2.4ghz rc amp

OzFlyer

Well-Known Member
Hello all, it has been ages since I was here, but I have moved house to another state. Massive distraction to my hobby:p

Anyway last time I was here I was recomended to use this booster to improve range of my dx6i. http://store.diydrones.com/ProductDetails.asp?ProductCode=WI-AMP-24-500

I have recieved it and have been experimenting with different input cables from tx. As you will read it's input is from 5dbm-20dbm. recommended not to go over 13dbm.

I have tried 5 foot rg174 and the green light on booster stays on for 2-3 seconds then turns off. I have also tried a 1 foot long great quality low loss cable and same problem.

The output of tx is 100mw, which is about 20dbm. I would have thought the 5foot rg174 cable would have attenuated the power enough to get it under or around 13dbm.

On opposite end of spectrum I tried a 15m long rg174 cable and light does not even turn on the booster.

Anybody have this booster and can work it??
 

OzFlyer

Well-Known Member
I realised today that having my regulator so close to the amp may not be a good thing for my range as apparently these 6v regs emit interferance. I actually had it strapped to the thing. Anyway I range tested it holding it as far away from amp as possible and walked as far as I could...300m or so. Big difference. I have now re-soldered it with a longer wire with ferrite rings. Maybe this will help.
We have storms now so hopefully a real flight to see what it can do tomorrow. Here is my budget long range system.
 

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Alex Villa

Super Moderator
I think that probably you have a bad contact on the barrel plug, make sure it has the appropriate inner diameter. I also bought one of this amplifiers, however I am still testing extending the range of the 2.4Ghz RC system via antennas, the latest antenna I used gave me 4.2Km. So I am guessing that by using the amp I could get 10Km+. I am very happy with it so far.
 

OzFlyer

Well-Known Member
When you say barrel plug, do you mean the power plug or the sma connection or the antenna connection?

I tested it today with a real flight. Only got 150m if that. I even put it on a little mast. Anyway if it wasn't for my return to home working perfectly I would have a dead plane. My plane circled above as i pulled tx apart and re connected the stock pig tail.

Ended up being a great flight with stock 200mw I got to 1350m away. Just imagine what I could do if this worked for me.
 

OzFlyer

Well-Known Member
I just looked up and seems you were talking about the dc plug and it is actually the one that came with the amp. However it does not fit in comfortable.

Something I do notice is when I first turn on tx the green light goes bright green, then after 2 seconds goes quite dull, but still there.
Does yours do this Alex?
 

Alex Villa

Super Moderator
Yes, I am talking about the DC plug. Relative to the amplifier I didnt even powered yet. The FRsky system gave me 1.6Km range with stock antennas. And 4.2Km with a very small 7Dbi patch antenna. I think tomorrow will test the amplifier.



 

CaptnKliegle

Well-Known Member
The issue is probably the coaxial power connector. There are numerous sizes out there in the consumer electronics world. Some are less than a few tenths of a mm difference. 5MMx2MM 5.1MMx2.1mm, etc... Both the inner and outer dimensions are critical in making a RELIABLE connetion. Word to the wise... get the exact connector or hardwire critical components such as amplifiers. The RF from the TXR will not 'pass thru' an unpowered amplifier typically as Ozflyer found out. Luckily RTH worked as programmed.:)

Kriss KA1GJU
 

OzFlyer

Well-Known Member
Hey thanks for the help. I might wait and see how Alex goes with his. I am not very experienced with pulling things apart and soldering straight on board. I will try if I have to. And I don't like the idea of going around trying to find a perfect plug. So lets see:)
 

loorio

Member
Very important!

Do not install two-way AMP for Hitec Aurora or other two-way telemetry systems radio!!!

Also amplify the incoming signal and....... :-( :-( my friend does not work with the radio telemetry, only the normal ppm control...
 

Jameson

Well-Known Member
This one is a one-way amplifier. I've tried it with Jeti Duplex system without any problems... In fact, I can't see any reason to make nor use two-way system: it should only maximize the incoming noise over limits...?
 

Alex Villa

Super Moderator
Ok, today I went to fly but didnt had time to test the amplifier in flight. However I did test that the amplifier does turn the green LED when there is signal input. FrSky Tx module has option to work with reduced output(2mW), and the LED didnt turn ON. Standard power output for the Frsky Tx module is 60mW.
Tests with the 1W amplifier has to be the next time I go flight. Probably next week. But I think it should work.
Today I tested that the Frsky module had less range, probably because the Tx battery was more discharged. Glitches started around 3-4km. My previous range test gave me solid signal until it reached 4.2km.
The 7dBi patch antenna is from Ebay.
 

Alex Villa

Super Moderator
The amplifier is supossed to work with WiFi modems. So it is two-way, I opened it and checked. It has LNA and path switching circuit, plus carrier autodetect.
 

OzFlyer

Well-Known Member
Alex, the thing that confuses me is the fact that I get a green light on the booster also. However when I trusted it I got a very nasty suprise at 150-200m.

When I power up with the battery connected to the amp I get a bright green light then after 2-3 seconds it goes to a dull green, but still there very faint compared to what it was.

I am planning on opening it up and have a look at it to see if I can solder direct onto the board for the dc power. That way I will be sure it is getting enough power from battery and there must be something else wrong.
 

OzFlyer

Well-Known Member
Decided to open and TRY to solder dc wires direct to amp.

I have decided that I don't want to spend any more money on this project so I have bit the bullet and opened her up. Maybe learn something also:)

Anyway I have hit a wall and need help. The socket that the dc coaxial plug goes into seems fixed in place quite well. So I am asking if I wanted to hard wire and solder my positive and negative wires onto my unit...Where would I solder them??
 

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Alex Villa

Super Moderator
The socket seems good to me, I don't think this is a power supply issue. If the LED keeps lit then definitely is not a power supply issue.
I am guessing that the amplifier is not getting enough RF signal on the input.
Can you test a different cable?
Also it could be the connection between the inside RF output of the Tx module and the SMA connector.
I would like to see a picture of that connection.
 

OzFlyer

Well-Known Member
Ok I took some photos.

First i'm showing you the little pig tail connector that I ordered with the amp. It has a sma female on one end which I installed into a hole I drilled on the side of my dx6i. It goes down to the ufl connector. And that is how I connect to my dx6i.

The female connector connects to a male sma on the end of my 5 foot long rg174 cable. That then connects to my amp.

I have also added another picture of a different cable I have tried. This one came with the amp and is ideal for use with 2.4ghz. Cant remember what it is called. This produces same results as rg174 cable.

I have tried both cables with all power settings US and EU and France with exact same results.

One thing I did notice is the little LED light inside dx6i. For the brief time between when I switch on tx and before this LED come on (2-3 seconds) the light on the amp comes on full power. Then when LED turns on it dampens down to a much duller light:confused:

And thanks Kelly also tried to wiggle cable and nothing.

I am at a loss with this. Defientely starting to come to terms with possibly having to get another amp:rolleyes:
 

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