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Old Jul 13, 2012, 05:40 AM
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Canberra, Australia
Joined Oct 2010
540 Posts
The lead on the left is for my goggles, the audio out of my HDD recorder goes to my speakers and the video out goes to my 7 inch monitor.

The 2 meters on the right were cheap from ebay ($5) and are there for wank factor and the black box above the meters has a 8v regulator in it for power to my goggles. Apparently (not confirmed by me) the Fat Shark goggles have a 5v linear regulator built in. The higher the volage differance the higher the heat so I use a 8v regulator to drop the power a bit before the goggles and the goggles dont get so hot.

Happy Days.
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Old Jul 13, 2012, 06:08 AM
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Austria / Vienna
Joined Feb 2007
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How to connect the RC305 / use with MFD-AAT

hi,

if you use the RC305 it would be better to use a "RSSI-buffer" using a "LM358N".
the rssi output of the RC305 has "inverted" logic compared to the diversity switch.
higher voltage = better signal.
therefore the rssi from rx1 has to be connected to the input of rx2 on the diversity!

here´s the link to the site of a german colleque with good pictures where you see how to do.
http://www.michael-heck.net/index.ph...d=36&Itemid=44

if you plan to use the diversity on a "MyFlyDream"-tracker you have to mod the diversity to switch the audio (embedded gps for the tracker) too.
this mod is very easy. you need a 5V-relais with one toggle switch. connect both audio signals to the toggle and the base to the trackerá audio in.
the relais is driven from the plus "before" one of the status-led´s of the diversity. for example if you take the led for rx1 you have to connect audio rx1 to "NO" and audio rx2 to "NC" on the relais.

cheers Thomas
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Old Jul 13, 2012, 07:28 AM
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Joined Sep 2011
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Hi Guys

Thanks for the responses.

joel0407: I love your idea with audio

Thint1: I don't follow. Could you explain further?

Regards

Jason
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Old Jul 13, 2012, 08:15 AM
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Austria / Vienna
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Quote:
Originally Posted by WhiteNite1971 View Post
Hi Guys

Thanks for the responses.

joel0407: I love your idea with audio

Thint1: I don't follow. Could you explain further?

Regards

Jason
Hi Jason,

sure, i can ... but what´s your question?

cheers Thomas
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Old Jul 13, 2012, 10:29 AM
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Hi Thint1

I don't understand what you are saying in the following paragraphs;

Quote:
if you use the RC305 it would be better to use a "RSSI-buffer" using a "LM358N".
the rssi output of the RC305 has "inverted" logic compared to the diversity switch.
higher voltage = better signal.
therefore the rssi from rx1 has to be connected to the input of rx2 on the diversity!

here´s the link to the site of a german colleque with good pictures where you see how to do.
http://www.michael-heck.net/index.ph...d=36&Itemid=44
From my understanding the diversity controller is measuring the RSSI voltage (analog input) of each video receiver and comparing them. The unit then simply switches the video signal based on this voltage. I imagine the unit is using some form of pulse wave modulation?

What is the purpose of the LM358N? Amplifier? Protect from voltage spikes?

Why swap the RSSI outputs to the RSSI inputs eg RX1 RSSI output goes to RX2 RSSI input?

King Regards

Jason
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Old Jul 13, 2012, 12:07 PM
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Austria / Vienna
Joined Feb 2007
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Quote:
Originally Posted by WhiteNite1971 View Post
Hi Thint1

I don't understand what you are saying in the following paragraphs;



From my understanding the diversity controller is measuring the RSSI voltage (analog input) of each video receiver and comparing them. The unit then simply switches the video signal based on this voltage. I imagine the unit is using some form of pulse wave modulation?

What is the purpose of the LM358N? Amplifier? Protect from voltage spikes?

Why swap the RSSI outputs to the RSSI inputs eg RX1 RSSI output goes to RX2 RSSI input?

King Regards

Jason
Hi Jason,

the rc305 rx isn´t designed to have a rssi-output.
but there is a possibility to do a "mod", but the voltage signal you will get when you connect the pin directly to the diversity is not designed to deliver also a current. so if you feed this voltage directly to the diversity, the voltage will break down (a little bit). this causes a rapidely switching between the inputs, when both receivers have nearly the same reception. the LM is an amplifier and the output signal is fed to the negative input. this is known as a "impedance converter". the result is a stabilized rssi-voltage.
there is always a chance to damage the receiver due a shortcut when you use a pin-plug like on the easy diversity and plug or unplug during the receiver is on.
if you build up the "rssi-buffer" you´ll get a better (continious) rssi-voltage and a shortcut only damage the LM358N, but this shortcut have to stay for a relatively long time. the time youneed to plug in the pin-plug is defenitely too short.
in short words the rssi-buffer act like a dampener and secures against shortcuts during "hot plugging".

for the diversity the better signal should supply a lower rssi - voltage, but the rc305 give higher values at better reception - so you need to invert the logic. the best way is to crossout the rssi-inputs, thats easier than building up an inverter pcb

cheers Thomas
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Old Jul 13, 2012, 07:10 PM
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Joined Sep 2011
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Hi Thomas

Thank you for your reply. Unfortunately my electronic understanding is basic. Could you clarify a few points?

Quote:
The voltage signal you will get when you connect the pin directly to the diversity is not designed to deliver also a current.
If there is voltage, shouldn't there also be current?

Quote:
If you feed this voltage directly to the diversity the voltage will break down (a little bit) which will cause rapid switching between the inputs.
Could you expand/simplify this? Is this due to resistance?

Quote:
The LM358N is an amplifier and the output signal is fed to the negative input This is known as a "impedance converter" and the result is a stabilized rssi-voltage.
RSSI output is fed to LM358N negative input? Is the basic purpose of the LM358N to convert an analog signal into a digital signal?

Quote:
There is always a chance to damage the receiver due a shortcut when you use a pin-plug like on the easy diversity and plug or unplug during the receiver is on.
if you build up the "rssi-buffer" you´ll get a better (continious) rssi-voltage and a shortcut only damage the LM358N, but this shortcut have to stay for a relatively long time. the time youneed to plug in the pin-plug is defenitely too short.
in short words the rssi-buffer act like a dampener and secures against shortcuts during "hot plugging".
So the LM358N has a dual purpose; to convert an analog signal into a digital signal and protect the diversity controller from short cuts?

Quote:
For the diversity the better signal should supply a lower rssi - voltage, but the rc305 give higher values at better reception - so you need to invert the logic. the best way is to crossout the rssi-inputs, thats easier than building up an inverter pcb .
???

If I don't add the LM358N then I need to be careful not to "hot plug" and be aware that I may experience rapid switching?

Really appreciate your help.

Kind Regards

Jason
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Old Jul 14, 2012, 03:44 PM
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Austria / Vienna
Joined Feb 2007
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hi Jason,
Quote:
If there is voltage, shouldn't there also be current?
yes, but in this case this is a voltage signal. the current is too low to hold the voltage when the impedance gets too low.

Quote:
Could you expand/simplify this? Is this due to resistance?
in principle yes.

Quote:
RSSI output is fed to LM358N negative input? Is the basic purpose of the LM358N to convert an analog signal into a digital signal?
no, the signal stays an anolg signal. the LM358N is a "dual differential input operational amplifier" http://www.alldatasheet.com/datashee...LA/LM358N.html with this application the LM358N is used as a impedance converter (or also called voltage follower in the wiki-link) http://en.wikibooks.org/wiki/Electro...p_Applications

Quote:
So the LM358N has a dual purpose; to convert an analog signal into a digital signal and protect the diversity controller from short cuts?
first part ... no, the analog signal is not modified to a digital signal. the signal is amplified in that way to be connected to low input impedance.
second part ...yes

Quote:
???
the diversity switches due comparisation of the rssi-voltages. the switching criteria is: the lower the voltage - the better the reception. but the RC305 is "inverted" he gives higher voltages at better receptions.
so if the rx1 is the one with the better reception he will give a higher voltage than rx2. if you feed this voltage to the rssi input2 .... the diversity will switch to rx1

Quote:
If I don't add the LM358N then I need to be careful not to "hot plug" and be aware that I may experience rapid switching?
if you don´t add the LM358N, you´ll have a diversity which switches between the receivers in the unneeded moments ... like i had before this mod

cheers Thomas
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Old Jul 16, 2012, 06:47 AM
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Hi Thomas

Thanks for your reply. I understand part of what you have written. I hope as I get more into electronics I understand it further.

Kind Regards

Jason
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Old Jul 24, 2012, 06:12 AM
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Hi Thomas

I have ordered a few LM358N IC's. I will let you know when they arrive.

Kind Regards

Jason
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Old Jul 24, 2012, 07:46 AM
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Austria / Vienna
Joined Feb 2007
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Quote:
Originally Posted by WhiteNite1971 View Post
Hi Thomas

I have ordered a few LM358N IC's. I will let you know when they arrive.

Kind Regards

Jason
Hi Jason,

if you know where the hot end of a soldering iron is, you´re qualified to to this mod

cheers Thomas
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Old Jul 24, 2012, 04:40 PM
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Hi Thomas

I definitely know where the hot end of the soldering iron is . I will try and post a diagram later today to confirm the connections to the IC.

Much appreciated.

Jason
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Old Jul 25, 2012, 12:53 PM
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Joined Dec 2011
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Quote:
Originally Posted by WhiteNite1971 View Post

1. Does the system run off 12V?

Will it also run from an 2S Lipo?

I don't want to stress my recievers and the fatshark with 12Volts...
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Old Jul 25, 2012, 05:07 PM
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Hi dichter04

I am running my diversity controller, monitor & receivers using one 1300mAh 3S battery successfully.

Regards

Jason
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Old Jul 27, 2012, 02:16 PM
voyager4
The Netherlands, NH, Den Helder
Joined Sep 2005
30 Posts
Have tried the easy diversity with two bevrc RC302 2.4ghz but that didn't work. Bevrc let me know that the RC302 have no pin with rssi
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