Pairing RDF900 with older 3d SIK radios?

I’m looking to match the range of my telemetry radios to meet the range of my rc receivers (about 1.5km.) Currently I have two 3dr sik radios, but I am seeing that the RFD900, looks like anyway, a drop in replacement for the ground side which will give me more range. From Ardupilot documentation:

“The hardware is closed source but the software is open and is based on the same software that runs on the SiK Radio meaning configuration and setup is extremely similar and these radios can even be paired with a 900Mhz SiK radio (i.e. you may choose to use one RFD900 on the ground, and a SiK radio in the aircraft).”

How much range will this allow if I use one RFD900 on the ground and one 3dr sik radio on my copter? Could also choose to use the RFD900 on the craft insted, and the 3dr on the ground? Bottom line, will I get 1.5km range from one RFD900 and one 3dr sik radio?

Then if so, how do I connect the RFD900 to my phone? Ardupilot documentation says “Connect one of the radios to your computer using the micro USB cable.” but where do I plug it into the RFD900? Do I need to make a cable for usb-c connetions? Any instructions for this? This is why I ask if I can use the RFD900 in the copter, and my 3dr sik radio on the ground (because it is already wired for easy plug-in to phones.) I’ve found RFD900a (not mentioned in Ardupilo discourse.) Will RFD900a also pair with 3dr sik radios? Is it the same as RFD900x and RFD900 but using different connectors?

I no longer need answers to this after finding in the sik radio section of the Ardupilot documentation that:
" Replace at least one of the two radios with a higher powered RFD900" (implies that it does not matter which one is on the ground or in the air.)

So this answers my question about if I can alternatively use the RFD900 on the craft and the 3dr sik radio on the ground instead - I can. Which makes the rest of my question irrelevant since the reason I’d want to do this is because the RFD900x does not have an option to connect via micro usb, mini usb, or usb-c, but has nice connection options for my flight controller.

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The RFD900 radios dont pair with the 3DR style radios.
Even though they all share some heritage, the RFD’s moved on to be more advanced and are not backwards compatible.

I must be missing something or mistaken about something I’m trying to describe maybe…

I’m going by “these radios can even be paired with a 900Mhz SiK radio (i.e. you may choose to use one RFD900 on the ground, and a SiK radio in the aircraft).” from: RFD900 Radio Modem — Copter documentation

Then what I am calling a 3dr radio is what is pictured here: SiK Telemetry Radio — Copter documentation

and I’m thinking that the documentation claims that the two will pair, but no? What is a “900Mhz SiK radio” not the same thing as " SiK Telemetry Radio?" (what I’ve bene referring to as a "3dr radio.)

In other words, will this: RFD900 Radio Modem — Copter documentation
pair with this: SiK Telemetry Radio — Copter documentation

or what is my other option to pair with? I’m wanting something that can plug into my phone running QGroundControl easily. The RFD900 doesn’t look convenient to use with a phone because of the connectors.

I am not sure you can even purchase that radio anymore as it not a 900/869+ or a 900/868x. these are probably some of their original radios that were pretty much the same as the original sik. Unless you have a pair of these 900 pictured in your post from rfd you will not be able to pair them with the 3dr radios like pictured. Also be aware that the wiki may not have every variant of radio that’s new so it may be outdated, plus things in the early days and even today are moving quickly. almost like buying a pc hahaha the second its off the shelf there is something newer or its outdated!
there is a button at the bottom of each page Github Issue Tracker. you can suggest edits to the wiki to make it more readable or up to date.
or if you want to make a small change to submit *
Edit on GitHub
. Often manufactures will leave it up to the community to make wiki entries or add to them as they often say its open source so its the community that must do this. Plus the wiki has been pretty much written by @hwurzburg with a bit of help here and there from others but he has taken the brunt of the work on!

I’ve managed to find (but haven’t bought) one RFD900, and I’ve got a pile of these:

Can they pair, do you know? I want to outfit two copters for longer range telemetry to my ground station, and I like the, what I am calling “3dr radios” because they are low power and have a convenient connection. It sounds like the only chance to pair with the older sik radios is the RDF900, but now I am confused as to what a “900Mhz SiK radio” is for sure… not the same thing as a “SiK Telemetry Radio” which operated at 915 Mhz?

I’m trying to find the “suggest an edit” button on GitHub for the RFD900 page. I won’t edit it myself, of course, because I’m still trying to grasp the terms (is a 3dr radio a SiK radio?) and figure out if the information is still relevant or if there are better options altogether. Not even close to editing, but I can suggest an edit if I find the button.

all those 3dr would pair but they need to be on the same firmware. I do remember a couple paired when not on the same but its been so long I cannot remember. Best bet would be to download the latest sik radio from here you want the hm_trp.ihx for those radios and individually update each one paying attention to the net id, number of channels and what frequency they were all on. best to just default them all that way they are standard. It has been awhile since I have used the sik 3dr’s. I do not know about the 2 unbranded ones or the frsky. maybe try and see what they are loaded with using the sik radio tab in Mission planner (MP). I would start with the radios that all look the same then play with the outliers. I fear they may not be compatible with the others but never know!

So many of the sik depending on the chipset can do a range of frequencies you can set them within the sik radio on MP such as 900 being able to do 900-928mhz (not sure if that’s exactly the band). Plus there was a hodgepodge of folks building them. I have had trouble linking amazon cheap radiolinks with the rest of my 900mhz radios even though they were 900mhz. As long as you can get all those 3dr 900mhz (915mhz) on same firmware with the same above mentioned parameters you should have more than enough radios for 2 copters. Often names are branding just like cube, pixhawk, yadda yadda. its super confusing given one manufacture calls something xx while the other calls them xx.

scroll to the very bottom and look here

I’ve paired all of them to all of them. They’re all currently paired. The problem with them is that I see they only have a range of up to 500 meters. So that’s why I was thinking of using the RFD900 as per Ardupilot documentation:
" Tip

If you’re looking for an alternative, the RFD900 Radio Modem is highly recommended by many community members (The SiK platform was based on the RFD900 and both platforms have continued to evolve). It provides a significantly better range."

What I am wanting to do is to pair my (not sure I am using the correct term):

with RFD900 (or anything else that offers more range.) I already have them working fine, I just want more range to keep up with my rc receivers.

lets see your parameters on those radios. I know @xfacta has posted some for his rfd’s but maybe we can help optimize what you have then if thats not enough can move onto others. RF signals to me are kind of unicorn and have read and watched plenty of videos/material and still sometimes have a hard time grasping it. I will say I have had very good luck RFD radios! I also have gotten more range than 500m with those 3dr radios so maybe a parameter or something could be off? You should get more range than 500 if in open space. whats your flying enviroment like where does that 500m drop off is it line of sight (LOS) or is there building or trees and other stuff impeding the signal.

If you want a great setup the rfd900x as the base station and a rfd900ux for airside are great. the 900ux is tiny and the 900x is just pretty much the bigger one of them all and was the original rfd900x variant.

I do see @tridge has relesed a new version Author: Andrew Tridgell
Date: Tue Mar 22 12:37:28 2022 +1100

prepare for 2.2 release

To my knowledge those old 3dr and the rdf900 aren’t compatible but again there is new firmware so I don’t know.

They’re all using these settings. I don’t actually know how much range they have because I’ve never actually tried them other than while setting them up, pairing them, and several arming tests. I did fly with a pair on my last copter, but probably never flew it more than 1/2 km. I was only going by what I’ve read, and when I saw it, I thought “well that’s not going to keep up with my receivers or how far away I commonly fly.” If I happened to lose ground control connection, I’d be worried, especially if the copter is far away. So that’s why I am looking to have ample range.

they are also running sik 1.7 on HM-TRP might not be bad to update to latest stable from what I can see above is 2.2, last version I used was 1.9. I think you will find the 3dr more than adequate for early testing. just make sure you have all of your GSC/controller failsafes set in case things may go bad.

Yes, they are, but… I’m done with that part and ready to move to the next step. I’ve been working on this project off and on for about 3 years (ridiculous, I know,) so I don’t really want to take chances on it.

If you feel they are at the limits go for the rfd’s! They will not pair with those sik radios (to my knowledge, hope someone says otherwise as I have plenty of them as well)! Not ridiculous at all you have put a lot of work into it and don’t want it to be a heap on the ground. Just changing a radio will not always help with range. RFD’s are a more power hungry and they require a power supply separate from the TELEM port so it may be some work which reading your posts your not afraid of. Like I said earlier if you have all of your failsafes setup properly and understand what each does it can help limit lost link issues if they were to happen. Good GPS lock and rtl on GSC loss works well and can help test range. If you do get the RFD 900x (US) or the 868x (non-us) then you can also pass your radio through depending on what radio system you are using and have the same radio for telem and control using sbus passthrough. Lots to think of. But if you feel like the 3dr’s are reaching their limits then I’d say your next best and least expensive kit would be rfd’s

It sounds like “RFD”'s are the way to go. I see several (confusing) options out there for telemetry.

I have seen reference to, and I’m not afraid of this. My copter has power outlets I’m not using, and I imagine I can step down the power with an Attopilot power module for it if I need to. My reason for wanting to use the 3dr radio on the ground side was that I don’t like exposing myself to any more high frequency waves than I need to. So I like the idea of lower power devices. Plus, it has to be able to connect to my phone with easeand preferably via cable. Those 3dr radios are awesome in this regard.

I saw something similar to this called “TBS Crossfire.” The reason I don’t go with that one is that it replaces my existing r/c receiver. Currently I transmit to a pair of redundant FrSky receivers on the craft, then I have a third on my camera gimbals (which are not compatible with Ardupilot.) I need it connected to all three, so the telemetry systems that replace my existing rc are out for me.

It’s looking like I will either bite the bullet and go for high power radio waves and use a pair of RDF900x’s, , or resign myself to flying within questionable range.

Sidenote: I do see some RDF900’s available on Alibaba and Banggood, but I don’t think they are made by RF Design.

nope stay away. go with RFD from their store. I have a crossfire on a mini quad its got some distance for RC but the mavlink connection leaves a lot to be desired. Very slow and not on par with rfd’s. I have a heap of the radios you showed earlier and all have been replaced with rfd’s for consistent connection and more peace of mind (sometimes! windows updates can really cause some issues!!!). I will say that RFD’s have also been a bear somewhat but things have progressed and things are very stable and the owners or employees have started in the last year posting here again as they had a lot of documentation that was contradictory or invalid. Price does not always mean better, but with RFD they have products that are recent although sometimes lacks current documentation even when it comes to their releases.

Maybe I am misremembering but I thought they had a reseller link on their webpage, but I could not find it. I also see they have adjusted prices based on the power of the USD-AUD exchange rate. Helibatics use to sell them in the US but that was a cpl years ago. anything rfdXXX-x or rfdXXX-ux radios will have compatibility between them. the rfdXXXu only works with rfdXXXu modems. Where as XXX in all these represent frequency (900 or 868) and the final lowercase letters denote models.

The early RFD900 might have paired with a 3DR, but that was ages ago. Any more recent RFD900X (series 1 or 2) or UX or just about anything else wont.
You’d have to by the pair, or a TXMOD set.

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@xfacta thanks for confirming that new x-ux models and probably even the + models will not pair with older sik raidos. don’t let this confuse you either not sure if their documentation has been brought into the future with all these new releases. All series 1 or 2 is, is the chip shortage and nothing else all compatibility is the same. but firmware loading is different and last time I checked RFD had not updated docs and was contradictory on their website! Have fun with the lack of conformity and all the vendors ask on the forums and discord to make sure you are getting what you expect, don’t rely on the vendors as its often not correct or is over sold.

I thought this was the case. Recently I bought a FTDI programmer which turned out to be inauthentic and utterly useless. Copies that don’t work right are not worth the time.

I might hold out looking for some used ones or old stock and give them a try. I haven’t found a better solution for what I want. I’m avoiding the TXMOD set because of the high power antennas plus the addition of wifi to the ground control. I’m in no rush, so maybe some old RFD900’s will show up on Ebay. If/when so, I will find out if they work with the SiK radios I have and post my findings. It sounds like, and I’ve now come across examples on YouTube, that I can actually probably get more than 500 meters range out of the radios I have. I see examples of people limiting to 10 channels and other settings changes, plus what fuego said with, [quote=“anon53993083, post:10, topic:94449”]
You should get more range than 500 if in open space.
[/quote] So I won’t be in any hurry to test or change the RDF900 to use what I have. I think I’ll limit my channels and do some testing off copter with some and see how they react.

you will not find authentic models, its not worth it! why use an f4 flight controller when firmware is now developed for H7 and to use an F4 you must lessen the capabilities! To me same principle applies, plus don’t trust ebay or ali documentation of what the products are.

CLONES unless they are of yourself are worthless hahah! IMHO

I’m not going to buy fakes - only used or old stock, but authentic.