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What's the BEST 35MHz Rx/Tx combination?

derabbink

Junior Member
#1
Hi everyone,

I am new to RC flight, and I want to get into FPV planes. But as a newbie to the field it is quite hard for me to get a complete picture of all the available technology.

I live in the Netherlands where we have rather strict rules about frequency use; in essence we are allowed to use 35MHz, 2.4GHz and 5.4GHz (amongst others) without a radio license.
Since 5.4GHz is not very powerful when transmitting through obstacles, I figured I'd want to use 2.4GHz for video, leaving 35MHz for controlling the model.

As a (pre)beginner, I don't have any hardware at all, and I want to avoid buying a lot of expensive equipment that I'll be replacing down the road. That's why I was thinking of starting out with a simple plane (HK Bixler 2) that I can keep adding stuff to, and a decent radio.

I understand that there are different nested (sub)categories of 35MHz communication:
  • channel configuration using chrystals
  • synthesized radio (non-chrystal tuning) better
    • PPM (analog data transmission)
    • PCM (digital data transmission) better
      • one-way communication
      • DSM (Digital Spectrum Modulation) two-way communication (plane talks back) better
        • FHSS (Frequency Hopping Spread Spectrum)
        • DSSS (Direct Sequence Spread Spectrum) better

Assuming this breakdown is correct, you'd simply have to follow the path through this nested structure along the nodes marked better, and you'd come up with the following requirements that a fictitious BEST Rx/Tx combination must satisfy:
  • synthesized
  • PCM
  • DSM
  • DSSS

Now my questions are
Is this information correct and complete?
Does such a Rx/Tx combination exist?
 

pgerts

Old age member
Mentor
#2
I think that you are mixing 35 and 2,4...

PPM or PCM - depending on expected interference from other radios on the same frequency.

I would rather say single or dual conversion - DUAL is the only i would trust.

As for range i would try to find an old Multiplex with the long antenna (twice the lengt of "normal" 35 MHz).

Syntesized are not any better than crystals for range.

It is possible to use 2,4 for both control and video if you know what you are doing.
There are plenty of space in the 2,4 band for "everything" as long as you are using equipment that not "collide".
 

derabbink

Junior Member
#3
So what you're saying is that DSM, FHSS and DSSS do not exist in the 35MHz domain?

I am not so much concerned with range, as I am with just having a decent FPV feed, and from what I understood, a 5.8GHz signal is just very fragile, especially if you're also using 2.4GHz.