Yes, I am aware of the very convenient amplifiers from Mitsubishi.Rudix wrote: I have not checked the actual dimensions but if you look at some of the commercial equipment by Yeasu/Icom/Kenwood in the amateur radio market it must be close to that ! You must see how small the RF PCB's are on these units (With a huge heatsink !!)
Some of these radios are the size of a normal car radio, runs from 1.8 - 470 MHZ all modes, there is even a 200W SSB/50W FM/AM version from Kenwood. All these radios are to the stringent European standards but I suppose they are slightly larger than what you want. You have to remember that these radios include a lot of other features like band scope, scanning, DSP and cross-band repeater wasting a lot of space.
Some of the handheld radios by these guys run 7-8W AM/FM from less than 12V and fit in the palm of you hand and include most of the features of the mobile units. These units, like all the modern kit, is all surface mount with no adjustable caps/inductors.
But I am no expert, just wondering
Looking forward to you radio and transponder releases !
Fly safe,
Rudi
PS, have you looked at some of the RF "blocks" by companies like Mitsubishi ?
But I can't use them.
Firstly, they are a tad pricey and we want to make an affordable radio - secondly, they are not suitable for use with a digital class D modulation scheme which is vital for us as we need to get efficiency up to high levels (so we don't need a heatsink). This we have working fine now resulting in an extremely power efficient radio during TX with remarkably low current requirements.
These building blocks still do not isolate you from one of the biggest problems you will face - that of you own RF power feeding back into your VCO with disasterous consequences. This is particulary bad with an AM radio. The only traditinal solution to that is distance and careful shielding.
Or you need to generate your frequency in a completely different way that is imune to interference. We have settled on a digital PLL (DPLL) running at 5 GHz. It's the only way we can generate a stable signal for the transmitter a mere 2 cm from the final whithout any form of shielding.
Our transmitter is now final and ready for production. The radio would have been in production had we not found a small issue with the receiver during test flights. We are picking up cell phone masts on two frequencies if within about 500 meters horizontal of them. Need to kill that !
Rainier
