Re: [Discuss-gnuradio] comparing SDR upconverters, thermal stability

[Daniel Pocock]

On 30/03/16 16:30, Marcus Müller wrote:
> Hi Daniel,
> 
> haven't made experience with any of these upconverters; but:
> 
> The really temperature-sensitive aspect of an upconverter is probably
> the oscillator, not the mixer. So the trick might really be  keeping
> your upconverter in the same environment as your SDR receiver (assuming
> both don't have overly well temperature-compensated or oven-controlled
> oscillators), as that will just as much limit your frequency accuracy.
> 
> Mixer circuits do exhibit conversion loss that tends to get worse with
> rising temperature, but that'll not distort your signal much.
> 

OK, so keeping the mixer cooled will help reduce loss but has nothing to
do with frequency stability?


> The core question here is whether you'll deterioriate your system
> performance if you keep your upverter far from your antenna; my guess is
> that you'd have an LNA close to the antenna, anyway, so keeping the
> upverter's oscillator warm and cozy near your SDR device won't be that
> complicated, probably.
> 

That is definitely quite a relevant point, where I live at present the
indoor temperature can often be a lot lower than indoor

> That brings one down to the question whether you have the chance to use
> the same oscillator for both your SDR device and the upconversion; that
> way, you'd only have to worry about one device drifting under any
> circumstance. Does your device give you the chance to couple out a clock
> or maybe transmit a sine?
> 

For people using low-cost RTL-SDR dongles that might be more than they
can expect

For the proper SDR boards (e.g. USRP, BladeRF, HackRF) is this feasible?