Hi Daniel,
shortly answering your questions:
On 30.03.2016 17:50, Daniel Pocock wrote:
> OK, so keeping the mixer cooled will help reduce loss but has nothing
> to do with frequency stability?
yes; well, the point is that the mixer is really just a multiplier,
built from a nonlinear device, and
If you can synthesize the LO for the upconverter using the RTL XO as a
reference, the drift may tend to cancel. I say "may" as this is a trick
used in dual or triple down conversion chains. If you can alternate between
low and high sided IFs, then the drifts will move in the opposite directions
Tsys is essentially irrelevant for HF receivers, since Tambient is much,
much higher (thousands of K) than even some really-poor RF engineering
scenarios.
At HF, galactic background can be very high--1e4K or more.
On 2016-03-30 10:30, Marcus Müller wrote:
> Hi Daniel,
>
> haven't made
On 30/03/16 16:49, mle...@ripnet.com wrote:
> All of them use reasonably good crystals or crystal XOs. Certainly a
> lot better than the RTLSDRs most of these were intended for.
>
> I assume that you're talking about frequency stability, rather than gain
> stability?
>
Yes, frequency
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
I know that some of them, like the HAMITUP, use a socket for the XO,
which one could easily replace with a TCXO. Check with the
manufacturers about the XO spec they use.
On 2016-03-30 11:43, Daniel Pocock wrote:
> On 30/03/16 16:49, mle...@ripnet.com wrote:
>
>> All of them use reasonably
All of them use reasonably good crystals or crystal XOs. Certainly a lot
better than the RTLSDRs most of these were intended for.
I assume that you're talking about frequency stability, rather than gain
stability?
On 2016-03-30 03:18, Daniel Pocock wrote:
> Hi all,
>
> Has anybody been
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
Hi all,
Has anybody been using any of the upconverters for SDR and has anybody
made any comparison of them?
I've seen some comments suggesting that many of the low cost models have
poor thermal stability[1], has anybody seen problems with this in
practice for receiving modes like SSB on
