My feeling is A Because of the low sunspot cycle the large signal performance of the RX is less a topic, the ICOM 7851 dynamic range, synthesizer and frequency concept is winning but expensive B The power amplifier from 100 W to 1500 Watt need to be catching up to the old Collins tube Amps with negative feedback, producing - 45 dB or better IMD products.
The military amplifier are fast on , reliable , durable and expensive... initially. The noisy blower may be a bad thing. I “only “ run 1 KW, and I am happy with it 73 de N1UL Sent from my iPhone > On Dec 12, 2018, at 10:47 AM, Bob kb8tq <[email protected]> wrote: > > Hi > > Usually on HF, the issue is large signal rejection. Phase noise very > definitely > gets into that part of things. Other components in the signal chain do as > well. > Once the synthesizer is no longer the weak link in the chain, spending more > to improve it (vs spending on the other components) probably does not make > a lot of sense. Since the synthesizer is *far* from ideal, that sort of begs > the > question of just how troublesome the other parts are and how much better a > device *could* be built. > > This does seem to be wandering a bit from a Time related topic ….. > > It does illustrate the point that “good enough” may be way far away from > “pretty good” and yet even more distant from “as good as it gets”. The > question on any system is always “how good do you need / what are you > doing?” …. > > Bob > >> On Dec 12, 2018, at 8:49 AM, jimlux <[email protected]> wrote: >> >> On 12/11/18 3:26 PM, Bob kb8tq wrote: >>> Hi >>> As I said, just how rational using these parts in a radio …. not at all >>> clear to me. >>> Back when I went to school, stuff that was this noisy was not in the >>> “greatest” category. >>> That was a *very* long time ago. >>> Oddly enough best performance synthesizers have gotten better. (as the >>> posted >>> presentations very clearly show). Just why a “high end” radio uses a less >>> than >>> ideal synthesizer likely relates more to cost (even at a price of thousands >>> of dollars) >>> than to anything else. >> >> Or "good enough" performance - driving to a 3 dB NF for a HF receiver while >> maintaining good strong signal performance is probably not worth it >> >> >>> Indeed cost also drives things like GPSDO’s and GPS modules. We often are >>> not >>> very eager to acknowledge that fact. >>> Bob >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
