At 08:42 AM 6/4/2003 -0400, you wrote:
>What are the advantages of using an external frequency reference, such as
>from a GPS receiver with a single RX-340? How important is that kind of
>accuracy for HF reception?
Well, beyond being incredibly picky, none -- *yet*. I'm not doing
interferometry or diversity reception, *yet*, but I may want to play with
it in the future.
For me it was a combination of a couple things: My receivers from a certain
far east company were *dead on* using the zero-beat-WWV-compare-USB-LSB
method (of course they've drifted since then) and the comment from one
of the designers when I went to T-T to evaluate the '340: "Frankly, we
assumed that everyone using this receiver would have an external reference,
so we didn't put that much work into the internal one." (paraphrased)
This was in response to why their demo '340 was about 25 kHz off at
15 MHz.
Also, I prefer a natural sounding voice, and listening to the HF-GCS nets
you can hear how good SSB can sound.
Finally, don't assume SSB-mode is used to receive SSB signals only. So-called
ECSS reception of AM is done with SSB and is sometimes preferable to sync. AM.
>Also, how far off in frequency was the RX340 in normal operation vs with the
>external reference?
Mine wasn't too far off -- about 15 Hz at 15 MHz. But that was more than
that certain far eastern company shipped their equipment with. Clearly
the latter company wasn't concerned only with meeting spec. I have two
identical receivers from them and both were that good.
>73,
>Mark
Eric
--
Eric F. Richards
efricha@dimensional.com
"The weird part is that I can feel productive even when I'm doomed."
- Dilbert
|