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| Beautiful rig, but... |
Well, thanks to a kind fellow on an .io groups forum for the Lab599 TX-500, I can finally, at very long last, answer the question: how stable in frequency is it?
The answer, unfortunately, was readily demonstrated as: 'poor'. As you can see from the table of transmissions today, there is a very signficant drift that suggests strongly there is either no, or an inadequate temperature compensation of the XO.
My Kenwood TS-480SAT suffered from the exact-same magnitude of drift before I installed a £15 generic Chinese TCXO. Since then, its drift has always been zero, without any 'warm-up' time.
It's a mystery as to why most rigs don't bother with this incredibly inexpensive but very valuable component. Given the dominance of digital modes now, it's even more strange. Apparently, many people are still just focusing on CW and SSB when creating a rig.
Well, that's Lab599 in the bin for me, I'm afraid. A real disappointment. With the delayed delivery of the TX-500, it was already looking like a non-runner, as the weather is already warm enough on many days to venture outside for some /P work.
It's worth noting that the Xiegu line of hand-portable transceivers have pretty much the same standard frequency stability - but at half the price or less of the TX-500. Not that they're any good for me, either.
The TX-500 also has a problem that Lab599 themselves accept, according to the forum, has occurred to "several" units, related to the audio amplifier circuit, causing the audio output to cease. I'm sure they will sort it out, but I would want to wait for a year or so for all those actual and potential problems to be ironed-out first.
At the moment, it's looking like the FT891 will tick all the boxes. TCXO as standard, good price, the option to take the power up beyond QRP when necessary, and a radio that gets good reviews from most. The main - and quite serious - drawback is its 2kg weight. But I can manage that easily enough; the TS480 is 4kg!
Alternatively, if I think I can live with purely QRP power levels, then the tried-and tested FT817ND, with its very acceptable 1.1kg weight and a much lower price tag, would be a good buy, I think.
As always, your views on a decent backpack-portable rig are welcome!
4 comments:
John, I have a FT-817ND. Can't remember if it was very stable? Never had any issues on WSPR as far as I remember. But if you wish I can do some testing. 73, Bas
Hi Bas. The ND can be fitted with a TCXO, which, with the Yaesu version, costs another £80 or something stupid like that. The Chinese generic version is about £12. It would be nice to see what the standard crystal can do, though, so a few cycles of WSPR with it would be very welcome! I suspect the ND is moving to my number one position; the extra kg with the 891 is a lot to put up with.
Interesting. If the TX-500 drifts that much on 7 MHz, it may well be unusable for data on the higher bands.
Hi John. Yes, you may be right. It's such an unfortunate omission for an otherwise near-ideal rig. Surely someone can make a fully-decent QRP radio, without charging £1300 for it?
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