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WWV 25MHz very useful.

March 01, 2015 04:35PM
With all of my test gear being old (+15 years), and way out of calibration, having a stable source to tune-up receivers, and transceivers, that's affordable is not only nice, but really essential. Recently, (Actually, within the last year.) I've noticed that my Kenwood TS-2000X transceiver was a bit off on pretty much everyone that I've QSO'ed with, or RX'ed in SSB and CW. Going to the TS-2000 Yahoo Groups I wasn't to only one to notice this, apparently there was a stock of TS-2000's that had their .5PPM master oscillators off FREQ right from the factory. (Yeah, nice... Huh??? Especially for what you pay for one of these rigs.) Fortunately, some dude wiser than I, wrote an article there about where you adjust that master oscillator FREQ. The only problem is finding a dead-nuts stable FREQ source to tune it up to. This dude lived next to a 1.3GHz (Or around that FREQ) beacon somewhere in New Jersey to tune his TS-2000 too. Now, most of us don't have that option, and that includes me. I'd thought about using the video carrier for FREQ's for VHF / UHF TV stations to calibrate FREQ counters. I've heard of that being done. However, with every major TV station in the USA now using digital 8VSB means to TX, a pilot carrier that exists for that is about 1/2 the amplitude of the multiplex info. So a FREQ counter on an 8VSB TV signal can't lock on and give you a correct reading, like it could with the old analog NTSC TV signal. Fortunately, we now have a way to better tune up our rigs with WWV that should be better than before. How? Let's go back 30-some years to an earlier Icom rig, the IC-745, or I should say its manual. In the manual itself it says that over the years that transceiver is going to drift, but included an external adjustment to correct this. It describes using the WWV's 10MHz signal to tune up to in either SSB, or CW, or test both. Icom says to tune the EXT CAL pots until you don't hear a hetrodyne between the rig's 100KHz marker and WWV carrier. I took it one step further where I tuned by ear at 20MHz and compared the tonal quality of the WWV tones and that dude's voice with WWV's AM tone and voice FREQ quality and USB / LSB tonal qualities. You can do the same with CW on many rigs. Most rigs are default set where the CW tones are dead-nuts 800Hz. Tune to WWV's 20MHz signal, goto CW mode and you'll hear the 800, or so Hz beat, and tune your RX to 20.000.800KHz, then tune EXT CAL on rig to where the HET beat is gone and tune for best WWV audio tonal qualities. That should put your rig +/-5Hz of dead-nuts on FREQ if you have a really good ear for differentiating tonal differences. OH YEAH!!! Forgot, before doing this let you rig warm up ON sitting idle for at least one hour. So, after remembering this older Icom trick I've contemplated (Not thought.) now why can't I apply this to other rigs. As far as I can observe, you can. OK, why is having a 25MHz dead-nut signal better than a 10MHz, or even a 20MHz signal to tune too? For those that have multiband rig that do HF, VHF, UHF, and even the microwave region, all of those bands depend on one central master oscillator. On 25MHz my TS-2000X was -40Hz lower than displayed. Not bad, really, but that offset FREQ discrepancy becomes way more pronounced when you go up in FREQ and multiplies to being hundreds of Hz in VHF, to KHz off in UHF and up. (Could someone do the math and see what being -40Hz off on 25MHz multiplies to at 144MHz, 432MHz, and 1.2GHz with a .5PPM oscillator?) So, having a dead-nuts FREQ source as high as possible for these newer multiband rigs is nice to have. Same deal to tune up to as I did with the older Icom rig, let the rig warm up for a hour, turn rig back off, take the cover off to expose where you need to go to FREQ adjust your master oscillator, power back up the rig, tune to 25.000000KHz, and listen to what WWV sounds like between AM and SSB's, or CW's, tonal qualities. I used my best pair of stereo headphones to listen, tweak oscillator, compare, and did this over and over for about an hour until I was content with how the 25MHz WWV sounded in AM, USB, LSB, and CW. Just about every high-end rig out there has a Yahoo Groups forum on it. Before doing anything, I would suggest checking some of these groups out since there are some pretty smart MF'ers out there puting out info on FREQ tuning rigs and problem solving. But beware, there's also idiots out there who don't know what the "F" they're totally doing. Was my means to dead-nuts tune my TS-2000X the right way? Probably not, but it certainly was the most affordable way to do it. And QSO'ing with other HAM's on rig's like TS-2000's, IC-756Pro's, Elecrafts, etc, I don't appear to be off on them, and they're a lot more dead-nuts on FREQ with what's displayed on my rig now. So, why not utilize the new 25MHz WWV? I'd rather our tax dollars go for paying for this than some B.S. wars out there. (Just my take.)
Subject Author Views Posted

WWV 25MHz very useful.

ThaDood 527 March 01, 2015 04:35PM

Re: WWV 25MHz very useful.

Radio Animal 400 March 05, 2015 03:43AM

Re: WWV 25MHz very useful.

ThaDood 326 March 05, 2015 12:31PM



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