Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang ---------------------------------------------------------------------- Chuck -
The W-4 is a good wattmeter. It is about as accurate as most of it's type offered by various manufacturers.
For example reading a Drake T-4XC at a typical 130W output can read anywhere from 121.5W to 138.5W on your W-4 and be within specifications. (Specification is +/- 5% of Reading (130W) +2W). On a Bird 43 with a 250W slug, it could read anywhere from 117.5W to 142.5W. (Specification is +/- 5% of Full Scale).
On the other hand, for your "500+ Watt" SB-200 the Drake could read anywhere from 455W to 545W (+/- 5% of reading +20W) for a 500W signal. The Bird 43 is a little different because your "500" watts is the full scale reading of the 500W slug, but if you have 525W you'd have to use a 1000W slug. For 500W, the 43 with 500W slug could be between 475 and 525. But for 525W, the 43 with 1000W slug could read anywhere from 475W to 575W. This is why Bird recommends selecting a slug such that the power reading is in the upper third of the scale.
All that being said, the Drake calibration is easily "fixed" (or screwed up, depending upon the accuracy of the calibrator and his reference) by the handy little pots inside. The Bird HAS no adjustments that are easily accessible and so is more likely to be accurate. That is until someone runs their 2KW out with a 10W slug inserted.
A Peak Reading wattmeter is convenient, since you don't have to "whistle up" your transmitter to see your actual output power. Normal CW or SSB transmissions show their actual power since the Peak Reading circuit "integrates" the spikes of power into an average reading that a meter can display instead of trying to follow (impossible) each spike.
73, Garey - K4OAH Atlanta
Drake C-Line Service Manual <http://hr99.home.mindspring.com/R-4C_Servicez/>
Chuck Wyatt wrote:
I've got the W-4, and thing it's pretty cool. Looks great anyway, maybe doesn't compare to a Bird in terms of performance, but who knows, sure costs less. Ok, dumb question: Why peak reading? When I whistle up my W-4, and see 500+ watts from my SB-200 is that still reading only "average" power?
-Chuck Wyatt
W1CEW (formerly KB5GC)
-----Original Message----- *From:* [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] *On Behalf Of *J. Michael Thurman *Sent:* Monday, May 16, 2005 8:56 PM *To:* [EMAIL PROTECTED]; drakelist@www.zerobeat.net *Subject:* Re: [drakelist] W-4 Wattmeter Modification
Try:
*_W4 WATTMETER CONVERSION TO A PEAK READING METER:
_*HI-RES Communications offers the famous PDC-1 kit to convert ANY Average Reading wattmeter to true Peak Reading! Other kits will join the PDC-1 in our kit line soon! HI-RES Communications, Inc., 8232 Woodview Dr., Clarkston, MI 48348-4058 USA ,
E-mail orders: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> , Phone and Fax orders: (248) 391-6660 (Safe to leave ALL ordering information!) http://home.att.net/~hi-res/kits/kits.html <http://home.att.net/%7Ehi-res/kits/kits.html> /from: http://www.wb4hfn.com/DrakeArticles/TechTips/DrakeResources.htm
73 es gud DX, Michael WN5T
At 06:22 PM 5/16/05, wrote:
"" <[EMAIL PROTECTED]> made an utterance to the drakelist gang ---------------------------------------------------------------------- Is there a modification to create a Peak reading meter out of the W-4?
Thanks,
Doug Coffman N9XTF
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