On Mon, 16 Mar 2009 17:19:20 -0400, Garey Barrell wrote: >It's like jacking up a Jeep and putting a Corvette engine, transmission >and wheels under it. What you end up with is neither a Jeep nor a >Corvette, but a collection of parts.
I'll add my "never to be humble" opinions to this, already expressed privately to Garey. I skimmed the article briefly, but have read the original incarnation on the WWW. Apparently the article is publically available at: http://www.arrl.org/files/qst-binaries/QS0409vanStralen.zip (12 MB download) >Adds an Audio Notch filter, DSP, Speech Processor, DAFC _AND_ LEDs in >place of the bulbs!!!!! Ugh. Digital junk. Takes away from the charm of the rig, and tends to generate crud and get in the way of the signal. DSP isn't all it's cracked up to be. I've got a RadShack DSP that I used now and again, mostly to reduce high frequency hiss in headphones when doing linear Oscar downlinks on 10 meters. Haven't used it in years, don't really miss it. I found that with a GOOD quality reciever ahead of it, the DSP didn't really add that much. The notch filter might be worthwhile, but I have an R7A now. And the aforementioned RadShack DSP has an auto-notch that workd fairly well. Higher-end esternal DSP boxen are even better in this regard, but nothing beats a true IF notch. The speech processor looks to be audio, can't be as effective as an SP7 (or similar design) RF speech processor. Old tech wins on this one. My LEDs are better. :) DAFC isn't such a big deal, the rig is pretty stable *if you have the fan installed correctly* (and it's not thermostaticlally controlled)! > A bunch of little boards stuck under the >parent board, That block the test points for frequency alignments.... >Further stuff on the ARRL Binaries site, another 13 MB (zipped), adding >a PA "drive" Attenuator with 16 transistors!, a Preamplifier, DDS PTO >replacement, AND of course a new fan, temperature controlled, blowing IN.... I'm staying away from the digital and DDS stuff. More failure points, possible introduction of digital noise, etc. Although I did occasionally use a preamp on 10 meters for satellite, it's not really necessary. I'm getting respectable MDS numbers out of the TR7, and it seems to be pretty flat across the HF band. It is definitely more than enough to hear the local noise floor on 10 meters under quiet conditions. The only benefit of a preamp is to amplify weak signals under quiet conditions to make them easier to hear; the downside is your IP3 goes down when you turn the preamp on. Not good during sunspots or running in a 'test. The TR7 IS NOT DEAF on 10 meters! Let's end this myth. I thought this fan nonsense was laid to rest, I PROVED that the fan works better when installed as intended. I invited others to duplicate my experiments to confirm or refute my findings, and no one has yet done so. You have to examine the fan as part of a COOLING SYSTEM, rather than as a device to spot cool one area. And it doesn't even do that as well when blowing in. I will continue to be vocal about that (as well as that awful Drake allband transmit mod)! Not to be totally negative, this gentleman has gone to an awful lot of work and appears to have done some quality work. I applaud his skills and initiative. If I had the tools and resources that he obviously does, I would probably convert my GT550A to a 4CX250 PA deck. I just think that a lot of this is not appropriate or unnecessary, and some could be done just as easily (and perhaps better) with external accessories. 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! "Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime." HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://radiojim.exofire.net http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
