If I buy one and it to you along with a six-pack, will you make it work good?!?!?
Bert New Watkinsville, Georgia Proudly Serving You Since 1964! > Date: Sun, 17 Apr 2011 21:31:08 -0500 > From: [email protected] > To: [email protected] > Subject: [IRCA] Dissecting the Grundig S350DL (Tecsun 3000) > > I got this radio at a pawn shop for $35 a while back and while it's not > the ideal DX box for SWL, my primary interest, it does do a very nice > job on MW after an alignment and a bit of tweaking. I've had it apart > and back together 4 times now, lacking a service manual or even a > schematic I'm proceeding cautiously. I've seen some claims that this > isn't a rebadged Tecsun but all the boards have "Tecsun PL-3000" > screened on them, you decide. I try to keep in mind that it is a sub > $100 receiver after all. > > I have semi locals during the day on 570 and 1490 that I used to align > it. The main problem on MW and the strongest plus is the "dual coil" > internal ferrite rod. The tuning on the rod would not line up with the > L.O. I haven't investigated if it's a padding cap out of spec, material > defect in the rod itself or just poor engineering. My guess is on the > crowded RF board it would have cost too much to add a couple of > components :( The dual coil is a balanced design similar to what I've > been using for about 25 years and the problem with my unit was that it > was not very balanced. One side was about 80KHz higher than the tuned > Freq. at 1520. The problem was solved with a 20pF trimmer cap > tack-soldered onto the back of the RF board and sliding the right hand > coil inwards.. > > Since the coil is not more adjustable without adding or removing > windings I had to peak the L.O. to the antenna coil. An S-meter was > added through a pot from the AGC pin on the display unit. Varying the > inductor of the MW L.O. and retuning to 570, noting the S-meter readings > gave me the low end, doing the same at 1520 with the L.O. variable cap > then repeating the process until there's no improvement to be made for > alignment then setting the added trim cap for highest signal on 1490 > made a huge improvement in sensitivity and selectivity across the entire > band. MW tuning now ranges from 505 to 1723 KHz rather than 519 to 1740 > when I got it. > > 1320 and 1140 used to pop up all over the place but now even those > ghosts have been exorcised :D > > I put AAs in it and went to a quiet hill north of town earlier. Had > paper but forget to bring a pen or pencil but it was snowing and cold > out anyway our Kia van has some weird noise generator even with the key > off so I had to go out and away from it :( I did a quick spin through > the band and was getting something on nearly every 10Khz with quite a > few multiples. Nulling is excellent! I was on a side lobe of 1320 (5KW) > and while I couldn't completely null it. I was able to get a weak > carrier on 1310. > > I've heard very good and very bad things about the S350DL/Tecsun 3000 > and I think there are good ones and bad ones. I suspect that substandard > or out of spec parts were put into a lot of them and factory QA is not > the best > > I have made some other modifications mostly to improve SW reception. > The S-meter, adding an F connector with a 4:1 un-un for external antenna > input that bypasses the rod antenna and LP filter entirely and using the > LP switch to switch from external to built in rod for SW and an > alignment. There are other problems that I could fix given time, > incentive and beer. The wide filter seems to be centered about 2KHz > above the narrow and some that are inherent to the design, images and > birdies from the display mostly. At this point I consider any further > attempts at improving it on SW as putting lipstick on a pig > > All I can say about the FM reception is that it works since I rarely use > FM and wouldn't miss it if it wasn't there. > > I was going to scrap it and harvest the ferrite rod, display and ICs but > for now at least it's the best MW portable I've ever owned and since I'm > still waiting on parts for upgrading my homebrew it's my primary > receiver for the time being. > > Tim Hills > Sioux Falls, SD > > _______________________________________________ > IRCA mailing list > [email protected] > http://montreal.kotalampi.com/mailman/listinfo/irca > > Opinions expressed in messages on this mailing list are those of the original > contributors and do not necessarily reflect the opinion of the IRCA, its > editors, publishing staff, or officers > > For more information: http://www.ircaonline.org > > To Post a message: [email protected] > _______________________________________________ IRCA mailing list [email protected] http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: [email protected]
