THANKS TO WB5VZL FOR PROVIDING THIS INFORMATION TO THE KA9FOX WEB SITE! ----------------------------------------------------------------------- From: Steven.M.London@att.com Date: 2 Aug 94 10:07:00 +0600 To: cq-contest@tgv.com Subject: Dunestar summary Thanks to AA6MC, KU4J, K0PP, KR0Y, WX0B, KR9U, AB6FO and W2VJN for their comments on Dunestar bandpass filters. Steve London, N2IC/0 n2ic@longs.att.com ------------------------------------------------------ Dunestar has designed the powdered iron cores out of the filters. The overheating of both the ICE and Dunestar filters was mainly in the cores. The durmica caps were also heating, but not to the point of destruction. Dunestar is now using NPO ceramics and says they are less lossy. I ran extensive tests on both manufacturer filters a while ago before they were changed because of the failures experienced by people. I have no info on degradation from band switching. ------------------------------------------------------ I can say that I have the older filter and run a TS950 with 150 watts with no problems. I have never measured attenuation. ------------------------------------------------------ Hi Steve, Our radio club bought two of the Dunestar 150 watt filters for Field Day this year. Out of the box one did not work at all, and the other didnt work correctly on 40 meters. The first one had ferrite beads on the leads shorting to a trace in the switching lines and had burnt the trace into and carbonized the PC board. That got to the second problem. The design of the filter is such that the top of the tank (double tuned circuits) drops back to the PC board which crosses to the other side of the filter under a shield. The PC board could not handle the 50 Watts that I was putting into it and arced to the ground plane. After cutting pads down in size to get further away from ground we were able to use one for Field Day, the other, I could not get 40 meters working at all. I havent called Dunestar yet as I figured I would just redo the filter to get it working before next Field Day. Unless Dunestar has changed the design, it wouldnt be worth my while even messing with the mailing and, hopefully not but, probably redoing them again anyway. I have heard on no other experience with Dunestar other than these two filters that we have. ------------------------------------------------------ I have two sets now of the model 6xx ( 150 watt ) 6 band filters and They work very well. we are able to run 3 bands at the same time on one ( 1 ) tower. I was one of the first to get the 150 watters ( I think, I inspired Ron to build them ) and my first one blew 10 meters causual dxing at 150 watts from my ic781...Ron sent me a 10 meter module to replace the broken one free. It was easy to replace. 4 solder points. 10 minuets. Done. The units are isolated with barier walls between all the filters. and a isolateion wall in between elements of each filter... I think they are great. attenuation is not noticable..all coils are air windings. Used with an amp at 65 watts for ( 1500 w ) you will not blow them up, We used them all contest season with no other failures I also have a 20m single unit and its also excellent. ------------------------------------------------------ I have a 100w Dunestar and it works pretty well. Loss much higher on 10/15 than any other band. Might ask Ron if new ones are the same. ------------------------------------------------------ I saw (and fondled) the Dunestar unit at the Seaside (Oregon) hamfest this spring. Wasn't open, but "looked" nice. I'm not a potential user however, due to the power limit ... I have an FT-1000 ... 200W+ I've used (borrowed) ICE filters and will be buying a set of them before the next contest season. They're very satisfactory. Will buy with BNC's as use them atop each radio and the change-over time not signifigant. ------------------------------------------------------ My neighbor has two of the new 160 - 10m Dunestar filters that he uses with an FT-1000 and they can definitely handle 150W w/o smoking. I didn't have a method to measure the insertion loss but would guess that it's very small (few .10th of db) (no audible difference when switched in/out). He is using a DX Solutions Smart Antenna Switch to drive the Dunestart filter that way everything is automatic when he changes bands on the radio. The new Dunestar has a DB-9 connector on the end to control band switching and can be set for positive relay logic (default) or negative logic (12v). ------------------------------------------------------ I have the Dunestar 600 as well as the ICE single-band bandpass filters. I don't have the equipment to answer your questions objectively, but subjectively the Dunestar is much more convenient than the ICE filters, but the Dunestar doesn't seem to provide the same isolation as the ICE filters. A fairer comparison might be to have ICE filters with a pair of switching boxes (like Top Ten Devices or Ameritron RCS-8Vs). I rejected that solution because of the amount of clutter in the shack; two switching boxes plus six ICE filters and twelve coax jumpers was a bit much for one rig, and I would have to double it for two rigs. I believe the specification of the Dunestar indicates less isolation than the ICE filters. I don't recall what those specs are, though. I have it at home and I'll try to remember to write it down for you over the weekend. My exciter has 100 watts of output, and I haven't blown up the Dunestar yet. I heard some war stories about their earlier model, but I understand the 600 to be more robust. I plan to add another Dunestar 600 soon. --