[Repeater-Builder] Re: Need DB4048 Duplexer Info
larynl2 lar...@... wrote: Thanx Paul, who responded directly, Randy, and Skipp. That puts me onto some things to check. So far the harness looks to be correct, with proper length jumpers made of RG9/B. I looked at all of the loops and they are also in good shape and correct size. Next I'll check each cavity individually on their respective notch frequencies. And maybe I should check all elements of the harness with a megger to find lightning damage/carbon tracks. Yeah, 1 watt and desense so bad it's not worth measuring -- something rather serious... Laryn K8TVZ You might try using only two of the cavities in a simple dual cavity duplexer test situation. I suspect what might quickly be labeled desense is actually part of or sourced to another problem. Regardless of the label one small iceberg should not sink this new fancy Titanic Ship. cheers, s.
[Repeater-Builder] Re: Need DB4048 Duplexer Info
Re: Need DB4048 Duplexer Info larynl2 lar...@... wrote: Hi all I'm working on a 1 mc. split repeater using this duplexer. I would recommend you visit the following web page: http://www.ke3ht.org/14703/db-4048.html Transmitter is a VHF Engineering; output is 1 watt. I'm using a Mastr II receiver with no preamp. Interconnect cables are RG142. The VHF Engineering Transmitter is actually a fairly well thought out circuit and when properly tuned is a more than fair performer. The Mastr II Receiver is a legendary good performing circuit so you're off to a great start. The old VHF Engineering receiver developed problems not worth fixing, so everything is on the bench for the new receiver and re-tuning. The original VHF Engineering Receiver really is/was crap when compared to any real commercial Land Mobile Radio Receiver. Desense was always an issue with this repeater, with 1-3db pretty normal. 1 watt and a Master II Receiver with a 1 MHz split? wow... So I decided to re-tune the duplexer. I used a signal generator and receiver. All ports were either terminated in 50 ohms or had a 10db pad in series with the generator and receiver during tuning for minimum signal through the respective halves. It seems to tune well and predictably. However, I'm getting 20db+ of desense with the duplexer operating into a known good dummy load. I can reduce the desense considerably by *winging it* and tuning the cavities while the repeater is operating. (Maybe that's the way I should tune it...!) So something isn't right. Someone with a Network analyzer or Spectrum Analyzer with a Tracking Generator would save you a lot of time figuring out what is really going on. I'm not totally convinced that this duplexer wasn't played with at some point, so it is possible that cables in the harness were mixed up. There is no labeling or other info on the duplexer, since the metal box that it was in when new is gone along with the nameplate. So it is not clear which side is which, and I may have been trying to use it reversed (although I don't think so). I believe that this duplexer was originally ordered for 2M, but I could be wrong, which could account for some troubles. So where would I find info on harness cable lengths so I can check them? Or if someone has one of these working on 2M and is willing to make some measurements that would be awesome. And which half of the duplexer is for the high and low frequencies? Laryn K8TVZ Start off with the web page I reference above... cheers, s.
[Repeater-Builder] Re: Need DB4048 Duplexer Info
Thanx Paul, who responded directly, Randy, and Skipp. That puts me onto some things to check. So far the harness looks to be correct, with proper length jumpers made of RG9/B. I looked at all of the loops and they are also in good shape and correct size. Next I'll check each cavity individually on their respective notch frequencies. And maybe I should check all elements of the harness with a megger to find lightning damage/carbon tracks. Yeah, 1 watt and desense so bad it's not worth measuring -- something rather serious... Laryn K8TVZ
[Repeater-Builder] Re: Need DB4048 Duplexer Info
Larry did you try RB site. Try this link http://www.repeater-builder.com/db/pdfs/db-4048.pdf Randy --- In Repeater-Builder@yahoogroups.com, larynl2 lar...@... wrote: Hi all I'm working on a 1 mc. split repeater using this duplexer. Transmitter is a VHF Engineering; output is 1 watt. I'm using a Mastr II receiver with no preamp. Interconnect cables are RG142. The old VHF Engineering receiver developed problems not worth fixing, so everything is on the bench for the new receiver and re-tuning. Desense was always an issue with this repeater, with 1-3db pretty normal. So I decided to re-tune the duplexer. I used a signal generator and receiver. All ports were either terminated in 50 ohms or had a 10db pad in series with the generator and receiver during tuning for minimum signal through the respective halves. It seems to tune well and predictably. However, I'm getting 20db+ of desense with the duplexer operating into a known good dummy load. I can reduce the desense considerably by *winging it* and tuning the cavities while the repeater is operating. (Maybe that's the way I should tune it...!) So something isn't right. I'm not totally convinced that this duplexer wasn't played with at some point, so it is possible that cables in the harness were mixed up. There is no labeling or other info on the duplexer, since the metal box that it was in when new is gone along with the nameplate. So it is not clear which side is which, and I may have been trying to use it reversed (although I don't think so). I believe that this duplexer was originally ordered for 2M, but I could be wrong, which could account for some troubles. So where would I find info on harness cable lengths so I can check them? Or if someone has one of these working on 2M and is willing to make some measurements that would be awesome. And which half of the duplexer is for the high and low frequencies? Laryn K8TVZ
Re: [Repeater-Builder] Re: Need wacom duplexer mod info
Hello Freddy, Have you tried to tune it to your frequency? You may not need to cut the inner tuning rod, as it just may have enough travel to go to your frequency. It's worth a shot. My 42MHz cans went to 53Mhz with no problems. The loops will probably need to be modified. 73, Joe, K1ike Doug N3DAB --- In Repeater-Builder@yahoogroups.com, ag4uw ag...@... wrote: Hello group!! I am looking for someone that has info on mods for the wacom 604B duplexers to put them in the ham band 604D. And does anyone know how to remove the the tuning rod from the wacom duplexers??? Does the big nut on the top unscrew or can it be removed??? I am looking for info but have not been able to find anything on doing this mod. If I can remove the copper rod from the can I was going to try to cut it shorter,(If you know how long the tuning rod is on the D model please let me know. It can not be cut off from the end because it has finger stock on that end and will have to be cut off at the top. If anyone has any info please let me know. if you have the info on how long to cut the tunning rod off are know how long the tuning rod is on the 604D or have any info on how to remove the rod please let me know. any info you may have would be great. Thanks Freddy N4XW Yahoo! Groups Links
[Repeater-Builder] Re: Need wacom duplexer mod info
hey Joe Yes I have tried that and it will only go to 42mhz They are 35mhz to 40mhz cans and they will only go to 42mhz. The tuning rod is not the real problem I have it out and all I will need to do is cut more threads on the threaded rod so it will unscrew further up the can but the cooper sleave is what I need to get out to cut off and Im not sure how it comes out. There is a big nut on top of the can but have put some preasure on it but have had no luck on geting it to break loose. I dont wont to mess up the can so I am giving it a shot on here to see if anyone has done this are has any info on how short to cut the sleave. I have tried a plug in the end of the can to make it 8 shorter but that does not make a big change. The A B and C models are 80 long and the D is 72 But with the test I have done shows that the length of the cans is not the problem, it has a little effect, but very little. I can not find any info on the internal specs on these. Telewave and TX RX dont have any internal specs or can they tell me much info on them. If I make this work I will post the info on here for all to have I just need to figure out how to get my hands on the internal specs and how to remove the sleave and the length of the D model and the loop info will be the next thing I am going to need. Freddy N4XW --- In Repeater-Builder@yahoogroups.com, Joe k1ike_m...@... wrote: Hello Freddy, Have you tried to tune it to your frequency? You may not need to cut the inner tuning rod, as it just may have enough travel to go to your frequency. It's worth a shot. My 42MHz cans went to 53Mhz with no problems. The loops will probably need to be modified. 73, Joe, K1ike Doug N3DAB --- In Repeater-Builder@yahoogroups.com, ag4uw ag4uw@ wrote: Hello group!! I am looking for someone that has info on mods for the wacom 604B duplexers to put them in the ham band 604D. And does anyone know how to remove the the tuning rod from the wacom duplexers??? Does the big nut on the top unscrew or can it be removed??? I am looking for info but have not been able to find anything on doing this mod. If I can remove the copper rod from the can I was going to try to cut it shorter,(If you know how long the tuning rod is on the D model please let me know. It can not be cut off from the end because it has finger stock on that end and will have to be cut off at the top. If anyone has any info please let me know. if you have the info on how long to cut the tunning rod off are know how long the tuning rod is on the 604D or have any info on how to remove the rod please let me know. any info you may have would be great. Thanks Freddy N4XW Yahoo! Groups Links
[Repeater-Builder] Re: Need wacom duplexer mod info
I googled WACOM 604 duplexer and came up with a bunch of info., you might try the same. I found a 2 page WACOM 604 flyer with the specs says the A,B and C cans are 80 tall, and the D can is 72 tall. Logic would say shorten the inner rod 8, but loop size might be smaller and the harness cables may be different length as well. LOL on your project. Hope some one else has more info to help you out. Doug N3DAB --- In Repeater-Builder@yahoogroups.com, ag4uw ag...@... wrote: Hello group!! I am looking for someone that has info on mods for the wacom 604B duplexers to put them in the ham band 604D. And does anyone know how to remove the the tuning rod from the wacom duplexers??? Does the big nut on the top unscrew or can it be removed??? I am looking for info but have not been able to find anything on doing this mod. If I can remove the copper rod from the can I was going to try to cut it shorter,(If you know how long the tuning rod is on the D model please let me know. It can not be cut off from the end because it has finger stock on that end and will have to be cut off at the top. If anyone has any info please let me know. if you have the info on how long to cut the tunning rod off are know how long the tuning rod is on the 604D or have any info on how to remove the rod please let me know. any info you may have would be great. Thanks Freddy N4XW
[Repeater-Builder] Re: Need wacom duplexer mod info
Yes Doug I found that info but there was nothing about a Mod. Yes I did look before I posted. ??? Freddy --- In Repeater-Builder@yahoogroups.com, n3dab rb_n3...@... wrote: I googled WACOM 604 duplexer and came up with a bunch of info., you might try the same. I found a 2 page WACOM 604 flyer with the specs says the A,B and C cans are 80 tall, and the D can is 72 tall. Logic would say shorten the inner rod 8, but loop size might be smaller and the harness cables may be different length as well. LOL on your project. Hope some one else has more info to help you out. Doug N3DAB --- In Repeater-Builder@yahoogroups.com, ag4uw ag4uw@ wrote: Hello group!! I am looking for someone that has info on mods for the wacom 604B duplexers to put them in the ham band 604D. And does anyone know how to remove the the tuning rod from the wacom duplexers??? Does the big nut on the top unscrew or can it be removed??? I am looking for info but have not been able to find anything on doing this mod. If I can remove the copper rod from the can I was going to try to cut it shorter,(If you know how long the tuning rod is on the D model please let me know. It can not be cut off from the end because it has finger stock on that end and will have to be cut off at the top. If anyone has any info please let me know. if you have the info on how long to cut the tunning rod off are know how long the tuning rod is on the 604D or have any info on how to remove the rod please let me know. any info you may have would be great. Thanks Freddy N4XW
[Repeater-Builder] Re: Need a duplexer
The T-1504 works very well if clean. The notches are difficult to tune perfectly if the inside of the cavity has been exposed to moisture. I have opened up cavities and cleaned with steel wool and coated with light grease and they tune much better. I am not sure if anyone else has had this problem, but with these duplexers I have had a hard time with tuning a pair of cavities with the stock phasing lines. I seem to be getting double peaks and the peaks just won't pull together down around 443 MHz. I went and made new phasing lines out of the same type cable, but just 1/2 inch longer on all lengths. Now the peaks pull together, therefore resulting in sharper pass band and less loss. Maybe it was just mine. 73, KC4FWC --- In Repeater-Builder@yahoogroups.com, Kevin Berlen, K9HX [EMAIL PROTECTED] wrote: A Motorola T-1504 series is an excellent choice. Should be available used for $125-$150. 73, Kevin, K9HX At 12:10 PM 4/12/2005, you wrote: Do you have any recommendations on 70cm duplexers capable of 100W? Thanks Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: Need a duplexer
derek_mcintyre wrote: I am not sure if anyone else has had this problem, but with these duplexers I have had a hard time with tuning a pair of cavities with the stock phasing lines. I seem to be getting double peaks and the peaks just won't pull together down around 443 MHz. I went and made new phasing lines out of the same type cable, but just 1/2 inch longer on all lengths. Now the peaks pull together, therefore resulting in sharper pass band and less loss. Maybe it was just mine. Nope, that is typical. Tuning with a small hammer is optional, but usually results in good results. Kevin Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: Need a duplexer
At 01:35 AM 4/13/2005 -, you wrote: I am not sure if anyone else has had this problem, but with these duplexers I have had a hard time with tuning a pair of cavities with the stock phasing lines. I seem to be getting double peaks and the peaks just won't pull together down around 443 MHz. I went and made new phasing lines out of the same type cable, but just 1/2 inch longer on all lengths. Now the peaks pull together, therefore resulting in sharper pass band and less loss. Maybe it was just mine. --I've seen many T1500 series duplexers that have the wrong cable kits on them for the frequency range being tuned. I'm not saying this is the case with you but it seems many folks who buy them don't understand the color coding of the cable kits. These are CRITICAL to proper performance. I have a couple of T-1504As and each one does 102 Db notches with 1.5 Db insertion loss. No slouch but of course, I have the correct cables installed :-) Ken -- President and CTO - Arcom Communications Makers of state-of-the-art repeater controllers and accessories. http://www.ah6le.net/arcom/index.html We now offer complete Kenwood TKR repeater packages! AH6LE/R - IRLP Node 3000 http://www.irlp.net Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: Need a duplexer
Doing some research I have found that each interconnecting jumper must be an electrical 1/4 wave or performance suffers. The jumpers attribute 6.5dB each to the isolation of the duplexer. I havn't gotten around to replacing the RG-214 jumpers on my set of 2M cavitys but it may help my performance as the original set is on 156Mhz some where. And if you can find one for cheap and circulator in place of the final RX/TX/ANT Tee helps cans with weak(70-80dB) isolation like the Wacom WP-639 and Sinclair Q2202E by providing approx an extra 20dB of isolation. I picked up a surplus EMR circulator over the weekend for $50 and already the customers have noticed much improvement. Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
