RE: [Repeater-Builder] Duplexers
--- Jeff DePolo [EMAIL PROTECTED] wrote: When you put the Bird between the TX and the duplexer, you have changed the length of the jumper cable, which upset the tuning. Adding a wattmeter or any other length of cable between the transmitter and the duplexer Tx input port has no effect on the tuning of the duplexer. It may change the load Z the transmitter sees, which may make the transmitter happier (or sadder) depending on the resulting Z, but in no way does it alter the tuning of the duplexer itself. Adding or removing cable lengths between the transmitter and duplexer also does not change the VSWR as seen by the transmitter (minimal cable loss effects notwithstanding). --- Jeff Jeff you have just made two statements that are the exect opposit of each other. If changing the length of cable makes a differance, then the swr as seen by the transmitter must change. As some transmitters can not be tuned for impedance mismatch, adding lengths of line may change the impedance where the transmitter will produce the maximan ammout of power out. If say the duplexer is setup for a 50 ohm load and the transmitter wants to load into a 60 ohm load, then changing the length of cable between the duplexer and transmitter may let the transmitter see 60 ohms instead of 50 ohms. The swr will not really change on the line as a whole, but at a given point it may match the impedance of the transmitter for maximum power transfer. Moody friends. Drama queens. Your life? Nope! - their life, your story. Play Sims Stories at Yahoo! Games. http://sims.yahoo.com/
Re: [Repeater-Builder] Duplexers
Ya you should be able to trim your coax so the transmitter sees 50 ohms, which should be every 1/2 wave. All this does it protect the transmitter, the standing waves are still there, they just gets dissipated/radiated by the coax. Also with cans usually, if I have enough time on my hands, I tune them one way (higher frequency = cans marked TX), then the other (lower frequency = cans marked TX). Almost every time you'll get a different outcome. Which way you tune them in the end depends on your situation, weather your putting out lots of TX power and need the isolation, or if you care about receive sensitivity. I find that usually one side of the duplexer will have a better insertion loss than the other, while the other will have better null than the other. The one with better insertion loss I usually put on the RX side (I can simply bump the TX power by a dB to compensate for the extra loss). This of course only applies to cans where you can not set the insertion loss. For cans that you can change the insertion loss you can spend hours on fiddleing. If you take your transmitter and put it into a dummy load what's its TX power? Also no one mentioned this (I think), but check you cables and connectors, I had one that was bad, produced a bunch of swr, cans were fine. Jesse On 8/25/07, Ralph Mowery [EMAIL PROTECTED] wrote: --- Jeff DePolo [EMAIL PROTECTED] jeff%40depolo.net wrote: When you put the Bird between the TX and the duplexer, you have changed the length of the jumper cable, which upset the tuning. Adding a wattmeter or any other length of cable between the transmitter and the duplexer Tx input port has no effect on the tuning of the duplexer. It may change the load Z the transmitter sees, which may make the transmitter happier (or sadder) depending on the resulting Z, but in no way does it alter the tuning of the duplexer itself. Adding or removing cable lengths between the transmitter and duplexer also does not change the VSWR as seen by the transmitter (minimal cable loss effects notwithstanding). --- Jeff Jeff you have just made two statements that are the exect opposit of each other. If changing the length of cable makes a differance, then the swr as seen by the transmitter must change. As some transmitters can not be tuned for impedance mismatch, adding lengths of line may change the impedance where the transmitter will produce the maximan ammout of power out. If say the duplexer is setup for a 50 ohm load and the transmitter wants to load into a 60 ohm load, then changing the length of cable between the duplexer and transmitter may let the transmitter see 60 ohms instead of 50 ohms. The swr will not really change on the line as a whole, but at a given point it may match the impedance of the transmitter for maximum power transfer. __ Moody friends. Drama queens. Your life? Nope! - their life, your story. Play Sims Stories at Yahoo! Games. http://sims.yahoo.com/
[Repeater-Builder] Re: Spectrum Repeater CW ID 'er Bipolar Prom
--- In Repeater-Builder@yahoogroups.com, Ron Wright [EMAIL PROTECTED] wrote: Ok, from what I can tell these are the numbers on the PROM: +B8620 DM74S287AN That is how it is on the PROM Does that look like the correct one? This is an ID77 board. thanks, Tim Comm Spec sells a programmable CW ID for about $60. However, what is the PROM...part number. I might have a programmer for it. Might even have the PROM. 73, ron, n9ee/r From: skipp025 [EMAIL PROTECTED] Date: 2007/08/24 Fri PM 12:53:33 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Spectrum Repeater CW ID 'er Bipolar Prom Spectrum Repeater CW ID'er Bipolar Prom If the IDer has a PROM then little can and should be done to go another way...a new PROM. Spectrum sells a replacement prom from about $55, which is kind of out of line for a price... but at least it's available. You can find/ask someone with a bipolar prom burner to make a new chip for you. But you have to find the chip and figure out how to map your call sign into the new part. One can also replace a Prom with an Eprom using a small adapter daughterboard, which is a path I've used many times. You need only have the eprom, programmer and set up the programming. Prom daughter/adapter boards run under $20 each... Another option would be to disable the factory ID'er and install an ID-O-Matic or similar ID unit. cheers, skipp Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
[Repeater-Builder] Re: Spectrum Repeater CW ID 'er Bipolar Prom
--- In Repeater-Builder@yahoogroups.com, skipp025 [EMAIL PROTECTED] wrote: Spectrum Repeater CW ID'er Bipolar Prom If the IDer has a PROM then little can and should be done to go another way...a new PROM. Spectrum sells a replacement prom from about $55, which is kind of out of line for a price... but at least it's available. You can find/ask someone with a bipolar prom burner to make a new chip for you. But you have to find the chip and figure out how to map your call sign into the new part. One can also replace a Prom with an Eprom using a small adapter daughterboard, which is a path I've used many times. You need only have the eprom, programmer and set up the programming. Prom daughter/adapter boards run under $20 each... Another option would be to disable the factory ID'er and install an ID-O-Matic or similar ID unit. cheers, skipp Thank you Skipp for the manual for the SCR-77. I can not contact Spectrum. They will not respond to there e-mails and when you call them you just getting a recording saying to leave a message, which I have, still no contact yet. I have also thought about installing another ID'er. What would be my best bet there. I have heard Com-Spec (Communication Specialists) makes a small simple ID'er. 73, Tim
[Repeater-Builder] UHF Maratrac: Low power in ham bands
I have a Maratrac that will only make about 20 watts at 446.500 and almost nothing a little below that. At 448.00 and above it makes full power. I have another Maratrac that makes full power down to 440.000. I did not check it any further. The radios look a little different inside. The one that has low power is HUE 2189B the good one is HUE2089B. What changes were made to the design that may be causing my problem? I want to put one of the radios in my service van and the other was going to be used as my repeater transmitter backup. I need it to transmit in the 443.000 range. Jimmy KS4KX
[Repeater-Builder] duplexer design
Dear all, I am Vikash Gupta from India. I am designing a duplexer having low frequency:230 MHz, High gfreuqency: 234 MHz. I am using coil with 8 no. of turns and 22 PF capacitor. I have to get Insertion loss 1.2 on both low and high sides. But I have a problem in getting this. I have got Rejection of more than 80 dB and Return loss of better than 20 dB on both sides. Please give me suggestion what I have to do? thanks in advance. Vikash - 5, 50, 500, 5000 - Store N number of mails in your inbox. Click here.
RE: [Repeater-Builder] Re: Spectrum - Bipolar Prom for CW ID 'er
That is the correct PROM. Mine is a 74287.But how do I program the prom?..Also, I don't need 25 of them.maybe 3. Thanks for the info...Now that I know where the PROM is in the CWID board and the part number maybe I can find someone to program it for me. THANKS! Tim - Original Message - From: skipp025 To: Repeater-Builder@yahoogroups.com Sent: 8/25/2007 12:09:11 PM Subject: [Repeater-Builder] Re: Spectrum - Bipolar Prom for CW ID 'er If the IDer has a PROM then little can and should be done to go another way...a new PROM. The original prom is probably a 74287 and they easy enough to find... still. There's a guy on Ebay selling tubes of them for just over $2 each, which is a great deal. LOTof 25 - MH74S287 - TESLA 74S287 - 74287 - ic -NEW Ebay Item number: 290104898405 I bought a few tubes from him and both he and they are the real deal. If you know the PROM type one might be able to program and replace. One problem is the PROMs are so old they are hard to find. Depending on the PROM I might be able to help. 73, ron, n9ee/r Proms don't seem to be that hard to find yet. cheers, skipp
[Repeater-Builder] UHF Maratrac: Low power in ham bands
I have a Maratrac that will only make about 20 watts at 446.500 and almost nothing a little below that. At 448.00 and above it makes full power. I have another Maratrac that makes full power down to 440.000. I did not check it any further. The radios look a little different inside. The one that has low power is HUE 2189B the good one is HUE2089B. What changes were made to the design that may be causing my problem? I want to put one of the radios in my service van and the other was going to be used as my repeater transmitter backup. I need it to transmit in the 443.000 range. Jimmy
[Repeater-Builder] SCR-77 CWID
Ok, the numbers on the PROM for the ID are as follows: +B8620 DM74S287AN Part number is U402 Thanks, Tim
Re: [Repeater-Builder] Need help ID ing transistor
Very good chance it's a plain vanilla 2N. Very common NPN small-signal silicon transistor. They also go by the name PN; same part, different lead bending configuration. They come in epoxy (as yours is) and small metal can, about 5mm in diameter. The PNP complement is 2N2907. With the component facing you, as it is in the photo, the leads are Emitter, Base, Collector, in that order. It looks like only the collector lead is still present. Bob M. == --- John Reid [EMAIL PROTECTED] wrote: Forgive me, I am still relatively new at this. I recently bought a controller for a good price, but now I need to figure it out. It arrived with a broken component, I believe it is a transistor but the numbers do not bring back anything with Google, could someone help me as far as what I need to buy to replace it it is similar to many numbers but no identical match. It is marked as such NT A46C a picture is here http://tinyurl.com/28z6tn Thanks in advance, and I hope you dont mind, but as I am learning I might ask a few questions every now and then. Take the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail, news, photos more. http://mobile.yahoo.com/go?refer=1GNXIC
[Repeater-Builder] Re: Spectrum Repeater CW ID 'er Bipolar Prom
Ok, these are the numbers on the current PROM: +B8620 DM74S287AN This a ID77 board part # U402 Thanks, Tim --- In Repeater-Builder@yahoogroups.com, Ron Wright [EMAIL PROTECTED] wrote: Comm Spec sells a programmable CW ID for about $60. However, what is the PROM...part number. I might have a programmer for it. Might even have the PROM. 73, ron, n9ee/r From: skipp025 [EMAIL PROTECTED] Date: 2007/08/24 Fri PM 12:53:33 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Spectrum Repeater CW ID 'er Bipolar Prom Spectrum Repeater CW ID'er Bipolar Prom If the IDer has a PROM then little can and should be done to go another way...a new PROM. Spectrum sells a replacement prom from about $55, which is kind of out of line for a price... but at least it's available. You can find/ask someone with a bipolar prom burner to make a new chip for you. But you have to find the chip and figure out how to map your call sign into the new part. One can also replace a Prom with an Eprom using a small adapter daughterboard, which is a path I've used many times. You need only have the eprom, programmer and set up the programming. Prom daughter/adapter boards run under $20 each... Another option would be to disable the factory ID'er and install an ID-O-Matic or similar ID unit. cheers, skipp Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
Re: [Repeater-Builder] UHF Maratrac: Low power in ham bands
I think the Maratrac is based on the MaxTrac radio. As such, you'd probably have to go through the Board Replacement - PA Alignment procedure which sets the output power at 16 discrete frequencies. On Radius radios (cousins of MaxTracs), the freqs go from 440-470, but on MaxTracs they usually go from 449-470. Some radios can be aligned to cover 440-470. Not all radios will work below 445 MHz without some other retuning, so even if the PA output is properly aligned, there may be other issues. You need the appropriate radio service software and paraphernalia that goes with it, plus a dummy load and a power indicating device (wattmeter or service monitor). Bob M. == --- jimmylpowell [EMAIL PROTECTED] wrote: I have a Maratrac that will only make about 20 watts at 446.500 and almost nothing a little below that. At 448.00 and above it makes full power. I have another Maratrac that makes full power down to 440.000. I did not check it any further. The radios look a little different inside. The one that has low power is HUE 2189B the good one is HUE2089B. What changes were made to the design that may be causing my problem? I want to put one of the radios in my service van and the other was going to be used as my repeater transmitter backup. I need it to transmit in the 443.000 range. Jimmy KS4KX Sick sense of humor? Visit Yahoo! TV's Comedy with an Edge to see what's on, when. http://tv.yahoo.com/collections/222
Re: RE: [Repeater-Builder] Re: Spectrum - Bipolar Prom for CW ID 'er
The problem the 74287 seems to be a very old part. My programmer will not program it. To program it you need a programmer. First you need to read the PROM you have, with a programmer, and then determine the data format used for the ID. Once you do this you can determine what data you need to program a new device and manually enter the data. Then program a new device. This is the procedure. 73, ron, n9ee/r From: [EMAIL PROTECTED] [EMAIL PROTECTED] Date: 2007/08/25 Sat PM 12:00:43 CDT To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Spectrum - Bipolar Prom for CW ID 'er That is the correct PROM. Mine is a 74287.But how do I program the prom?..Also, I don't need 25 of them.maybe 3.Thanks for the info...Now that I know where the PROM is in the CWID board and the part number maybe I can find someone to program it for me. THANKS! Tim  - Original Message - From: skipp025 To: [EMAIL PROTECTED]: 8/25/2007 12:09:11 PM Subject: [Repeater-Builder] Re: Spectrum - Bipolar Prom for CW ID 'er If the IDer has a PROM then little can and should be done to go another way...a new PROM. The original prom is probably a 74287 and they easy enough to find... still. There's a guy on Ebay selling tubes of them for BRjust over $2 each, which is a great deal. BRBRLOTof 25 - MH74S287 - TESLA 74S287 - 74287 - ic -NEWBREbay Item number: 290104898405 BRBRI bought a few tubes from him and both he and they are the BRreal deal. BRBR If you know the PROM type one might be able to program and BR replace. One problem is the PROMs are so old they are hard BR to find.BR Depending on the PROM I might be able to help.BR 73, ron, n9ee/rBRBRProms don't seem to be that hard to find yet. cheers, skipp Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
Re: [Repeater-Builder] duplexer design
Sounds as if you are designing a duplexer with coils and caps. It is often this approach will not have a high enough Q to have a notch at one freq and at the same time pass freq with low enough insertion loss. Normally duplexers use cavities which are made from coax made from heavy metal tubes, inter and outer conductors. Not your typical coax, but follow the same format. You may have the notch on both frequencies, but what is the insertion loss at the desired pass freq. 73, ron, n9ee/r From: sms mms [EMAIL PROTECTED] Date: 2007/08/24 Fri PM 12:11:46 CDT To: repeater repeater-builder@yahoogroups.com Subject: [Repeater-Builder] duplexer design Dear all, I am Vikash Gupta from India. I am designing a duplexer having low frequency:230 MHz, High gfreuqency: 234 MHz. I am using coil with 8 no. of turns and 22 PF capacitor. I have to get Insertion loss 1.2 on both low and high sides. But I have a problem in getting this. I have got Rejection of more than 80 dB and Return loss of better than 20 dB on both sides. Please give me suggestion what I have to do? thanks in advance. Vikash  5, 50, 500, 5000 - Store N number of mails in your inbox. Click here. Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
Re: [Repeater-Builder] Re: Spectrum Repeater CW ID 'er Bipolar Prom
At 01:55 PM 08/24/07, you wrote: --- In Repeater-Builder@yahoogroups.com, skipp025 [EMAIL PROTECTED] wrote: Spectrum Repeater CW ID'er Bipolar Prom If the IDer has a PROM then little can and should be done to go another way...a new PROM. Spectrum sells a replacement prom from about $55, which is kind of out of line for a price... but at least it's available. You can find/ask someone with a bipolar prom burner to make a new chip for you. But you have to find the chip and figure out how to map your call sign into the new part. One can also replace a Prom with an Eprom using a small adapter daughterboard, which is a path I've used many times. You need only have the eprom, programmer and set up the programming. Prom daughter/adapter boards run under $20 each... Another option would be to disable the factory ID'er and install an ID-O-Matic or similar ID unit. cheers, skipp Thank you Skipp for the manual for the SCR-77. I can not contact Spectrum. They will not respond to there e-mails and when you call them you just getting a recording saying to leave a message, which I have, still no contact yet. I have also thought about installing another ID'er. What would be my best bet there. I have heard Com-Spec (Communication Specialists) makes a small simple ID'er. 73, Tim Or bypass the entire controller and use a low end NHRC or ICS controller to do it all.
