[Repeater-Builder] Re: 24 vdc to 12 vdc
Ron, et al, A corollary of Kirchhoff's law says that all currents are equal in a series circuit and all voltages are equal in a parallel circuit. Tapping a load across the lower battery represents a parallel circuit of the bottom battery and the load (radio) using 12 volts, and this parallel circuit is in series with the upper battery. If I supply 10 amps from the 24 volt charging circuit the upper battery receives 10 amps. However, if the load (radio) draws 5 amps the bottom battery can only get the other 5 amps to charge it. Hence the application of Kirchhoff's law of currents equal in a series circuit. There is no way for the bottom battery ever to be equally charged with the top battery as the radio has drawn away some of the current from the bottom battery. This current can never be replaced in this configuration. If the charging current drops to 5 amps then the top battery get 5 amps and the bottom battery gets none. If the charging device is off then the bottom battery continues to supply 5 amps to the load (for a while!) If this condition continues very long the terminal voltage of the bottom battery will be depressed towards 12 volts or lower but the 24 volt charging device doesn't know this and will attempt to apply full charging voltage (probably 28 volts or so) to the two seriesed batteries. If the depressed voltage on the bottom battery is down to 12 volts (typical) the top battery will get 16 volts, not a healthy situation! It only get worse as the condition continues. Now there are solutions. One can switch batteries (top with bottom) every few hours but who would actually do this? Or one could put a phantom load across the top battery, something that draws about the same current as the radio but this would be rather wasteful of energy and tricky to make work. Many 12 to 14 volt linear power supply circuits (Astron or ARRL handbook) can be adapted to convert the 24 - 28 volt source down to 12 - 14 volts just by injecting the +24 volts into the power supply after the main rectifier diodes. But here again the power supply will use up about as much power as the load. (Kirchhoff's law again) If conserving power is important then a switching supply would be in order as some of them are more than 90 % efficient. 73, Al, K9SI Re: 24 vdc to 12 vdc Posted by: Ron Wright [EMAIL PROTECTED] n9eerptr Date: Tue Mar 25, 2008 5:04 am ((PDT)) Depending on the load connecting across one battery, the one connected to ground or the lower of the 2 12 batteries, will work. I would not do is load is heavy because I am sure the charging system is for both batteries and draining one much more than the other could upset things. Kirchhoff's current law says the sum of the currents will be zero. Kirchhoff's voltage law says sum of voltages will be zero. Not sure why revelant here, but I am sure Kirchhoff had something else to do with voltage and current sources. Would like to know. 73, ron, n9ee/r From: Al Wolfe [EMAIL PROTECTED] Date: 2008/03/24 Mon PM 04:36:54 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: 24 vdc to 12 vdc This is a very common issue in aircraft. The most obvious question is does your jeep use 2 each 12 volt batteries? If so, simply connect your radio across one of 'em. This is done all the time but is a very, very bad idea. Ever hear of Kirchhoff's law? Check it out. It's a very quick way to ruin two batteries. Get a real converter. The switching kind are much more efficient than the linear voltage dropping kind. Al, K9SI
Re: [Repeater-Builder] False DTMF Muting On CAT-1000 Controller
At 3/28/2008 12:07, you wrote: If we were muting DTMF, we'd have had no idea why he was complaining. If DTMF mute is on tones are being muted, they must not be too bad. One system I maintain has ADMs set to a bit longer than the DTMF detect time, the DTMF mute delay is set to the same time, ~100 milliseconds. If anyone is having DTMF encoding problems, we'll hear it. Around here, not using DTMF muting is just asking for trouble. Bob NO6B
[Repeater-Builder] Re: Compa Station Help
Actually, I wouldn't be too concerned about the condition of the rest of the station. As stated earlier, the channel elements are often removed to prevent operation on the previous user's channel. Not a big deal. The cards are often kept as spares, particularly if the station was disposed of through a repair shop. The missing PA power leads are a bit unusual but, at most, five minutes to replace them. If you want to make a repeater, you don't need an antenna relay but they can be found too, if needed. I wish I had a dollar for every ham repeater that is made from converted mobiles, these are ALL intermittent duty transmitters. With reduced power and a cooling fan (mainly for peace of mind) this station will be more reliable than 80% of the so called continuous duty ham gear out there. I'd take that station anyday in preference to a Kensu desktop repeater. The receiver is easily converted with a recoiled RF front end available very reasonably. Your biggest challenge is going to be that HIGH split transmitter. Tom --- In Repeater-Builder@yahoogroups.com, Milt [EMAIL PROTECTED] wrote: Intermittent duty base station that has been robbed of parts. No channel elements in the receiver, probably none in the transmitter. No station control card. No high current leads to the final. As noted by earlier posts this is not a unit that will handle long periods of transmission. Also no antenna relay (not that you need one for what you want to do). Given the number of missing parts I would be very suspicious of the overall condition of the unit. Milt N3LTQ - Original Message - From: [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Friday, March 28, 2008 9:01 PM Subject: Re: [Repeater-Builder] Compa Station Help How about some pictures? They are a little big and some are redundant but hopefully it should give you guys some idea of what I have. http://www.highwayusa.com/motorola/pict0001.jpg http://www.highwayusa.com/motorola/pict0002.jpg http://www.highwayusa.com/motorola/pict0003.jpg http://www.highwayusa.com/motorola/pict0004.jpg http://www.highwayusa.com/motorola/pict0005.jpg Vern On Fri, 28 Mar 2008 19:12:06 -0500 (CDT) Ron Wright [EMAIL PROTECTED] wrote: Vern, Usually the easiest way to find what band and band segment it are on is to look at the Channel Elements, the small cans in the exciter and receiver. They unplug. A label on the top of the cans gives its frequency. However, to prevent them being put back on the same freq some pull the elements. Most always one can get to them thru a panel behind the receiver. Same with some exciters. There were 3 ranges for VHF as someone stated. Wonder what the heat sink looks like. The continuous duty has large 17w x 7h x 6 deep heat sink. Otherwise it is built into the main chassis or is tube amp. Mot made a number of variations of these. They do make good repeaters. Just takes some work. One clue if it is a repeater and not a base station is the card cage usually has a Squelch Gate card. This controls rx to tx keying. I think others gave you lots of good info with the repeater builders site. The power supply tells lots. Might describe it. 73, ron, n9ee/r From: [EMAIL PROTECTED] Date: 2008/03/28 Fri PM 01:19:10 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Compa Station Help I have a Compa Station with the model number C73RTB-1106C. I am looking for some help figuring out what this is split, etc and how to make it into a repeater. First things first is that there is no power leads hooked up except for the one to the control board box. I can see where there are places for heavy cables from the power supply to the transmitter. Is there seperate power for the receiver or does that come from the ribbon cable? How can I get this thing to key up to see what the TX frequency is? If I find out the TX freq can I sweep the recv side with a freq generator to figure out where it opens up? Are these crystal controlled or can they be adjusted to get the right frequency pair? Thanks, Vern Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome. Yahoo! Groups Links
Re: [Repeater-Builder] Re: Compa Station Help
Tom, Some good points. Hard to beat a Micor. If many repeater builders really knew much they would be using the Micor or the like instead of the plug and easy way out. I like the Kensu. Thought would add something. How about Kensucom, hi. 73, ron, n9ee/r From: tallinson2 [EMAIL PROTECTED] Date: 2008/03/29 Sat AM 01:43:36 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Compa Station Help Actually, I wouldn't be too concerned about the condition of the rest of the station. As stated earlier, the channel elements are often removed to prevent operation on the previous user's channel. Not a big deal. The cards are often kept as spares, particularly if the station was disposed of through a repair shop. The missing PA power leads are a bit unusual but, at most, five minutes to replace them. If you want to make a repeater, you don't need an antenna relay but they can be found too, if needed. I wish I had a dollar for every ham repeater that is made from converted mobiles, these are ALL intermittent duty transmitters. With reduced power and a cooling fan (mainly for peace of mind) this station will be more reliable than 80% of the so called continuous duty ham gear out there. I'd take that station anyday in preference to a Kensu desktop repeater. The receiver is easily converted with a recoiled RF front end available very reasonably. Your biggest challenge is going to be that HIGH split transmitter. Tom --- In Repeater-Builder@yahoogroups.com, Milt [EMAIL PROTECTED] wrote: Intermittent duty base station that has been robbed of parts. No channel elements in the receiver, probably none in the transmitter. No station control card. No high current leads to the final. As noted by earlier posts this is not a unit that will handle long periods of transmission. Also no antenna relay (not that you need one for what you want to do). Given the number of missing parts I would be very suspicious of the overall condition of the unit. Milt N3LTQ - Original Message - From: [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Friday, March 28, 2008 9:01 PM Subject: Re: [Repeater-Builder] Compa Station Help How about some pictures? They are a little big and some are redundant but hopefully it should give you guys some idea of what I have. http://www.highwayusa.com/motorola/pict0001.jpg http://www.highwayusa.com/motorola/pict0002.jpg http://www.highwayusa.com/motorola/pict0003.jpg http://www.highwayusa.com/motorola/pict0004.jpg http://www.highwayusa.com/motorola/pict0005.jpg Vern On Fri, 28 Mar 2008 19:12:06 -0500 (CDT) Ron Wright [EMAIL PROTECTED] wrote: Vern, Usually the easiest way to find what band and band segment it are on is to look at the Channel Elements, the small cans in the exciter and receiver. They unplug. A label on the top of the cans gives its frequency. However, to prevent them being put back on the same freq some pull the elements. Most always one can get to them thru a panel behind the receiver. Same with some exciters. There were 3 ranges for VHF as someone stated. Wonder what the heat sink looks like. The continuous duty has large 17w x 7h x 6 deep heat sink. Otherwise it is built into the main chassis or is tube amp. Mot made a number of variations of these. They do make good repeaters. Just takes some work. One clue if it is a repeater and not a base station is the card cage usually has a Squelch Gate card. This controls rx to tx keying. I think others gave you lots of good info with the repeater builders site. The power supply tells lots. Might describe it. 73, ron, n9ee/r From: [EMAIL PROTECTED] Date: 2008/03/28 Fri PM 01:19:10 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Compa Station Help I have a Compa Station with the model number C73RTB-1106C. I am looking for some help figuring out what this is split, etc and how to make it into a repeater. First things first is that there is no power leads hooked up except for the one to the control board box. I can see where there are places for heavy cables from the power supply to the transmitter. Is there seperate power for the receiver or does that come from the ribbon cable? How can I get this thing to key up to see what the TX frequency is? If I find out the TX freq can I sweep the recv side with a freq generator to figure out where it opens up? Are these crystal controlled or can they be adjusted to get the right frequency pair? Thanks, Vern Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome. Yahoo! Groups Links Ron Wright, N9EE 727-376-6575 MICRO
Re: [Repeater-Builder] Re: 24 vdc to 12 vdc
Al, Your point is well taken and I understood this. However, for the most part a rig is not going to be drawing much current, in receive most of the time. Little affect on the charge/discharge of the lower battery. This is why in a previous post I said depends on the load if wanting to connect across the lower battery. I think the solution to this topic came from you and others long ago. Use a 24-12 converter. They are about the same price as a battery. However, for the typical 50 W rig I would have no problem connecting across the bottom battery. The batteries get lots more abuse from the vehicle. A 1 amp draw 99% of the time is little compared to the typical draw from the other stuff. If drawing the currents you are talking about, again connecting to the lower battery would be a problem. 73, ron, n9ee/r From: Al Wolfe [EMAIL PROTECTED] Date: 2008/03/29 Sat AM 01:07:34 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: 24 vdc to 12 vdc Ron, et al, A corollary of Kirchhoff's law says that all currents are equal in a series circuit and all voltages are equal in a parallel circuit. Tapping a load across the lower battery represents a parallel circuit of the bottom battery and the load (radio) using 12 volts, and this parallel circuit is in series with the upper battery. If I supply 10 amps from the 24 volt charging circuit the upper battery receives 10 amps. However, if the load (radio) draws 5 amps the bottom battery can only get the other 5 amps to charge it. Hence the application of Kirchhoff's law of currents equal in a series circuit. There is no way for the bottom battery ever to be equally charged with the top battery as the radio has drawn away some of the current from the bottom battery. This current can never be replaced in this configuration. If the charging current drops to 5 amps then the top battery get 5 amps and the bottom battery gets none. If the charging device is off then the bottom battery continues to supply 5 amps to the load (for a while!) If this condition continues very long the terminal voltage of the bottom battery will be depressed towards 12 volts or lower but the 24 volt charging device doesn't know this and will attempt to apply full charging voltage (probably 28 volts or so) to the two seriesed batteries. If the depressed voltage on the bottom battery is down to 12 volts (typical) the top battery will get 16 volts, not a healthy situation! It only get worse as the condition continues. Now there are solutions. One can switch batteries (top with bottom) every few hours but who would actually do this? Or one could put a phantom load across the top battery, something that draws about the same current as the radio but this would be rather wasteful of energy and tricky to make work. Many 12 to 14 volt linear power supply circuits (Astron or ARRL handbook) can be adapted to convert the 24 - 28 volt source down to 12 - 14 volts just by injecting the +24 volts into the power supply after the main rectifier diodes. But here again the power supply will use up about as much power as the load. (Kirchhoff's law again) If conserving power is important then a switching supply would be in order as some of them are more than 90 % efficient. 73, Al, K9SI Re: 24 vdc to 12 vdc Posted by: Ron Wright [EMAIL PROTECTED] n9eerptr Date: Tue Mar 25, 2008 5:04 am ((PDT)) Depending on the load connecting across one battery, the one connected to ground or the lower of the 2 12 batteries, will work. I would not do is load is heavy because I am sure the charging system is for both batteries and draining one much more than the other could upset things. Kirchhoff's current law says the sum of the currents will be zero. Kirchhoff's voltage law says sum of voltages will be zero. Not sure why revelant here, but I am sure Kirchhoff had something else to do with voltage and current sources. Would like to know. 73, ron, n9ee/r From: Al Wolfe [EMAIL PROTECTED] Date: 2008/03/24 Mon PM 04:36:54 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: 24 vdc to 12 vdc This is a very common issue in aircraft. The most obvious question is does your jeep use 2 each 12 volt batteries? If so, simply connect your radio across one of 'em. This is done all the time but is a very, very bad idea. Ever hear of Kirchhoff'wbrs law? Check it out. It's a very quick way to ruin two batteries. Get a real converter. The switching kind are much more efficient than the linear voltage dropping kind. Al, K9SI Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
Re: Re: [Repeater-Builder] False DTMF Muting On CAT-1000 Controller
Nate, I've been designing 8870s and 8880s in things for over 15 years. Good chip and it has lasted. Pin 3 is simply the output of the internal op-amp and using a feed back resistor to 2 and driving with another one can set the AC gain over a wide range. The gain is feedback/driving resistor unless you wish to drive the non-inv input. The 1/2 Vcc source, pin 4, was cleaver by Mitel to simply use with a single 5 V supply. As to the other gain pins it is best not to use these for some other manufactures of the chip do not provide them. California Micro Devices, probably one of the biggest manufacture, does not. Really with the op-amp and allowing of adjusting its gain one does not really need these. For the 8880 the analog input is the real easy part. The CPU interface is much more difficult, but really simple design. The only same pin out of the 8870 to 8880 is the input op-amp. After that all changes. I normally do away with the steering circuit for RC adjusting the attack/decay decode times. I do both in software and tie pins 16 17 together on 8870, 18 19 on 8880. This give instant decode/release time, but use software for the timing. As with any op-amp using a dif amp, as the 8870 8880 do, single ended or dif input can be done. Looks like you cut and pasted your posting, hi. Referred to figures not included. Oh well. 73, ron, n9ee/r From: Nate Duehr [EMAIL PROTECTED] Date: 2008/03/28 Fri PM 08:09:36 CDT To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] False DTMF Muting On CAT-1000 Controller Ron Wright wrote: The voltage levels on most DTMF decoders are set by the IC designer. On decoders like the 8880 and 8870 pin 3 is what the internal op-amp of the IC is producing and this parameter is determined by the IC designer. As with any IC one needs to supply the proper levels to the device to allow it to achieve what is needed. Pin 1 is the non-inverting op amp input, Pin 2 is the inverting op-amp input, and Pin 3 is Gain Select, described below. From the MT8870 datasheet: GS: Gain Select. Gives access to output of front end differential amplifier for connection of feedback resistor. The input arrangement of the MT8870D/MT8870D-1 provides a differential-input operational amplifier as well as a bias source (VRef) which is used to bias the inputs at mid-rail. Provision is made for connection of a feedback resistor to the op-amp output (GS) for adjustment of gain. In a single-ended configuration, the input pins are connected as shown in Figure 10 with the op-amp connected for unity gain and VRef biasing the input at 1/2VDD. Figure 6 shows the differential configuration, which permits the adjustment of gain with the feedback resistor R5. Same pin-out on the 8880. You can build it as a single-ended input or a differential one, and mess with GS... depending on how you built your audio circuit... The input op-amp, has a decent amount of gain available in the op-amp itself, too... because it' meets the specs to pull a tone up from -31 dBm (dBm referenced to 1mV into a 600 ohm impedance input -- the typical telco reference for dBm) and won't fully reject tones until -37 dBm. These chips can hear DTMF tones that are incredibly low amplitude... on quiet circuits. The problem is... radios aren't quiet circuits. The published error rate at -31 dBm is 1 in 10,000 without background noises. They're very good decoders. But depending on how they're hooked up, generic statements like 3 V P-t-P aren't ALWAYS correct... unless the repeater controller is feeding the op-amp in the unity-gain single-ended configuration. Nate WY0X Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
Re: Re: [Repeater-Builder] Compa Station Help
Vern, Yep you got a Micor...a mobile repackaged as a base station. Might look at the PA. The more transistors the higher the power. The PA came in 45/60/110 W. However, in this configuration if using for repeater turn down to maybe 50% rated power out. This is adjusted with a pot in the Power Control Module, just to the right of the PA. Also add a fan. However, before you get started find what band split it is on. It is VHF (can tell by the 5 inline helicals in the receiver), but need to know segment. As another posting there were 3, 136-150, 150-160 and 160-174. The 160-174 is useless for Ham. Some trouble moving 150-160 down to 146, mainly with receiver. Exciter and PA will most often tune with maybe 10% reduction in power. The power supply is 25 Amp continuous duty Mot used in their 100 W repeaters. Very good power supply for this. 73, ron, n9ee/r From: [EMAIL PROTECTED] Date: 2008/03/28 Fri PM 08:01:23 CDT To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Compa Station Help How about some pictures? They are a little big and some are redundant but hopefully it should give you guys some idea of what I have. http://www.highwayusa.com/motorola/pict0001.jpg http://www.highwayusa.com/motorola/pict0002.jpg http://www.highwayusa.com/motorola/pict0003.jpg http://www.highwayusa.com/motorola/pict0004.jpg http://www.highwayusa.com/motorola/pict0005.jpg Vern On Fri, 28 Mar 2008 19:12:06 -0500 (CDT) Ron Wright [EMAIL PROTECTED] wrote: Vern, Usually the easiest way to find what band and band segment it are on is to look at the Channel Elements, the small cans in the exciter and receiver. They unplug. A label on the top of the cans gives its frequency. However, to prevent them being put back on the same freq some pull the elements. Most always one can get to them thru a panel behind the receiver. Same with some exciters. There were 3 ranges for VHF as someone stated. Wonder what the heat sink looks like. The continuous duty has large 17w x 7h x 6 deep heat sink. Otherwise it is built into the main chassis or is tube amp. Mot made a number of variations of these. They do make good repeaters. Just takes some work. One clue if it is a repeater and not a base station is the card cage usually has a Squelch Gate card. This controls rx to tx keying. I think others gave you lots of good info with the repeater builders site. The power supply tells lots. Might describe it. 73, ron, n9ee/r From: [EMAIL PROTECTED] Date: 2008/03/28 Fri PM 01:19:10 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Compa Station Help I have a Compa Station with the model number C73RTB-1106C. I am looking for some help figuring out what this is split, etc and how to make it into a repeater. First things first is that there is no power leads hooked up except for the one to the control board box. I can see where there are places for heavy cables from the power supply to the transmitter. Is there seperate power for the receiver or does that come from the ribbon cable? How can I get this thing to key up to see what the TX frequency is? If I find out the TX freq can I sweep the recv side with a freq generator to figure out where it opens up? Are these crystal controlled or can they be adjusted to get the right frequency pair? Thanks, Vern Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome. 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: Compa Station Help
Actually, I wouldn't be too concerned about the condition of the rest of the station. You might not be, and I would not be concerned if I had the station or was considering it. I do not know what the original poster's level of experience is, thus my comment. If I was looking at this station I would see a good supply of spare parts, and/or a possible conversion to 220 since it reportedly has a high range transmitter. I would not consider this station a good candidate for a first time project. With no channel elements and a high split radio it will be hard to determine if the station has any problems BEFORE an attempt is made to change frequency. Simply grabbing a set of elements and restuffing them is a sure way to add to your overall level of frustration/stress. If I were going to try to do anything with this unit I would want to find a set of channel elements in the high range. I would then attempt to get the station working in the range that it was built for. Find and if possible fix any issues that are present. Determine what is needed to convert to the lower range. THEN AND ONLY THEN would I attempt to change the frequency of the radio. No, changing the frequency range in which the radio operates is not rocket science, it simply takes a service manual, proper test equipment, time, parts, patience, an understanding of what is going on, and a willingness to learn. Now back to repeater-building. MIlt N3LTQ
Re: Re: [Repeater-Builder] Re: Compa Station Help
Milt, Very good advice. I would not even try to move the unit down with the existing boards if they are the higher split. If going to 222 then would be something to start with. If putting on 2 meters would be nice to pick up a mobile for 136-150 range and simple unplug the boards...well exciter and receiver, and remove these from the mobile. They just plug in. Of course finding a 136-150 is difficult, but Canada did use this band more and I see other equipment like the GEs in this range. Milt, you and others on this board, and I started messing with the Micor a few years back. It is obvious from all the reply's that many have worked with the Micor. The commercial guys couple decades back. Of course then we could not afford the $3000+ for one so many used Motracs. It was fun working with the Micor. Once got a manual (Mot made excellent manuals) one could really work with them, learned how to work with them and as with many Hams enjoy this kind of thing. So Vern you got a project, if you want, that can lead to a good repeater. 73, ron, n9ee/r From: Milt [EMAIL PROTECTED] Date: 2008/03/29 Sat AM 06:19:09 CDT To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Compa Station Help Actually, I wouldn't be too concerned about the condition of the rest of the station. You might not be, and I would not be concerned if I had the station or was considering it. I do not know what the original poster's level of experience is, thus my comment. If I was looking at this station I would see a good supply of spare parts, and/or a possible conversion to 220 since it reportedly has a high range transmitter. I would not consider this station a good candidate for a first time project. With no channel elements and a high split radio it will be hard to determine if the station has any problems BEFORE an attempt is made to change frequency. Simply grabbing a set of elements and restuffing them is a sure way to add to your overall level of frustration/stress. If I were going to try to do anything with this unit I would want to find a set of channel elements in the high range. I would then attempt to get the station working in the range that it was built for. Find and if possible fix any issues that are present. Determine what is needed to convert to the lower range. THEN AND ONLY THEN would I attempt to change the frequency of the radio. No, changing the frequency range in which the radio operates is not rocket science, it simply takes a service manual, proper test equipment, time, parts, patience, an understanding of what is going on, and a willingness to learn. Now back to repeater-building. MIlt N3LTQ 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: 24 vdc to 12 vdc
Ron and All, EZGO Golf Carts do this all the time with there electric golf carts, they tie the tail lights and head light if any to the lower two 6 volt set of batteries. I admit it is not the best way to go about it but it seems to work, as Ron said, it depends on the load and in the case of the carts the duty cycle. Paul -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright Sent: Saturday, March 29, 2008 5:22 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: 24 vdc to 12 vdc Al, Your point is well taken and I understood this. However, for the most part a rig is not going to be drawing much current, in receive most of the time. Little affect on the charge/discharge of the lower battery. This is why in a previous post I said depends on the load if wanting to connect across the lower battery. I think the solution to this topic came from you and others long ago. Use a 24-12 converter. They are about the same price as a battery. However, for the typical 50 W rig I would have no problem connecting across the bottom battery. The batteries get lots more abuse from the vehicle. A 1 amp draw 99% of the time is little compared to the typical draw from the other stuff. If drawing the currents you are talking about, again connecting to the lower battery would be a problem. 73, ron, n9ee/r From: Al Wolfe [EMAIL PROTECTED] Date: 2008/03/29 Sat AM 01:07:34 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: 24 vdc to 12 vdc Ron, et al, A corollary of Kirchhoff's law says that all currents are equal in a series circuit and all voltages are equal in a parallel circuit. Tapping a load across the lower battery represents a parallel circuit of the bottom battery and the load (radio) using 12 volts, and this parallel circuit is in series with the upper battery. If I supply 10 amps from the 24 volt charging circuit the upper battery receives 10 amps. However, if the load (radio) draws 5 amps the bottom battery can only get the other 5 amps to charge it. Hence the application of Kirchhoff's law of currents equal in a series circuit. There is no way for the bottom battery ever to be equally charged with the top battery as the radio has drawn away some of the current from the bottom battery. This current can never be replaced in this configuration. If the charging current drops to 5 amps then the top battery get 5 amps and the bottom battery gets none. If the charging device is off then the bottom battery continues to supply 5 amps to the load (for a while!) If this condition continues very long the terminal voltage of the bottom battery will be depressed towards 12 volts or lower but the 24 volt charging device doesn't know this and will attempt to apply full charging voltage (probably 28 volts or so) to the two seriesed batteries. If the depressed voltage on the bottom battery is down to 12 volts (typical) the top battery will get 16 volts, not a healthy situation! It only get worse as the condition continues. Now there are solutions. One can switch batteries (top with bottom) every few hours but who would actually do this? Or one could put a phantom load across the top battery, something that draws about the same current as the radio but this would be rather wasteful of energy and tricky to make work. Many 12 to 14 volt linear power supply circuits (Astron or ARRL handbook) can be adapted to convert the 24 - 28 volt source down to 12 - 14 volts just by injecting the +24 volts into the power supply after the main rectifier diodes. But here again the power supply will use up about as much power as the load. (Kirchhoff's law again) If conserving power is important then a switching supply would be in order as some of them are more than 90 % efficient. 73, Al, K9SI Re: 24 vdc to 12 vdc Posted by: Ron Wright [EMAIL PROTECTED] n9eerptr Date: Tue Mar 25, 2008 5:04 am ((PDT)) Depending on the load connecting across one battery, the one connected to ground or the lower of the 2 12 batteries, will work. I would not do is load is heavy because I am sure the charging system is for both batteries and draining one much more than the other could upset things. Kirchhoff's current law says the sum of the currents will be zero. Kirchhoff's voltage law says sum of voltages will be zero. Not sure why revelant here, but I am sure Kirchhoff had something else to do with voltage and current sources. Would like to know. 73, ron, n9ee/r From: Al Wolfe [EMAIL PROTECTED] Date: 2008/03/24 Mon PM 04:36:54 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: 24 vdc to 12 vdc This is a very common issue in aircraft. The most obvious question is does your jeep use 2 each 12 volt batteries? If so, simply connect your radio across one of 'em. This is done all the time but is a very, very bad idea. Ever hear of Kirchhoff'wbrs law?
Re: [Repeater-Builder] Re: Compa Station Help
The reason the power supply leads are missing is that I got it from the local used supply store. They had taken every thing out of the cabinet and were going to sell the cabinet and power supply seperate and probably throw the rest out. Vern On Sat, 29 Mar 2008 06:43:36 - tallinson2 [EMAIL PROTECTED] wrote: Actually, I wouldn't be too concerned about the condition of the rest of the station. As stated earlier, the channel elements are often removed to prevent operation on the previous user's channel. Not a big deal. The cards are often kept as spares, particularly if the station was disposed of through a repair shop. The missing PA power leads are a bit unusual but, at most, five minutes to replace them. If you want to make a repeater, you don't need an antenna relay but they can be found too, if needed. I wish I had a dollar for every ham repeater that is made from converted mobiles, these are ALL intermittent duty transmitters. With reduced power and a cooling fan (mainly for peace of mind) this station will be more reliable than 80% of the so called continuous duty ham gear out there. I'd take that station anyday in preference to a Kensu desktop repeater. The receiver is easily converted with a recoiled RF front end available very reasonably. Your biggest challenge is going to be that HIGH split transmitter. Tom --- In Repeater-Builder@yahoogroups.com, Milt [EMAIL PROTECTED] wrote: Intermittent duty base station that has been robbed of parts. No channel elements in the receiver, probably none in the transmitter. No station control card. No high current leads to the final. As noted by earlier posts this is not a unit that will handle long periods of transmission. Also no antenna relay (not that you need one for what you want to do). Given the number of missing parts I would be very suspicious of the overall condition of the unit. Milt N3LTQ - Original Message - From: [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Friday, March 28, 2008 9:01 PM Subject: Re: [Repeater-Builder] Compa Station Help How about some pictures? They are a little big and some are redundant but hopefully it should give you guys some idea of what I have. http://www.highwayusa.com/motorola/pict0001.jpg http://www.highwayusa.com/motorola/pict0002.jpg http://www.highwayusa.com/motorola/pict0003.jpg http://www.highwayusa.com/motorola/pict0004.jpg http://www.highwayusa.com/motorola/pict0005.jpg Vern On Fri, 28 Mar 2008 19:12:06 -0500 (CDT) Ron Wright [EMAIL PROTECTED] wrote: Vern, Usually the easiest way to find what band and band segment it are on is to look at the Channel Elements, the small cans in the exciter and receiver. They unplug. A label on the top of the cans gives its frequency. However, to prevent them being put back on the same freq some pull the elements. Most always one can get to them thru a panel behind the receiver. Same with some exciters. There were 3 ranges for VHF as someone stated. Wonder what the heat sink looks like. The continuous duty has large 17w x 7h x 6 deep heat sink. Otherwise it is built into the main chassis or is tube amp. Mot made a number of variations of these. They do make good repeaters. Just takes some work. One clue if it is a repeater and not a base station is the card cage usually has a Squelch Gate card. This controls rx to tx keying. I think others gave you lots of good info with the repeater builders site. The power supply tells lots. Might describe it. 73, ron, n9ee/r From: [EMAIL PROTECTED] Date: 2008/03/28 Fri PM 01:19:10 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Compa Station Help I have a Compa Station with the model number C73RTB-1106C. I am looking for some help figuring out what this is split, etc and how to make it into a repeater. First things first is that there is no power leads hooked up except for the one to the control board box. I can see where there are places for heavy cables from the power supply to the transmitter. Is there seperate power for the receiver or does that come from the ribbon cable? How can I get this thing to key up to see what the TX frequency is? If I find out the TX freq can I sweep the recv side with a freq generator to figure out where it opens up? Are these crystal controlled or can they be adjusted to get the right frequency pair? Thanks, Vern Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome. Yahoo! Groups Links
Re: [Repeater-Builder] Re: Compa Station Help
I wouldn't mind having it on 220 if nothing else then for the learning experiance of doing it. Vern On Sat, 29 Mar 2008 07:25:10 -0500 (CDT) Ron Wright [EMAIL PROTECTED] wrote: Milt, Very good advice. I would not even try to move the unit down with the existing boards if they are the higher split. If going to 222 then would be something to start with. If putting on 2 meters would be nice to pick up a mobile for 136-150 range and simple unplug the boards...well exciter and receiver, and remove these from the mobile. They just plug in. Of course finding a 136-150 is difficult, but Canada did use this band more and I see other equipment like the GEs in this range. Milt, you and others on this board, and I started messing with the Micor a few years back. It is obvious from all the reply's that many have worked with the Micor. The commercial guys couple decades back. Of course then we could not afford the $3000+ for one so many used Motracs. It was fun working with the Micor. Once got a manual (Mot made excellent manuals) one could really work with them, learned how to work with them and as with many Hams enjoy this kind of thing. So Vern you got a project, if you want, that can lead to a good repeater. 73, ron, n9ee/r From: Milt [EMAIL PROTECTED] Date: 2008/03/29 Sat AM 06:19:09 CDT To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Compa Station Help Actually, I wouldn't be too concerned about the condition of the rest of the station. You might not be, and I would not be concerned if I had the station or was considering it. I do not know what the original poster's level of experience is, thus my comment. If I was looking at this station I would see a good supply of spare parts, and/or a possible conversion to 220 since it reportedly has a high range transmitter. I would not consider this station a good candidate for a first time project. With no channel elements and a high split radio it will be hard to determine if the station has any problems BEFORE an attempt is made to change frequency. Simply grabbing a set of elements and restuffing them is a sure way to add to your overall level of frustration/stress. If I were going to try to do anything with this unit I would want to find a set of channel elements in the high range. I would then attempt to get the station working in the range that it was built for. Find and if possible fix any issues that are present. Determine what is needed to convert to the lower range. THEN AND ONLY THEN would I attempt to change the frequency of the radio. No, changing the frequency range in which the radio operates is not rocket science, it simply takes a service manual, proper test equipment, time, parts, patience, an understanding of what is going on, and a willingness to learn. Now back to repeater-building. MIlt N3LTQ Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
Re: Re: [Repeater-Builder] Re: Compa Station Help
Vern, There are basically 2 power leads from the power supply. 1 is a multi-wire cable that plugs into the card cage usually and the other is a large, #12, two wire that goes from the heavy terminal on the rear of the supply to the main chassis set of terminals, usually in the upper right. The multi-wire cable hopefully is there. It is just wirings coming out of the PS chassis and carries the low current 9.6V and 13.8V. The larger 2 wire is easy to make and supplies the power for the PA. 73, ron, n9ee/r From: [EMAIL PROTECTED] Date: 2008/03/29 Sat AM 07:51:35 CDT To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Compa Station Help The reason the power supply leads are missing is that I got it from the local used supply store. They had taken every thing out of the cabinet and were going to sell the cabinet and power supply seperate and probably throw the rest out. Vern On Sat, 29 Mar 2008 06:43:36 - tallinson2 [EMAIL PROTECTED] wrote: Actually, I wouldn't be too concerned about the condition of the rest of the station. As stated earlier, the channel elements are often removed to prevent operation on the previous user's channel. Not a big deal. The cards are often kept as spares, particularly if the station was disposed of through a repair shop. The missing PA power leads are a bit unusual but, at most, five minutes to replace them. If you want to make a repeater, you don't need an antenna relay but they can be found too, if needed. I wish I had a dollar for every ham repeater that is made from converted mobiles, these are ALL intermittent duty transmitters. With reduced power and a cooling fan (mainly for peace of mind) this station will be more reliable than 80% of the so called continuous duty ham gear out there. I'd take that station anyday in preference to a Kensu desktop repeater. The receiver is easily converted with a recoiled RF front end available very reasonably. Your biggest challenge is going to be that HIGH split transmitter. Tom --- In Repeater-Builder@yahoogroups.com, Milt [EMAIL PROTECTED] wrote: Intermittent duty base station that has been robbed of parts. No channel elements in the receiver, probably none in the transmitter. No station control card. No high current leads to the final. As noted by earlier posts this is not a unit that will handle long periods of transmission. Also no antenna relay (not that you need one for what you want to do). Given the number of missing parts I would be very suspicious of the overall condition of the unit. Milt N3LTQ - Original Message - From: [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Friday, March 28, 2008 9:01 PM Subject: Re: [Repeater-Builder] Compa Station Help How about some pictures? They are a little big and some are redundant but hopefully it should give you guys some idea of what I have. http://www.highwayusa.com/motorola/pict0001.jpg http://www.highwayusa.com/motorola/pict0002.jpg http://www.highwayusa.com/motorola/pict0003.jpg http://www.highwayusa.com/motorola/pict0004.jpg http://www.highwayusa.com/motorola/pict0005.jpg Vern On Fri, 28 Mar 2008 19:12:06 -0500 (CDT) Ron Wright [EMAIL PROTECTED] wrote: Vern, Usually the easiest way to find what band and band segment it are on is to look at the Channel Elements, the small cans in the exciter and receiver. They unplug. A label on the top of the cans gives its frequency. However, to prevent them being put back on the same freq some pull the elements. Most always one can get to them thru a panel behind the receiver. Same with some exciters. There were 3 ranges for VHF as someone stated. Wonder what the heat sink looks like. The continuous duty has large 17w x 7h x 6 deep heat sink. Otherwise it is built into the main chassis or is tube amp. Mot made a number of variations of these. They do make good repeaters. Just takes some work. One clue if it is a repeater and not a base station is the card cage usually has a Squelch Gate card. This controls rx to tx keying. I think others gave you lots of good info with the repeater builders site. The power supply tells lots. Might describe it. 73, ron, n9ee/r From: [EMAIL PROTECTED] Date: 2008/03/28 Fri PM 01:19:10 CDT To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Compa Station Help I have a Compa Station with the model number C73RTB-1106C. I am looking for some help figuring out what this is split, etc and how to make it into a repeater. First things first is that there is no power leads hooked up except for the one to the control board box. I can see where there are places for heavy cables from the power supply to the transmitter. Is there seperate power for the receiver or does that come from the ribbon cable? How can
[Repeater-Builder] uPC8016T datasheet - anyone have it? (UNCLASSIFIED)
Classification: UNCLASSIFIED Caveats: NONE Anyone have this datasheet? It is a UHF mixer SOT-6 My military internet here really freaking sucks and doesn't like to load pages... Thanks, ~Benjamin, KB9LFZ Classification: UNCLASSIFIED Caveats: NONE
