RE: [Repeater-Builder] Re: Hamtronics versus Commercial (Kenwood) Repeater Selection
The question that pops into my mind concerns the proposed 200 watt power amplifier. I have to wonder where the notion to run an alligator system originated. I see four possible answers: 1. We have this 200 watt amplifier, so we are duty-bound to use it regardless of whether it is necessary or not. 2. We subscribe to the policy that more power is always better, and it always increases coverage. 3. We have performed a thorough analysis of coverage, and have determined that less power will result in insufficient coverage. 4. We know that 50 watts is enough, but a real powerhouse station will give us bragging rights. Once again, I must recall my favorite repeater-coverage dictum: Repeater coverage is determined by receiver performance, not by transmitter power. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of skipp025 Sent: Sunday, March 07, 2010 9:13 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Hamtronics versus Commercial (Kenwood) Repeater Selection k9bf k...@... wrote: Skipp I appreciate your reply. I currently have an old Johnson CR1000 that a converted to the 440 band about ten years ago. It has worked ok but its time to move on. Why is it time to move on? I have been offered a remote receive site in the center of my town of 100,000. It is the top of a building about 230 feet high so not much feedline to deal with. I already have a R304 and a T304 hamtronics in a box with an NHRC-micro controller for the remote site. It will link back on 440.1 MHz. So what I want to do is replace my Johnson with several more Hamtronic receivers feeding a LDG voter controlled by an NHRC-10. If you're not pressed or paying for physical space there's nothing wrong with the EF Johnson equipment if its performance is decent. What you get out of the Hamtronics gear is probably a smaller size. On the transmit side I want to use a T304 or T306 to feed two watts into a Vocom 200 watt amplifer. I will be using an Astron 70 amp power supply and a Motorola duplexer. The repeater site will have two antennas. One up at about 200 feet for transmit and receive. Another up about 100 feet to receive my remote links. I am excited about this project. Can you give me anymore advice? thanks Ben K9BF I can tell you the 200 watt amplifier is going to be a real beast to tame. Especially if you think a 4 cavity Motorola Duplexer is going to be enough protection. I honestly can tell you to first get more realistic with a 35 to maybe 65 watt power level, get the system up and the gremlins worked out first. Then use the high powered amplifier and be able to restore the low power operation back when everything hoses up real bad with the Vocom 200 Watt Amp the first time you try and use it. Don't reach for too much pie or it will probably fall of the shelf on the floor. And there's no good 5-Second Rule for pie on the floor. Start your system out reasonable and then expand from a known good working bench mark. s.
Re: [Repeater-Builder] Re: Hamtronics versus Commercial (Kenwood) Repeater Selection
How would you stack a Kenwood TKR against a Motorola R1225? On Tue, Mar 2, 2010 at 9:44 PM, Eric Lemmon wb6...@verizon.net wrote: Skipp, I agree with nearly every point you made, having had experience with both the Kenwood and Hamtronics repeaters. However, Hamtronics and similar repeaters have one serious deficiency: A total lack of PA protection against high SWR due to antenna or feedline problems. In addition, the Hamtronics PAs have no active power control circuitry; if the supply voltage goes up, the output power goes up, and vice-versa. The Kenwood TKR-x50 repeaters, on the other hand, have both active power control and high SWR protection built-in. I have a Hamtronics REP-200 repeater in service right now on 224.500 MHz, and I took the precaution of hanging a single ferrite isolator on its TX output to protect the very simple 15 watt PA. So far, so good... 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com] On Behalf Of skipp025 Sent: Tuesday, March 02, 2010 9:35 AM To: Repeater-Builder@yahoogroups.com Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Re: Hamtronics versus Commercial (Kenwood) Repeater Selection A Hamtronics versus a Kenwood Repeater... If you are considering purchasing the Hamtronics REP-200 repeater, I would spend my money on a Kenwood TKR750/850 series repeater. They are about the same price, but the Kenwood is a much better built piece of equipment and has a decent built-in controller for basic operation. As a huge and long time fan of Hamtronics gear and of course a full Kenwood Dealer and Service Station... I have to say I'm in a corner regarding the above statements... Both complete Repeaters are in the same price range and of course the Kenwood is a commercial quality/spec unit. But the Hamtronics unit is also quite usable, has more desired Amateur Radio Operational features (because of the internal controller). The Hamtronics Repeater in basic form is lower in transmit power output and the chassis is not as rugged (thick metal chassis parts). But there's nothing wrong with the supplied chassis of the Hamtronics Repeater if you buy the pre-made complete repeater versus installing transmit and receive modules in your own box of your selected size and material(s). Unless you install an additional external repeater controller onto the Kenwood Repeater... you don't get an Auto-patch (telephone interconnect), the ability to command CTCSS (PL) and Carrier Squelch operation on/off and a number of other bells and whistles you could research by inventorying the feature set page of the Hamtronics Repeater Controller Manual (on their web page). If you were looking to buy just the individual pieces from Hamtronics and put your own repeater chassis together, I would prefer to use just about any commercial equipment instead of those pieces. ... which shows a fairly obvious bias against Hamtronics Equipment for what-ever reason good or bad. There's nothing wrong with current Hamtronics, Hi-Pro and similar products if you understand what you get when you buy them. They tend to be very decent performers and in the case of the Hamtronics unit... probably also FCC Type Accepted. I am not sure what features you are looking for in the controller but there is a large amount of support available in the amateur community for Arcom, NHRC, CAT, ICS, and Link-Comm controllers. The Pacific Research Controller does not seem to be used much in our area but it looks like it will do most things a person would need. So will the Hamtronics COR-5 Repeater Controller Good luck with your project. I suspect the selection of radio products would obviously come down to motivation and money. If you bought a ready to rock-and-roll Kenwood TKR-850 Repeater (from me :-) you'd be pretty much in a plug play situation once you had a duplexer antenna scheme in place. You could then or later install an external repeater controller onto the TKR-850 if you needed additional operational features not available with the stock TKR-850 repeater controller. If you were interested in a converted surplus radio package, you could save a bit of money and probably have to get more into the technical details of the equipment while trying to get it on the air. There are also a fairly large number of usable repeaters made from surplus Mobile Radios connected back to back with basic logic and audio cables. You could also go with a more modular and hand constructed Hamtronics, Hi-Pro Modular type of repeater project, which is a favorite topic of mine. You will learn a lot more about both repeater and radio operation if you construct your own repeater. There is a serious glut of cheap, high quality surplus radio gear available at flea markets and Ebay...
Re: [Repeater-Builder] Re: Hamtronics versus Commercial (Kenwood) Repeater Selection
I would go with the kenwood every time. Better front end and more built in controller features We (my employer) have tons of the TKR-X50's out there working hard every day running 50 (or 40) watts day in and day out with seldom a problem... 73 Norm - Original Message - From: Repeater-Builder@yahoogroups.com Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Repeater-Builder@yahoogroups.com Sent: Wed Mar 03 08:50:29 2010 Subject: Re: [Repeater-Builder] Re: Hamtronics versus Commercial (Kenwood) Repeater Selection How would you stack a Kenwood TKR against a Motorola R1225? On Tue, Mar 2, 2010 at 9:44 PM, Eric Lemmon wb6...@verizon.net mailto:wb6...@verizon.net wrote: Skipp, I agree with nearly every point you made, having had experience with both the Kenwood and Hamtronics repeaters. However, Hamtronics and similar repeaters have one serious deficiency: A total lack of PA protection against high SWR due to antenna or feedline problems. In addition, the Hamtronics PAs have no active power control circuitry; if the supply voltage goes up, the output power goes up, and vice-versa. The Kenwood TKR-x50 repeaters, on the other hand, have both active power control and high SWR protection built-in. I have a Hamtronics REP-200 repeater in service right now on 224.500 MHz, and I took the precaution of hanging a single ferrite isolator on its TX output to protect the very simple 15 watt PA. So far, so good... 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com ] On Behalf Of skipp025 Sent: Tuesday, March 02, 2010 9:35 AM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Re: Hamtronics versus Commercial (Kenwood) Repeater Selection A Hamtronics versus a Kenwood Repeater... If you are considering purchasing the Hamtronics REP-200 repeater, I would spend my money on a Kenwood TKR750/850 series repeater. They are about the same price, but the Kenwood is a much better built piece of equipment and has a decent built-in controller for basic operation. As a huge and long time fan of Hamtronics gear and of course a full Kenwood Dealer and Service Station... I have to say I'm in a corner regarding the above statements... Both complete Repeaters are in the same price range and of course the Kenwood is a commercial quality/spec unit. But the Hamtronics unit is also quite usable, has more desired Amateur Radio Operational features (because of the internal controller). The Hamtronics Repeater in basic form is lower in transmit power output and the chassis is not as rugged (thick metal chassis parts). But there's nothing wrong with the supplied chassis of the Hamtronics Repeater if you buy the pre-made complete repeater versus installing transmit and receive modules in your own box of your selected size and material(s). Unless you install an additional external repeater controller onto the Kenwood Repeater... you don't get an Auto-patch (telephone interconnect), the ability to command CTCSS (PL) and Carrier Squelch operation on/off and a number of other bells and whistles you could research by inventorying the feature set page of the Hamtronics Repeater Controller Manual (on their web page). If you were looking to buy just the individual pieces from Hamtronics and put your own repeater chassis together, I would prefer to use just about any commercial equipment instead of those pieces. ... which shows a fairly obvious bias against Hamtronics Equipment for what-ever reason good or bad. There's nothing wrong with current Hamtronics, Hi-Pro and similar products if you understand what you get when you buy them. They tend to be very decent performers and in the case of the Hamtronics unit... probably also FCC Type Accepted. I am not sure what features you are looking for in the controller but there is a large amount of support available in the amateur community for Arcom, NHRC, CAT, ICS, and Link-Comm controllers. The Pacific Research Controller does not seem to be used much in our area but it looks like it will do most things a person would need. So will the Hamtronics COR-5 Repeater
Re: [Repeater-Builder] Re: Hamtronics versus Commercial (Kenwood) Repeater Selection
skipp025 wrote: The more famous surplus commercial radio 224 MHz conversions replace the PA with a Hybrid RF Amplifier Module... wonder if they also include SWR Protection? They don't - at lease not all do, but in the case of the MICOR mobile - the power set functionality (power level setting, power leveling, and SWR protection) is retained. This is because the VHF directional coupler works very well at 220 MHz, and if done right, can still drive a power transistor; which then controls the hybrid module. Scott Zimmerman/Repeater Builder builds a nice PC interface board that allows all of this to happen easily: http://www.repeater-builder.com/products/ampbd.html The picture on the right (MICOR mobile installation) shows the TO-220 pass transistor and you can see the little purple lead from the power set board coming through the PA wall and connecting to the base of the pass transistor. Because, in a MICOR, the power set control is done with circuitry that is separate from power amplifier board - this protection is not difficult to maintain. The interface board allows easy installation of the hybrid and even incorporates the reverse polarity diode that gets removed when you discard the original MICOR VHF PA. In the case of the GE MASTR II, power control is done with a simple pot, and all SWR protection, leveling, etc. is bypassed/eliminated - at least with this interface board. Maybe someone has hacked the MASTR II PA to allow for the incorporation of its protection in a 220 conversion - but I have never saw it if it has been done. Kevin Custer
Re: [Repeater-Builder] Re: Hamtronics versus Commercial (Kenwood) Repeater Selection
On 3/3/2010 3:19 PM, Kevin Custer wrote: In the case of the GE MASTR II, power control is done with a simple pot, and all SWR protection, leveling, etc. is bypassed/eliminated - at least with this interface board. Maybe someone has hacked the MASTR II PA to allow for the incorporation of its protection in a 220 conversion - but I have never saw it if it has been done. If you ask me, there's such a simple/cheap fix, that no one cares. It's called an isolator. Nate WY0X
Re: [Repeater-Builder] Re: Hamtronics versus Commercial (Kenwood) Repeater Selection
At 3/3/2010 14:19, you wrote: skipp025 wrote: The more famous surplus commercial radio 224 MHz conversions replace the PA with a Hybrid RF Amplifier Module... wonder if they also include SWR Protection? In the case of the GE MASTR II, power control is done with a simple pot, and all SWR protection, leveling, etc. is bypassed/eliminated - at least with this interface board. Maybe someone has hacked the MASTR II PA to allow for the incorporation of its protection in a 220 conversion - but I have never saw it if it has been done. Kevin Custer Most RF power modules sold today are spec'd to withstand 20:1 VSWR. That's a lot of reflected power, probably more than what you'd ever see if your repeater antenna opened or shorted due to the feedline duplexer losses. Bob NO6B
RE: [Repeater-Builder] Re: Hamtronics versus Commercial (Kenwood) Repeater Selection
Skipp, I agree with nearly every point you made, having had experience with both the Kenwood and Hamtronics repeaters. However, Hamtronics and similar repeaters have one serious deficiency: A total lack of PA protection against high SWR due to antenna or feedline problems. In addition, the Hamtronics PAs have no active power control circuitry; if the supply voltage goes up, the output power goes up, and vice-versa. The Kenwood TKR-x50 repeaters, on the other hand, have both active power control and high SWR protection built-in. I have a Hamtronics REP-200 repeater in service right now on 224.500 MHz, and I took the precaution of hanging a single ferrite isolator on its TX output to protect the very simple 15 watt PA. So far, so good... 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of skipp025 Sent: Tuesday, March 02, 2010 9:35 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Hamtronics versus Commercial (Kenwood) Repeater Selection A Hamtronics versus a Kenwood Repeater... If you are considering purchasing the Hamtronics REP-200 repeater, I would spend my money on a Kenwood TKR750/850 series repeater. They are about the same price, but the Kenwood is a much better built piece of equipment and has a decent built-in controller for basic operation. As a huge and long time fan of Hamtronics gear and of course a full Kenwood Dealer and Service Station... I have to say I'm in a corner regarding the above statements... Both complete Repeaters are in the same price range and of course the Kenwood is a commercial quality/spec unit. But the Hamtronics unit is also quite usable, has more desired Amateur Radio Operational features (because of the internal controller). The Hamtronics Repeater in basic form is lower in transmit power output and the chassis is not as rugged (thick metal chassis parts). But there's nothing wrong with the supplied chassis of the Hamtronics Repeater if you buy the pre-made complete repeater versus installing transmit and receive modules in your own box of your selected size and material(s). Unless you install an additional external repeater controller onto the Kenwood Repeater... you don't get an Auto-patch (telephone interconnect), the ability to command CTCSS (PL) and Carrier Squelch operation on/off and a number of other bells and whistles you could research by inventorying the feature set page of the Hamtronics Repeater Controller Manual (on their web page). If you were looking to buy just the individual pieces from Hamtronics and put your own repeater chassis together, I would prefer to use just about any commercial equipment instead of those pieces. ... which shows a fairly obvious bias against Hamtronics Equipment for what-ever reason good or bad. There's nothing wrong with current Hamtronics, Hi-Pro and similar products if you understand what you get when you buy them. They tend to be very decent performers and in the case of the Hamtronics unit... probably also FCC Type Accepted. I am not sure what features you are looking for in the controller but there is a large amount of support available in the amateur community for Arcom, NHRC, CAT, ICS, and Link-Comm controllers. The Pacific Research Controller does not seem to be used much in our area but it looks like it will do most things a person would need. So will the Hamtronics COR-5 Repeater Controller Good luck with your project. I suspect the selection of radio products would obviously come down to motivation and money. If you bought a ready to rock-and-roll Kenwood TKR-850 Repeater (from me :-) you'd be pretty much in a plug play situation once you had a duplexer antenna scheme in place. You could then or later install an external repeater controller onto the TKR-850 if you needed additional operational features not available with the stock TKR-850 repeater controller. If you were interested in a converted surplus radio package, you could save a bit of money and probably have to get more into the technical details of the equipment while trying to get it on the air. There are also a fairly large number of usable repeaters made from surplus Mobile Radios connected back to back with basic logic and audio cables. You could also go with a more modular and hand constructed Hamtronics, Hi-Pro Modular type of repeater project, which is a favorite topic of mine. You will learn a lot more about both repeater and radio operation if you construct your own repeater. There is a serious glut of cheap, high quality surplus radio gear available at flea markets and Ebay... so all bets are off on pricing on that type of gear... you might even find people willing to donate equipment for little or nothing. When 224 MHz band repeater operation is desired... there is less plug and play gear available, so cases like building a
