RE: [Repeater-Builder] Re: GE uhf high power
To All: GE Did make a solid state 200 watt UHF Transmitter. They used a 100 watt PA driver to two 100 watt PA's less the 40 watt driver board and then recombined the two 100 watt to get 200 watts out. They sure are not efficient! I agree it would be better to use a 100 watt PA at reduced power. However the 100 watt PA's are rated at 100 watts continuous power output. (That is key down for 24 hours with no degradation in power output). Fred W5VAY (Retired GE Mobile Radio) _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Joe Burkleo Sent: Thursday, September 04, 2008 12:54 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: ge uhf high power Also as Nate said, GE did not make a high power solid state amp. The Mastr II high power stations that I referred to use a normal Mastr II solid state PA to drive a tube amplifier to acheive the 225-250 Watts on UHF or 375 Watts on VHF. If you are not familiar with high power tube transmitters and working with high voltages, stay away from these. They are not for the faint of heart, and the voltages present can be quite deadly. Joe - WA7JAW --- In Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com, Joe Burkleo [EMAIL PROTECTED] wrote: You might try contacting Larry K7LJ. He posts on here occasionally and I know he had a couple of these the last time I talked to him, but that was a couple months ago. They are more like 350 Watts. Joe --- In Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com, kb4ptj kb4ptj@ wrote: hi i am looking for ge uhf solid state high power 88 splyt 200watts kb4ptj@
Re: [Repeater-Builder] Re: GE uhf high power
Fred Seamans wrote: To All: GE *Did* make a solid state 200 watt UHF Transmitter. They used a 100 watt PA driver to two 100 watt PA’s less the 40 watt driver board and then recombined the two 100 watt to get 200 watts out. They sure are not efficient! I agree it would be better to use a 100 watt PA at reduced power. However the 100 watt PA’s are rated at 100 watts continuous power output. (That is key down for 24 hours with no degradation in power output). Fred W5VAY (Retired GE Mobile Radio) Yes, someone pointed that out to me off-list. There was an optional setup that could be purchased that used two of the 100W PA's driving into a combiner setup to get to something near 200W. It's not common to find those on the used market -- so I'll stick by my comment to the gentleman looking for one, he's *probably* not going to find one... Thanks to Larry and some other folks who e-mailed off-list to get the correct info out -- always good to be accurate! :-) Nate WY0X Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * Your email settings: Individual Email | Traditional * To change settings online go to: http://groups.yahoo.com/group/Repeater-Builder/join (Yahoo! ID required) * To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] * 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: ge uhf high power
In fact, they DID make high power non-tube amps. They used the standard amps, divided the drive, then combined the output of each amp to get the higher power. Joe M. Joe Burkleo wrote: Also as Nate said, GE did not make a high power solid state amp. The Mastr II high power stations that I referred to use a normal Mastr II solid state PA to drive a tube amplifier to acheive the 225-250 Watts on UHF or 375 Watts on VHF. If you are not familiar with high power tube transmitters and working with high voltages, stay away from these. They are not for the faint of heart, and the voltages present can be quite deadly. Joe - WA7JAW --- In Repeater-Builder@yahoogroups.com, Joe Burkleo [EMAIL PROTECTED] wrote: You might try contacting Larry K7LJ. He posts on here occasionally and I know he had a couple of these the last time I talked to him, but that was a couple months ago. They are more like 350 Watts. Joe --- In Repeater-Builder@yahoogroups.com, kb4ptj kb4ptj@ wrote: hi i am looking for ge uhf solid state high power 88 splyt 200watts kb4ptj@ Yahoo! Groups Links
Re: [Repeater-Builder] Re: GE uhf high power
Fred Seamans wrote: To All: GE *Did* make a solid state 200 watt UHF Transmitter. Thanks Fred, I was hoping that you or Jeff DePolo would jump in there soon and straighten these guys out. BTW: I have one of the stations that Fred mentioned at one of my sites. It belongs to Jeff DePolo. It will run 200+ watts all day and night, and with a good MASTR II receiver (hand selected) with a Chip Angle preamp, it takes all of the 200 watts to keep up with it. It is matched pretty well with a modern 35 watt mobile. Kevin Custer
Re: [Repeater-Builder] Re: GE uhf high power
Kevin Custer wrote: I was hoping that you or Jeff DePolo would jump in there soon and straighten these guys out. Yeah yeah yeah... I know, I know. Sheesh. BTW: I have one of the stations that Fred mentioned at one of my sites. It belongs to Jeff DePolo. It will run 200+ watts all day and night, and with a good MASTR II receiver (hand selected) with a Chip Angle preamp, it takes all of the 200 watts to keep up with it. It is matched pretty well with a modern 35 watt mobile. Now THAT I'd like to see the math on. Just how high does receiver sensitivity have to get to balance with a typical say, oh... .15uV modern UHF mobile and it sending out 35W... what would the perfect numbers be. Someone who enjoys the math more than I do maybe will feel bored enough to calculate it. I guess you'd need the antenna gain numbers also. What are you running on that system, Kevin? Nate WY0X
Re: [Repeater-Builder] Re: GE uhf high power
The math isn't that hard. 200W (53.01 dBm) is about 7.6 dB over 35W (45.44 dBm), so the RX would have to be about 7.6 dB better than 0.15 uV (-123.5 dBm), or about -131 dBm which is 0.06 uV. The antenna gains and losses cancel each other out since they apply to both TX and RX. Joe M. Nate Duehr wrote: Kevin Custer wrote: BTW: I have one of the stations that Fred mentioned at one of my sites. It belongs to Jeff DePolo. It will run 200+ watts all day and night, and with a good MASTR II receiver (hand selected) with a Chip Angle preamp, it takes all of the 200 watts to keep up with it. It is matched pretty well with a modern 35 watt mobile. Now THAT I'd like to see the math on. Just how high does receiver sensitivity have to get to balance with a typical say, oh... .15uV modern UHF mobile and it sending out 35W... what would the perfect numbers be. Someone who enjoys the math more than I do maybe will feel bored enough to calculate it. I guess you'd need the antenna gain numbers also. What are you running on that system, Kevin? Nate WY0X
Re: [Repeater-Builder] Re: GE uhf high power
Although what Joe says is true, the system is balanced more so than the math would indicate. This is due to most users ears requiring more than .15uV sensitivity to pick out a weak signal. realize that the SINADs of BOTH the repeater and the mobile rig would be additive when the mobile is in a fringe area. If a user is into the system and is, say 50% noise and the repeater's transmitter is being received at an S1, say 30% noise, that adds to 80% noise. That's pretty noisy!! For a typical user's DSP (the one between their ears) to be able to process a weak signal into the repeater's receiver, they need to be able to hear the repeater's transmitter almost full quieting. This is the reason that all links between receivers strive to be absolutely full-quieting and have good audio characteristics. If not, all of the system noise and distortions are additive. Scott Scott Zimmerman Amateur Radio Call N3XCC 474 Barnett Rd Boswell, PA 15531 - Original Message - From: MCH [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Thursday, September 04, 2008 4:38 PM Subject: Re: [Repeater-Builder] Re: GE uhf high power The math isn't that hard. 200W (53.01 dBm) is about 7.6 dB over 35W (45.44 dBm), so the RX would have to be about 7.6 dB better than 0.15 uV (-123.5 dBm), or about -131 dBm which is 0.06 uV. The antenna gains and losses cancel each other out since they apply to both TX and RX. Joe M. Nate Duehr wrote: Kevin Custer wrote: BTW: I have one of the stations that Fred mentioned at one of my sites. It belongs to Jeff DePolo. It will run 200+ watts all day and night, and with a good MASTR II receiver (hand selected) with a Chip Angle preamp, it takes all of the 200 watts to keep up with it. It is matched pretty well with a modern 35 watt mobile. Now THAT I'd like to see the math on. Just how high does receiver sensitivity have to get to balance with a typical say, oh... .15uV modern UHF mobile and it sending out 35W... what would the perfect numbers be. Someone who enjoys the math more than I do maybe will feel bored enough to calculate it. I guess you'd need the antenna gain numbers also. What are you running on that system, Kevin? Nate WY0X Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.169 / Virus Database: 270.6.16/1651 - Release Date: 9/4/2008 6:57 AM
Re: [Repeater-Builder] Re: GE uhf high power
Nate Duehr wrote: KC wrote: BTW: I have one of the stations that Fred mentioned at one of my sites. It belongs to Jeff DePolo. It will run 200+ watts all day and night, and with a good MASTR II receiver (hand selected) with a Chip Angle preamp, it takes all of the 200 watts to keep up with it. It is matched pretty well with a modern 35 watt mobile. Now THAT I'd like to see the math on. Just how high does receiver sensitivity have to get to balance with a typical say, oh... .15uV modern UHF mobile and it sending out 35W... what would the perfect numbers be. Someone who enjoys the math more than I do maybe will feel bored enough to calculate it. I guess you'd need the antenna gain numbers also. What are you running on that system, Kevin? Hi Nate, et al, First, the antenna gain doesn't matter, since its gain affects BOTH the receiver and the transmitter; not withstanding some slight difference due to frequency or difference due to pattern because of change in frequency. The antenna is a DB-420, so pattern and gain differences between the TX and RX frequencies are minimal. In a typical mobile installation, the USABLE sensitivity will rarely be the rated sensitivity due to man made noise, noise from the vehicles computer and other electronics operating in or around it. Even the fuel pump can cause serious receiver performance degradation. I use a Kenwood TM-742A Japanese mobile rig for 2M, 220, and 440. This radio is spec'd at .16 uV (-123 dBm) for 12 dB SINAD. I own 3 of these and none of them are any better than -120 dBm connected right to the service monitor. Now, connect it to the mobile antenna you will likely never realize the bench sensitivity in a mobile environment - I certainly don't. My 1988 Chevy truck installation allows me to realize about .35 uV (-117 dBm) on UHF. The repeater site I mentioned above is in the middle of no-where, and there is nothing else around it for miles and miles. At this site it is easy to realize the full potential of receiver sensitivity. The receiver above has a usable sensitivity of -126 dBm (.112 uV) for 12 dB SINAD in full repeat, connected to the repeater antenna. Connected to the service monitor - I really don't know, it's less than any accurate measurement I can make. The difference in sensitivity between the repeater receiver and my mobile radios advertised sensitivity is 3 dB The difference in sensitivity between the repeater receiver and my mobile radios actual bench sensitivity is 6 dB The difference in sensitivity between the repeater receiver and my mobile radios actual vehicular sensitivity is 9 dB To be perfectly balanced using my mobile installation in comparison: The repeater would need to run 70 watts if I was blessed with a mobile rig that really had its rated sensitivity and I could realize all of it operating in my mobile. The repeater would need to run 140 watts if I were to realize the actual measured sensitivity of my rig operated in my mobile - (which I cannot). The repeater would need to run 280 watts to be balanced since my actual vehicular sensitivity is -117 dBm. From this, it's easy to see that running 200 watts is a necessity, when you have a /real/ good repeater receiver and a quiet site to realize its capabilities - even on UHF. Sometimes we forget that a change of 3 dB is double or half. A repeater that is perfectly balanced only needs a 3 dB betterment on its receive to require the transmitter power to double to remain balanced. There are plenty of repeaters out there that work perfectly well. Many have no preamp. Adding a good preamp can easily add 3, 6 dB, sometimes if the site is clean 9 or more dB can be realized with really good preamps. If you have a 50 watt repeater that is balanced, adding a preamp that gives 9 dB of usable sensitivity suddenly requires you to run 400 watts to operate the same as it did. Some folks seem to think that running big power is evil, but it's not as long as you do _your homework_ and can benefit from some of these modern preamps that really work well. Your homework might involve running a MASTR II PLL exciter on VHF, a better duplexer, or a Tube Type PA so you don't need to change out your duplexer to isolate this additional receiver sensitivity and BIG power. Kevin Custer
Re: [Repeater-Builder] Re: GE uhf high power
Scott Zimmerman wrote: Although what Joe says is true, the system is balanced more so than the math would indicate. This is due to most users ears requiring more than .15uV sensitivity to pick out a weak signal. realize that the SINADs of BOTH the repeater and the mobile rig would be additive when the mobile is in a fringe area. If a user is into the system and is, say 50% noise and the repeater's transmitter is being received at an S1, say 30% noise, that adds to 80% noise. That's pretty noisy!! Yep, yep. Totally understand. Maybe for this type of analysis we should use the receiver's 20 dB quieting point instead of the 12 dB SINAD point. For a typical user's DSP (the one between their ears) to be able to process a weak signal into the repeater's receiver, they need to be able to hear the repeater's transmitter almost full quieting. This is the reason that all links between receivers strive to be absolutely full-quieting and have good audio characteristics. If not, all of the system noise and distortions are additive. Absolutely. More comments below as to why I find this all fascinating. Scott Scott Zimmerman Amateur Radio Call N3XCC 474 Barnett Rd Boswell, PA 15531 I knew we'd go there to the additive receiver sensitivity part -- I just wanted to see the numbers. There are days I wish I had time to do this stuff for a living... but that'll never happen. Too busy playing telco at work. On the wireline side of things, VoIP is gettin' pretty darn good! We got HD Audio VoIP phones on our desks at work last week, and internal calls sound bloody AMAZING. I think they're using G.722.1 Annex C for a CODEC, but it may be full 64 Kb/s -- makes all the digital radios I'm playing with as a hobby sound shamefully bad, really. Hell it makes the analog rigs sound bad too, 'cause the phones have good quality mics and speakers. Even when going through the PSTN gateway, they sound great. 2-way radio tech seems to be in a race to the bottom in audio quality. Just look at cell phones to see who 2-way radio manufacturers are copying. My GSM phone sounds like utter CRAP compared to my old brick analog phone, and it's not getting better. Of course, we hams and repeater geeks all know the driving business reasons... they're having to save on RF on-air bandwidth. Most folks don't know that. Meanwhile the rest of the telecom world is going the other way... Hey, we can make this phone sound BETTER!. Or more often than not, Hey we can do full framerate VIDEO... why are we talking on a phone in 2008? It's all kinda interesting, really -- if we could somehow get Brain-DSP effectiveness numbers (like MOS score, or other subjective tests done in digital two-way) for analog, and then apply them... it would be possible to state pretty confidently that a particular system, analog, digital, whatever... doesn't matter... if it's set up a particular way, we would be able to mathematically predict how many users would enjoy it, how many would find it adequate and how many would dislike it. Then it could be engineered from the start to sound acceptable or better to some percentage of users. Of course, wireless is going to fall further and further behind wireline... because of video adoption. But voice-only calls will never go away completely... they'll just become the alternate way to join a meeting in progress, over the long-haul. Interesting stuff to study, really -- because the voice quality issues learned in even an analog repeater applies to the human ear interface questions that are plaguing the digital repeater world today. DVSI's CODEC's truly do sound like crap, but they're what the world's using so far for the major systems. And I'm not knocking DVSI really, I'm knocking that race to the bottom bandwidth-wise. VARIABLE bitrates and TRUNKING *mixed together* seem to be the final solution. If only one user is active, they get beautiful audio. 100 users active, the quality goes down, but the communication still goes through. That seems long-term to me what will *eventually* happen... but it'll take years and years because infrastructure is expensive to upgrade/replace -- and I'm not seeing manufacturers make DSP code upgradeable in the field in repeater technology yet... maybe I've missed it, since I don't work in that industry. Just think, maybe in ten years we'll fully understand analog to the point where it can be mathematically proven like the old telco engineering levels were when it was the Bell system, but at the same time, technology will have marched on, away from analog. There really was some good engineering going on at Bell Labs before divestiture, and it all got thrown in the dumpster... choice is nice, but well-engineered always works isn't something you get from three large heavily-competing telcos (which is what we'll eventually end up with), either. That only comes in that environment by
Re: [Repeater-Builder] Re: GE uhf high power
...and that's on UHF. Let's talk low-band! Kevin, thanks for the thoughtful math. 73, Paul, AE4KR - Original Message - From: Kevin Custer To: Repeater-Builder@yahoogroups.com Sent: Thursday, September 04, 2008 4:08 PM Subject: Re: [Repeater-Builder] Re: GE uhf high power Nate Duehr wrote: KC wrote: BTW: I have one of the stations that Fred mentioned at one of my sites. It belongs to Jeff DePolo. It will run 200+ watts all day and night, and with a good MASTR II receiver (hand selected) with a Chip Angle preamp, it takes all of the 200 watts to keep up with it. It is matched pretty well with a modern 35 watt mobile. Now THAT I'd like to see the math on. Just how high does receiver sensitivity have to get to balance with a typical say, oh... .15uV modern UHF mobile and it sending out 35W... what would the perfect numbers be. Someone who enjoys the math more than I do maybe will feel bored enough to calculate it. I guess you'd need the antenna gain numbers also. What are you running on that system, Kevin? Hi Nate, et al, First, the antenna gain doesn't matter, since its gain affects BOTH the receiver and the transmitter; not withstanding some slight difference due to frequency or difference due to pattern because of change in frequency. The antenna is a DB-420, so pattern and gain differences between the TX and RX frequencies are minimal. In a typical mobile installation, the USABLE sensitivity will rarely be the rated sensitivity due to man made noise, noise from the vehicles computer and other electronics operating in or around it. Even the fuel pump can cause serious receiver performance degradation. I use a Kenwood TM-742A Japanese mobile rig for 2M, 220, and 440. This radio is spec'd at .16 uV (-123 dBm) for 12 dB SINAD. I own 3 of these and none of them are any better than -120 dBm connected right to the service monitor. Now, connect it to the mobile antenna you will likely never realize the bench sensitivity in a mobile environment - I certainly don't. My 1988 Chevy truck installation allows me to realize about .35 uV (-117 dBm) on UHF. The repeater site I mentioned above is in the middle of no-where, and there is nothing else around it for miles and miles. At this site it is easy to realize the full potential of receiver sensitivity. The receiver above has a usable sensitivity of -126 dBm (.112 uV) for 12 dB SINAD in full repeat, connected to the repeater antenna. Connected to the service monitor - I really don't know, it's less than any accurate measurement I can make. The difference in sensitivity between the repeater receiver and my mobile radios advertised sensitivity is 3 dB The difference in sensitivity between the repeater receiver and my mobile radios actual bench sensitivity is 6 dB The difference in sensitivity between the repeater receiver and my mobile radios actual vehicular sensitivity is 9 dB To be perfectly balanced using my mobile installation in comparison: The repeater would need to run 70 watts if I was blessed with a mobile rig that really had its rated sensitivity and I could realize all of it operating in my mobile. The repeater would need to run 140 watts if I were to realize the actual measured sensitivity of my rig operated in my mobile - (which I cannot). The repeater would need to run 280 watts to be balanced since my actual vehicular sensitivity is -117 dBm. From this, it's easy to see that running 200 watts is a necessity, when you have a real good repeater receiver and a quiet site to realize its capabilities - even on UHF. Sometimes we forget that a change of 3 dB is double or half. A repeater that is perfectly balanced only needs a 3 dB betterment on its receive to require the transmitter power to double to remain balanced. There are plenty of repeaters out there that work perfectly well. Many have no preamp. Adding a good preamp can easily add 3, 6 dB, sometimes if the site is clean 9 or more dB can be realized with really good preamps. If you have a 50 watt repeater that is balanced, adding a preamp that gives 9 dB of usable sensitivity suddenly requires you to run 400 watts to operate the same as it did. Some folks seem to think that running big power is evil, but it's not as long as you do your homework and can benefit from some of these modern preamps that really work well. Your homework might involve running a MASTR II PLL exciter on VHF, a better duplexer, or a Tube Type PA so you don't need to change out your duplexer to isolate this additional receiver sensitivity and BIG power. Kevin Custer
[Repeater-Builder] Re: GE uhf high power
Fred, I stand corrected. As always, you can teach an old dog new tricks. Thanks for the correct information. Joe - WA7JAW --- In Repeater-Builder@yahoogroups.com, Fred Seamans [EMAIL PROTECTED] wrote: To All: GE Did make a solid state 200 watt UHF Transmitter. They used a 100 watt PA driver to two 100 watt PA's less the 40 watt driver board and then recombined the two 100 watt to get 200 watts out. They sure are not efficient! I agree it would be better to use a 100 watt PA at reduced power. However the 100 watt PA's are rated at 100 watts continuous power output. (That is key down for 24 hours with no degradation in power output). Fred W5VAY (Retired GE Mobile Radio) _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Joe Burkleo Sent: Thursday, September 04, 2008 12:54 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: ge uhf high power Also as Nate said, GE did not make a high power solid state amp. The Mastr II high power stations that I referred to use a normal Mastr II solid state PA to drive a tube amplifier to acheive the 225-250 Watts on UHF or 375 Watts on VHF. If you are not familiar with high power tube transmitters and working with high voltages, stay away from these. They are not for the faint of heart, and the voltages present can be quite deadly. Joe - WA7JAW --- In Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com, Joe Burkleo joeburkleo@ wrote: You might try contacting Larry K7LJ. He posts on here occasionally and I know he had a couple of these the last time I talked to him, but that was a couple months ago. They are more like 350 Watts. Joe --- In Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com, kb4ptj kb4ptj@ wrote: hi i am looking for ge uhf solid state high power 88 splyt 200watts kb4ptj@
[Repeater-Builder] Re: ge uhf high power
You might try contacting Larry K7LJ. He posts on here occasionally and I know he had a couple of these the last time I talked to him, but that was a couple months ago. They are more like 350 Watts. Joe --- In Repeater-Builder@yahoogroups.com, kb4ptj [EMAIL PROTECTED] wrote: hi i am looking for ge uhf solid state high power 88 splyt 200watts [EMAIL PROTECTED]
[Repeater-Builder] Re: ge uhf high power
oops, UHF are 225-250 Watts, it is the VHF that are 350 Watts. Joe --- In Repeater-Builder@yahoogroups.com, Joe Burkleo [EMAIL PROTECTED] wrote: You might try contacting Larry K7LJ. He posts on here occasionally and I know he had a couple of these the last time I talked to him, but that was a couple months ago. They are more like 350 Watts. Joe --- In Repeater-Builder@yahoogroups.com, kb4ptj kb4ptj@ wrote: hi i am looking for ge uhf solid state high power 88 splyt 200watts kb4ptj@
[Repeater-Builder] Re: ge uhf high power
Also as Nate said, GE did not make a high power solid state amp. The Mastr II high power stations that I referred to use a normal Mastr II solid state PA to drive a tube amplifier to acheive the 225-250 Watts on UHF or 375 Watts on VHF. If you are not familiar with high power tube transmitters and working with high voltages, stay away from these. They are not for the faint of heart, and the voltages present can be quite deadly. Joe - WA7JAW --- In Repeater-Builder@yahoogroups.com, Joe Burkleo [EMAIL PROTECTED] wrote: You might try contacting Larry K7LJ. He posts on here occasionally and I know he had a couple of these the last time I talked to him, but that was a couple months ago. They are more like 350 Watts. Joe --- In Repeater-Builder@yahoogroups.com, kb4ptj kb4ptj@ wrote: hi i am looking for ge uhf solid state high power 88 splyt 200watts kb4ptj@
