[Repeater-Builder] Re: Looking for Microwave Associates 7R011T Isolator Tuning Procedure
Don't ever throw that catalog out... If it was worth your time, I'd pay you for some photocopies or page scans. thanks skipp Micheal Salem [EMAIL PROTECTED] ,wrote: Skip: I did look it up when I got home in my ancient M/A-COM catalog (From 1982, no less. It is hard to throw this stuff away). For those who are interested, the 7R011 is specified at 125 watts. The insertion loss is .9 db typical with 1.3 db max. The isolation can be as high as 60 db with 50 db typical. That may require breaking out the HP435B and an RF head to tune it. But I could get a good null right down to zero indication at 10 watts in and a 1 watt Bird element on the output and expected that I had at least 40 db or more of isolation. It is described as a metro style isolator. The 44004 load that comes with the typical IM panel that includes the 7R011 is rated at 100 watts and I would agree with Skipp that it would not be a good idea to dump more than 100 watts through the device. With 125 watts in and an insertion loss of .9 db. there probably isn't more than 100 watts in the dummy load, but you could be dissipating a lot of power in heat in the isolator in an open antenna condition. Micheal Salem N5MS Norman, Oklahoma skipp025 wrote: I would have to look it up, but I think that this isolator takes up to at least 100 watts. That would be when it is in resonance. I have run 65 watts through it with not much trouble. Micheal Salem The port loads are under sized if you want real protection. The units operate just fine at 100 watts fwd power... at least that's what Motorola had been blowing through them for some decades. As long as the antenna system works as it should, the loads are probably ok for lower power levels. But I wouldn't trust the supplied port loads as a failsafe. skipp Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: Looking for Microwave Associates 7R011T Isolator Tuning Procedure
Where would one expect to find the low pass filters to use with this isolator? If they are hard to find or are expensive, does anyone have a LPF design the can share which is capable of 50W on 70cm which can be constucted in a die cast aluminum box? I have an ridiculously expensive and bulky KL 3TNF500/1000 tunable bandreject filter [which is overkill] I'm using temporarily. Steve WA6ZFT On Saturday 07 May 2005 08:50, skipp025 wrote: Don't ever throw that catalog out... If it was worth your time, I'd pay you for some photocopies or page scans. thanks skipp Micheal Salem [EMAIL PROTECTED] ,wrote: Skip: I did look it up when I got home in my ancient M/A-COM catalog (From 1982, no less. It is hard to throw this stuff away). For those who are interested, the 7R011 is specified at 125 watts. The insertion loss is .9 db typical with 1.3 db max. The isolation can be as high as 60 db with 50 db typical. That may require breaking out the HP435B and an RF head to tune it. But I could get a good null right down to zero indication at 10 watts in and a 1 watt Bird element on the output and expected that I had at least 40 db or more of isolation. It is described as a metro style isolator. The 44004 load that comes with the typical IM panel that includes the 7R011 is rated at 100 watts and I would agree with Skipp that it would not be a good idea to dump more than 100 watts through the device. With 125 watts in and an insertion loss of .9 db. there probably isn't more than 100 watts in the dummy load, but you could be dissipating a lot of power in heat in the isolator in an open antenna condition. Micheal Salem N5MS Norman, Oklahoma skipp025 wrote: I would have to look it up, but I think that this isolator takes up to at least 100 watts. That would be when it is in resonance. I have run 65 watts through it with not much trouble. Micheal Salem The port loads are under sized if you want real protection. The units operate just fine at 100 watts fwd power... at least that's what Motorola had been blowing through them for some decades. As long as the antenna system works as it should, the loads are probably ok for lower power levels. But I wouldn't trust the supplied port loads as a failsafe. skipp Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: Looking for Microwave Associates 7R011T Isolator Tuning Procedure
Hi Micheal, The attachments sent to the group don't come through to those of us reading posts on line with a web browswer. Would you or anyone who received the attachment please Email forward me a copy? Mucho Thanks skipp [EMAIL PROTECTED] skipp025 at yahoo.com Micheal Salem [EMAIL PROTECTED] wrote: Steve: As a matter of fact, I do have tuneup instructions that I got from Microwave Associates. They are attached. I have successfully tuned a 7R011 using these. I did not have a power meters, but could use a smaller element in a Bird wattmeter and got pretty good isolation. Micheal Salem N5MS Steve Rodgers wrote: Does anyone have a tuning procedure they could share for the Microwave Associates 7R011T dual-stage UHF Isolator? I have 2 of these tuned on 454 and 462MHz. I've never attempted to tune isolators so any tips would be useful. Can these be tuned with a tracking generator/spectrum analyzer? Steve WA6ZFT Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: Looking for Microwave Associates 7R011T Isolator Tuning Procedure
Micheal Salem [EMAIL PROTECTED] wrote: I could never get it anywhere near the specs. So, I called Microwave Associates and spoke to someone in their repair department. I described what had happened and what I had done. He told me that this was very tricky to do and that they used nonmagnetic copper vises to position the isolator just right when assemblying or repairing it. The key information above non-magnetic tools. He told me to be sure and use brass or other nonmagnetic materials when mounting it and to not to take it off the panel. ding, ding, ding... jackpot. You alway want to try and use non magnetic hardware and tools where possible. Some of you might have noticed the mention of Stainless Steel or Brass in the recent Wacom Duplexer post. Another reason is to avoid embedding steel or other unwanted metals from a brush/tool into the subject item. One of the problems in tuning was getting enough sensitivity to read the reverse hookup (RF into the antenna port and measure power coming out of the transmitter port). I had a 1 watt UHF slug, so that I could read .1 watt and that could be about 30 db from 10 watts. One must be cautious, the final adjustment location moves around with heat. and it doesn't take much. In my opinion, the supplied terminations should be swapped for higher power loads. I recently got another 7R011 and will have to dig out an aluminum panel to put it on and get some dummy loads. Many Motorola Radio Sites on the West Coast used the MA Tx combiner systems. They were made up of the ever popular Motorola T-1500 BP Cavities (with the proper loop settings) and the mentioned 7R011 units in combinations as 4 frequencies per panel. Not really the best for close spaced frequencies, but they did work really well. cheers, skipp Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: Looking for Microwave Associates 7R011T Isolator Tuning Procedure
Micheal Salem [EMAIL PROTECTED] I think that they may be concerned about off resonance circulating currents or voltages during tuneup which could demagnetize (or change the permanent fields of the internal magnets and damage the isolator. Heat... I would have to look it up, but I think that this isolator takes up to at least 100 watts. That would be when it is in resonance. I have run 65 watts through it with not much trouble. Micheal Salem The port loads are under sized if you want real protection. The units operate just fine at 100 watts fwd power... at least that's what Motorola had been blowing through them for some decades. As long as the antenna system works as it should, the loads are probably ok for lower power levels. But I wouldn't trust the supplied port loads as a failsafe. skipp Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: Looking for Microwave Associates 7R011T Isolator Tuning Procedure
You will notice the MA UHF Isolators drift with heat a lot more than largers current dual port products. Instrument tuning is not the best option, except maybe to get it in the ball park. They are tuned just like dual port telewave types. Never trusting one specific method, I use both the typical under-power tune method along with a tracking spectral display. One bad part about the MA units... you have to make a call about the tuning, tune them cold (at room temp) or tune them warm, depends on the duty cycle of the transmitter. They change value a lot more quickly than most or all of the other brand circulators and isolators I have/own/use. The Decibel Products instructions are floating around on the web... cheers, skipp Steve Rodgers [EMAIL PROTECTED] wrote: Does anyone have a tuning procedure they could share for the Microwave Associates 7R011T dual-stage UHF Isolator? I have 2 of these tuned on 454 and 462MHz. I've never attempted to tune isolators so any tips would be useful. Can these be tuned with a tracking generator/spectrum analyzer? Steve WA6ZFT Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: Looking for Microwave Associates 7R011T Isolator Tuning Procedure
What power levels have you seen the drift issue at? I'm not going to run more than 30W into these units. On Thursday 05 May 2005 19:22, skipp025 wrote: You will notice the MA UHF Isolators drift with heat a lot more than largers current dual port products. Instrument tuning is not the best option, except maybe to get it in the ball park. They are tuned just like dual port telewave types. Never trusting one specific method, I use both the typical under-power tune method along with a tracking spectral display. One bad part about the MA units... you have to make a call about the tuning, tune them cold (at room temp) or tune them warm, depends on the duty cycle of the transmitter. They change value a lot more quickly than most or all of the other brand circulators and isolators I have/own/use. The Decibel Products instructions are floating around on the web... cheers, skipp Steve Rodgers [EMAIL PROTECTED] wrote: Does anyone have a tuning procedure they could share for the Microwave Associates 7R011T dual-stage UHF Isolator? I have 2 of these tuned on 454 and 462MHz. I've never attempted to tune isolators so any tips would be useful. Can these be tuned with a tracking generator/spectrum analyzer? Steve WA6ZFT Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
