[Repeater-Builder] RE: Micor to 222 MHz PA Conversion
Joe Burkleo wrote: > Has anyone ever tried to take a Micor VHF PA to 222 by changing parts > on the PA board? Yes, the transistors will not make it. Motorola designed it that way. > If so what results have you had? I have never seen or heard of anyone that has had any great success with a conversion of the PA, so... , here is a cure: http://www.repeater-builder.com/products/ampbd.html I also recommend the receiver and exciter conversions outlined here (referred to as the 'new method'), as they work better than others on the Internet: http://www.repeater-builder.com/rbtip/micor-index.html#220 Regards, Kevin Custer
[Repeater-Builder] Re: Micor to 222 MHz PA Conversion
Kevin Thanks for the information. I figured that if anyone had tried it you would be aware. I was just looking for more than 30 Watts out. Can these modules be considered continuous duty if they are properly mounted on a Micor station PA chassis. Joe - WA7JAW --- In Repeater-Builder@yahoogroups.com, Kevin Custer <[EMAIL PROTECTED]> wrote: > > Joe Burkleo wrote: > > Has anyone ever tried to take a Micor VHF PA to 222 by changing parts > > on the PA board? > > Yes, the transistors will not make it. Motorola designed it that way. > > If so what results have you had? > > I have never seen or heard of anyone that has had any great success with > a conversion of the PA, so... > > , here is a cure: > http://www.repeater-builder.com/products/ampbd.html > > I also recommend the receiver and exciter conversions outlined here > (referred to as the 'new method'), as they work better than others on > the Internet: > http://www.repeater-builder.com/rbtip/micor-index.html#220 > > Regards, > Kevin Custer >
[Repeater-Builder] Re: Micor to 222 MHz PA Conversion
Kevin, Thanks for all of your information. When we get deeper into this project I am sure I will be talking to you more in-depth about the dual module PA. Milling the Micor PA deck is not a problem for me as I do a lot of metal work as well. I can see where the adapter would work very well for those who do not have knowledge or access to a milling machine. Joe - WA7JAW --- In Repeater-Builder@yahoogroups.com, Kevin Custer <[EMAIL PROTECTED]> wrote: > > Joe Burkleo wrote: > > Kevin > > Thanks for the information. I figured that if anyone had tried it you > > would be aware. > > > > I was just looking for more than 30 Watts out. > > > > Scott and I have been successful in building small IPA's (intermediate > power amplifiers) that take the power from the exciter and make 3/4 to 1 > watt with a single transistor. This stage then feeds a Wilkinson power > divider and it feeds two of these brick devices. Another WPD is used to > combine the power. About 75 to 80 watts is possible. We have a > prototype that has one brick module (as the IPA) feeding four more, and > over 150 watts is possible. > > We never fully developed the 150 watt high-power version because the > single brick PA we build will easily deliver enough drive for any good > external 220 PA, however we do have several of the 75 watt versions in > service. > > Can these modules be considered continuous duty if they are properly > > mounted on a Micor station PA chassis. > > > > Absolutely - especially if running one or two modules. > > In addition, we actually use the MICOR power set control to retain all > of its features (SWR protection, power leveling, etc.) The AMP BD that > Scott builds has the pass transistor built on it and it is run from the > power set control lead that originally went to the MICOR PA. > > Scott also builds a custom heat spreader that is used to mate the module > to the MICOR heatsink. This eliminates the need to machine a flat spot > on the heatsink that big enough for the surface of the module. While > Scott doesn't advertise these, I feel sure he would sell them > individually; they are used in /our/ custom 220 MICOR conversions. The > heat spreader is not necessary in a MASTR II conversion, as there are no > protruding 'bosses' for the original mounting of the RF power output > transistors. The pictures in this document shows the mounting > arrangement he has developed: > http://www.repeater-builder.com/products/ampbddocs.pdf > > Good luck and let us know how you make out... > > Kevin Custer > Repeater Builder >
[Repeater-Builder] Re: Micor to 222 MHz PA Conversion
Joe, Are you in the process of building or do you already have a Micor on 220? I am starting on a 220 conversion project with a high band mobile and am running into problems finding some of the silver-mica caps to use in the conversion. Any idea on sources? Thanks, Jordan
Re: [Repeater-Builder] Re: Micor to 222 MHz PA Conversion
Joe Burkleo wrote: Kevin Thanks for the information. I figured that if anyone had tried it you would be aware. I was just looking for more than 30 Watts out. Scott and I have been successful in building small IPA's (intermediate power amplifiers) that take the power from the exciter and make 3/4 to 1 watt with a single transistor. This stage then feeds a Wilkinson power divider and it feeds two of these brick devices. Another WPD is used to combine the power. About 75 to 80 watts is possible. We have a prototype that has one brick module (as the IPA) feeding four more, and over 150 watts is possible. We never fully developed the 150 watt high-power version because the single brick PA we build will easily deliver enough drive for any good external 220 PA, however we do have several of the 75 watt versions in service. Can these modules be considered continuous duty if they are properly mounted on a Micor station PA chassis. Absolutely - especially if running one or two modules. In addition, we actually use the MICOR power set control to retain all of its features (SWR protection, power leveling, etc.) The AMP BD that Scott builds has the pass transistor built on it and it is run from the power set control lead that originally went to the MICOR PA. Scott also builds a custom heat spreader that is used to mate the module to the MICOR heatsink. This eliminates the need to machine a flat spot on the heatsink that big enough for the surface of the module. While Scott doesn't advertise these, I feel sure he would sell them individually; they are used in /our/ custom 220 MICOR conversions. The heat spreader is not necessary in a MASTR II conversion, as there are no protruding 'bosses' for the original mounting of the RF power output transistors. The pictures in this document shows the mounting arrangement he has developed: http://www.repeater-builder.com/products/ampbddocs.pdf Good luck and let us know how you make out... Kevin Custer Repeater Builder
[building-repeaters] Re: [Repeater-Builder] Re: Micor to 222 MHz PA Conversion
Eric, I just swap the modules from a Mobile into the station PA heatsink if I have one die. They are the same modules, different heatsink. I have found that if you back down the last output stage of the exciter a little, the tripler and first stage of the PA is much happier and the PA's will last a lot longer during our hour long plus nets. Doing this I am still able to get well over 75 Watts out of the PA, but DON'T DO IT. 75 WATTS MAX. The other question I have, is have you been retuning the tripler and circulator? If not, that could be where part of your problems are coming from. Good Luck, Joe - WA7JAW --- In Repeater-Builder@yahoogroups.com, [EMAIL PROTECTED] wrote: > > Kevin, > > I've been meaning to postabout a similar project, and this prompts me to ask - have you done this to "rebuild" a UHF amp? > > I have several dead TLD-1713 UHF 75w PAs, and need a good PA or two at the moment. Rather than messing with trying to find Moto transistors, caps, and Z-matches, I was thinking of stripping the heatsink down, buying two Mx UHF 40-50w modules, and trying to combine them. > > I was curious as to how they would hold up under continuously linked repeater duty > > Can you provide some more details on the 'Wilkinson" power dividers? I have experience with HF torroid combiners/splitters, but UHF is another animal altogether. Do you sell them with the boards? > > Is it as simple as mounting the two modules (and the supporting RB circuit boards), the combiner/splitters, and wiring it all up? > > I'd like to get a UHF one together asap. > > Thanks > Eric > KE2D
[building-repeaters] Re: [Repeater-Builder] Re: Micor to 222 MHz PA Conversion
I usually retune the tripler filter on my spectrun analyzer/tracking generator, and also re-tune the circulator. So the drive level into the amp is fine, and the circulator is ok. It is definitely PA issues, such as intermittent substrates, bad chip caps, Z-matches, etc... I have done the mobile-to-heatsink trick a number of times; more vhf than uhf, but 100w uhf mobiles aren't too common anyore around here. Just looking for a more modern solution. The mobile trick is probably cheaper though. Eric KE2D --- In Repeater-Builder@yahoogroups.com, "Joe Burkleo" <[EMAIL PROTECTED]> wrote: > > Eric, > I just swap the modules from a Mobile into the station PA heatsink if > I have one die. They are the same modules, different heatsink. > > I have found that if you back down the last output stage of the > exciter a little, the tripler and first stage of the PA is much > happier and the PA's will last a lot longer during our hour long plus > nets. Doing this I am still able to get well over 75 Watts out of the > PA, but DON'T DO IT. 75 WATTS MAX. > > The other question I have, is have you been retuning the tripler and > circulator? If not, that could be where part of your problems are > coming from. > > Good Luck, > Joe - WA7JAW > > > --- In Repeater-Builder@yahoogroups.com, kk2ed@ wrote: > > > > Kevin, > > > > I've been meaning to postabout a similar project, and this prompts > me to ask - have you done this to "rebuild" a UHF amp? > > > > I have several dead TLD-1713 UHF 75w PAs, and need a good PA or two > at the moment. Rather than messing with trying to find Moto > transistors, caps, and Z-matches, I was thinking of stripping the > heatsink down, buying two Mx UHF 40-50w modules, and trying to > combine them. > > > > I was curious as to how they would hold up under continuously linked > repeater duty > > > > Can you provide some more details on the 'Wilkinson" power dividers? > I have experience with HF torroid combiners/splitters, but UHF is > another animal altogether. Do you sell them with the boards? > > > > Is it as simple as mounting the two modules (and the supporting RB > circuit boards), the combiner/splitters, and wiring it all up? > > > > I'd like to get a UHF one together asap. > > > > Thanks > > Eric > > KE2D >
Re: [building-repeaters] Re: [Repeater-Builder] Re: Micor to 222 MHz PA Conversion
Kevin, I've been meaning to postabout a similar project, and this prompts me to ask - have you done this to "rebuild" a UHF amp? I have several dead TLD-1713 UHF 75w PAs, and need a good PA or two at the moment. Rather than messing with trying to find Moto transistors, caps, and Z-matches, I was thinking of stripping the heatsink down, buying two Mx UHF 40-50w modules, and trying to combine them. I was curious as to how they would hold up under continuously linked repeater duty Can you provide some more details on the 'Wilkinson" power dividers? I have experience with HF torroid combiners/splitters, but UHF is another animal altogether. Do you sell them with the boards? Is it as simple as mounting the two modules (and the supporting RB circuit boards), the combiner/splitters, and wiring it all up? I'd like to get a UHF one together asap. Thanks Eric KE2D -- Original message -- From: Kevin Custer <[EMAIL PROTECTED]> Joe Burkleo wrote: Kevin Thanks for the information. I figured that if anyone had tried it you would be aware. I was just looking for more than 30 Watts out. Scott and I have been successful in building small IPA's (intermediate power amplifiers) that take the power from the exciter and make 3/4 to 1 watt with a single transistor. This stage then feeds a Wilkinson power divider and it feeds two of these brick devices. Another WPD is used to combine the power. About 75 to 80 watts is possible. We have a prototype that has one brick module (as the IPA) feeding four more, and over 150 watts is possible. We never fully developed the 150 watt high-power version because the single brick PA we build will easily deliver enough drive for any good external 220 PA, however we do have several of the 75 watt versions in service. Can these modules be considered continuous duty if they are properly mounted on a Micor station PA chassis. Absolutely - especially if running one or two modules. In addition, we actually use the MICOR power set control to retain all of its features (SWR protection, power leveling, etc.) The AMP BD that Scott builds has the pass transistor built on it and it is run from the power set control lead that originally went to the MICOR PA. Scott also builds a custom heat spreader that is used to mate the module to the MICOR heatsink. This eliminates the need to machine a flat spot on the heatsink that big enough for the surface of the module. While Scott doesn't advertise these, I feel sure he would sell them individually; they are used in our custom 220 MICOR conversions. The heat spreader is not necessary in a MASTR II conversion, as there are no protruding 'bosses' for the original mounting of the RF power output transistors. The pictures in this document shows the mounting arrangement he has developed: http://www.repeater-builder.com/products/ampbddocs.pdf Good luck and let us know how you make out... Kevin Custer Repeater Builder
Re: [building-repeaters] Re: [Repeater-Builder] Re: Micor to 222 MHz PA Conversion
If you want to see how many hoops we jumped through to convert a high-band VHF Micor to 220 go here: There's a PA link near the top. http://home.comcast.net/~micorrepeater/ de WD7F John in Tucson - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] ; Repeater-Builder@yahoogroups.com ; [EMAIL PROTECTED] Cc: Kevin Custer Sent: Wednesday, September 03, 2008 7:29 AM Subject: Re: [building-repeaters] Re: [Repeater-Builder] Re: Micor to 222 MHz PA Conversion Kevin, I've been meaning to postabout a similar project, and this prompts me to ask - have you done this to "rebuild" a UHF amp? I have several dead TLD-1713 UHF 75w PAs, and need a good PA or two at the moment. Rather than messing with trying to find Moto transistors, caps, and Z-matches, I was thinking of stripping the heatsink down, buying two Mx UHF 40-50w modules, and trying to combine them. I was curious as to how they would hold up under continuously linked repeater duty Can you provide some more details on the 'Wilkinson" power dividers? I have experience with HF torroid combiners/splitters, but UHF is another animal altogether. Do you sell them with the boards? Is it as simple as mounting the two modules (and the supporting RB circuit boards), the combiner/splitters, and wiring it all up? I'd like to get a UHF one together asap. Thanks Eric KE2D -- Original message -- From: Kevin Custer <[EMAIL PROTECTED]> Joe Burkleo wrote: Kevin Thanks for the information. I figured that if anyone had tried it you would be aware. I was just looking for more than 30 Watts out. Scott and I have been successful in building small IPA's (intermediate power amplifiers) that take the power from the exciter and make 3/4 to 1 watt with a single transistor. This stage then feeds a Wilkinson power divider and it feeds two of these brick devices. Another WPD is used to combine the power. About 75 to 80 watts is possible. We have a prototype that has one brick module (as the IPA) feeding four more, and over 150 watts is possible. We never fully developed the 150 watt high-power version because the single brick PA we build will easily deliver enough drive for any good external 220 PA, however we do have several of the 75 watt versions in service. Can these modules be considered continuous duty if they are properly mounted on a Micor station PA chassis. Absolutely - especially if running one or two modules. In addition, we actually use the MICOR power set control to retain all of its features (SWR protection, power leveling, etc.) The AMP BD that Scott builds has the pass transistor built on it and it is run from the power set control lead that originally went to the MICOR PA. Scott also builds a custom heat spreader that is used to mate the module to the MICOR heatsink. This eliminates the need to machine a flat spot on the heatsink that big enough for the surface of the module. While Scott doesn't advertise these, I feel sure he would sell them individually; they are used in our custom 220 MICOR conversions. The heat spreader is not necessary in a MASTR II conversion, as there are no protruding 'bosses' for the original mounting of the RF power output transistors. The pictures in this document shows the mounting arrangement he has developed: http://www.repeater-builder.com/products/ampbddocs.pdf Good luck and let us know how you make out... Kevin Custer Repeater Builder
Fw: [building-repeaters] Re: [Repeater-Builder] Re: Micor to 222 MHz PA Conversion
Forgot to addI never persued the SWR power reducing beyond the simple divider. Our converstion won't drop power all the way to zero when there's an SWR problem..yet. Once, the controller got confused and keyed the repeater over night at about 60 watts out without a problem. I think it's bullet proof in that respect. de WD7F John in Tucson - Original Message - From: WD7F - John in Tucson To: Repeater-Builder@yahoogroups.com Sent: Wednesday, September 03, 2008 8:46 AM Subject: Re: [building-repeaters] Re: [Repeater-Builder] Re: Micor to 222 MHz PA Conversion If you want to see how many hoops we jumped through to convert a high-band VHF Micor to 220 go here: There's a PA link near the top. http://home.comcast.net/~micorrepeater/ de WD7F John in Tucson - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] ; Repeater-Builder@yahoogroups.com ; [EMAIL PROTECTED] Cc: Kevin Custer Sent: Wednesday, September 03, 2008 7:29 AM Subject: Re: [building-repeaters] Re: [Repeater-Builder] Re: Micor to 222 MHz PA Conversion Kevin, I've been meaning to postabout a similar project, and this prompts me to ask - have you done this to "rebuild" a UHF amp? I have several dead TLD-1713 UHF 75w PAs, and need a good PA or two at the moment. Rather than messing with trying to find Moto transistors, caps, and Z-matches, I was thinking of stripping the heatsink down, buying two Mx UHF 40-50w modules, and trying to combine them. I was curious as to how they would hold up under continuously linked repeater duty Can you provide some more details on the 'Wilkinson" power dividers? I have experience with HF torroid combiners/splitters, but UHF is another animal altogether. Do you sell them with the boards? Is it as simple as mounting the two modules (and the supporting RB circuit boards), the combiner/splitters, and wiring it all up? I'd like to get a UHF one together asap. Thanks Eric KE2D -- Original message -- From: Kevin Custer <[EMAIL PROTECTED]> Joe Burkleo wrote: Kevin Thanks for the information. I figured that if anyone had tried it you would be aware. I was just looking for more than 30 Watts out. Scott and I have been successful in building small IPA's (intermediate power amplifiers) that take the power from the exciter and make 3/4 to 1 watt with a single transistor. This stage then feeds a Wilkinson power divider and it feeds two of these brick devices. Another WPD is used to combine the power. About 75 to 80 watts is possible. We have a prototype that has one brick module (as the IPA) feeding four more, and over 150 watts is possible. We never fully developed the 150 watt high-power version because the single brick PA we build will easily deliver enough drive for any good external 220 PA, however we do have several of the 75 watt versions in service. Can these modules be considered continuous duty if they are properly mounted on a Micor station PA chassis. Absolutely - especially if running one or two modules. In addition, we actually use the MICOR power set control to retain all of its features (SWR protection, power leveling, etc.) The AMP BD that Scott builds has the pass transistor built on it and it is run from the power set control lead that originally went to the MICOR PA. Scott also builds a custom heat spreader that is used to mate the module to the MICOR heatsink. This eliminates the need to machine a flat spot on the heatsink that big enough for the surface of the module. While Scott doesn't advertise these, I feel sure he would sell them individually; they are used in our custom 220 MICOR conversions. The heat spreader is not necessary in a MASTR II conversion, as there are no protruding 'bosses' for the original mounting of the RF power output transistors. The pictures in this document shows the mounting arrangement he has developed: http://www.repeater-builder.com/products/ampbddocs.pdf Good luck and let us know how you make out... Kevin Custer Repeater Builder
Re: [building-repeaters] Re: [Repeater-Builder] Re: Micor to 222 MHz PA Conversion
[EMAIL PROTECTED] wrote: > Kevin, > > I've been meaning to postabout a similar project, and this prompts me > to ask - have you done this to "rebuild" a UHF amp? I have not, but there is no reason one could not. There is 2 watts (approximately) from the MICOR LLA, plenty to split and drive several modules in parallel. > > I was curious as to how they would hold up under continuously linked > repeater duty We run them in repeater service with little trouble on the module itself. > > Can you provide some more details on the 'Wilkinson" power dividers? > I have experience with HF torroid combiners/splitters, but UHF is > another animal altogether. Google is your friend Basically they are 1/4 wavelength in 75 ohm coax (VF corrected). > Do you sell them with the boards? Sorry, no we don't. > > Is it as simple as mounting the two modules (and the supporting RB > circuit boards), the combiner/splitters, and wiring it all up? Yes... Kevin
