[Repeater-Builder] Re: High Power Mastr II base station conversion to 2 meters
--- In Repeater-Builder@yahoogroups.com, "William E. Janes" wrote: Is this a reasonable project to undertake converting > to 2 meters (TX 145.XXX)? We've had one of these beasts on 147 for 8 years and never a problem. (Well, one shorted power supply diode). We didn't change any cable lengths, however I don't know how yours might act in the 145 range. Ours is completely stable and clean at any power level between maximum and (essentially) zero. It simply sits there and works. >Obviously the tuning instructions will need to be > followed precisely. Assuming you have the Z matchers in each final amp, tune them, using a 50 ohm dummy load and wattmeter, for best overall efficiency, not according to the manual. Each final amp in our unit draws 12.5 amps for an output of ~175 watts. Laryn K8TVZ
[Repeater-Builder] Re: W1GAN and square duplexers aka homebrew duplexer
Since your post I've been googling like hell and found one Dutch design of a copper clad duplexer by PA0NHC, but this also has two loops per cavity and uses 8 cavities. However it answers the question about square enclosures and could be a reference design. Furthermore I found a design by WB3AYW which uses 16 gallon transmission fluid barrels as cavities in BPBR configuration using 4 cavities. This one looks easy to build and is somewhat similar to the beer keg duplexer which has been made professionally in the seventies afaik. The problem with these is that a 4 cavity duplexer gets pretty big and will hardly fit into a 19" cabinet. Does anyone know of any other particular homebrew design, especially one which uses some kind of available enclosure similar to the barrels but more space-saving? I also found some notice that the heliax duplexer, which is well-known for 6 meters, could also be built for 2 meters, but no detailed info was given. If anyone knows more about this, please tell... --- In Repeater-Builder@yahoogroups.com, DCFluX wrote: > > There were a couple of designs that used copper circuit boards to form > square boxes for the outer jacket of the duplexer. > > Size maters as the inner to outer diameter ratio effects the impedance > of the cavity. It is my understanding that the optimum impedance for > a cavity is approx 70 ohms. Not sure if this is true for cavities, but > with helical resonators square shields have higher Q than round ones. > > You would also probably be better off using a BpBr style design, as I > remember W1GANs was for pass cavities which would require 6, BpBr can > get away with use 4, they would be similar but only have 1 coupling > loop that has a high quality trimmer capacitor such as a johansen or a > coaxial gimmic in the ground leg of the loop to set the notch > frequency. > > On Fri, Apr 24, 2009 at 4:19 AM, cruizzer77 wrote: > > Hi > > > > Most of you who are into duplexers will know W1GAN's old QST-article "A > > Homemade Duplexer for 2-Meter Repeaters". > > > > His design uses 4" copper tubes, but today many duplexer manufacturers use > > square aluminium profile as duplexer bodies, i.e. Sinclair but others as > > well. Now I wondered if W1GAN's design could be used for building such an > > aluminium square tube duplexer as well and if it would work equally well. > > Does anybody know? > > > > Instead of the 4" round tube, would a 4" square tube be used, or does the > > circumference matter? > > > > Kind regards > > > > Martin > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > >
[Repeater-Builder] Re: KENWOOD TKR 720 REPEATER REPAIR - HELP
Peter - Contact your local (country or region) Microchip distributor or dealer. http://www.futurlec.com/Memory/93LC46.shtml http://ww1.microchip.com/downloads/en/DeviceDoc/21621d.pdf Getting Started with Microchip’s Serial EEPROMS http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2128¶m=en025151 Serial EEPROM Application Note http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011136 http://ww1.microchip.com/downloads/en/AppNotes/00572.pdf NORMALLY, with a microprocessor -- a command (stored with on-board firmware) is issued to store parameters to the EEPROM.
RE: [Repeater-Builder] High Power Mastr II base station conversion to 2 meters
> OK GE Mastr II experts, I have a question for you. Our club > has been the benefactor of a local law enforcement agency's > upgrade. We have acquired a VHF (155 mHz) Mastr II base > station with 3 solid state PAs that total a rated output > power of 225 watts. It appears to have a single PA power > split into two outputs. each driving a second PA that is then > summed back into a single output. I know the cable lengths of > the splitters and combiners are critical. Also understood is > the importance of cooling. What I am asking the experts on > the list is: Is this a reasonable project to undertake > converting to 2 meters (TX 145.XXX)? Obviously the tuning > instructions will need to be followed precisely. This station > has been in reliable service to the original owner for years. > We are wondering about the reliability post conversion. If we > do the conversion we would clean the old heatsink compound, > replace it, and re-torque the transistor mounting screws, and > change the appropriate cable lengths. The spliters and combiners are Wilkinson type. The critical-length cables (75 ohm, teflon) are inside those splitter/combiner modules. They should probably be scaled accordingly for the frequency differential. The RG-8 (or RG214 in some stations) cables that go between the PA's and the splitters/combiners are critical length only in that they must be equal, but otherwise they don't need to be scaled to frequency. The PA's will mostly run fine on 145 MHz, though efficiency may drop off. If these have the adjustable Z-matcher on the output (which they should), tune for *best efficiency*. Those 225 watt solid-state highband stations have a lot of added hardware for just 3 dB more output over a regular 110 watt station. Unless you really need the extra 3 dB, you'd probably be better off putting the "finals" and the extra power supply on the shelf and just running the station as a 110 watter. I have a bunch of the 200 watt UHF versions of those stations, and have mostly stopped using them because there is, at a minimum, 3X the number of points of failure. --- Jeff WN3A
[Repeater-Builder] Re: RFS PD220-N Question Regarding Mounting Clamps
Thanks Randy for that additional information. Eric, I stand corrected, the part number you gave me is correct. However, I simply need the top sway bracket not the complete side mount kit. I will call Wisco tomorrow to see if they would sell me just the top bracket. Does anyone have a top sway bracket that they can offer me? Thanks... --- In Repeater-Builder@yahoogroups.com, "Yahoo" wrote: > > DB5004S-MTD > > Jeff > > -Original Message- > From: Repeater-Builder@yahoogroups.com > [mailto:repeater-buil...@yahoogroups.com] On Behalf Of n2len > Sent: Saturday, April 25, 2009 5:16 PM > To: Repeater-Builder@yahoogroups.com > Subject: [Repeater-Builder] Re: RFS PD220-N Question Regarding Mounting > Clamps > > Hello Eric, > Sorry I wrote the incorrect model. It's the PD220-2. > > The side mount part number you gave me is not what I am looking for. What I > need is the top insulated support mount. I can't find it unless I am missing > it somewhere. Telewave sells a similar product which I guess I can > substitute it if I can find a RFS equivalent. > > Here is the link for the Telewave ANTM432 > > http://www.telewave.com/pdf/TWDS-7046.pdf > > > --- In Repeater-Builder@yahoogroups.com, "Eric Lemmon" wrote: > > > > Len, > > > > I'm not sure what a "PD220-N" antenna is, since the PD220 antennas > > listed in my Celwave catalog have a digit after the hyphen. Anyway, > > the side mount kit for a PD220 antenna is the PD503. It is adjustable > > to mount the antenna between 6" and 7' away from the tower. The PD556 > > is a shorter version that is limited to an offset of 3'. Both of > > these kits mount on tower legs up to 2.375" diameter. There are other > > kits for larger leg diameters, up to six inches. > > > > -Original Message- > > From: Repeater-Builder@yahoogroups.com > > [mailto:repeater-buil...@yahoogroups.com] On Behalf Of n2len > > Sent: Saturday, April 25, 2009 1:48 PM > > To: Repeater-Builder@yahoogroups.com > > Subject: [Repeater-Builder] RFS PD220-N Question Regarding Mounting > > Clamps > > > > > > > > Maybe someone can give me a specific part number to order. I just > > purchased a RFS PD220-N to be mounted on a Rohn 45 at the 170 foot > > level. (190 total to the top) I will be replacing this antenna with a > > Brand New Comtelco BSLL150-XL3 which has performed horribly. What a > > BIG MISTAKE! > > Here is my question: We currently have a lower base dual side arm > > bracket mount that slides in and out from the tower with a small > > vertical pole for the bottom brackets for the base of the antenna. > > What are the correct upper insulated side mounts to protect the antenna > from swaying in the wind? > > RFS PART NUMBER? > > How many are actually needed? > > Are they ordered by length or are they adjustable like the lower base arm? > > We can top mount the antenna, however I dont want the antenna to crack > > from the winter wind and severe ice in the NYS mountains. > > > > Also, There are 2 towers the same height at this site. Literally right > > next to each other. Should it make a dirrerence in polarization if the > > top of the antenna clears the top of the tower? > > > > Should we make the tip clear or not? > > > > Input needed > > > > Warm Regards, > > Len N2LEN > > > > > > > > > > > Yahoo! Groups Links >
[Repeater-Builder] KENWOOD TKR 720 REPEATER REPAIR- HELP
Last week I received a Kenwood TKR 720 VHF HAM band repeater for repair. It was traveling all over the country for the last five years to get a proper repair! On this travel it lost many spares, which includes the EEPROM chip (94LC 46)from the IC socket and the shielding covers. Comparing with another TKR 720, I could set right most of the Boards. The earlier experts who tried to remove the various modules from the double sided TX-RX card, taken away few SMD resistors also, may be unnoticed. Two of the 1K resistors were from the RX and TX line, which made the equipment deaf and dumb (=dead)! The front panel also have another 94LC 46 soldered, near the micro controller uPD75104G-604-1B. My present problem is to replace the micro controller which is not functioning,( I replaced it from the other set along with the 94LC46 to confirm the defect!) Can I procure the micro controller from any source and replace it simply by soldering? OR Need a pre-programmed one from the KENWOOD? Very remote chance for us. Can any of our supporters locate one for me on payment? Do we have to replace the nearby 94LC 46 also? How to program it? I have the KPT50 for the EEPROM programming of the TKR 720, but it can only be used for the frequency and other parameters set inside of the KPT 50. Commends are thankfully welcome PETER VU2PJP
Re: [Repeater-Builder] HENRY RF AMP C40D02 Manual
>From www.radiodan.com: C40D02, 2-40 watt Mobile, 10 MHz approx. bandwidth, FM only This is NOT a continuous-duty amplifier; it's meant for a mobile setup which would typically be 5/5/90%. It would need a "R" after the model number to indicate repeater (i.e. continuous) duty. Bob M. == --- On Sun, 4/26/09, Romy wrote: > From: Romy > Subject: [Repeater-Builder] HENRY RF AMP C40D02 Manual > To: Repeater-Builder@yahoogroups.com > Date: Sunday, April 26, 2009, 3:08 AM > Hi, > > This is a 40 Watt PA, I need to know if this is 40 Watt > 100% duty cycle. > Does anyone has a pdf manual for this PA. > > Thanks, Romy
[Repeater-Builder] HENRY RF AMP C40D02 Manual
Hi, This is a 40 Watt PA, I need to know if this is 40 Watt 100% duty cycle. Does anyone has a pdf manual for this PA. Thanks, Romy
