[Repeater-Builder] Re: Lookling to build a 220MHz repeater
Hi Duane, I am in the process of building a 220 repeater as well, pretty much from spare parts and whatever I can find. I found an exciter that once was part of a Clegg FM-76, and some sort of VHF Engineering receiver kit that was put together decades ago. The exciter runs around 500 mW and I have a Ramsey PA-20 power amp that should do 25 watts with that drive. I have heard of people taking Clegg FM-76's apart and using the receiver/transmitter and PA boards to make their repeaters with good success. I have several FM-76's and the Midland version of this radio but wouldn't dare take them apart just because I like the radios like they are. I have read the posts some people have made concerning old VHF Engineering boards other cheap kits and how they are junk, but I'll bet it largely depends on who puts them together. My OM has a VHF Engineering 220 repeater that has been runnig for 25 years with almost no down time. Hamtronics makes neat little boards for TX and RX, visit their page and see what they have to offer. Some people use Kendecomm (spelling?) which I am not familiar with, and also Spectrum made a 220 MHz repeater. I have heard of people making great success with modifying the Mastr II's but never tried (looks time consuming) I am in the process of making/modifying my own 220 duplexer. Where did you get yours and how much did you pay? What kind of antenna were you going to use? Contact me off list if you like 73, KC4FWC Hello everyone, I recently purchased 4-cavity duplexer for a 220MHZ repeater. I'm thinking about using a GE Mastr II mabile radio for the Rx/Tx part. I'm very green at this and figuring this out on my own. Do I need 2 Mastr II radios, or will one work? I will modify it for 220 service once I know how many I need to get. Also, is the NHRC-3/M2+ a good comtroller for $189? Or is there a better one. This will be a low power repeater . Looking to run 30-50 watts. Thanks for the help, Duane KD5NFQ 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: Need a duplexer
The T-1504 works very well if clean. The notches are difficult to tune perfectly if the inside of the cavity has been exposed to moisture. I have opened up cavities and cleaned with steel wool and coated with light grease and they tune much better. I am not sure if anyone else has had this problem, but with these duplexers I have had a hard time with tuning a pair of cavities with the stock phasing lines. I seem to be getting double peaks and the peaks just won't pull together down around 443 MHz. I went and made new phasing lines out of the same type cable, but just 1/2 inch longer on all lengths. Now the peaks pull together, therefore resulting in sharper pass band and less loss. Maybe it was just mine. 73, KC4FWC --- In Repeater-Builder@yahoogroups.com, Kevin Berlen, K9HX [EMAIL PROTECTED] wrote: A Motorola T-1504 series is an excellent choice. Should be available used for $125-$150. 73, Kevin, K9HX At 12:10 PM 4/12/2005, you wrote: Do you have any recommendations on 70cm duplexers capable of 100W? Thanks 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] Help: Converting 150 MC cavities to 222 MC??
Hello group, I have been working on building a duplexer for 222 MHz from old 150 MHz cavities. I have three Decibel products cans, which look the size of regular 150 MHz cans, but have been told they are actually an old 450 MHz all pass-band duplexer. I don't know the model number but they are beige in color and look really old. They will tune very good throughout the 440-470 band, but also work good on 144-174, too. The plunge rod is nearly identical to the old Wacom 2M ham duplexers. Since it is just a pass band cavity, there are two coupling loops, one input, and one output. Using the same loops, I cut one of the rods down nearly 4 inches, then spliced with a 1 inch copper coupling and soldered together. Now the can tunes a good pass band at 222-225 MHz also. I really wanted to create a hybrid ring 3 cavity duplexer for a new 220 repeater, two cavities on RX and one for TX, band-pass, band- reject, like the Wacom deals with the rod on the side which has a plexiglass looking dielectric that slides in and out in order to determine the position of the notch. I took my existing 220 duplexer (Wacom) loops out and the reject stub also, and tried to duplicate it as closely as possible. So far the results look promising. I am using 3/8 hard drawn copper for the sleeve, and a piece of #10 wire for the inner conductor, and some vinyl tubing to slide in and out to vary the capacitance. I couldn't find any better means of making a capacitor than this, and my first question is, will this be stable in an uncontrolled environment? 90 deg in summer and 40 in winter. Second, I measured the capacitance of the Wacom stubs and get somewhere around 7 pF. I have a bunch of piston type caps that will give this value, plus or minus, but don't know exactly how to incorporate this into the hybrid ring design. I am tired of randomly trying pieces of copper straps for different lengths of coupling loops and wonder if anyone has a proper way to determine coupling loop lengths? Third, the repeater will not be operating in a high RF environment. Would it be more practical to use each can as a notch only (reject) cavity? If so, how in the world do you make coupling loops to work for band reject only? I have tried taking one loop, running it down the cavity for several inches, then directly back up and to ground again. Then taking a tee connector and going across it, but with the tracking generator, my notch is only like 6 dB deep which obviously won't work. Any suggestions or links you can think of to help me build a 220 duplexer out of the parts I have mentioned above? I have a decent shop and can do light precision machine work. Thanks. 73, KC4FWC http://www.w4dex.com/kc4fwc/224480.htm 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: Homebrew a 2M/440 crossband coupler?
Thanks for all replies. I have several of the Comet diplexers with PL-259's, one Pro-Am model, one Larsen, and one made by Daiwa. One person commented on the duplex noise and I tend to get alot of this from all of these except the Larsen, which burnt up several years back with 60 watts of UHF running through it. A 3.3 pico capacitor smoked, and I replaced it with two 5.6's in series and all worked OK, but I had to run the power down a little in order to keep things from smoking again. If you look closely the paperwork on the comets and diamonds say 200 watts but in the fine print, it says 200 watts SSB. I am planning to run one line of 7/8 up a 350 foot tower, but want 2M and 440 repeaters, with two separate antennas. I don't want to use a dual band antenna because the fiberglass comet and diamonds seem to disappear when hit by lightning.. I'd rather use 2 separate antennas and one feedline, and split it once up top and once on bottom. I plan to put the diplexer in a box atop the tower. One person mentioned replacing the pigtails on the unit to make the duplex noise disappear. I replaced the ones on my Daiwa unit with some small hardline used on microwave equipment that is RG-58 sized. The duplex noise went away. Thanks for the suggestions. 73, KC4FWC 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] Homebrew a 2M/440 crossband coupler?
Hello Group, Does anyone have, or know where I can get plans to homebrew a 144/440 MHz crossband coupler (aka diplexer) ?? I would like to find something with wideband characteristics (ie, low pass, high pass) such as some of the diamond or comet models, but needs to be able to handle 100 watts FM continuously from each band, without excessive loss and without duplex noise, or little capacitors smoking. Any suggestions, other than the Telewave models that cost over $300? Thanks, KC4FWC 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] Duplex noise/LMR-400 w/sticky stuff?
Hello Group, I have read the messages and heard the debates about using LMR-400 or 99/13 type cables with aluminum foil mixed with tinned copper braid, and the duplex noise it presents when used on the output of the duplexer to the antenna. I have tried to stay away from this since I got serious about higher powered ( 110 watt) transmitters used for duplex service. I recently ran across a pile of LMR-400 DB I believe it's called, it has a sticky substance throughout and is said to be water tight. I used a 90 foot piece of this cable on a VHF repeater running ~ 80 watts out of the duplexer and feeding a very reliable, duplex noise free antenna on the tower. I couldn't believe the duplex noise I get from somewhere, and I am thinking it's the cable itself. When injecting a signal through a directional coupler, I am receiving ~ 0.25 uV for 20 dB SINAD while running full power. But each time I even think about touching the feedline, a ton of noise occurs (better than 30 dB of duplex noise). I have tried both crimp on and compression N-type connectors but no difference. The duplexer is a new Wacom with 214 interconnect cables. Can this LMR-400 really be the cause of noise this bad? There are two pagers (152.480 and 158.700) about 1/2 mile from the site. No other transmitters besides a few UHF repeaters. Everything at the site has an isolator on the transmitter output, including my 2M repeater. Something is arc'ing somewhere. Any suggestions besides changing the entire feedline to something more reliable, such as 1/2 inch Heliax or hardline without braid? Thanks, KC4FWC Derek. 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] FS: Snap Disc 110 deg Stats
I ordered 8 Snap-Disc type thermostats which close at 110 degrees (F) and open at 90 deg (F). They are made by White Rodgers and the model number is 3F01-110. They are too big for the space I have, so I'd like to move them to someone who can use them. All 8 for $40 and I'll even pay shipping. They are an excellent temp range for activating fans on power amps for repeater service. They have ears with 2 holes for mounting. 73, KC4FWC E-mail direct if interested at [EMAIL PROTECTED] 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: GE Mastr II/IDA Controller - Selective COR?
--- In Repeater-Builder@yahoogroups.com, John J. Riddell [EMAIL PROTECTED] wrote: Regarding the time out problem in the GE Mastr II, check the repeater control board, 19D417385 G2 and add a .01 capacitor from pin 5 of U-1 and U-2 (555 timers) to ground. * I'm not sure if I have the same kind of control board as you are talking about. Mine says 19B234871 P1 Is this board layout the same? Thanks, Derek 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] GE Mastr II/IDA Controller - Selective COR?
I am using a full blown GE Mastr II repeater station with an IDA control board (I suppose this is a factory installation). It has a speaker on the front, with a volume control and a few selector switches, and jumpers on the board which select time out, hang time, etc. I have a CW identifier interfaced as well. I am not using any additional controller with this station and am having a strange problem. Quite often, the repeater seems to drop users. It's not a time-out timer problem. Users will be talking. One will un-key, and the next one will pick it up, but the repeater will NOT repeat! When he finally unkeys, the next user will pick it up and it will work just fine. It's not one user in particular. There is no time frame associated with it. It's like the unit has selective COS. It drops whoever it wants to. Is there anything that you can think of that would make this happen? I have changed hang times all over the place, even took the time out timer to 10 minute mode. In the manual there is a master timer but I don't think this is a timing issue. If I can't get this straightened out, I'll probably wind up having to put an external controller on the thing. Any suggestions? Thanks KC4FWC 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: GE Mastr II/IDA Controller - Selective COR?
Thanks much for the info. Just the type of answer I was searching for. I'll try that this weekend. Thanks again, KC4FWC Regarding the time out problem in the GE Mastr II, check the repeater control board, 19D417385 G2 and add a .01 capacitor from pin 5 of U-1 and U-2 (555 timers) to ground. These were ommitted by GE for some reason, and if missing can make these timers unstable. Quoting the Sams 555 timer applications sourcebook, Page 18: If the control pin (Pin 5) is not used, it is recommended that it be bypassed to ground with a .01 mfd capacitor to prevent any noise from altering the calculated pulse width 73 John VE3AMZ Waterloo, Ontario. 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/
