Re: [Repeater-Builder] Re: Homebrew a 2M/440 crossband coupler?
I've got a Comet diplexer that has been combining a 2 meter repeater & a UHF repeater for about 3 years. The antenna was a Comet GP-15 (2m/6m/440) fed with about 70 feet of 7/8 inch heliax. While antenna sharing & using a Comet for the repeater antenna was certainly not my preference, my UHF repeater showed very little if any difference from the former 8 bay open dipole it had been using in the exact same spot. My coverage & hearing weak signals seemed to stay about the same. The UHF duplexer is a Phelps-Dodge 6 cavity pass/reject going in to a Micor receiver with an ARR pre-amp and an extra Motorola pass cavity. The transmitter is 30 watts. I can't answer for any changes on the 2 meter side as it is not my repeater & was a new addition to the location. (a LNG complicated story in ham radio politics brought me to the situation of sharing my location) The 2 meter duplexer is a Tx-Rx 4 cavity reject only. The transmitter is 30 watts. The changes I did make: On the Comet diplexer, I removed the UHF connectors & replaced them with N connectors. I re-inforced the connections to the center pins & made sure the grounds of the connectors were very well grounded to the shell of the diplexer. I also insisted that the other repeater use Rg-214 for their jumpers & I gave them about a 20 foot piece to make their jumpers with. Our repeaters are about 10 feet apart from each other. My system already used Rg-214 for all jumpers except for one very short Rg-223 jumper in a tight spot. The only troubles I did have was audio from the 10 watt college FM radio station coming in on audio input for my internet connection to the repeater. A few ferrite beads immediately stopped it. (their antenna is about 20 feet above mine) -- Original Message -- Received: Wed, 02 Feb 2005 07:36:41 AM CST From: "derek_mcintyre" <[EMAIL PROTECTED]> Subject: [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/
Re: [Repeater-Builder] Re: Homebrew a 2M/440 crossband coupler?
At 2/2/2005 06:12 AM, you wrote: >Good morning All, >There is a small company called Austin >that makes a very nice Diplexer even >comes standard with type "N"'S in a nice >copper box. They even make it for tri-band We bought one several years ago specifically for diplexing a VHF & UHF system onto one antenna. However the box was not well assembled IMO & the loss on the 440 side was high (0.75 dB, their spec. was 0.5 dB). I was able to get the loss to just above 0.5 dB by drilling out the rivets, opening the case & adjusting something on the circuit board (can't remember just what). This was all done on a VNA so band isolation was not compromised. Even after the tuning the loss would go up if the connectors were flexed due to the flimsy case, so we ended up using a Comet duplexer instead. Much lower loss. I also have an Austin triplexer that is much older. The construction of that unit is rock solid: well shielded & connectors don't flex at all. Bob NO6B 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: Homebrew a 2M/440 crossband coupler?
Good morning All, There is a small company called Austin that makes a very nice Diplexer even comes standard with type "N"'S in a nice copper box. They even make it for tri-band use. I be live HRO sells Austin. We have used them for some of the Hams on our tower to combine 3 repeater on to one hard-line type coax and the split it back off to three antennas up the tower. We have had a few working for many years with no problems. Very Best, Dean Westbrook, EE,PE. Cook Towers, INC. 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 the Yahoo! Terms of Service.
[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/
