mobile duplexers generally have poor performance, not enough for a decent repeater. The model you suggested is one of the worst.
------ Original Message ------ Received: Sun, 03 Jan 2010 10:04:33 PM PST From: "Michael H. Cox" <michaelh...@gmail.com> To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Mastr II mods and parts > Any reasons? > Thanks, > > Michael H. Cox > michaelh...@gmail.com > > -----Original Message----- > From: "JOHN MACKEY" <jmac...@usa.net> > Date: Sun, 03 Jan 2010 21:55:33 > To: <Repeater-Builder@yahoogroups.com> > Subject: Re: [Repeater-Builder] Mastr II mods and parts > > I would not recommend that duplexer for a repeater. > > ------ Original Message ------ > Received: Sun, 03 Jan 2010 08:47:16 PM PST > From: Michael Cox <michaelh...@gmail.com> > To: Repeater-Builder@yahoogroups.com > Subject: Re: [Repeater-Builder] Mastr II mods and parts > > > Will this Duplexer work with the Mastr II repeater? > > > > > http://cgi.ebay.com/UHF-50W-6-CAVITY-DUPLEXER-FOR-REPEATER-FREE-TUNING_W0QQitemZ350300447727QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item518f88a3ef > > > > > > > > > > > > On Sun, Jan 3, 2010 at 9:32 AM, WA3GIN <wa3...@comcast.net> wrote: > > > > > > > > > > > For fun we operated a 400 watt erp repeater with two antennas and no > > > duplexer. We were able to achieve about 100db attenuation by using the > roof > > > equipment penthouse. The transmit antenna was mounted on the top of the > > > penthouse and the receive antenna was installed diagonally from the > transmit > > > antenna on the roof below the penthouse. Each antenna was physically > > > separated by the penthouse structure. Transmit performance was good and > > > receiver performance was good about 270 degrees minus the abstructed > zone. > > > No feedback or other issues. Eventually, we installed TXRX 6 can duplexer > > > and utilized the penthouse antenna. Receive coverage regained 360 degree > > > coverage. So, it is doable if you have the right antenna site. > > > > > > Best, > > > dave > > > wa3gin > > > > > > > > > ----- Original Message ----- > > > *From:* Kevin Custer <kug...@kuggie.com> > > > *To:* Repeater-Builder@yahoogroups.com > > > *Sent:* Sunday, January 03, 2010 11:12 AM > > > *Subject:* Re: [Repeater-Builder] Mastr II mods and parts > > > > > > > > > > > > Michael Cox wrote: > > > > > > Thank you for your help. I appreciate it! I've put a couple of > questions > > > inline below. > > > > > > Well - you'll need a duplexer no mater the price... <grin> > > >> > > > > > > I was under the impression that if I had two antennas, I could get by > > > without a duplexer. Thanks for the heads up. > > > > > > > > > While two antennas will work, and you'd initially think there is a cost > > > savings using two antennas, that isn't always the case. > > > > > > The determining factor usually ends up being the length and size of > > > feed-line necessary to get from the repeater to the antenna. On UHF, > unless > > > the feed-line length is really short, you'll want to use some type of > > > hard-line cable. The cost of this cable, depending on type and length, > can > > > be costly. It may be less costly to use one antenna and a duplexer then > to > > > install two antennas and have two runs of feed-line. In addition, you'll > > > usually end up with a better balanced system using one antenna because > using > > > two can cause a disparity if both antennas don't have the exact same > pattern > > > - which could be difficult to achieve depending on the tower space > > > available. In installations where you have to pay rent on tower space - > > > it's usually by far cheaper to purchase a duplexer. > > > > > > RE: Power Amplifier > > > > > > Are these what I'm looking for? > > > > > > > > > Generically - Yes. > > > > > > It looks like there is a UHF and a VHF version of the PA. Is that > > > correct? > > > > > > > > > Yes. > > > > > > Are they not compatible with each other? > > > > > > > > > No. > > > > > > VHF and UHF are two totally different bands. You cannot use a UHF PA on > a > > > VHF repeater and vice-versa. The third one you listed is a Mobile PA - > not > > > something you'll want. > > > > > > You want a UHF Station PA like the second one you listed - but it isn't > the > > > exact one either. The one you want requires 200 mW of drive - not 20 > watts > > > - but, the correct one looks very similar to the one in your number two > > > listing. > > > > > > I don't presently see a good candidate on eBay - but they show up all the > > > time. > > > > > > Duplexer - used WACOM Products WP-678 (or similar), also available > from > > >> eBay. > > >> > > > > > > I couldn't find any on eBay. Any guesses what I'd be paying for > something > > > like this? > > > > > > > > > $250 plus shipping. > > > > > > > > > > > > > > >> Controller - I recommend a NHRC model that plugs into the "Systems" > > >> board, or, one of the Pion & Simon models that plug into the card cage. > > >> > > >> http://www.nhrc.net/ge-stuff.php > > >> http://www.pionsimon.com/products.htm > > >> > > > > > > > > > It looks like I can use the NHRC-4/M2 to make it a linked repeater. If I > > > go with the Ham repeater, I'll most likely do that. That would require, > if > > > I understand correctly, another radio connected in, so that will have to > be > > > done later with future funds. :) > > > > > > > > > Correct. > > > > > > > > > If I decide to make it a GMRS repeater, I won't have to worry about that > > > and will go with the PSE508-2, as its a little less expensive. > > > > > > > > > Also a good choice. > > > > > > Kevin > > > > > > > > > > > > > > > > > > > > -- > > ----------------------------------------------- > > Michael H. Cox > > michaelh...@gmail.com > > > > > >
