Hi Tim, Is usually a good idea to test the Duplexer while on a dummy load. I usually like to use my Marconi 2955 "Duplex" mode to tune the duplexer. Once I am happy with that then I go to the antenna see how that looks. I like to use the lowest value element I can find for my bird meter to tackle the reflected power. And I like to use an HT programmed in 1 mhz steps (11 channels, so I can compare 5 mhz up and down) That gives me a reference in what direction I need to focus tuning. If you are on 440, be sure to keep reference to the transmit freq first. Then give it a sanity check on the input freq. Be safe when you head to the hill and be sure you don't go alone. Never know what you can get into in those remote locations right. Good Luck Richard
________________________________ From: tahrens301 <[email protected]> To: [email protected] Sent: Tuesday, August 25, 2009 3:22:52 PM Subject: [Repeater-Builder] Re: DB-4050WB Duplexer Hi Richard, Thanks for the info. This is a new installation, and I do have some reflected power. That will be taken care of very soon. Fortunately, all the repeater components are still here at the house. Running the 'real' heliax to the DB-224 on a pole, so it's pretty close to what it'll be like on the hill. Thanks again, Tim W5FN --- In Repeater-Builder@ yahoogroups. com, Richard Fletcher <rickflet03@ ...> wrote: > > Hi Tim, > > The most common cause for "desense" is connections and not actually the > duplexer. Especially if there was no "desense" prior. First I would check the > link from the duplexer to the hard-line (If this fits into your site > configuration) put a meter right there where the hard-line comes into the > building. If you get any reflected power, then your desense problem is most > likely at the antenna or from the meter and up the cable. If you think there > is a power reduction there, well that jumper to the hard-line is bad. If that > looks good, then check all the connections on the station (before you start > turning the screws). Believe me, I have had to re-tune many a duplexer that > someone turned the screws on because of "desense" that was a cabling issue > and not the duplexer. > God luck on the adventure.. > > BR > -Richard > > > > > ____________ _________ _________ __ > From: tahrens301 <tahr...@... > > To: Repeater-Builder@ yahoogroups. com > Sent: Tuesday, August 25, 2009 12:43:30 PM > Subject: [Repeater-Builder] DB-4050WB Duplexer > > > Hi Folks, > > I was checking e-bay for duplexers last night, and came across a > DB-4050 that the user said was a pass/reject duplexer. > > It looks almost identical to one that has been giving me some desense > issues, but had a marking of SP-1894. > > The cabling looks a bit different, but functionally equivalent. > > Has anybody used one of these, and is it really a pass/reject, or just > a group of notch cavities? I've seen the specs on the data page here, > but it only gives the specs & doesn't call it anything specifically. > > I don't plan on bidding on it, as I have a 6 cavity BpBr Wacom coming > from a friend, but after all of the pain I've had with the DB prod > box, was just curious. > > Thanks! > > Tim W5FN >
