--- In Repeater-Builder@yahoogroups.com, "skipp025" <[EMAIL PROTECTED]> wrote: > > "vintageaudio2004" <[EMAIL PROTECTED]> wrote: > > as a first step we will be ordering the Telewave > > TPCP-1546C preselector, it has 6 cavities and has a pretty > > good looking skirt (-80db @ 4MHz down). > > The above is a bpbr duplexer, not a pre-selector. You > can easily special order it as a pre-selector, but you'd > better understand what you need to have in the receive > side pre-selection. You need both a window filter with > tight skirts and a quality notch function. Getting it to > play in one package is possible, but tricky to do it right.
No, the TPCP-1546C is a preselector, take a look: http://www.telewave.com/pdf/TWDS-2006.pdf I think you are confused with the TPRD-1546C which is indeed a duplexer. > > Additionally wanted to order a Lo-Pass filter to put at > > the output of the Tx combiner, as a "just in case". > > How 'bout a Telewave TLF-150 ? > > Sure, but it's "a pop-corn fart" and won't do much for > you. I'd actually be more worried about it in series with > all the tx power. It becomes a weak link in the TX side > when you have reflected power problems. OK got it. It's out. > > > ("these are not the Droids you're looking for... move along") > > Aaaah, Star Wars fan. Me too, but not so much of the later episodes. Nothing like the first one (was it "Episode IV" ?). > > A casual fan... not much more. But the line is pretty funny. Yeah, me too, but since you remembered that line, I tought you might probably be a bit more of a fan than you think you are. > Go with Telewave... just order what's going to work right. I > like and use tons of Telewave goodies. > > > But remember your final tx and rx antenna systems should include > > > some notch cavities. Telewave makes good notch cavities and > > > they should be able to offer coax T options, which lean the > > > series cavity response over. I must have been reading your mind. Yesterday I was going again over the specs of the TPCP-1546C, and came across that "C" which stands for [Compact]. So I though that since we really don't have much of in a way of size constrains, why possibly put compact size ahead of better performance, and found the TCPC-1556 which is a full size cavity Preselector. So basically we still would rather go one step at a time, not that I want to dismiss your great advise, or don't fully appreciate and now also understand your suggestions, but since this way we are going to be able to apply each solution at a time, that would enable us to re-evaluate the system, determine how far it improved, and then decide if we need additional filtering, by also taking into account our customers real needs. Not that I would not love to buy all the stuff at once and get it over with, and I would also be very happy if this system could be honed to absolute perfection. BTW since you mentioned portable performance of the system, these are only going to be used close to the site, maybe 1-3 miles away tops, and most other operations will use mobile 25W units (GM660's) with 3/4 wave antennas. The system requirements originally submitted by the customer only called for a 12-15 mile radius, and that with mobile units. Thick vegetation with lots of humidity, and some low hills and terrain depressions where at that time our main consideration. On the other hand for the same price we got them much more range (no way where we going to use any other repeater besides a 100W MTR2000). The added range made them very happy, as sometimes they must travel outside of the working areas and any additional communications range is very valuable in such remote areas in case of emergencies, or whatever else calls they might need to place. Another important consideration is that we also need to put our feet on the ground in respect to the price tags of the added filtering, so going in steps seems also to be the right decision in that angle. Don't really want to add it up unless it would be strictly required, as any additional expenses, unforeseen as they may have been, will in this case have to come out of our own pockets. As of now I just placed an order for the TCPC-1556, and asked them to close the window to narrowly just let pass our Rx range, and put maximum rejection on the Tx range. Also to make the skirts as steep as it be practically possible, even if insertion losses grow to 3-4dB, or maybe even a bit more. Coping with them on the Rx side should be relatively painless, easy to compensate, and as you pointed out earlier, well worth. I'll keep you posted of any new developments. Have a great day, and thanks again for your excellent advise. Saludos, Alex 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/
