John, I don't mind letting everyone in on a good deal. Len Pringle is a Ham, and he's Telewave's Sales Manager. Contact Len at <[EMAIL PROTECTED]> Don't waste your time with the non-Hams!
Telewave billed me $1,238.25 plus tax and shipping. That's with the 25% Amateur Radio discount. Although the TPRD-1456 is not listed in the catalog, it definitely is a "stock" item, since all duplexers are normally assembled to order and tuned up for specific frequency pairs. The TPRD-1456 is identical to the TPRD-1556 in price and construction, and differs only in the loops and the cable lengths. I buy duplexers, isolators, impedance matchers, and loads from Decibel Products, RFS/Celwave, EMR Corporation, Telewave, TX-RX, and Sinclair, both for myself and my employer. I have no financial connection to any of these companies, and I choose between them based on price, performance, availability, and/or the unique characteristics of the component(s) I need. 73, Eric Lemmon WB6FLY johnmichaelwelton wrote: > > Eric, thanks for the valuable info. I initially budgeted for the 1556 > duplexer and noticed this afternoon that it only goes down to 148 > Mhz. So I called Telewave and they didn't have a listing on the 1456 > that's why I asked abt the 4 cavity duplexer. the sales guy started > giving me some story about a custom build getting up to the $3-4K > range that didn't make sense to me. I'll call back and see what's up, > he did sound rather young and inexperienced on the phone. Do you mind > saying what you paid for the TPRD1456 (or email privately if you > like). > > John/N4SJW > > --- In [email protected], Eric Lemmon <[EMAIL PROTECTED]> > wrote: > > John, > > > > I used CommShop to come up with the minimum required duplexer > isolation > > for a 2m transmitter putting out 50 watts, and a receiver of 0.35 uV > > sensitivity 600 kHz away. The answer was 87.2 dB. > > > > Bear in mind that computer programs like CommShop that calculate > > duplexer isolation have to make many assumptions, including the > response > > characteristics of a typical receiver and the spurious harmonics of > a > > typical transmitter. For example, a MICOR Sensitron receiver is far > > superior to the majority of synthesized mobile radio receivers, and > a > > tube-based GE MASTR PA is much quieter than the majority of solid- > state > > PAs. Nevertheless, I don't think the TPRD1454 duplexer is a good > > choice. > > > > For a few hundred bucks more, Telewave will sell you the TPRD1456 > > duplexer, which has six cavities and better than 95 dB of > isolation. I > > just bought a TPRD1456 duplexer directly from Telewave for a new 2m > > repeater I'm putting up, and I measured it with my network analyzer > > right after it arrived. The insertion loss was -2.1 to -2.3 dB, > and the > > isolation was -104 to -108 dB. These are very good numbers, and > will > > ensure that my 100 watt MICOR repeater will have zero desense. > > > > Most duplexer manufacturers will agree that a duplexer with six 5" > > cavities will almost always out-perform a duplexer with four 8" > > cavities. However, when you have a Decibel Products or RFS/Celwave > > duplexer with four 8" copper cavities that are silver-plated, you're > > talking high performance and big bucks! The Telewave cavities are > > similar in quality and performance to the now-defunct WACOM > products. > > > > Bottom Line: Go for a minimum of 90 dB of isolation. > > > > 73, Eric Lemmon WB6FLY > > > > johnmichaelwelton wrote: > > > > > > Need to get several 2M duplexers for a hospital project. The > Telewave > > > TPRD1454 (4 cavity, 5 in) provide 77dB isolation (~$750). I'll be > > > using 40-50 watt Mitrek's into DB220 or DB224 antennas. Is the > 77dB > > > going to be a headache = should I spend an extra 1.5 to 2K per > > > duplexer for better isolation or will Telewaves work reasonably > well? > > > I need 4 so price does matter. > > > > > > thanks, > > > > > > John/N4SJW > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > 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/
