Adding to what Eric has said, ldf4-50 (and ldf5-50) can be had cheaply, cheaper than new lmr-400. Keep your eyes open and you'll find stuff. I went on a scavenging spree for my VHF weak-signal stuff; the best deal I got was 65 feet of LDF5-50 for $50. Next spring when I unrolled it, it was 130 feet, making for about .38 a foot. That was a great deal, with ldf5-50 more normally going for $1 - $2 a foot. LDF4-50 is cheaper yet, at about $1 a foot when you find a good price.
Connectors for ldf4-50 were about $8 from a couple of folks in the flea market at Dayton, so with a little digging you can find those, too. --STeve Andre' wb8wsf en82 On Wednesday 17 June 2009 21:34:42 Eric Lemmon wrote: > Aisen, > > Changing the RG-8 to LMR400 will reduce the feedline loss by about 0.8 dB, > which is a small improvement, but LMR400 is known to cause major problems > in duplex service. RG-8 will have about 2.2 dB loss in 50 feet, and LMR400 > will have about 1.4 dB loss, at 458 MHz. A far better choice would be > Andrew LDF4.5 Heliax with 0.5 dB loss, or LDF5 with 0.4 dB loss. Lose the > RG-58 jumpers, and replace them with good, double-shielded cable such as > RG-400 or RG-214. These jumpers should be fabricated with the proper > high-quality connectors on each end (no barrels or adapters), and should be > no longer than necessary. > > What is the make and model of your duplexer, and of your antenna? > > 73, Eric Lemmon WB6FLY > > > -----Original Message----- > From: Repeater-Builder@yahoogroups.com > [mailto:repeater-buil...@yahoogroups.com] On Behalf Of aisendwight > Sent: Wednesday, June 17, 2009 6:11 PM > To: Repeater-Builder@yahoogroups.com > Subject: [Repeater-Builder] Re: Need tips for repeater performance > > > > --- In Repeater-Builder@yahoogroups.com > <mailto:Repeater-Builder%40yahoogroups.com> , "NORM KNAPP" <nkn...@...> > > Well, I guess this is called "A rookie decision"!!!. > > Sorry, it's been like 18 years since I had any contact with radio stuff > (back in my days as WP4MPS) now I'm back at the commercial level and I see > I've had a bad start (yeez!!!!) Well., I'll have to find some use for that > cable. Ok, keep it coming please... > > wrote: > > BATTLE STATIONS!!!!!! RED ALERT!!!!!! > > We got LMR-400 here! > > > > ----- Original Message ----- > > From: Repeater-Builder@yahoogroups.com > > <mailto:Repeater-Builder%40yahoogroups.com> > <Repeater-Builder@yahoogroups.com > <mailto:Repeater-Builder%40yahoogroups.com> > > > > To: repeater-builder@yahoogroups.com > > <mailto:repeater-builder%40yahoogroups.com> > <repeater-builder@yahoogroups.com > <mailto:repeater-builder%40yahoogroups.com> > > > > Sent: Wed Jun 17 19:41:18 2009 > > Subject: [Repeater-Builder] Need tips for repeater performance > > > > > > > > Hello everybody: > > > > I'm into increasing the performance of my repeater. I've already ordered > > 50 Ft. of LMR-400 to replace the cheap RG-8. Yet, I wonder if there is > something else I could do. > > > The Duplexer is pre tuned to my freq. (458.0 repeater RX / 453.0 repeater > > TX). The duplexer is connected to the radios (my repeater is built out of > two Motorola M120's) using RG-58 jumpers of about 24 inches long. Could > that be affecting performance? When I check the TX power thru the duplexer > I'm getting about 10W yet the TX radio is programmed for 30W. I know that > I'll lose some power with the duplexer, but seems to me that I'm losing too > much. SWR won't go below 2.1 no matter how much I adjust the antenna bays. > > > So, what could be done? I imagine that swapping the RG-8 for the LMR-400 > > will help but I still wonder if that would be enough. Any help will be > greatly appreciated. > > > Aisen
