"After testing several times the more power that was put into the feedline the higher the SWR was higher"
usual reaction , you will reach a point where the vswr rises no more with aerial adjustments ( capacitive inductance in the cable I guess) "Anyone think that will help SWR any?" It may but that's not certain and not the right answer . ________________________________ > To: [email protected] > From: [email protected] > Date: Sun, 24 May 2009 15:36:58 +0000 > Subject: [Repeater-Builder] Re: New Transmitting Antenna SWR Question > > > > > > > > > > > > > > > > > > > > > > > > > > > > It came with some cutting charts to cut the 3 inside elements inside of a > plastic tube. I cut those and checked the SWR with 10 ft piece of RG-58 25 > watts input and it read 1.5-1. Assumed everything was okay. Cable was put on > a dummy load and cable tested great with no shortages and very low loss. 3-4 > watts from 40 watt input. After testing several times the more power that was > put into the feedline the higher the SWR was. The lower power I put in the > lower the SWR was. My tower that it is on is not grounded and the antenna > calls for DC ground for lightning protection so I might need to ground the > antenna. Anyone think that will help SWR any? > > > > --- In [email protected], Wayne Leake wrote: > >> > >> I can't say for certain, but have you checked the antenna prior to > >> putting it on the tower? > >> I have a high gain antenna ion a twoer, need to get the heliax > >> connected to it, but i tested in on a post before I put it on the > >> twoer > >> > >> Also, LMR400 is not recommended for full duplex use. that type of > >> cable can cause noise problems under full duplex conditions. > >> I sometimes test cables as well, connecting them to a good dummy > >> load, and test several ways. > >> I have an analyzer, actually 2 of the, one only for the 70 centimeter > >> band, and also check with a Bird 43 watt meter looking at reflected as > >> well as forward power. > >> > >> matter of fact, I have some coax assembled by Cable Expertys taht > >> turns out some has fare more loss than another, both 100 feet About 65 > >> watts from a GE Mastr II repeater on the 440 band shows about 4 watts > >> at the other end, and one less than 1 watt. Something not right there. > >> So it is possible the coax and/or connectors have a problem > >> By mounting my antenna low and using a known good jumper from my 440 > >> analyzer. I determined the SWR was very low on the antenna. And > >> testing cables will show you where the problem might be. > >> Also, where are you inserting the meter? That can make a difference > >> I tested my loss in my duplexer by testing watts before it and watts > >> out. Found good for the rated insertion loss. > >> And little reflected power on the transmitter side of the duplexer. > >> the word is, test, test and test. > >> test each part of the antenna system to locate where the problem really is... > >> > >> Wayne WA2YNE > >> > >> > >> On Sat, May 23, 2009 at 8:17 PM, agrimm0034 wrote: > >>> > >>> > >>> Currently just upgraded my home built GMRS Maxtrac repeater to a new 6.5db > >>> Gain Tran-Max antenna. Says SWR should be 1.5 - 1 or less and I have a > >>> reading of 2.5 - 1. I'm using LMR 400 ultra low loss cable at 40 ft putting > >>> in 40 watts of power. The antenna is mounted on 40 ft tower old 3 legged > >>> style. Nothing is around the antenna and check cable to make sure it wasn't > >>> shorted and everything seems to be fine. Any ideas on how to make the > >>> Standing Wave better? > >>> > >>> > >> > > > > > > > > > > > > > > > > > > > > > _________________________________________________________________ Looking for a fresh way to share your photos? Check out the new Windows Live Messenger http://windowslive.ninemsn.com.au/article.aspx?id=792335
