Hi guys and gals,
Well, to make a long story short my Rig Experts AA-170 has quite working. Looks normal but a 56 ohm resistor at the end of the 75 ohm coax reads infinite. On the MFJ-259b it reads 56 ohms. Check SWR and the MFJ reads 7.499.2 Mhz 1.1:1 SWR R=56/57 ohms X=0. Coax is 55' 4 3/8" long when I got very near 7500 KHz. With the shorted coax the MFJ-259b read 7.484.2 to 7.523 Mhz, 20.2 SWR, R=2 ohms, X=0. Seems like the velocity factor is considerably higher than what was stated to me by DX Eng.. The velocity factor is some where around 0.84401... as best I can figure it. So I guess that makes it 0.84 VF FWIW. Anyway, I have it figured that 55' 4 3/8" will do the trick for my 80 meter 4-Square at 3.750 Mhz. But why my RE analyzer went out today I don't have any idea. Back to the MFJ! Terry KI7M > On June 9, 2018 at 6:59 PM terry burge wrote: > > > Good point Wes. I will see if I can find a decent value of resistor. My > Rig Experts AA-170 was purchased because I did not trust the readings my > MFJ-259b was giving me while working on my hytower. Pretty penny for these > antenna analyzers. But I will bet if it won't do the stub frequency checks it > won't do the velocity factor and more. Did work pretty good for checking SWR > and feedpoint impedance on antennas like the hytower. Really liked it until > this. > > > Terry > > KI7M > > > > On June 9, 2018 at 5:11 PM Wes Stewart wrote: > > > > > > Since he said the coax was 75-ohm, a 75-ohm termination would be > > better. > > > > > > On 6/9/2018 5:07 PM, Richard (Rick) Karlquist wrote: > > > > As a sanity check, terminate the coax with a 50 ohm resistor > > and verify > > > > > > > that you have good coax. Flat line at 1:1 SWR, etc. > > > > > > Rick N6RK > > > > > > On 6/9/2018 4:57 PM, terry burge wrote: > > > > > > I don't know what is wrong here but I keep getting in > > > this situation where my > > > > > > > > > > typing starts running back over my writing. I > > > will try again to reply. > > > > > > > > > > > > Joel, > > > > > > > > I have tried all that the manual says without success. > > > > All I see is the > > > > horizontal solid and dashed lines of R and X. No > > > > indication of a resonance > > > > point anywhere from 1880 KHz up to 10,500 KHz. Go > > > > figure? At least my > > > > mfj-259b is working old as it may be. Rig Experts is > > > > going to get a nasty > > > > note I think. Disappointing, huh? > > > > > > > > > > > > Terry > > > > > > > > KI7M > > > > > > > > On June 9, 2018 at 2:54 PM Joel Harrison wrote: > > > > > > > > > > > > > Hi Terry, > > > > > > > > > > I replaced the 1/4 lines on my 80 meter 4 square > > > > > this past fall and used > > > > > my AA-170 to set the length with no problem. > > > > > > > > > > Just select "all" for the mode and set the freq > > > > > you're aiming for and then > > > > > trim the line until X equals zero with the far > > > > > end open. Should work fine. > > > > > I always calculate the length x VF then add a few > > > > > feet to start. > > > > > > > > > > 73 Joel W5ZN > > Hi guys and gals, > > > > > > > > > > > > > > > > > > > > > > I have got DX Engineering 75 ohm foam > > > > > coax to make the > > > > > > > > > > > > > > > > stubs/feeders for > > > > > > my Comtek 80 meter 4-Square and am finding > > > > > > some difficulty. > > > > > > Neither my > > > > > > MFJ-259B nor my Rig Experts AA-170 seem to > > > > > > indicate a 1/2 WL at > > > > > > 7500 KHz > > > > > > or a 1/4 WL at 3750 KHz? Or any frequency > > > > > > up or down from there. > > > > > > Seems to > > > > > > me the last time I did this a few years ago > > > > > > I didn't have a problem > > > > > > getting a 1/2 WL dip indicating a resonance > > > > > > location. But now I > > > > > > just don't > > > > > > get any indication of a resonance. > > > > > > > > > > > > > > > > > > DX Engineering said they had got some 75 > > > > > > ohm foam coax that > > > > > > instead of > > > > > > 0.84 VF was more like 0.80 down to 0.76 VF. > > > > > > But checking all the > > > > > > way down > > > > > > to 6000 KHz on 40 meters or 2500 KHz on 80 > > > > > > meters fails. > > > > > > > > > > > > > > > > > > My test is to use either antenna analyzer > > > > > > with a PL-259 installed > > > > > > at one > > > > > > end and an open or a short at the other. I > > > > > > started with 57'7" of > > > > > > coax. > > > > > > Tried both with the coax in a roll and > > > > > > strung out. What am I doing > > > > > > wrong? > > > > > > > > > > > > > > > > > > Terry > > > > > > > > > > > > KI7M > > > > > > > > > > > > 😞 > > > > > > _________________ > > > > > > Topband Reflector Archives - > > > > > > http://www.contesting.com/_topband > > > > > > > > > > > > > > > > > > > > > > > _________________ > > > > > > > > > > > > > > > > > Topband Reflector Archives - > > > > > > http://www.contesting.com/_topband > > > > > > > > _________________ > > > > > > > > > > > > > > Topband Reflector Archives - > > > > > http://www.contesting.com/_topband > > > > > > _________________ > > > > > > > > > > > Topband Reflector Archives - > > > > http://www.contesting.com/_topband > > > > > > > > > > > > _________________ > > Topband Reflector Archives - http://www.contesting.com/_topband > > > > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > _________________ Topband Reflector Archives - http://www.contesting.com/_topband