VTVM Necessary? - Printable Version
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+--- Thread: VTVM Necessary? (/showthread.php?tid=5756)
VTVM Necessary? - Elijah - 01-12-2013
I have several Philcos and Zenith radios that are in need of alignment. No problem with the AM but some have FM and I'm wondering if I need a VTVM for that purpose as most instructions say to use either that or an oscilloscope. All I have is a signal generator, an analogue DVM and a Fluke DMM.
RE: VTVM Necessary? - dixierat - 01-13-2013
A VTVM or FET voltmeter is highly desirable for alignment.You adjust a trimmer or inductance to get a peak response. This is easier with a VTVM or FET meter because the meter response is quickly observed after an adjustment and you observe when the needle reverses indicating the peak has been passed.With a DMM there is a longer settling time after adjustment and you have to remember the last reading to detect passing the peak rather than watching direction change of the needle. I have no experience with an analog DVM.
RE: VTVM Necessary? - Elijah - 01-13-2013
After looking at several I found one by EICO, a model 249, that I bought. I remember using a Simpson and Triplett many moons ago but never a VTVM. Another piece of equipment added to my repertoires.
RE: VTVM Necessary? - dixierat - 01-13-2013
Eico made good instruments. I use 950 bridge and a 147 sig tracer. Good choice.
RE: VTVM Necessary? - Elijah - 01-13-2013
I recently picked up an HP 8656B Signal generator and an Elenco 9500. I should be good to go.
RE: VTVM Necessary? - codefox1 - 01-13-2013
VTVM nice to have. Digital meters can drive you nuts when trying to peak alignments. Old Funcional Heathkit or Eico fine for this. Just wanting to get peaks, absolute accuracy not relevant if you catch my drift.
RE: VTVM Necessary? - gvel - 01-13-2013
"Digital meters can drive you nuts when trying to peak alignments."
Not "can" but WILL drive you nuts, when trying to peak alignments!
