RF VTVM

Discussion in '"Boat Anchor" & Classic Equipment' started by KI9R, Jul 11, 2011.

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  1. WA7PRC

    WA7PRC Ham Member QRZ Page

    It's worth pointing out that in high RF fields, fancy digital and even FET meters are often useless. The simple VOM to the rescue. The Simpson 260 and its cousins are still the kings in that area.
     
  2. W0LPQ

    W0LPQ Ham Member QRZ Page

    Yes Bryan ... they certainly are .. the 260 is the best analog meter I have found ... there was a book, FET Circuits, I think by Forrest Mims that had a FET VOM adapter, using a P-Channel FET ... I think a 2608. I used that in conjunction with the 260 for low voltage stuff ... but like you said ... RF causes problems. And to think ... some people think they are antiquated and not worth using.... nah...!
     
  3. WA7PRC

    WA7PRC Ham Member QRZ Page

    There was a time when I worked in broadcast engineering (KEZX-FM) and around these parts, there are hills/mountains that are favorite transmitter sites. Cougar Mountain, where our xmtr was located, was one of the more crowded peaks. It's said there's more than a megawatt of RF in the air up there. We also used the 260 on "RF Hill".
     
  4. KE0ZU

    KE0ZU Ham Member QRZ Page

    WARNING !!

    Bashing old test equipment carte blanc is not a good idea. There are select pieces of gear first introduced in the 40s that still are a very capable solution today, 70 years later.

    Although not all that unique, the HP 410B and C are good general purpose VTVMs with a very good RF Probe.
    [​IMG]

    Another good RF meter is the HP3406 which is good to about 1.2 Gigs.
    [​IMG]
    Boonton also made a number of RF volt meters and many show up on ebay. Regardless which you purchase,BE SURE IT COMES WITH THE ORIGINAL PROBE, otherwise its useless.
     
    Last edited: Jul 25, 2011
  5. KA1MDA

    KA1MDA Ham Member QRZ Page

    The FLUKE meter I use at work has a special mode to eliminate these problems. It changes the input impedance of the meter from 10 Mohms to 3 Kohms so as not to confuse the recent vo-tech grads
     
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