I hear ya.? This from the reissued EMRFD, page 7.10:
Care must be exercised when picking resistors for attenuator applications.? Many power resistors use wire wound construction, often hidden in ceramic, making them too inductive for RF use.? Carbon composition and the various types of film resistors are generally suitable for RF through UHF.
There's a table below that paragraph the summarizes resistors tested with an HP-8714 network analyzer.? The two resistors with the lowest inductance at RF was a 47¦¸ carbon composition (0.0095 ?H) and a 47¦¸ metal oxide (0.0099 ?H).? A Tru-Ohm 100¦¸ 'non-inductive' measured 0.24 ?H and a 50¦¸ wirewound was 6.4 ?H.
For what it's worth.
Andy
On Sun, Dec 17, 2017 at 08:50 pm, N8DAH wrote:
Hmm I was told by a few elmers around my club I should avoid metal anything wire/oxide/film when dealing with RF for it may become an inductor..... I have 6x 390's 1w coming I will see if 3x will fit, its R10 and may be a hard squeeze but we will see.
If the metal oxide is working for you w/o fail I may just pick up what I need. Thanks for the heads up and the offer.
?
?73
? David
