Re: Hand Capacitance With the SRF Series of Sony Radios


Well stated, Jay and something we all should take note of.

At 62, I fortunately or not remember many older receivers and other hardware -- including some test equipment -- that many times had metal chassis, with metal knobs connected through metal shafts to metal parts connected to those metal chassis...:)...

Perhaps one of many reasons that metal gave way to plastics, also with the use of nylon shafts on both critical and non critical surfaces.

Thank you again for the information.


--- In ultralightdx@..., "Jay" <jaypolicow@...> wrote:


All true. Here are two few more tidbits about hand capacitance effects. I generally find it most noticeable on smaller radios...I think that larger radios provide a stronger ground reference (their chassis) that tends to minimize the effect...most very small radios seem show it much more although they do vary.

There are a few notable exceptions though due to design is the Zenith Trans-Oceanic R-7000 (not the Royal 7000). Every R-7000 I've seen shows hand capacitance effects but only at or above about 15 MHz where the station detunes the moment you let go of the tuning knob.


--- In ultralightdx@..., "JRTENN" <joerotello@> wrote:

If the radio has a built-in whip, it's likely that has a capacitance effect, like all receivers with whips do, but if yours perhaps has an internal ferrite antenna that's located very near -- especially directly under -- the plastic case, that's also another capacitance effect that will be seen. Also seen when the internal or whip antenna may not be bypassed enough electronically or an internal ground is missing or open, etc.

Your RFI/EMI background level might be so high that your body and hands are acting as RFI/EMI radiators right back into the receiver.

Various reasons for what you are seeing...and hearing.


--- In ultralightdx@..., "Kitsaplorax" <kitsaplorax@> wrote:

I was listening to my favorite station in Seattle/Mercer Island, AM 880 KIXI and noticed that (with their reduced signal strength after dark) this radio has substantial hand capacitance.

Tuning the station dead-on and removing my hand reveals a lot of hiss. This doesn't seem to be a tuning issue. Going up or down doesn't remove it. The static is present on all of the AM stations.

Has anyone else noticed this? Of course if one has the radio clipped to their body it wouldn't be present. It isn't present when using an outboard antenna.

Any suggestions?


Gordon Cooper
Bremerton WA USA

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