RadioBanter - View Single Post - Relationship Between Antenna Efficiency and Received Signal Strength

Jerry Stuckle · January 24th 14, 01:21 PM posted to rec.radio.amateur.antenna

On 1/24/2014 6:40 AM, wrote:
On Thursday, January 23, 2014 9:45:31 PM UTC-6, Jerry Stuckle wrote:

It is also an issue on HF, especially with less expensive receivers.

You don't see it on the S-Meter because the meter is set such that the

typical receiver noise doesn't show up. But it is there. And it does

affect weak signal intelligibility.

I didn't say that internal receiver noise would show on the
S meter.
I suppose it's possible receiver noise could effect weak signal
reception on HF, but it's going to have to be a really low
level not to override the internal receiver noise on any modern
radio, unless it's some kind of abnormal birdy or whatever.
I just don't see it being a much of a problem on HF, particularly
20m.
If external noise or signals picked up by the antenna don't
override the internal receiver noise on 20m, something is broke
somewhere.
And if the system is that broke, might as well forget anyone hearing
him, particularly running QRP.
He should do OK with a small loop as long as it's built and working
right.

Low antenna efficiency affects not only the received signal, but the
received noise.

And yes, many inexpensive "modern" receivers suffer from poor front
ends. And since transistors (especially bipolar) typically generate
more noise than tubes,
noise can be a worse problem now than in the 60's. You can get low
noise transistors, but these are more expensive.

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