r8600 waterfall - i think i am not understanding it

[grueic8600]

what does the waterfall show me? specifically the blue background where there are no stations spiking.

i have a 1m active loop antenna, indoors. and i'll rotate it occasionally. sometimes when i rotate it the blue background of the waterfall will fade, sometimes to black depending on where i have my ref level set.

is the blue background of the waterall noise? it doesn't seem to be as tonight i noticed i was able to get stronger signal from quieter stations when i rotated the antenna. but the blue background was brighter, or more of it.

so now what i'm thinking is, the blue background - in fact the whole waterfall shows overall signal strength, which is why it all brightens up when pre.amp is turned on or when i increase the rf gain.

so i used to think the blue background was the noise floor and i could tune my antenna rotation by rotating the antenna until i visually saw the blue get weaker or disappear. but it never really sounded like there was less noise. the noise for the most part sounds the same compared to the stations, just overall weaker or stronger.

since the loop has nulls, all i was doing was weakening the signals i was getting, but still getting the stronger ones. am i correct about this? in otherwords, if i want to pick up some weaker stations, rotating the antenna will help me get them. but also rotating the antenna helps eliminate nearby noise sources but could be at the expense of not getting weaker stations.

thanks!

 

[devicelab]

Yes the blue background on the WF can represent the 'noise floor' at your location -- on your antenna -- on that frequency -- at that time of day. I said it this way for a reason -- there a lot of variables that can affect the WF display.

IMHO, the blue background should be your noise floor. Now, it's subjective in that some people prefer a black background while the default is blue. It's possible to tweak the WF settings such that a 'zero' noise floor is black -- and strong signals will be rather obvious. I've linked a YouTube video showing what I'm talking about. You'll also see other shots were there's a light blue background with various signals. Again, it's subjective how you want to display this information. There's no 'correct' answer.

You can search YouTube for other videos. The WF display settings are very similar on the R8600 as they share a similar design to the ICOM 7300.

The annoying thing about WF displays is that some settings can drastically affect your overall output. Also those settings may change depending on time of day and general background noise. (Usually lower frequencies have more noise than higher frequencies -- but this is not always the case.)

The REF level is very important and is used to set your WF noise floor. A 0 db REF level is neutral. If you go lower (negative) then you're saying that you have interference or high background noise. A higher setting means you're saying that you have a very good noise floor and that you need to amplify it. The issue with REF level is that it will change with frequency range so it may not be a static setting for you. It might be best to keep track of your REF level settings at first.

I prefer a clean blue background and then proper RF signals will show up. Some people prefer a black background (as per the video) and the RF signal contrast stands out more. (This depends on other WF settings too.)

Your antenna is another issue. Because it's indoors you may get a lot of noise from electronic devices and other noise sources. Your REF level may be all over the place depending on your noise levels. Also, your RF signals may not be very high -- so your noise floor may mask your actual RF signals.

I'd recommend starting with the WWV stations first. So during the day, start at 10 Mhz AM and 15 Mhz AM. At night, 2.5 and 5.0 Mhz AM. Use these stations as a baseline for your *initial* WF settings. Also understand that AM stations are very different than SSB stations. So this may also affect your display slightly.

I'd recommend tuning to AM broadcast stations and using those bands to help find your ideal REF level settings. That should get you started in the right direction.

Oh and for HF reception, an outdoor antenna is a must. If you're just listening to broadcast stations then you may be OK but you'll have so much better reception if the antenna is outside and ideally away from any houses or structures.

NOTE: In that video, you'll notice his settings look really good and contrast-y but his SPAN setting (how much he sees around the frequency) is very narrow. This SPAN setting will affect how your signals look on the screen. I don't recommend a narrow SPAN -- especially if you're hunting for signals. It doesn't matter much if you're just listening to broadcast stations or strong signals. I'd keep it at 100 khz (+50 on each side) or thereabouts. You can tweak this to your liking of course.

 

[grueic8600]

wow awesome thank you! yeah, so it is all relative so to speak in terms of what it's showing. we are just tuning it to our liking.

funny you mention about how it can look different on different frequencies as i have noticed that quite a bit... on 75/80m or i see a lot more of the 'background", but on 40m with same ref level i see a lot less - yes, depending on time of day. i thought maybe my antenna was tuned more for the 40m band, but it's not it's just different.

i can't wait to try my antenna outdoors - just waiting for warmer weather! but i have been very pleasantly surprised at what i'm receiving indoors! and further, i can't believe how much changing it's position by as little as 6ft can make such a big difference!