Fizzing sound .

Not the coax i don't think but you never know lol.
It's electrical noise from around the house.
Phone chargers and the likes anything can cause that noise.
The only way to stop it is to find the culprit by unplugging things one by one and see if the noise drops.

Hi Pauline, I have a feeling you haven't connected the pl259 plug into the radio properly.
(The screw in plug on the coax)
Sometimes they don't push in all the way but the threaded collar can still be screwed on.

There is an option on the 9900 to turn off both the inbuilt SWR meter and the hi SWR cut out.
I leave both switched on on mine.

I'll have a look for a couple of videos to help you later

Thank you.

https://youtu.be/x8wkpIM68a8?feature=shared




https://youtu.be/-4KCvU81KL4?feature=shared




https://youtu.be/rjy0eFXxVaY?feature=shared

How does the built in SRW work?
Does it actually tune the antenna & keep it stable?
Or do I need to use an external SWR along with the internal one.
Many thanks.

Pauline Flynn wrote:

How does the built in SRW  work?
Does it actually tune the antenna & keep it stable?
Or do I need to use an external SWR  along with the internal one.
Many thanks.

The built in swr meter works the same as an external meter.
It only measures the Standing Wave Ratio and shows you the reading.
This is reflected RF power going to your aerial.
So say you are putting out 10 watts transmit power. A 1-1 reading should mean no power is reflected back to your radio. 
The higher the reading the more reflected power.
The auto cut out protects you from transmitting if it gets too high. 
Too much power going back to the radio can damage the internal components.

Tuning the antenna is done by altering the height manually.
Your silver rod should have marks for each section and set for 11meters. 
But they still may need fine tuning/small up or down settings.
Have a shufty through those videos and others Fred in the shed etc have and I'm sure the penny will drop

That's great thank you, the penny has dropped .

I go along with everything that Alan & Nige have said re: your swr.

As for the original problem of 'Fizzing' if that isn't sorted can you possibly add an audio or video clip of the noise in a post, it will help with diagnosis. 

The 'fizzzing' noise when transmitting sounds like RF getting into he shack. Ive had it before, You get that weird noise when talking. I had it coming back through a speaker and a power supply before. I few ferrite rings around the speaker cable and power cable going to the power supply sorted it out.