I’ve tried it, but discovered my uW variable attenuator passes nothing below 2GHz.
They can be had cheap for TV if you still have an interest
An attenuator will “attenuate” the signals you want by exactly the same amount as the noise you don’t. By adding an attenuator, you’ll be trading long range (weak) signals for local.
An attenuator compliments a filter, but it does not replace it.
That goes without saying, and is obvious conclusion from the graph in my post which was linked. I am posting that graph here for ready reference.
I still have a rough time assimilating a single graph without a watermark to illustrate whether or not a change in setup is having an affect. Example:
I’d be looking to take fish out of my diet and scratch my head over ham. In reality it’s the same untouched feeder dealing with air traffic.
That said, I can somewhat identify from the previous post that Pro Stick Plus seems to present an issue in that setup, but so does fish on mine. As constructive criticism, I think it would help to show a side-by-side against a watermark setup since air traffic and environment are so unpredictable.
I’m comparing apples to oranges, but that’s my whole point. Please don’t take this the wrong way, I mention this with full respect.
If you want to compare two settings and switch back and forth let’s say 3 times then you could say it’s likley the change is not traffic 
Same goes for really drastic message rate changes.
Also some people have less drastic changes in message rate during a typical day.
(1) The drop and rise is drastic and very steep, almost a vertical rise/fall, very distinct as compared to your ham & fish example.
(2) Removal & insertion of filter and attenuaters was repeated several times, and each time a steep change took place.
(3) That test was done 4 years ago 
. I have done another test 2 months ago 
with same steep drops & rise. You can see it here:
NOTE:
Every time I removed and inserted the Filter, I made sure that all connectors are fully tightened, so the drastic drop is not due to loose connection.
I’m not dogging you amigo, just trying to help with an idea to make your tests that much better is all. I know you have gobs of equipment laying around, may as well put it to use. 
I never took anything you mentioned as “dogging me”. I always take it as a constructive advice / criticism intended for help, correction & improvement, and I am thankful to you for it.
This test involves FA Antenna and ProStickPro (Blue).
Unfortunately I have only one FA antenna and one ProStick Plus (Blue), so I cannot do a true side-by-side test.
I dont have “gobs of equipment laying around”
My Dongles are:
My Filters are:
My Antennas are:
Not specific to you, but I’ve wondered about about this point. N-connectors are very tolerant of tightening because the mating surface isn’t the RF connection. SMA’s are quite a different design and can be a bit finicky.
For interest, how do you satisfy " fully tightened". (finger tight?, 12" shifter? …?)
Tightened by fingers, then rechecked.
Sorry, I don’t understand.
“rechecked” how?
Tightened carefully by fingers, ensuring no cross threads, and the nut turns smoothly and fully. Put it back.
After few seconds grabbed it again and tried to tighten by fingers to ensure it is already fully tightened.
The correct torque for a brass SMA is 6"-Lbs, 8"-Lbs for steel.
Their performance can be very poor when loose.
A torque wench is a useful tool and the only way you’ll get it “fully tightened”.
Thanks for useful advise. I will purchase one.
I have finger-tightened SMA connector innumerable number of times. I am Lucky that up till now I never got poor performance by finger tightening of SMA connectors (except when I removed the external filter, seems the filter had bad threads on its connectors ). However, apart from above, your advise to use a torque wrench is sound, as it eliminates any chance of a loose connection. It is a simple and low cost tool which all of us should have & use.
Finger tight plus a quarter turn works well for me. I live in a very small condo so I don’t have much storage space for tools. My equipment resides on a 12" by 16" shelf in a closet.
That’s probably about right.
My torque wrench is about 2/3 the size of a toothbrush.
Just remember SMA connectors were never designed for a large number of mating cycles. They were designed for semi-permanent use on microwave rigid coax. I think the original design limit was only about 100 cycles.
True, but that’s the brand name connectors with QC. Probably better after 100 cycles than the chinese connectors when new!!
Let me see if I can find the picture of the “name brand QCd” connector that was cycled a few too many times and cross-threaded to boot. 
It had enough metallic dust in it to short out. Just sayin… 
The work-around I use to avoid that possibility is to fit my equipment with M-F adapters.
At first sight, these just look like they will add a bit of avoidable miss-match until you realise how short lived SMA connections can be.
Fit these adapters and your wear surfaces become disposable.
Simple and excellent solution
