it will kill any out of band noise an striong RF signals (for example if there is a transmitter on a nearby hillside). it also stops the front ends in modern handhelds from collapsing and hearing NOTHING! Its very likely that S4 of noise would have been reduced. I bought one and use it on every single activation I make, in conjunction with spectrum communications slim G. and get plenty of contacts!
HTH
Alan
Forget the amp - throwing out a kilowatt wonāt help you hear the replies. Iāve done very well with just a cheap and cheerful handheld, like the ubiquitous Quansheng, and recently managed 96 miles to another Quansheng user using the stock antennas. Iām not familiar with DK7ZB but have had some success (and a lot of fun) with a home made ātape measure yagiā. Definitely recommended!
I find it works well as a rule.
One Yagi to rule them all 
Thanks Alan.
So itās Ā£45 for the filter.
Now the question is whether I buy that, or put the money towards a HT with a better front end. Shame some of the well regarded models are no longer in production.
Iāll keep researching. 
Handy that works is what you want. A suitable 2m handy went for only Ā£27 last week on eBay.
How many summits where you operate have masts? I donāt think the filter will do much if there arenāt any.
I use a Baofeng plus slim jim and donāt have problems here in G/NP or G/LD.
I made the same point a few years ago [about using my FT1D/RH770/slim jim] for the same regions but got shot down in flames saying I hadnāt covered enough summits. I was also told my rx may well have been desensitized by a āmastā (without my realizing it) but that person didnāt explain why Iāve given 5/7-5/9 reports to at least a few chasers (often many more) on all my 2m FM SOTA and WOTA activations.
I can only think of 4 summits where Iāve had or heard of problems, namely, the Great Orme, Cyrn y Brain & Brown Clee Hill & Billinge Hill. No doubt there are others but I havenāt heard of them or activated them. I have used my Sotawatch filter on the latter 3 with OK results.
Iāve activated the Great Orme but used my FT817ND to avoid any issues.
IO82 is even better than IO83 for VHF activity.
So I had another interesting experience this evening, activating G/DC-001. Noise level with squelch off was S5, occasionally S6 (photo below). Difficult to manage, but I got there.
I made CQ calls via the Quansheng & flowerpot antenna, then Iād switch on my 1701 (sporting a rubber duck) to listen to responses. This bagged me my first QSO, despite the faff.
The next few were from members of the Holsworthy club (life savers), who werenāt too far away - they were audible on the Quangsheng.
Two marginal QSOs which I didnāt log - I got was a callsign (via listening on the 1701), and finally the last QSO from someone audible on the Quangsheng.
Definitely need to invest in kit to mitigate this. That said, Iāve activated all summits that Iād tried so far with the flowerpot antennaā¦ and most importantly Iām having fun.
Hi Richard, conditions have been very good on 2m lately, our QSO was 212 km or 132 miles in old money & my first contact onto Dale Head so was very pleased with that, I was running 20w into an X50 collinear & have a decent take off from home but your station was doing the heavy lifting & it was great to make the contact, hope to catch you again. 73.
Neil
Lots of people giving you great advice, just got to figure out what works for you.
I advise people not to do what I did when I was activating full time,
Carrying an FT897, a 12ah Slab, at least 3 antennas, plus anything else I thought I might need in a tight spot. 
Never took a kitchen sink though 
Good luck , but most of all have fun out there, but be careful
Carrying the linear and a battery has never been an issue. Iāve done activations with the 817 barefoot, but have had significantly better results using the 25w linear (with integral low noise preamp) and a 5el yagi (7dB gain) and about 4.5m of low loss coaxā¦ about 110w ERP. This has bagged me some super contacts over difficult paths. Probably the most memorable was working Don G0RQL in Devon from Hoy (Orkney).
It can be worse ā¦ rumour has it one activator takes an Anvil with him! (Joke)
One point that maybe worth considering, and not knowing your home location, is do you have any trivial summits near to home.
They make ideal summits for doing multiple visits without the worry of not qualifying. Hence various configurations can be tested. Even if its just practiclsing setting up while outdoors.
You could then have different configurations available depending on your chosen summit. You could probably take more gear up Gun (g/sp-013) than say Tryfan but you would already have the knowledge of size/weight etc from the local summit practise.
Others have more experience of same summit multiple times and they may have other words of wisdom.
Ian
I will try and it lightweight
I think i might need a dog as well, good company
