Define "better," and I'm serious.
I've had an RH77CA alongside my RS800 for about 14 years now (had an RS800 in the early 1990s actually but sold it, then got another one, sold that one, then got this one I still have around 2004 or so). As for something "better" well, I'm sure that there's something that would be better - a telescopic whip would technically be better since it can be manually tuned to rather precise frequencies across a wide range (working as a 1/4 wave considering the limitations on the length).
The RH77CA by design is for use on 2m and 70cm
as a transmitting antenna and that has basically nothing to do with the fact that it - and most any antenna or even a piece of wire for that matter - can work as a wide bandwidth receive antenna which is why Diamond puts that info on the packaging sleeve the RH77CA comes in from the factory. A lot of people focus entirely too much on that info unfortunately but the basic gist is this: yes it's tuned as a dual band antenna to perform better in the 2m (144-148 MHz) and 70cm (420-450 MHz) bands
with respect to transmitting so the better performance would be in those two ranges primarily but that doesn't have much effect on the fact it can receive across a much wider range - I and I'm sure many other people use the RH77CA from CivAir (118-136 MHz) all the way into the area around 940 MHz or so, at least I do, and it works fantastic across all of it.
As for something actually better, well, if you mean a single antenna that covers a wide range and you want it to be small and around 15" or less in size, I don't think there's going to be much out there that's not a clone of the RH77CA besides the aforementioned telescopic whip which you can tune but, of course that means having to manually adjust it for the bands you wish to monitor and change it each time you jump around the bands so, yeah, a multipurpose wideband receive antenna is what we all dream of having that covers everything and does it great.
One way to improve event he RH77CA's abilities would be to get an antenna extension cable to move the antenna away from the scanner itself - there are some that even come with a suction cup attached to the antenna end so you can stick it on a window or flat surface - moving any indoor use antenna to a window or even better on the outside of a window will improve signal reception quite a bit, sometimes pretty dramatically depending on your monitoring setup.
Least that's my take on things. I do keep my eyes on any potential successors to the RH77CA but so far it's proven it's worth and paid for itself multiple times over since I bought it, same thing can be said about the RS800 which even though it's designed for 800 MHz use it works extremely well all the way down to the CivAir band - I was amazed at how well it was pulling in some air traffic one time after I realized I hadn't swapped antennas when I changed the bands I was monitoring, I thought the RH77CA was still attached. I think it's tuned to roughly 860 MHz since years ago the public safety range was 851 to 869 MHz but that changed so now it's just 851 to 861 MHz at least here in the US).
It's pretty crazy to think that 6.5" RS800 can do so well across that wide range far outside what the specs say it's supposed to do. Definitely one antenna I can't recommend enough, right there with the RH77CA. They're my two most used antennas, hands down, and they've worked great on physical scanners and also using RTL sticks for SDR purposes the past few years.
I'm sure there could possibly be a small similar antenna to the RH77CA that does just as well and perhaps even slightly better but I've yet to find such a thing myself.
