I've found a study out of the Netherlands which actually measured the receiver sensitivity of 10 each car radios, portables and handhelds. Sensitivity was measured for 20db Signal to Noise Ratio and 46db. The testers generated a stereo signal that was either directly fed into the receiver antenna jack, or indirectly fed (and then a factor was applied for the losses). Any radio that could not generate a stereo signal at those levels was rejected and not measured. At the end, 9 car receivers were included, along with 5 portables and 6 handhelds.
I suspect that the results are probably more accurate and real world useable than manufacturer supplied numbers. The measured sensitivity was in dbuv, and I converted all of them to uv. I also did some rounding so they're not exact (but they're pretty close).
Here are the results, which are the voltages applied to the input of the radio to generate signals with the specified SNR's.
Car Radios (9 in Total)
20db SNR: Average 1.3 uv, Best <1.0 uv, Worst 6.3 uv
46db SNR: Average 80 uv, Best 56 uv, Worst 800 uv
Portables (5 in Total)
20db SNR: Average 4 uv, Best 2.3 uv, Worst 5.6 uv
46db SNR: Average 100 uv, Best 56.2 uv, Worst 141 uv
Handhelds (6 in Total)
20db SNR: Average 8 uv, Best 2.3 uv, Worst 28.2 uv
46db SNR: Average 400 uv, Best 200 uv, Worst 1000 uv
Some Considerations
No home stereo receivers were tested, although they more than likely rival the car receiver results. That has to still be verified.
There was one car receiver that tested very poorly and it somewhat skewed the results. Most car receivers were around the 1-1.5uv sensitivity mark for a 20db SNR. A few were under 1uv.
Typically, portables did much more poorly than car receivers, and the handhelds performed more poorly than the portables (although one handheld, the Sony ICF-C1200, rivalled the portables. Interestingly enough, the worst handheld was also a Sony, so name brands are no protection against bad radios. The best portable was a Sony, the CFD-S550. The best car receiver was the JVC KS-FX480, but there was a Kenwood & a Blauplunkt that rivalled it.
I'm struggling a bit right now to make sense of these numbers, as I have no good idea of what a 20db SNR sounds like (nor a 46db SNR either).
It takes a much greater field strength to get that 46db SNR. If you take the average for the portables - 100uv - then you only would be able to get that type of signal at 3 meters from the transmitting antenna (if you're running at 250uv/m at 3 meters). Obviously, you can hear that signal much further than that with decreasing SNR - a sensivity of 4uv with 20db SNR (the average for portables) translates to a range of 75 meters or about 250 feet.
Anyway, I just thought I'd throw this out there for discussion. No major surprises, just more grist for the mill.
Shows that reciever sensitivity(and image rejection) has as much to do with range as the transmitter power. How can we convince people to get better radios so they can listen to us better. Most better radios are in the past and can be had on ebay(GE, Realistic, old Sonys and others with tuned RF stages). Sangean is the only current manufacturer making decent radios now and the CC radio is also sangean. To get car radio performance in your home you have to get a HI-FI tuner. Tivoli radios work well too...even the PAL portables.
Mark
So to go 1700 feet which would be about 1/4 mile we're talking about 1750uV/M. Not we have a number to try and shoot for. We could try an even 1800uV/M. Now it really isn't that bad when you start to look at the realistic field strength numbers. the Sony Boombox you talked about is the same one I have. It don't do too bad compared to some of the portables out there now. And 250 feet is better than the Whole House FM Transmitter's claim of 150 feet, but I'd say more like 250-600 from reports I saw.
Great work we can use some of these numbers to play with.
I have always wondered who are the engineers who design radios for the marketplace. They must keep generating new designs because radios only stay on the market for a brief time, and newer models are not necessarily better, they are often worse. Some one explain to me why we can't just stay with a good design.
I currently have a curiosity about so-called "work-site" radios that are made rugged and have strong audio amps. I have an order placed for a Sangean U1 but for some reason it's been on back-order for a month.
Youtube has a few "radio reviews" but what I could find was a total waste of time and not useful.
The data Artisan posted demonstrates very well how widely the quality varies.
I think radio popularity might be helped by better quality control at the manufacturer level.
Poorly performing radios leave a very poor impression of the whole radio experience.
OK what we need to do as well is have the FCC impose the same sensitifity on Radio's that was around 1983. Radio's back then had very low uV sensitivity. It sickens me now these Radio's are so damn cheap but Good Radio's can be purchased on Amazon. German made Radio's are great too. Pay attention to what is sold in the UK for people over there are more appreciative in their music and thus better Audio equipment. I'd like to see some high end boom boxes and home receivers rival the Car Stereo receivers. I sure miss my Rotel tuner I had a few years back before I had to sell them so I could pay for my Wife's medical expenses. I knew when I sold the equipment that I'd have a hard time ever acquiring this type of equipment again. My Classaie separate power amp and pre amp was awesome.
But I'd say in order to get folks to get better Radio's you'd have to have listeners discover your station in the first place and put links to Good affordale Radio's and higher end boom boxes that could receive your station further than mose newer Radio's. Listeners when they don't have easy access to the Internet will buy these Radio's and tell their friends. If I had an electronics store I'd be pickey about the Radio's I sold.
The old Pioneer "Super Tuners" were great car receivers back in the day. 1.9 uV sensitivity. Great selctivity as well. If my memory serves me they used ceramic filters.
A lot of the 1979 receivers also were doul conversion receivers as well. That and the ceramic filters made a real difference. We need to also concentrate on making he FCC start to impose better receivers. Reason being more powerful stations again cause more chance for interference its a two way street for the NAB and the Radio manufactures of these poor recceivers coming into the USA these days. With technology improving all the time so too should Radio receivers. You can best bet your bottom dollar tht cell phones, Police Radio's, public safety Radio's have the best receivers in them. There is no reason for a poor FM receiver to be allowed to be sold in the USA period, but I've seen some real pieces of junk and its why before I even would buy a Radio I want to hear the Radio and play around with it. I'm very much a pita to the stores about this. They don't want to allow me to tune around, I go elsewhere to buy a FM receiver.