Icom IC-F21GM Battery Question


Anybody else out there have or familiar with the Icom IC-F21GM Radio? If so, I’d like to know if it’s possible to prevent the radio from switching down to 1 watt mode when using the 6xAA battery adapter (BP-208N). I see that the standard battery packs have an additional metal contact towards the middle of the casing. Is this just a simple metal contact or is there more to it?

My thought is - I’d like to be able to use 6 Sanyo Eneloop cells as they are the same voltage and battery type as the battery packs, but are more convenient for me in some situations. But I’d like to retain the full 4-watt output, so I’m looking for a way to “trick” the radio. Thanks for any help.


On the ICOM f4001 the switch happens when the batteries are low. Not based on the pack you select.

Actually, I discovered a solution to my initial question some time ago after searching the net for an answer. Amazingly enough, you can trick the IC-F21GM into operating at the 4-watt mode on Eneloop cells with a simple piece of foil. A guy with a motorcycle blog figured this out and explains it all here:


A clever but very simple and effective solution. Basically this allows you to use the otherwise inaccessible high power output mode with 6 Ni-Mh cells and the standard battery pack, or a DC power source as he’s using in the example.

Furtheremore, I had an authorized dealer contact Icom about using Eneloop type cells with the IC-F21GM and it is totally safe and do-able, provided you use common sense and don’t try to charge the cells with the Icom charger for this radio. Apparently, Icom’s warning against using Ni-Mh cells with this unit was issued many years ago and does not take into account modern AA sized cells which you can charge with a separate charger.

By the way, I’ve tested alot of popular FRS & GMRS radios, and the IC-F21GM is the most powerful non-ham/business radio I’ve ever used. Clearly communicates at least 1.33 miles in my city which has alot of thick foliage. Probably could go well beyond that, but I never tested it any further.

Hope this helps somebody.

That’s impressive. My Icom f4001 is still taking second place to some of the corner store Motorola GMRS…

Hmm…sounds like something isn’t right, but I’m not familiar with the F4001. I have used the Motorola EM1000r’s (similar to the MR350’s) and while they are excellent for a consumer radio, they’re not amazing for range. Your Icom should be easily beating them for talking distance. Somebody at BuyTwoWayRadios may be able to help you figure out what’s wrong - they’ve been a great resource for me.

On a side note - Alot of people on these forums have touted the newer Cobra consumer radios that use a proprietary lithium battery as being the best of the current bubble-pack variety for range. They’re probably right, however, I tried the CXR925’s based on reviews here and was terribly disappointed in the build quality and ergonomics. I returned them almost immediately. To me, they felt like a toy in my hand. Then I came across some older Cobra PR-DX900’s. I figured if the newer ones have good range, the older ones might have similar performance. Overall, I found them to be the best ‘consumer’ radios I have ever used. It seems to me that the secret here might be the quality of the receiver is just as important as the transmitter. I don’t know if they’re just as good as the CXR925’s in terms of talking distance, but I’ve used Motorolas, top of the line Midlands, and even the Kenwood TK-3131’s, and I would put the DX900’s up against any of them for range and usability. Perhaps not as rugged as the Midlands, but I’m not rough on my equipment anyway.

As a matter of fact, I was so impressed with the DX900’s, I ended up selling my IC-F21GM and using the Cobras instead. I compared them on range, and while the F21GM is definitely more powerful with a full 4 watts and large whip antenna, the DX900’s give me most of the talking distance, but in a much smaller package. Plus they have an illuminated display, and only need 4xAAA cells instead of the massive 6xAA pack. I may buy an F21GM again someday if I need the power, but I just can’t justify the size and weight of it for everyday use.

To lengthen the battery life on the DX900, I use the excellent Maha PowerEx 950mAh Low Self-Discharge cells, which give you a bit more runtime than Eneloops.

While this model is discontinued now, you can find them on eBay fairly often for less than $30 each.

I like my Icoms for their professional feel but I do feel that they do more than I need. And they do less than I would like as well. e.g. they don’t have easy channel selection and they are heavy but they cover frequencies that I don’t even need.

I originally wanted them for the removable antenna. I figure I can rig something up in my back pack and get super range. I may still do this but I’m leaning on going to Motorola for my wife. Most everyone else is using Motorola and they are definitely at or above my Icom.

I’ll keep mine and probably do an external antenna or something. Especially while riding my bike when I can have a mounted one. Well see…

For handheld use I think the dealer might have given me the wrong antenna. Its all that I can guess. My antennas don’t have the colored band on them that Icom shows so I am not even sure which antennas are on :confused: