My BMW R1150 GSAA at Deals' Gap

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Entries in ICOM F21GM (5)


ICOM IC-F21GM Transmit Audio - How to speak and be heard

While recently riding in the mountains of North Carolina with a small group of GMRS radio equipped riders, one of the riders commented that my audio was a lot "lower" than that of fellow rider Ed Gray. Ed has the exact same Autocom intercom (Active 7 Smart) and GMRS radio (IC-F21GM). This got me thinking again. I hate it when that happens.

I was already "eating" the microphone in my helmet, so that didn't seem to point to the low audio problem and I know from Elizabeth's POV that she hears me loud and clear from the pillion. The Autocom doesn't have any user-adjustable controls for transmit audio, nor does the ICOM radio. However, I did begin to wonder about the FM Mode selection button on the radio. By default, these radios are all supposed to be set to FM Narrow, which takes up less radio spectrum every time you transmit. FM Wide is also an option and effectively adds a bit of punch to your signal.

Pressing and holding the Wide/Narrow button ensures that radio is in FM Narrow mode. I felt pretty certain that I was going by the book and using Narrow, so I tried a little test.

With the radio removed from the bike, rubber antenna and battery installed, I enlisted the help of a scanning receiver and headphones so that I could listen to myself when transmitting.

With the radio in FM Narrow mode, I was able to hear myself, but the audio lacked life. I pressed the Wide/Narrow button once (didn't hold it) which changes the mode to FM Wide. I repeated the test, but oh what a difference. The audio was substantially louder and easier to copy.

I'm going to leave my radio in FM Wide mode for future rides and ask for some comparison to Ed's audio. If Ed's willing, I also intend to run a little test with his radio, comparing his transmit audio as it is right now (no button pressing) to what it sounds like after a single press of the Wide/Narrow button (without holding). I'm expecting no change in audio, which will confirm that he's been running his radio in FM Wide mode.

Then, I guess the next question is whether there's anything wrong from the FCC's POV in running these radios in wide mode. More later.


ICOM's F21GM GMRS radio almost gone, but not forgotten

ICOM has discontinued the F21GM radio. It's no longer mentioned in literature at the Icom America website and supplies have just about dried up at dealers. Because I managed to damage mine in the polarity reversal fiasco, I started a dialog with ICOM's parts department about fixing it or getting replacement parts. I heard back from "Brian" who indicated they have just a small handful of radios available as parts. He did qualify the statement by saying that when they're gone, they're gone.

ICOM's Parts Department can be reached at 800-346-0495.

While researching what I would do if I couldn't find a F21GM, I checked out the F21 DTC. The DTC is a 16 channel "programmable" UHF radio that looks pretty much like the GM. It uses all of the same accessories and other than having to pay someone to program the appropriate GMRS frequencies into it, it's a good replacement option.

While talking to an the fine folks at Action Communications in Tuscon, AZ (authorized ICOM dealer) about purchasing a DTC, I found that he had five remaining F21GM radios in stock, so I purchased two at the same price as the DTC. If you are looking for a GM or for that matter a DTC, you should consider giving them a call at 520-792-0326.


Batteries America CBE-210N Battery Eliminator - Definitely  Different

I did something stupid earlier in the month. I accidentally reversed the polarity to my Batteries America CBE-210N battery eliminator and well... you can guess the result of that. Once you let the smoke out of some components, they just don't work very well any more. The same went for the ICOM F21GM radio, too. All in all, it was a very costly mistake.

However, since the specs of the 210N seemed to indicate it was different inside from the old 210, I figured why not crack the case and see.

Compare back to my older posting on this subject (August 15, 2009) and you will see that the 210N is much different. Instead of a single voltage regulator, there are two (L7808CV), so there's a bit of simplification going on in getting to that reduced voltage ( 7 VDC) that the ICOM radio is happier with.

So, I am now the happy owner of another (2) ICOM F21GM radios and a new CBE-210N. This time, I hope I've learned from my mistake and will keep the smoke locked up inside the respective components where it belongs.


Batteries America CBE-210N Battery Eliminator Update (no hack required)

My original CBE-210 Battery Eliminator used with my ICOM F21 GM failed on a day ride during the 2009 BMW MOA Rally in Gray, TN. Actually, what failed was a wire external to the eliminator. I had cut the cable shorter years ago to remove the cigarette lighter plug and the coiled portion fo the cable and replace it with a pair of Anderson Powerpoles. One of the small gauge wires just broke, leaving me unable to use the radio for bike-to-bike communications with the other GS rider in our party.

After returning from the rally and extended trip to Wisconsin that followed, I ordered up a replacement battery eliminator from Batteries America. I happened to notice that the original CBE-210 was no longer available and had been replaced by the CBE-210N. I'm guessing, but I bet the N means "new". This morning, I snapped the new battery eliminator on the back of the radio and did a little testing.

Before I snapped it on, I took the opportunity to check to see if the "new" model connected the small metal contact in the back of the eliminator to the Negative power contact that connects to the radio. My last post detailed a "hack" that was required with the original CBE-210 to allow the radio to be operated at full power. The N model DOES make the necessary connection internally so I removed the aluminum foil "hack" from the inside of the radio. Cool!

The other thing I noticed was that the filtered DC output of the eliminator is no longer 9 VDC, but reduced to 8 VDC which is closer to the 7.2 VDC supplied by a normal battery pack. Interesting.

With the eliminator in place and connected to bike power, I did a few transmit tests to see if any of the annoying squealing sounds of the past could be heard on my signal and from the speakers in my helmet. Elizabeth and I took turns alternating between transmitting and listening on a spare radio.

I'm cautiously saying that the problem experienced over the years has gone away! There was definitely some alternator noise still present on my signal, but it was not disturbing the audio enough to worry about. Gone was the squealing that made it hard for others to hear what I was saying. It was also not heard in the helmet either. It's possible that the original CBE-210 was providing too many volts to the radio, causing the problem.

With this possible improvement, I need to take an extended ride with the guys and see what they think!


Power-output level "hack" for the ICOM F21GM GMRS Radio

As mentioned previously, I have an ICOM GMRS "handy-talkie" mounted in the Jesse top-box on the R1150GS Adventure. It's cabled to the AutoCom intercom and draws bike power (12 VDC) through a battery eliminator product CBE-210 from Batteries America.

On a whim, I checked to make sure I had the radio set to transmit at the highest possible power (4 watts) since I have it cabled to a permanently mounted Antenna Specialists/PCTEL ASP7795 3dB gain UHF antenna on the top of the Jesse top-box. The ICOM user guide provides a procedure that requires you to push a sequence of buttons and listen for a series of beeps to confirm that the setting change was made. Well, no luck. It seemed to be stuck permanently on the low (1 Watt) output level.

ICOM F21GM GMRS RadioI removed the radio from the bike where it would be easier to work on and in the process, found that using the ICOM-supplied BP-222N Ni-Cd battery pack instead of the battery eliminator, I had no problem adjusting the output power between the 3 levels using the procedure described in the user guide. WTF?

There must be some way the radio can tell the difference between one battery pack and another.

Here's the radio and the CBE-210 battery eliminator:

And here's the radio with the BP-222N Ni-Cd battery pack:

They look pretty much the same on the inside, don't they?

I figured it had something to do with that small spot of exposed metal in the middle of the battery back and that small "push button" switch on the radio itself, but wasn't sure - yet.

Now, here's yet a 3rd picture. This time, it's the radio with ICOM's alkaline battery pack that allows AA batteries (6) to be used for power.

Note the lack of the exposed metal patch on the battery pack. Hmmm, getting warmer.

Since there's no way that alkaline pack would support 4 watt transmit for very long, I surmised that the metal patch (or lack of it) had some influence on the telling the radio it could be programmed to mid or high power settings.

I did some quick checks with my trusty multi-meter and determined that there was continuity between the metal patch and the Negative connection on the Ni-Cd battery pack from ICOM. Ah-ha! The CBE-210 from Batteries America "looks" the same, but there's no similar continuity. Bummer!

I bet the fine folks at Batteries America didn't know the F21GM uses this connection (other ICOM radios sold to the amateur radio community don't so it doesn't matter - IC-V82 and IC-U82 models in particular).

More testing with the meter revealed that the Negative battery connection was actually connected directly to the metal chassis within the radio when the battery was snapped in place. I also determined that what I originally thought was a "push button" switch on the radio was actually just a spring-loaded contact designed to press (and keep pressing) against that metal patch on the battery.

The Hack:

I determined that that little spring-loaded contact just needed to be kept "in contact" with the Negative/ground provided by the battery. Since that Negative connection was actually connected to the radio's chassis I figured a small piece of aluminum foil folded a few times for extra thickness and placed over the contact would do the trick.

The picture above shows the foil before I added a small piece of clear packing tape over it to keep it in place. Miles later, the radio's still happily transmitting at the 4 Watt (highest) level and I'm a happy camper. Problem solved.

Ed Gray's made the same modification to his radio and also continues to be happy with the results.