Odd power output F221S radios

[dorcse]

First a big thank you to all who participate here and are willing to share their knowledge. I personally have learned a lot by reading your helpful posts. So thank you all very much!

My question: I recently acquired 5 ICOM F221S radios. The history on these is they were sold as surplus and in their previous lives they were installed on school buses in the State of MO. After reading the radios with the CS-F100S software and saving the config file, I did some testing.

All 5 radios appear to be set to high power on all channels. However, 4 of the radios register just 17 watts each. This varies slightly from radio to radio.

Just 1 of the 5 radios puts out 32 watts. The config settings for that radio appear to be the same as the others. As a test, I read that particular radio into the software and then wrote that config file to the other 4 lower power radios. Nothing changed. Those 4 radios still each emit about 17 watts. So this does not seem to be a software setting, at least not one that I can easily see in the software. Or am I missing something? Perhaps these 4 radios all just suffer from some low power problem? (For that matter, even the 1 radio that can put out 32 watts is not that close to the max power these are cable of, 45 watts.)

For fun I changed the programming for each of the 4 radios putting out only 17 watts from high power to the L2 and L1 settings . Power readings under these settings were about 10 watts and 2.5 watts on each radio. Hmmmm.

I believe that there are some further service settings to adjust power? If these are in the CS-F100S software, do you know how I could access that area of the software to check this? Or are those settings only available in some separate software used by ICOM techs?

I'll get use out of these radios no matter what, so I'm not hung up about the power issue. But I would like to hear your opinions as to why almost all of these are operating at pretty low power despite being set to high.

Cheers and thank you!

Ed

 

[mmckenna]

Just 1 of the 5 radios puts out 32 watts. The config settings for that radio appear to be the same as the others. As a test, I read that particular radio into the software and then wrote that config file to the other 4 lower power radios. Nothing changed.

That's to be expected. Other than the High, Low 2 or Low 1 settings on the individual channels, the alignment data for the radio is not carried over in the programming.

Those 4 radios still each emit about 17 watts. So this does not seem to be a software setting, at least not one that I can easily see in the software. Or am I missing something? Perhaps these 4 radios all just suffer from some low power problem? (For that matter, even the 1 radio that can put out 32 watts is not that close to the max power these are cable of, 45 watts.)

For fun I changed the programming for each of the 4 radios putting out only 17 watts from high power to the L2 and L1 settings . Power readings under these settings were about 10 watts and 2.5 watts on each radio. Hmmmm.[

So, a couple of things….

The type of watt meter you are using, and what that watt meter is connected to (antenna or 50Ω load) will impact what it reads.
I'd not put a lot of faith in any sort of hobby/ham grade SWR/power meter.
If you were running something like a Bird 43 into a good 50Ω load, then you can take the power output readings seriously.
Still, as you've noticed, there's a big discrepancy between the radios. And since it follows the L2 and L1 settings, it's likely an alignment issue.

I believe that there are some further service settings to adjust power? If these are in the CS-F100S software, do you know how I could access that area of the software to check this? Or are those settings only available in some separate software used by ICOM techs?

There is a service piece of the software, but where, I don't recall. I have CSF-100 somewhere, and I'd need to dig it up.

However, there is much more to it that just going into the service software and cranking up the power until it reads what you want. Resist the urge to do that, no matter how strong it is.
----
Usually there are multiple steps involved in setting RF power output. It also requires the correct test equipment to do it correctly.
That means an accurate watt meter into a good dummy load. That pretty much rules out the hobby grade stuff. Usually the manufacturers will spec out an accuracy allowance on the test equipment, and in reality you are looking at something like a Bird 43 with the right slug into a reliable 50Ω load.
You also have to watch the DC current consumption of the radio. Usually the alignment instructions have a RF wattage range that is considered acceptable, and it also requires keeping the DC current draw below a certain amount. Get it wrong, and you are just generating heat that will damage the radio.
You also need to make sure that when you adjust power output, the spurious emissions stay within specs.
In reality, you need to have a service monitor to do this correctly.
If you do not have these pieces of test equipment, it's really worth taking the radios to a shop to have them aligned. If the power output is not to manufacturer specs, there's no telling what else could be out of alignment on the radios.

I'll get use out of these radios no matter what, so I'm not hung up about the power issue. But I would like to hear your opinions as to why almost all of these are operating at pretty low power despite being set to high.

OK, good, that's the other thing. Sometimes people get hung up on RF output power as the only measure of a radios performance.

It's possible the radios are out of alignment.
It's possible that the FCC license for the radios previous owners only allowed a certain ERP, and the tech adjusted this to stay in compliance.
It's possible someone tried to "fix" the radio without knowing what they are doing.
It's also known that most radios will do their designed RF output in a certain range. Get out on the edges of the radios designed frequency, and it's not uncommon to see the RF power drop.

It's also possible that your test equipment is out of whack, and that's causing it to read low.
If you are reading power output by feeding it into an antenna, high SWR will result in a lower RF output reading.[/QUOTE][/QUOTE]

 

[dorcse]

Thanks much for your reply!

I thought about the alignment issue possibility.

One thing that seems odd though is that each of the four have the same output power. So it seems unlikely they are each out of whack to the same exact degree?

Anyway, I think you are right about the possibility the power had intentionally been limited on these four radios. I know they were part of a repeater system. They had been programmed for repeater and talk-around. I have the frequency pair and know where they were used. I may just do a little digging in the FCC database regarding power to see IF that tells me anything. Come to think of it, I recall a few of the units still have a sticker attached by the local (I presume) service shop that maintained the radios. Perhaps I'll give them a ring and ask nicely if they recall anything about these.

These radios are obviously quite old. But so far in my limited testing they perform really well and sound damn good. Transmissions are nice and clean, too. I have some M1225 Motorolas. These are nicer, IMHO.

One last thing, ultimately I plan to use a couple of these to replace some mobiles I have set up in a portable repeater (those M1225s). I thought I might try to do some testing to see which radio has the best receive capability (best ears.) Without any sophisticated test equipment, I thought a decent test might be to subjectively rate receive capability of each unit with no antenna attached while transmitting from a HT at specific distances and locations. The idea about no antenna is that I won't have to travel very far to do the test and it might expose the clear winners and losers quite quickly? But maybe this idea is rubbish?

Cheers!

 

[mmckenna]

These radios are obviously quite old. But so far in my limited testing they perform really well and sound damn good. Transmissions are nice and clean, too. I have some M1225 Motorolas. These are nicer, IMHO.

I ran a few of the 221 (non-S models) on GMRS and 70cm ham back in the early 2000's. I like them and they were good radios. Weak spot on them was always the microphones. I had issues with the internal circuit board mounted PTT switch failing.

One last thing, ultimately I plan to use a couple of these to replace some mobiles I have set up in a portable repeater (those M1225s). I thought I might try to do some testing to see which radio has the best receive capability (best ears.) Without any sophisticated test equipment, I thought a decent test might be to subjectively rate receive capability of each unit with no antenna attached while transmitting from a HT at specific distances and locations. The idea about no antenna is that I won't have to travel very far to do the test and it might expose the clear winners and losers quite quickly? But maybe this idea is rubbish?

That would likely give you a good idea which ones are the better receivers.