This morning, a reader wrote:
Good morning, Dan. So on Ham Nation last night they kept going on and on about AM and encouraging people to use it. I understand there is a frequency window that should be used, but they seemed to be trying to reduce apprehension but suggesting how great it is. So what’s the big deal about AM?
Simply put, Bob Heil, K9EID, is a big proponent of AM and likes to use his show to promote its use—just like I am a big proponent of CW and use my blog to promote CW. There are several reasons why hams might be apprehensive about using AM:
- It’s viewed as “ancient modulation” by some, and is a less efficient mode than single sideband.
- There are a lot fewer operators that use AM. One reason that Heil is pushing it is so that there are more people that he can talk to.
- Generally, modern transceivers output less power when operating AM than they do when operating SSB. For example, the IC-7300 has an output power of 100 W PEP on SSB, but only 25 W on AM.
Now, I am only speculating as to why Bob Heil thinks it’s such a great mode, but here are some things that come to mind:
- It sounds better than SSB. Remember that Heil is a sound guy.
- There’s a certain sense of nostalgia that older hams have for AM. AM was a big thing when Heil got started in amateur radio, and perhaps he feels a bit nostalgic about using it.
- It’s easier to build an AM transmitter than it is to build a SSB transmitter. That’s what the Pine Board project was all about.
- It’s fun! Like any other mode, it’s just something that’s fun to do. Heil has fun operating AM and wants others to have fun operating AM, too.
Is it as great as Heil makes it out to be? Well, it all depends on what floats your boat. Just like CW, some guys will have fun operating AM. Others will just blow it off. I tried it once when I was using the IC-7300, and it was amusing, but I don’t think that I’m going to become a regular AM user anytime soon.
I think equipment makes a difference in the experience. If you have an old Collins broadcast transmitter that has been modified for 160 or 80 meters, then its a blast to put something like that back on the air. It gives you something to talk about during your QSOs.
Just taking a modern YaeComWood and turning the switch to AM, maybe not so much.
Homebrewing a QRP AM rig? Maybe, if you can make yourself heard among all the Collins broadcast guys (see first paragraph). It may be easy to homebrew an AM rig, but it can be much more daunting to get any real power out of one (build a high-power AM modulation full-carrier transmitter).
Like everything in life and hamdom, your mileage may vary.
73,
— Dave, N8SBE
Let’s think twice about saying that modern radios use less power on AM, I’ll even hesitantly say they use more power!
Why do modern transceiver drop the power? It’s because they an AM signal has more power than a SSB. That’s why DSB has twice the power as SSB. Now, granted, a lot of that power may be worthlessly transmitted, but that’s not the statement.
It’s just like RTTY or other continuous carrier signals, you have to decrease the PEAK power on radios because of the high AVERAGE power.
Oh, and don’t forget that in today’s age, there’s a LOT of folks that love to listen to AM Talk commercial stations.
Squelch circuits even work with AM signals.
Just about all of the aviation radio is AM.
“Generally, modern transceivers output less power when operating AM than they do when operating SSB. For example, the IC-7300 has an output power of 100 W PEP on SSB, but only 25 W on AM.”
I see this statement all the time, and I think this is very misleading, and confusing to even some of the seasoned hams. This is an apples to oranges comparison, because SSB 100 watts is the PEP, but the 25 watts AM is the carrier.
More accurate (but useless) comparison would be to say SSB is 0 watts carrier, and AM is 25 watts carrier. In theory, same transmitter will also have 100 watts PEP SSB and 100 watts PEP AM.
“Less power” argument comes from the fact that 25% of the AM power is wasted to the carrier, resulting in only 75% of the power used for the modulation, but SSB uses 100% of the power for the modulation. Further argument could be made that since AM duplicates the same information on the upper and lower sideband, it further wastes power. I don’t know if I agree that the power is wasted to the carrier, as it provides quiet silence between words and sentences, and better audio fidelity, which is surprisingly pleasant.
In my opinion, AM is a good ragchewing mode, but not so good for working DX.
There’s a 6 meter AM net on Monday evenings in the Raleigh, NC area. It’s not uncommon to have 20+ check-in’s. We’ve had skip check-in’s from as far away as Maine. Some people use modern rigs, but most use boat anchors. I have a Hallicrafters SR-46 from the mid-1960s. Great fun.
There’s another 6 meter AM net run out of north Florida that attracts ops in Georgia and Alabama. Believe it’s Sunday night. Some people in Raleigh have been able to get into it, but I’ve not been that lucky.