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HF'S ON AM

Stellasstillarat

Active Member
Aug 14, 2014
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I've read an original posting (2012) and all responses. I don't want to beat the subject into the ground but after hearing my first hf transceiver on AM I'm shocked at the attempt or lack of by yaesu, icom, Kenwood and what I'm guessing all the other manufacturers to build a transceiver that will operate on AM with decent sounding audio. I had an excellent qso with 351 Oliver from Germany on 27.575 usb. His signal happened to be off the chart as conditions couldn't have been better. He was operating a yaesu1000 mk V. His audio was hands down the best I've ever heard. Incredable! Our qso eventually went to the question of hf's on AM. He'd never used his on AM as he exsplaned he only operated ssb. He suggested we go to AM. We did and wow! What a mess! Basically inaudible. I've researched the subject as much as one could. Reading all the qst Q n A's on the subject. Some writing thay tricked there friends on AM net's where all the old timers use their valiants, kw1's and all those wonderful plate modulated transmittters while using his hf transceiver adjusted correctly to operate on AM and wrote that the other operaters said "what have you done. Your Johnson ranger sounds most excellent tonight". Is this possible? He went on to write that some not all hf's can be run on AM to sound like a plate modulated rig. After all my research on the subject I find that getting an hf to sound good on AM is unlikely and plate modulated type audio? Doubt it! Some say running them with 20-25 watts and tweaking the radios eq and using a mic that's not specially geared for ssb will get you above average audio on AM. I found a post about a modification that can be done on the icom 761 that will make it sound as good as any palate modulated transmittter/transciver. It consists of adding a variable output adjustment to lower the output wattage on AM to 15-20 watts. The author did mention some other adjustments to get it there (don't recall all details) but I'm sceptical. I don't understand why these manufacturers even add AM transmitt? Why not just leave the AM receive only? The reason I'm interested in this subject is I enjoy ssb tremendously but ocastionaly like to do some local AM rag chew and usually switch to one of my several tube rigs. My daily ssb rig is a uniden Madison and I'm comfortable knowing if I want to switch between ssb and AM my audio will be loud, crisp and clear at close too 100% modulation (with the amp 200 watts). I still haven't purchased my first hf transceiver as this poor AM audio has become a sticking point for me. Has anyone had any success getting there hf to sound as good or better than a hight end older cb like a Madison, 2000 etc. etc? Like everything else the web postings ate sll over the place. It can definitely be done (great audio). It definitely can't be done. So can on get an hf too sound good to excellent or not?
 

Yes amateur radios are not the best on am, , they are mostly designed for ssb and cw not am. You have probably noticed they only run around 25 watts also...
I have an ALINCO DX70T , which runs 45 watts on am and it sounds good<they tell me that on 75 meters>., You might want to pick one up, they go for $375 usually or less, 100 watts on ssb, 45 on am, and to modify if I remember remove a diode or two<it is on the internet>.
Look on qthdotcom for hf radios, or search MARS<radios are opened there>.
73
DOCTOR/795
 
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Thanks for the information. I failed to mention that I'm not yet a licensed ham operator . I hope to have my technicians license towards the end of the summer. I know my operating privileges will be limited but I'm hopeing there will be operaters that use AM on the band's a technicians license allows one to operate. I do own two ef Johnson transmitters but don't have the real estate that's need to add one to my station. I'm hopeing to get many replyes to my post. I will research every suggested transceiver that has the capacity of sounding good on AM. It would be great to be able to switch between ssb and AM without having to change radios. I know there are boat anchors that sound great on ssb and AM. It baffles me why one of the manufactures of hf transceivers doesn't put the audio technology that I'm sure is available to get a transceiver to sound excellent on AM as thay do on ssb. If I'm understanding the hf's actually insert a carrier while using the AM mode. My technical understanding is poor but from what I'm getting it a quasi AM and not true amplitude modulation being transmitted from them. My Madison sounds great on ssb as well as AM. Why isn't there an hf that can do the same? Is it because it's 11 meters? I know many cb's can be moded to operate into the 10 meter band. I'm assuming that if a Madison sounds as good on 10 as it sounds on 11 (dont know won't bootleg) meters the technology should also work on 15 20 and so on but that's way out of my knowledge and understanding of radio communications. Thanks my friend and happy dxing. P.s. please don't be to rough on me i If there's something in this post that's so far off. I'm a slow learner and have never understood much beyond keying the mic Thanks again.
Yes amateur radios are not the best on am, , they are mostly designed for ssb and cw not am. You have probably noticed they only run around 25 watts also...
I have an ALINCO DX70T , which runs 45 watts on am and it sounds good<they tell me that on 75 meters>., You might want to pick one up, they go for $375 usually or less, 100 watts on ssb, 45 on am, and to modify if I remember remove a diode or two<it is on the internet>.
Look on qthdotcom for hf radios, or search MARS<radios are opened there>.
73
DOCTOR/795
 
Amateur HF radios aren't really designed for AM operation. I'm pretty sure the only reason they even have an AM mode is to listen to broadcasts in the GC portion of the receiver.

If you absolutely MUST run an HF rig on AM make sure to keep the carrier WAY down.

Better to keep an HF rig for SSB and a regular CB for AM.
 
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Well, not to burst the bubble before you start but in the US a Tech. class has only one location I know of where you may operate Ancient Modulation and that is 6 meters on 50.400. and activity is almost non-existent.
The Tech class is Not allowed to operate AM mode on 10m only SSB and CW.
The General and Extra class has a few more options.

However 99.9% of all Amateur Radio "Voice" operations Worldwide on HF use SSB.
There are a few specific locations (frequencies) where AM is operated on HF, but the space for accepted operation is limited, and is frowned on anywhere else.
The AM vs. SSB war was fought and lost on HF over 50 yrs ago, and SSB won.
Sorry but that's the facts!
The most avid AM operators will tell you, that it's a losing proposition to try and operate outside of those specific "windows" where AM operation is considered acceptable.
All the Best
Gary
 
There is a LOT of misunderstanding as to the operation of an HF radio on AM. First off ALL AM transmitters insert a carrier. That is what AM is.....a modulated carrier. Operation of an HF radio is quite different than a CB radio. On CB power levels are changed when you flip the mode switch from 4 watts on AM to 12 watts on SSB. With an HF radio the power is continuously variable on ALL modes and the operator is responsible for operating it correctly. Also most CB'ers and some hams do not understand that the typical 100 watt HF radio is in fact putting out 100 watts when the AM carrier is set to 25 watts because a properly modulated AM carrier of 25 watts will peak to 100 watts. Try and squeeze any more out of it and it will sound like crap and be undermodulated due to ALC compression. Most of the crappy AM performance of HF radios is due to improper and most likely uninformed operation. The last thing is that most CB'ers are so used to LOUD!! audio that they do not fully understand what NORMAL AM actually sounds like. Modern HF radios can be made to sound quite reasonable on AM if the operator is aware of the requirements of what it takes to do so.
 
if i remember right from the old days some rigs had to have a am filter for it to work in the am mode right,,, the ones with gc reception had it built in but needed passband and such to sound good,,,,
 
Define "good sounding". On CB it usually means that its bass heavy crud with too much emphasis on lower frequencies so it both lacks articulation and doesn't sound like the person does in real life.

Amateur radio is about communications quality, the aim on AM to sound as much like the person would in the same room within a 6kHz bandwidth which CBers seem to not care about.

If you want to sound like a broadcast station get a broadcast station license.
 
I've been told my icom 746 sounds really good and like me. I haved used it for 11m AM dx a couple times and got good responses back. Clean clear audio. I don't run my my mic gain or rf power all the way open either. 8-10 is as far as I go. I use the stock hm-12 mic with it.
 
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