AM TX Settings

Here are the tips that I have received from on the air tests. Of course if your microphone or voice is much different than mine, there may need to be some different audio settings.

I use the Yaesu Dynamic Microphone MD-100a8x. Dynamic low impedance mikes are less prone to rf getting into them by the way, as compared to condenser and high impedance mikes. Normally I run this mike with out using any of the audio tailoring options switch able on the bottom of the mike base. However in the AM mode, it was suggested that I run this mike with the High Emphasis enabled, and low cut off. It works good for me this way in AM mode, but I have all these options by passed for ssb (thru switch setting).

Turn off the mike processor, and set audio gain where you normally use it for sideband (11-12 o'clock or so?) Adjust the Rf power output to no more than 25 watts. Speak into the mike and adjust the Rf for the best output where the rf output meter doesn't show any downward swings. A slight wiggle is ok, but no downward dippings as you speak. If it does, your audio will be muddy and poor quality. Be careful of the AM tube operators that speak of upward modulation settings. For them on the tube circuits that support it, that is very desirable .... you cant adjust the MP for that anyway.

I found that making adjustments a few inches from the mike is best, but be careful to not get to close to the mike after you make your settings, or you will see the dipping. It is easier to speak lower and quieter in the AM mode and still have good audio, than in ssb where we speak up to keep the meter output readings peaking You can experiment with the EDSP on and off for audio checks. I have my menu 4-4 Tx Audio Edsp set to 3. With the EDSP button by the Contour knob off, my audio is crisper. With it on, I have a fuller sound. To those that have a good S meter reading on me compared to their noise, some like the Edsp on during Tx. For those that I am weaker to, of course they like the better intelligibility of the Edsp off.

Menu 5-9 Tx Edsp Filter 6.0 kHz / 2.0 kHz makes no difference in the AM mode. I have mine set to 2.4 for use in Ssb though.... at least until the Fcc says it is ok to run 6 kHz wide transmitted single side band. I have heard rumors that they might start ticketing those that are running 6 kHz ..... some OO's are now sending warnings to those that they hear operating this way.

One guy says he limits his MP rf output to 10 watts and feeds an external linear amp for a couple hundred to four hundred watts.... he sounded great in AM mode! He also runs the Yaesu Dynamic Microphone MD-100a8x. Because of the power output and class A audio difference with the MkV, and its different way of setting filter characteristics, I don't know what the settings are there.... I would suspect that 50 watts would be the output setting area, class A audio, and the rest about the same.

For the Field model of the 1000, I would expect the same as the MkV except back to the 25 watt output level as the MP.

I would be interested in hearing from others that have worked that out for those two rigs.

73 from Bill - WD8ARZ

Further Commentary on HF Audio:

Here is a partial review of the various aspects of hf transmitted audio so as to reduce the confusion between personal choices vs performance. This applies to all radios, and not just to FT1000MP. I am also specifically meaning SSB or AM audio and not FM. I am also ignoring overall power output, but comparing the same signal under different audio situations.

There are various exceptions to parts of what is discussed here, there always are. Please keep in mind the over all objective and points being made, and not getting lost in the exceptions, if, than and buts....thank you in advance.

How audio "sounds" is greatly affected by what method is being used to "hear" it. I am ignoring the differences between speakers, headphones, internal vs. external, etc. But those do make a over all big difference, especially to reduce listening fatigue. What I am referring to is whither your listening to your self through the monitor mode, your asking a local within a couple of miles of you, a local less than 50 miles, one between 100 and 300 miles, one more than a thousand miles away, and band conditions at the time of the check. Band conditions are QRM, QRN, fading, and weak or strong signal conditions. Lets not forget that the person receiving your audio also has adjustments that make a difference, not to mention his/her own ear performance (did I mention attitude?? hi hi).

It is human nature to want to hear the best possible audio and for it to be as natural as possible, if the bandwidth allows it. However what sounds "good" and what is intelligible are not the same things. By intelligible I mean the ability for your spoken words to be understood, "to be heard". Research has proven over and over again that intelligibility is in the higher frequency components of speech, and not in the lower. However hifi sounds is generally supported with the lower frequency range. Thus 100hz -3800hz audio will sound great and be preferred by most listeners, and 400-2000hz will be judged to narrow. Pushing higher audio frequencies with out lows will also be crispy and annoying to some.......but... Facts are that there is more energy in low frequency components of audio and your RF output. Thus your RF output will put most of its power into the low frequencies, And This Part Of Your Signal Will Travel Farther As It Is Stronger In Watts. So it should be easy to see that tests with locals will provide high frequency components to your signal that those Further Away May Not Receive As Well, Or At All. Lost higher frequencies in your audio means reduced or lost intelligibility. Its a fact that 300/400-19900/2100 range audio is considerably more intelligible under noisy, long range communications....even though it receives poor Local reports. Even though the higher frequency components may be in your signal when they leave your station along with the lows, the received side is swamped with the lows, and the highs cant be sorted out very well, especially in noisy conditions.

Bottom line is that there is no ONE way to set your various audio adjustments to meet all the different Qso circumstances that exist. That's why the adjustments are in the radio in the first place, so you can Change them to suit the situation at hand. For local or strong signal conditions with out Qrm/Qrn use wide audio range settings, and little to no compression. For other circumstances start reducing the lows, increasing the highs, and use some compression. It is not unusual for a far station to love your audio, and one close in to complain about it.....but the one complaining can still make out what your saying, Satisfy the local or strong signal, and sacrifice the further weaker one. A weaker signal can out perform a stronger one on long haul contacts just due to audio characteristics.

Keep in mind that compression will average out audio output for the entire audio frequency range being used. Thus if your sending lots of lows, lows will dominate the compression effects. That's why some start at the mike for setting the first audio range, then the if filters, and any DSP options.

If you have tailored your audio to fit the long haul HF QSO, and used narrow if filters, and some compression to keep your low audio output level up, your transmitting signal will be so much more effective because its power is being used to transmit Intelligible audio that is needed on the other end, and not wasted in lows that don't support intelligibility.

It should now be clearer that the settings used in transmitting and receiving HF signals can have a lot of options. Just because they are not set for the circumstances being used doesn't make the radio a good one or a bad one. Good audio starts with your vocal cords, the noise in your room, the mike, runs through the entire radio to the antenna, HF conditions, the receiver, speaker and ears on the other end. A problem with any part of that path can ruin audio. Many older folks or noise damaged ears suffer in the higher frequencies. It is normal for them to compensate their audio to make up for what their ears are poor at. So before saying good or bad, why not instead compare the circumstances and say better than or worse than, or for this circumstance its............etc, but more importantly, Can The
Words Be Made Out?

I especially like using mode/filter diversity techniques in dual receiver rigs. Bringing the human brain into play to sort signal information is very effective in copying signals under various conditions. When the left ear hears one version, and the right ear a different version, a spatial effect, almost 3d kicks in that make for very enjoyable listening of what was poor audio or band conditions. But if the information needed is not in the signal to begin with, or is not in proportion to the ability to sort it, even this technique doesn't help. (On a AM shortwave station, put one receiver on Usb, and the other on Lsb. Use stereo speakers or headphones.
Also try wide filters on one, narrow on the other, DSP on one, not on the other, etc etc. Similar effects for Ssb and terrific affects for Cw)

Distortion is due to wrong impedance mikes, too high gain levels, wrong AGC settings, RFI, alc, phase noise in switching power supplies, incorrect filter or DSP settings, poor antenna connections or bad coax, phase/fading band conditions, signal overload, noise blanker on with strong signals not far away from the operating frequency, low battery voltage, shielding and grounding problems, etc etc. Distortion is not what I am trying to discuss here, just to avoid it.... hi hi Distortion is not the same as frequency effects.

Sorry, but I can not respond to requests for help with certain makes or models of gear, or circumstances that you use it under. But it is hoped that this simplified generic treatment of audio will help you develop a plan to evaluate the way you configure your radio so you can find what is best for your gear, voice/ears, HF conditions, distance, and personal needs.

Bill Stamps - WD8ARZ wd8arz@ix.netcom.com

Adjusting the FT1000MP for AM Transmission by K1DEU

Adjusting the FT-1000 MP or most any 100 watt output SSB transceiver for AM transmission. IE. Is your voice lopsided ?

If you had a symmetrical voice, which a female or a very high pitched male have , 100% modulation of a 25 watt carrier would produce 100 watts PEP. Deep sounding males ( thanks to their larynx ) can easily be asymmetrical ( lopsided ) up to 150% which would mean that a 12.5 watt carrier would produce 100 watts PEP. I run a carrier level of 10 to 15 watts on AM for little distortion. I can push it to about 20 watts, but other fussy people notice the distortion. I also have audio phase reversal switches on my microphones. With a Oscilloscope you can quickly get your audio phase properly set for about a negative going 95 % and well over a positive going 100% ( up to 145% ) modulated carrier. Thus your output wave form would be identical to your audio input wave form. The last thing we want to do is over modulate with negative going ( over - 100% ) modulation as substantial adjacent channel noise is produced when the low level mixer is cutoff (carrier cutoff). Therefore with a MP ( 100 PEP) I recommend 15 watts and a Mark 5 ( 200 PEP ) 30 watts with audio phase set for more positive going than negative going modulation. You can feed your mike directly into a scope to check your asymmetry. But put scope on RF for proper phase setting as even some factory mikes are backwards. In SSB there is no need for any phase check.

With no modulation .. RF power level on front panel fully clockwise. AM position. Set internal carrier level pot to 15 watts output for a MP... 30 watts for a Mark 5. These are the maximum carrier amounts for an asymmetrical (male) voice ! he 15 watts applies to any 100 watt PEP output transmitter. Now when you modulate, crank up the Mike gain watching a watt meter on Average ( not peak ) Power, until the carrier power only occasionally kicks downward. This downward kick is your carrier being cutoff, resulting in distortion. No downward deflection would be distortion free. Without compression or peak limiting a little downward would be acceptable to keep the average up. If you monitor yourself with good headphones ( I like Sony CD10's about $20) , as you bring up the Mike gain you should hear the distortion as you start to kick your external average watt meter downward. When set properly with little average downward, now observe the Internal PO (power out) meter. You should see your 15 watts of carrier and as you modulate your peaks of 100 watts or slightly higher should show momentarily. Although your carrier power is only 15 watts your PEP will be 100 watts or slightly higher. Yaesu properly automatically disables ALC and Processing in AM. By the manual I set my metering menu hang time to two seconds (2000 ms) for all functions. For excellent modulation reports I use a $30 dollar Radio Shack Mike #34069 with a Radio Shack wind sock plugged into the RCA Phone Patch input on the rear and the FT-1000 MP's internal TX EQ Menu 4-4 set to #4. And then to roll off some lows on SSB ( as my voice is too bassy ) : Menu 7-7 SSb-t at 150-3100 or 200-3100 .


This site was last updated 08/27/07