What rigs do you use for AM operation and why do you like using AM?
Displaying 1-15 of 15
| Sep 1st 2011, 00:42 | |
W1RFIAdminTotal Topics: 0 Total Posts: 0 |
Okay, we aren't lively enougn on this forum, so let me start a topic. Hopefully, we can get a lot of good pointers and URLs that I can use to update one of ARRL's technical information pages. In one of the other forum areas, there was a brief discussion of AM operation, with a poll. The poll did show that a number of hams are interested in AM operation, so let's start a thread that is focused more on getting people who use the mode to share more information with those that might be interested in trying it. Now, I'm a CW op, so phone of all sorts is rare for me. But in the AM circles, I've noted that some are focused on using older equipment, using converted broadcast transmitters and homebrew designs, while others simply take their modern transceiver and try its AM mode. (Occasionally, the some of the first group have been a bit less than supportive of those using commercial SSB/CW/digital equipment in the AM mode, but that's what I have used the times I've operated AM.) So, if the proponents of AM can explain what they like about the mode, and offer some encouragement and advice to those who haven't yet tried it, we may be able to get a few more folks trying something new for them, even if it's the oldest phone mode we have. Those interested in learning can ask a few questions, and hopefully, one of the experienced AM folks will be willing to serve as an Elmer. And let's avoid the terms "slopbucket, ancient modulation and ricebox." I'd think that those that like AM will do better at getting others interested if they use kinder terms for the non-AM phone modes and the non-tube rigs than some like to use. In my world of QRP, we are usually delighted when a QRO op cranks down the 100 watt rig and gives QRP a try. "Real" QRPers usually are into homebrewing and "real" QRP rigs, but being a QRPer, or AMer, or anything else in ham radio, does not necessarily mean that one is interested ONLY in that mode or operating convention. 73, Ed Hare, W1RFI ARRL Lab Technical forums moderator |
| Sep 1st 2011, 06:01 | |
KM3FTotal Topics: 0 Total Posts: 0 |
Here is an example of something a bit rare for AM. On 2 meters I normally run SSB using a transverter 28 to 144 conversion driving a solid state amplifier 30 watts in 160 watts out. However, wanting to be all mode, I modified the transverter input for adjustable RF drive so the output could be controlled downward for AM mode operation. Sometimes we use this mode for the evening just to be different and for the audio. Point is, there are some things to know about setting up for AM using equipment meant for either SSB or FM. Basicly for my equipment, the transverter output full on is about 28 watts + driving an amplifier that is matched to that power level for peak envelope power without over driving either unit. Going to AM mode and staying within the equipment linear operation, required the transverter drive to be lowered to about 7 watts carrier output into the amplifier who's max drive is 30 watts. What all this means is 7 watt carrier x 4 = 28 watts peak envolope modulation AM power drive to the same amplifier without over driving either unit and causing distortion and splatter. These are the types of operating parameters not often known to many hams for setting up to use the AM mode cleanly with the equipment at hand and why it needs to be considered. How neat is it to have a 150 watts clean peak envolope power on 2 meters AM and still be able to use "clean" speech processing and outboard/inboard audio EQ when needed for the long haul contacts in either mode. Works really nice for me. |
| Sep 19th 2011, 16:39 | |
K8WHBTotal Topics: 0 Total Posts: 0 |
Ed, it has been many many moons since I've operated 2M AM - back when I was first licensed (1962) 2M AM was the only phone a Novice could do. With the help of my uncle I constructed a 2M AM transmitter from an article in the Handbook and had a ball with it. Presently I'm just running FM & packet on 2M, but I have plans to build a plate-modulated AM amp for 2M using my FM rig as the oscillator/multiplier chain (and tapping the audio circuitry to drive the modulator). Not sure if I'll do it solid state or tube, though I'm tending toward using a 4X150 or a 4CX250 (my Kenwood TM-D710 should be able to drive either tube just fine). |
| Sep 21st 2011, 01:59 | |
W8JITotal Topics: 0 Total Posts: 0 |
Some modern SSB rigs are much cleaner than old "plate" modulated rigs. This is because of nonlinearity when a beam power tetrode is modulated. As a matter of fact, it is impossible to plate modulate a tetrode properly. It has to be modulated on a grid as well as the plate, or in an earlier stage along with the plate, or have a complex form of envelope correction. The only PA stage that can be directly plate modulated with low distortion is a triode hard-switched with RF drive. Pro-iron folks are not necessarily correct. A typical FT1000D, properly adjusted, produces much better AM than almost any older plate modulated rig. Most other solid state SSB radios will too, with fixed external ALC bias applied. http://www.w8ji.com/amplitude_modulation.htm 73 Tom |
| Sep 24th 2011, 00:58 | |
WA2CWATotal Topics: 0 Total Posts: 0 |
I presently spend most of my AM operating using a Flex 5000 driving an old Heath SB-200. Although the rig doesn't glow as pretty as my tube receivers and transmitters, my screen has lots of pretty colors. The quality of the AM reception and the great quality of the transmitted audio, are hard to beat. After using one of these rigs, it's hard to go back to some old tube rig other then for nostalgic or sentimental reasons. Probably why I keep my Heatkit Apache around. It's the first transmitter I built after I passed my General Class license. Pete, wa2cwa |
| Oct 6th 2011, 16:24 | |
KF0XOTotal Topics: 0 Total Posts: 0 |
I have an old DX-100 and an SP-600 that I use on HF for AM and I always get good reports. However it is s myth that you need to use old boat anchors to have a good time on HF AM. I have also used an Icon 756 Pro and the audio was very good. I just didn't mention my rig unless I was asked. I have always liked AM and tubes. I believe that tubes give a richer warmer sound. If you want to get on you can do it for less than 200 bucks. You don't need big amps or large antennas. All you need is a goot transmitter (DX-35) for example, reasonable receiver,( Halicrafters S-40) and a dipole. That will get you on 20 meters 14.286 or up on 10 meters 28.1 to 28.2 . There you can have a great time, meet alot of good people and hear great quality audio. All with stuff you can get at a ham fest at very reasonable prices. 73 Norb KF0XO |
| Oct 7th 2011, 00:54 | |
WA2CWATotal Topics: 0 Total Posts: 0 |
I suspect you really meant to say 29.0 to 29.2 MHz. Phone band starts at 28.3 MHz. Pete, wa2cwa |
| Oct 11th 2011, 02:19 | |
K4TOJTotal Topics: 0 Total Posts: 0 |
Here's a question about something I've noticed while looking at transceivers. I have a Kenwood TS-930S which will transmit 100W in all modes including AM. Most of the current rigs may transmit 100W in all modes but AM. For some reason, they limit AM to 25W, 40W or 50W max. So the question I have is why is this? Do they limit AM because they don't make the finals like they used to? |
| Oct 12th 2011, 18:56 | |
W1VTSuper Moderator Total Topics: 0 Total Posts: 0 |
Yes, things are much different these days. Today, the final does all the work. Thus, the final not only produces the 25 watts of carrier power, but the sidebands as well. This requires a linear amplifier, which has less efficiency than class C amplifiers used in the old days. More heat produced for the same amount of power. In the old days, the final produced just the RF carrier--there was a separate high power audio amplifier and modulation transformer to produce the high level audio for plate modulation. This worked well, but you added additional size and weight—those rigs are big and heavy! Zack Lau W1VT ARRL Senior Lab Engineer |
| Oct 12th 2011, 22:05 | |
W8JITotal Topics: 0 Total Posts: 0 |
Your TS930 will not run 100 watts of AM. If you read the manual, the carrier power is supposed to be adjusted to 15-20 watts carrier OUTPUT power. Older rigs were rated in input power. Your Kenwood is rated 80 watts AM input power, and 15-20 watts carrier output power. Nearly all AM rigs, at least for Ham use, were a combination of screen and plate modulation. About 60-80% of the modulation power came from the modulator stage, with the remainder of modulation power from the screen of the PA tube. It was a combination of efficiency and plate modulation. http://www.w8ji.com/amplitude_modulation.htm Older rigs like my Ranger were 65 watts AM input power. That was about 30 watts carrier power. Remember everything prior to 1982-83 was rated in plate input power. A 2KW Heathkit SB-220 amplifier is rated at about 600 watts CW output, and around 1100 watts SSB PEP output. Those old rigs were not as big as the advertised power makes them appear because of the change from inoput power to output power in the early 1980's. 73 Tom |
| Oct 13th 2011, 05:18 | |
KE8DOTotal Topics: 0 Total Posts: 0 |
The 25 watts AM carrier power will be 100 watts PEP when modulated 100%. Also, on AM the heating effect of the full time carrier on the amplifier must be accounted for in the duty cycle. 73 Don KE8DO 35+ years FCC First Class Radio Telephone License |
| Feb 3rd 2012, 00:04 | |
VE5RBTotal Topics: 0 Total Posts: 0 |
I have sucessfully used my Yaesu FT 857 on AM. I got compliments on my audio too. I haven't been on the air much latelt but I really enjoyed AM. |
| Feb 3rd 2012, 19:22 | |
W1RFIAdminTotal Topics: 0 Total Posts: 0 |
At 100 watts of carrier power, the rig would be flat-topping very badly, generating lots of splatter up and down the band. One needs to adjust the carrier power to 15-20 watts to keep the PEP at or below the rated PEP of the rig. It's wonderful to use modern rigs on AM, but keep the power level as specified for AM, to keep the rig clean and operating below the point at which it may overheat. If the rig manual doesn't specify an AM carrier level, adjust it to 25% of the PEP rating of the rig and modulate the rig accordingly. If you have an *accurate* PEP reading watt meter, adjusting the audio level until the rig achieves its PEP rating on voice peaks is as high as you want to go. Some "PEP" wattmeters significantly underestimate PEP for voice modes, so it's also a good idea to listen to your transmitted signal on a separate receiver and ensure that there is no significant splatter up and down the band. 73, Ed Hare, W1RFI |
| Sep 22nd 2023, 15:40 | |
WA3VJBTotal Topics: 0 Total Posts: 0 |
The presence of AM on HF has continued to grow in the dozen years since Ed Hare posted this topic. This allows a more comprehensive answer to Part 1 of his question. The Icom IC-7300 has become the most popular radio logged among hundreds of operators in the nationwide AM Rally that takes place early in the year. The Yaesu FTDX10 draws consistently good reaction among AMers as they welcome newcomers who select the mode and try out this transceiver. The Elecraft KX3 did a firmware upgrade which added AM to transmit and receive, encouraging licensed radio hobbyists to try the mode on transmit as well as in SWL activity. The Anan, Flex, and Sun SDR transceivers all produce outstanding AM on transmit and receive, according to those of us who have worked the stations and may own these rigs ourselves. There today is a commercially built, quarter kilowatt AM transmitter for 40-80-160 meters called the "Super Senior" from Index Labs that has sold dozens of examples to AM enthusiasts. Reception of AM activity on HF has been greatly enhanced by internet-based SDR receivers such as the constellations offered by the KiwiSDR and WebSDR platforms. The ARRL has embraced the activity of AM on HF with a showcase restoration of a retired broadcast transmitter now on 75 and 160 meters; a QST Product Review of the Super Senior, and the dedication to AM of the weeknight voice bulletin outlet of W1AW on 7290Kc. Because of these developments, we in the AM community seldom hear judgments of people not using "vintage" vacuum tube rigs to join us on the bands. Advice and fellowship exist among several internet pages on the topic, including two on Facebook, one on QRZ.com, and two independent websites, amfone.net, and amwindow.org. I help manage this one: www.facebook.com/groups/amodgroup/ Mod-U-Later Paul/VJB |
| Nov 23rd 2023, 15:25 | |
KQ4GUITotal Topics: 0 Total Posts: 0 |
I am going to be using my FT-840 this Friday- Sunday for the AM jamboree. I will be using 25w hoping to make 25 QSOs for an award! I hope there will be enough hams who will be using AM and will be able to hear me. |
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