- May 18, 2020 at 8:31 am #114979
Yes, I’ve joined the majority on these hobby radio forums and made the switch to AM!
Oldies WMRK is now on 1630 in Toronto.
Recently purchased a Talking Sign(predecessor of the Procaster) from a forum member in like new condition, believe it was Artisan’s originally, and certified with RSS-210 section A2-2/part 15 FCC, operating at 90 mW into antenna(lab test results), with 3 meter 14 gauge wire antenna indoors taped to a wall, I get better range then my Decade MS-100 BETS-1 did.
Did another walk around test with a Sangean radio and a passive tuneable loop and with the loop did 1 1/2 to 2 times times the range I was getting with the MS-100! Listenable.
With the loop it’s as good as the car but would have a hard time doing a video with a radio, Grundig loop, and a camera! Don’t have anyone to carry the camera.
I realize I don’t need the outdoor set up as the indoor install is good. A little humming was solved(almost) by using a desktop “brick” style 12 volt power supply but a little humming is there with computer and compressor/EQ connected but changing radio position nulls it.
The tunable loop in the right position eliminates the hum too. But the hum wasn’t outside. I will get another desk top power supply for the compressor as it takes 12 volts also. But may consider a Schlockwood 200 AM processor.
FM here, unless I move was just not good anymore….one spot left here and on that frequency 90.7 the only place with space each side has a repeater station there that duplicates a local CBC station about 60 miles north of here and comes in sometimes and kills my range.
Yes, AM has lots of space to go, a simple set up similar to FM gets you legally farther, MUCH farther in the USA, no field strength restriction and is much safer. The only disadvantage…not as good audio fidelity but with tweaking it’s not bad and that is outweighed by other advantages. I grew up with AM anyways. The Talking Sign has full sounding audio and does sound as good as the other stations.
Don’t get quite to the volume of the other stations as Gerry at Procaster told me it does only 85% modulation but not a big deal. If I tried to give it more volume that the Sean Cuthbert compressor is allowing it would just cause splatter. If I can find another of these I will get a second.
So there it is. I am converted. Hobbybroadcaster may like me now.
AM is your friend and I see that now. Feel more connected now as more do AM than FM with this hobby and yes I see why. Harder to get listeners but It doesn’t matter to me as much as it did before.
Update: After realizing that the Talking sign was not frequency accurate and a constant tone drowned me out when the sky wave kicked in at night and couldn’t adjust the frequency to stop the beating with the other stations in July 2020 I got a procaster new and that replaced the Talking Sign and works perfect. On 1630. Thought I would go back and update this old post.May 18, 2020 at 12:29 pm #114982
Very interesting post and thanks for sharing your thoughts and experiences.
AM is still my preferred way to reach out, including to my most important, and probably only, listener…Me..
Your comment about AM ‘fidelity” deserves a bit of a contradicting response. My AM system has a measured audio bandwidth of 20 to 17000 Hz,, better than FM due to the FM stereo pilot which limits the audio to about 15000 Hz. The measured THD from transmitter input to receiver output (using my BC 1004 C) is less than one percent. One down side is it is not stereo. Admittedly, the failure in AM is background noise and poor receivers. Like most things, AM is a trade off, the most advantageous being the greater range compared to legal FM.
NeilMay 18, 2020 at 12:43 pm #114983
Reply to Neil..
Is the response of 20-17000 HZ the frequency response of the transmitter itself or what you are getting on the air? It’s the radio end of things that limits it as it has to fit in the narrower plus or minus 5 kHz allowed bandwidth, unless you have a GE super that has the wide feature.
Would like to find another one of these Talking Signs for back up but if this stops working I can always get a Procaster and use it like this one. This one is convenient as the tuning of the antenna meter is external with control on back. This was 1/3 the price of the procaster.May 19, 2020 at 6:18 am #114988ArtisanRadioParticipant
Total posts : 529
<p>Yes, that is likely the transmitter I sold to that Forum member.</p><p>I’ve found that RSS210/Part 15 AM transmitter range is highly dependent on where you live, far more than legal FM.</p><p>When I was on Bowen Island, I was never able to get much range from AM transmitters, and that included the Talking Sign, Procaster and Hamilton Rangemaster. That was because the island was a rock sticking out of the ocean, and had very poor ground conductivity. Even where my house was in the middle of nowhere with little electrical interference, range was negligible. It was even worse where I had my storefront, due to man made noise from surrounding stores, and a nearby hydro substation.</p><p>All that changed when I moved to the Vancouver mainland in my current location, which is basically a river flood plain. Ground conductivity is excellent, and range with the same transmitters, even in a suburban area, increased noticeably. I was able to hear the Talking Sign you own up to a mile away on a decent car radio. Mind you, that was with a ‘creative’ installation – I mounted the transmitter on the ceiling of a room with an outside wall, drilled a hole in that wall and ran the antenna wire through the hole and up a pvc pipe to get it as high as possible (and away from any inside interference). The tip of the wire was above the roofline of my one level house, and it made a huge difference – range was pretty much identical to a Procaster I had mounted on my roof.</p>May 19, 2020 at 12:25 pm #114991
Mark asked “Is the response of 20-17000 HZ the frequency response of the transmitter itself or what you are getting on the air?”
The audio response and THD were measured from the transmitter input to the receiver output. The BC-1004 receiver I use has an adjustable IF bandpass with steep skirts, and it was set to maximum IF BW for the test (specified +/- 16 kHz) hence my comment about poor receivers. The frequency response of the audio section of the transmitter was measured to be 20 to 17000 Hz which suggests that this in the limiting factor in my system and it matches the bandwidth of the receiver.
Be this as it may, we cannot practically realize the audio frequency response I reported since, I assume, not many folks have wide IF AM receivers. It is not a failure of AM per se but is rather a failure of availability of good receivers and legal limitations on AM broadcast bandwidth..
NeilMay 20, 2020 at 10:55 am #114993RichParticipant
Total posts : 196
Clearly Neil has taken the time to design, install, and optimize his transmit antenna system in order to achieve that 15-16 kHz audio frequency response at the output of his receiver.
Even if/when the transmitter itself has that modulating bandwidth, probably the r-f bandwidth of most Part 15 AM antenna systems, perfectly optimized, is narrower than usefully will pass all of those r-f sidebands out to carrier freq +/-16 kHz.May 20, 2020 at 4:10 pm #115005
Switched to 1500 from 1670 as radios sold before 1990 don’t get there. If I remember even the GE Super doesn’t have the expanded band. Only the Super radio 3 has the expanded band.
Mentioned that I wasn’t getting to the volume of the other stations with the line input so I tried to see what would happen with the MIC in jack which is a tip ring sleeve 3.5mm female audio jack and it worked much better! sounded clearer and got to the level of the other stations with lots to spare from the output of the Sean Cuthbert processor. Go figure!
Sent Gerry(Procaster) an email about that for advise if that’s the way it should be or not.May 20, 2020 at 10:13 pm #115008
My comments re AM “fidelity” were directed to the technology and for support I included measurements of my system. There is nothing inherently limiting the AM bandwidth other than legal restrictions. As I read Part 15 rules, there is no restriction on bandwidth of such transmissions.
Rich commented that the audio bandwidth may be limited by the transmitter antenna Q and he is correct, however, my measurements were made using a base coil tuned antenna attached to my transmitter so the Q may be lower than assumed.
Anyway, it is rather moot since the frequency response of my system is beyond that available to most users of AM and is therefore academic, and my point is that limitations on AM radio are legislative and not technical.
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