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Post by mark on Oct 26, 2020 17:12:46 GMT
Picked up this 1970s Sony radio in mint shape. Model ICF-9550. Made in the mid 70s when radios like this were made with good AM reception and sound unlike the radios of now. Doesn't sound muffled at all. And these things lasted forever. Will be switching my station back to 1500 from 1630 with a miniscule loss in range to be received on all radios. These don't have the expanded band. 1500 is the second quietest spot at night here. So many good quality receivers to be had but you have to go into the past to get them. So for all of us on AM here's a typical receiver where your station will sound good. Notice separate bass, treble and loudness controls.  |
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Post by Boomer on Oct 26, 2020 21:04:07 GMT
I love that style of radio, the type that would be in offices of all kinds, doctor, lawyers, usually tuned to the local FM 'Beautiful Music' station. I saw them everywhere, it seemed to be de rigueur in 1970s office spaces to have a radio like that.
I have a knock-off version that would have been cheaper. It too has a nice full AM sound, with at least a 5 inch speaker. Most of the better quality AM sound comes down to having a wider IF bandwidth, and lower distortion detector in those radios.
I can see how 1500 is one of the better frequencies for Toronto, being in the pattern null of 50 kilowatt WFED 1500 in Washington DC, an opportunity for the small station. Dr. Bob also has station MRAM on 1500 as well.
Boomer
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Post by mark on Oct 27, 2020 1:35:21 GMT
Here's my new frequency dead on..  |
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Post by Boomer on Oct 27, 2020 8:03:06 GMT
Nice setup
I like 1500 also, but haven't used it for a long time. It was the first crystal-locked frequency I had. The transmitters I'd used before were all VFO, the beginner science project type. I'd gotten a surplus 1000 khz crystal and built a Colpitts oscillator circuit for it. Surprisingly it had a strong output on 1500, and I never figured out why that was, but it was repeatable, I built at least 3 of them when I got more 1 mhz crystals.
Older radios are a reason I haven't done as much in the extended band. Half of my radios don't even go to 1700, though every one makes it to 1620, even if it's right on the edge. A few older radios make it to 1650, even though they weren't designed for the expanded band.
I guess you still have your mini laptop feeding a compressor?
Boomer
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Post by mark on Oct 27, 2020 16:36:16 GMT
Yes...small laptop for Zara going to a Behringer 9 band EQ and the processor with the Procaster for compression and modulation depth.
Any radio, even the Ge supers, made before 1990 don't have the expanded band but the best radios were made in the 70s. Realistic(Radioshack), Panasonic, Sony, Hitachi, GE, Zenith....If you have one of these they are fantastic....https://www.radiomuseum.org/r/sony_tfm_7250w.html
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Post by Boomer on Oct 29, 2020 3:16:11 GMT
You'll have to change your station IDs to 1500 now, but then again it can be refreshing to go on a new frequency after using one for a long time. At least you know that at 1500, you can reach all radios, and the number itself is even and easier to remember, AM 15.
I think the compressor in the Procaster is pretty good too, I haven't really put it to the test, but sound-wise it seemed to be just fine.
Great that you have the fine Sony radio!
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Post by mark on Nov 4, 2020 0:43:43 GMT
Thanks but that Sony wasn't so great.  The front end couldn't handle the strong signal in the room with my Procaster unless I detuned the antenna greatly. Not happening. It was just distorted and I could null the signal with the tuneable loop just off peak but to hell with it. When I first tried it I was in a position where it seemed to work but moved it and it was badly distorted. Worked great on all normal commercial stations. I didn't pay much and sold it to antique place that buys stuff.
Some models don't have a good enough AGC to handle the strong signal.
As for my promos that mention frequency I have a folder for 1630 and 1500 so I can switch between those spots and just switch the folders in the broadcast laptop for Zara. I really like 1500 as you said easy to remember and sounds better than 1630.
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Post by Boomer on Nov 4, 2020 5:42:31 GMT
A common problem in that scenario! The near field of the signal is so close it can be measured in volts, and it maxes out the AGC in many radios. I get that on my carrier current station too, since I'm putting power into the AC lines that also feed the house, the signal strength is high in all rooms. Some radios can take it relatively well, others get distorted, usually starting as intermodulation on the bass, where a bass note tears up the mids and highs.
Every radio is different, and there are a few things you can do, easiest is when the radio has terminals for an external AM antenna, and you can take a short piece of wire and short the AM terminal to the ground terminal. The terminals are usually connected to a few turns of wire on the loopstick bar antenna inside of the radio, and shorting that de-senses the antenna bar, kills the 'Q' and sensitivity. That might reduce the overloading enough to get you out of distortion. You'll probably only get the strongest signals in the area after that.
Aluminum foil loops can also help, wrapping a piece around a whole radio so it meets and becomes a shorted turn might help, and I've even put foil around the internal ferrite bar to lower signals into it, especially good for open back radios.
Anyone with other ideas they've tried?
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