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 Post subject: 0-100 Log Scale to Khz.
PostPosted: May Sun 04, 2014 9:38 pm 
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Joined: Aug Sat 31, 2013 11:22 pm
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Location: Ft.Worth, Texas
Does anyone have a scan or a link to a 0-100 log scale to modern KHz ? Thanks

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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Sun 04, 2014 9:49 pm 
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Location: Vieques,PR 00765 USA
No such thing, really. Every tuning capacitor would give somewhat different results.

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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Sun 04, 2014 9:59 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Some early radios came with a log so customers could write down dial numbers vs. frequency. About the only thing we can say is lower numbers were higher frequency. Agree with Bill.

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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Sun 04, 2014 10:04 pm 
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Joined: Aug Sat 31, 2013 11:22 pm
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Location: Ft.Worth, Texas
Thanks. I thought their might be a quick reference somewhere.

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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Sun 04, 2014 10:35 pm 
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I assume we are talking about "log" as in logging. As stated the scale would be totally arbitrary, and would depend on the specific design of the set. Since every set is different, there would be no standard reference / "decoder ring"

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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Sun 04, 2014 10:40 pm 
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Joined: Aug Mon 16, 2010 7:01 pm
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Location: USA
I never thought of log scales as anything useful. You can log reception of stations with the frequency anyway, and that would be more meaningful when comparing different radio sets. Seems that log scales were just to give the impression that the radio has one more band on it :lol:


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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Mon 05, 2014 12:51 am 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Silver Spring MD, USA
If the scale has a fine enough resolution, then it can be helpful for logging shortwave or amateurs on crowded bands. With an analog dial, sometimes just a small turn will tune onto another station. That's where that log scale might come in handy for noting that spot for future reference.

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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Mon 05, 2014 1:03 am 
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Location: Ft.Worth, Texas
I just figured that 50 on one radio was the same KHz and 50 on another. I didn't realize they varied that much.

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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Mon 05, 2014 1:05 am 
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Location: Santa Rosa, CA
Log scales were used with early TRF radios. Since each radio would receive a little bit differently (for example, depending on how the antenna loaded the first stage), manufacturers simply used arbitrary scales. When you tuned in a station that you like, you wrote down the numbers in your log. Many of the sets were "3-dialers" so you wrote down the settings of the 3 dials that gave you best reception.

Here is a log for a simple one-dial Atwater Kent set:
Image

Fancier sets had more dials, so more numbers to record.

Image

Rich


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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Mon 05, 2014 1:42 am 
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Location: Cleona, PA
On a one-dial 0 to 100 set, you can make a logging chart on a piece of graph paper. Lay out 0-100 on one axis, and let the other axis represent frequency of the band you're interested in. Now tune a number of stations with known frequency and plot them as points on the graph, the more stations the better. Depending on how the set tracks you'll see a line more or less curved resulting and you can join the points using a French curve if necessary. Then use the graph when tuning.

I did this back when I was in junior high in the fifties and interested in the 75-meter 'phone band, listening on a Heathkit AR-3 I had built. I tuned a local broadcast station on band A at 1450Kc as my fixed point, then switched to band B which put me in the middle of the 75 meter band. Then I plotted bandspread logging scale vs. frequency, the latter obtained by listening to various QSO's on the band. After I had several I saw that the plot made a straight line, which I drew with a straight edge. It was straight because the range covered was so small, and it all fit on a 3 x 5" card. Then when listening if I heard the participants say they were moving up to a given clear spot, I could move right up and be waiting spot on for the QSO to continue.

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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Mon 05, 2014 1:50 am 
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Location: Santa Rosa, CA
Quote:
I never thought of log scales as anything useful. You can log reception of stations with the frequency anyway, and that would be more meaningful when comparing different radio sets. Seems that log scales were just to give the impression that the radio has one more band on it :lol:


The point was to be able to find the same station again in the future. Think of it as the combination to a safe. You hear KDKA for example. The announcer tells you it's 1020 kcs (or 290 meters). You tweak the dial(s) on your radio for best reception and write the numbers in your log. KDKA might be at 50-37-88 on your particular radio. Set dial one at 50, dial 2 at 37, and dial 3 at 88 and you should be right on, or at least close to KDKA.

Rich


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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Mon 05, 2014 4:18 am 
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Joined: Aug Mon 18, 2008 3:17 pm
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Location: Dallas Tx.
Dials that matched the original with frequency markings were sold for specific model single dial radios. I have one on my AK 35.
The Marconi dial plates for circular plate capacitors had a 0 to 30 scale with markings closer together near 30 giving a approximate frequency increases. You still had to mark the station locations on it by call letters and/or frequency. It just made finding additional stations easier.
Straight line frequency variables usually came with marked dial plates usually with a range of 0 to 300.
PM me your email address and I'll send a couple examples.


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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Mon 05, 2014 5:13 am 
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Joined: Sep Thu 23, 2010 6:37 am
Posts: 12437
Location: Powell River BC Canada
There were three tuning schemes:

Straight line frequency, straight line wavelength, straight line capacity.

Each had their own unique shape of tuning capacitor rotors.

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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Mon 05, 2014 1:52 pm 
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Joined: Aug Mon 18, 2008 3:17 pm
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Location: Dallas Tx.
Other tuning schemes were book capacitors that had linear capacitance until around 15% closed.
And slider variable caps.
Also variable MU coils on the same tuning shaft as the variable cap.


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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Mon 05, 2014 11:54 pm 
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Location: Ohio 45177
Actual frequency dials did not really become available on BC receivers until the superhets were well into production in the 30's as it seems to me. Actually some of the TRFs of the very early 30s also had frequency as I suppose public demand required it and superhets were starting to be seen alot more. AK seemed to not have freq. on their superhet dials and some others. If you are tuning a TRF you will probably see variations in the tuning positions 1-2-3 dials. But probably nothing widely varying as they used essentially the same tuned circuits in all stages and there would be some tracking variation but not a huge amount, I would think. You will just have to determine your own dial versus KHz chart. If it is a regenerative, you will notice a variation anyway, if certain things change, like the antenna, the amount of coupling to the antenna, and even if the tube is changed.

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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Tue 06, 2014 12:39 am 
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Joined: Sep Thu 23, 2010 6:37 am
Posts: 12437
Location: Powell River BC Canada
The HRO radio had plug in coil sets, and each one had a frequency to dial number chart on the front.
The tuning dial as a big National type with digits showing in the window.

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VE7ASO VE7ZSO
Amateur Radio Literacy Club. May we help you read better.
Steve Dow
ve7aso@rac.ca


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 Post subject: Re: 0-100 Log Scale to Khz.
PostPosted: May Tue 06, 2014 1:37 am 
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Joined: Aug Mon 16, 2010 7:01 pm
Posts: 279
Location: USA
I was thinking of radios that have 2 or more scales, one labeled "log" and the other scales are marked with frequencies. In this case, log scales are not all that useful, except maybe if your favorite DX station tunes in atop a log scale mark.

Look at some radios from Australia, many had no log or frequency scales, but just radio callsigns printed on the dial.
Image
Image


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