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Operation on 1710 kc

If you bothered to read the document you'd note the transmitter was allegedly operating at a power level 6,600 times greater than allowed on that frequency. 200,000 microvolts was the alleged field strength reading while 30 mv is allowed at 30 feet on that frequency.

Thus, operating on that frequency is fine just as long as you use an acceptable Part 15 AM transmitter that will not exceed that power level.
 
William C. Walker said:
If you bothered to read the document you'd note the transmitter was allegedly operating at a power level 6,600 times greater than allowed on that frequency. 200,000 microvolts was the alleged field strength reading while 30 mv is allowed at 30 feet on that frequency.

Thus, operating on that frequency is fine just as long as you use an acceptable Part 15 AM transmitter that will not exceed that power level.
Click to expand...

Mr. William C Walker,

If YOU bothered to read the document you would see that 30 microvolts/m is the limit, not 30 millivolts/m! There's quite a difference, in case you hadn't noticed.

Next time, don't get snippy so quickly. That's for the other board.
 
William C. Walker said:
... Thus, operating on that frequency is fine just as long as you use an acceptable Part 15 AM transmitter that will not exceed that power level.
Click to expand...

However a radiated field intensity (not a power level) of 30 microvolts/meter likely is below the electrical noise level on 1710 kHz almost everywhere outside of a screen room, so 1710 kHz is a poor choice for anyone wanting to "broadcast," legally anyway.
//
 
R. Fry said:
However a radiated field intensity (not a power level) of 30 microvolts/meter likely is below the electrical noise level on 1710 kHz almost everywhere outside of a screen room, so 1710 kHz is a poor choice for anyone wanting to "broadcast," legally anyway.
Click to expand...

Exactly! Section 15.219 is not applicable, Further, it would be difficult or impossible for most users to measure their signal to determine if it is in compliance or not. That level is so low that it's approaching the limit for spurious emissions.
 
I know that it is 30 microvolts and not 30 millivolts. Wrong abbreviation.

The point is this. You can still broadcast on 1710 regardless of whether or not Audioguy thinks it is wise not to.
 
William C. Walker said:
The point is this. You can still broadcast on 1710 regardless of whether or not Audioguy thinks it is wise not to.
Click to expand...

If an unlicensed operation on 1710 kHz is legal, then the number of potential receivers within its useful (~150 microvolt/meter) coverage contour will be limited to those within a dozen feet or so of its antenna.

The wisdom of such "broadcasting" is left to readers to decide.

Other issues here are (1) whether or not the output power of a transmitter rated for 100 milliwatts input power, Part 15 AM certified or not, can be adjusted low enough on 1710 kHz to produce the legal field when used with a given antenna system, and (2) how a typical user would know whether or not the limit was being met while having no capability of measuring it accurately -- if that was even possible given the electrical noise level compared to the legal FCC limit for 1710 kHz transmit systems.
//
 
druidhillsradio said:
One thing I do believe, this station was not operating anything close to a part 15 transmitter.
Click to expand...

I would agree with that, but there are problems for anyone who would like to operate legally on 1710. The allowed field strength is so low as to be practically unusable (30 microvolts/meter isn't a very good signal on most AM receivers). Part 15.219 does not apply, so you're on your own to determine whether the field strength is within limits. And nobody can afford the necessary equipment to measure field strength accurately. Also there don't appear to be any certified Part 15 transmitters for 1710 except the Rangemaster, and I would guess that the inclusion of 1710 on the grant was an oversight on the part of either the test lab or the FCC. In any case there's no way to adjust the unit such that you would be certain to comply with the field strength limit (except maybe to disconnect the antenna, which would defeat the whole purpose).

Perhaps we should consider asking the Commission to make 1710 available for Part 15 operation. It's doubtful that frequency is being used for much of anything right now.
 
In another thread, I gave a formula for the radiated power from an electrically-short vertical antenna over ground, given a field strength reading at a known distance from the antenna:

Pr = 1.111(10^-11)[(Ed)^2], where

Pr is the radiated power,
E is the electrical field strength in uV/m, and
d is the distance in meters from the antenna at which the field strength reading is made.

In the case of the transmitter operating on 1710 kHz discussed in this thread, E = 200,000 uV/m, and d = 114 m. Pluging E and d into the formula gives a radiated power of Pr = 5775 mW = 5.775 W. The radiated power is the total RF power generated by the antenna and radiated into space. There are power losses in the antenna, and so the output power of the transmitter is higher than the radiated power. The input power applied to the final stage is higher than the output power of the transmitter because of the inefficency of the final stage. Unless the 1710 kHz operator is using a really big antenna, the antenna efficiency is not very high. So, it is likely that the input power to the output stage of his transmitter is at least 25 watts, and maybe 50, or even 100 watts. This definitely is not a Part 15 AM transmitter operating on 1710 kHz.
 
I've mentioned in another post somewhere, that a local FCC enforcement type told me personally, that with all the FM pirate activity here in Florida, the last thing he was worrying about, was a certified Part 15 transmitter (Rangemaster) running 100 mW, 50 KHZ above 1700, unless there was an interference complaint.

Your mileage may vary. :)
 
You probably mean, "5 kHz above 1705 kHz."

Please pardon me if my question is a little indelicate, but why is Druid Hills Radio back on 1610 kHz?
 
You're joking, right? Neither the comment about Fry or your car radio seems credible. I'm persisting because I'd really like to know.
 
LibertyNT said:
Ive seen a good number of cars that only go to 1700.
Ive seen a good number that dont go past 1620 ;)
Click to expand...

1710 would sure be nice. I'd like to see a "by appointment" channel where we'd have a chance to dx these flea powers with
only one or two on channel. I have a few radios which won't go there.
Alll my old car radios I have tweaked up to get up to 1690, but lose 530,540,550.
My sangean cuts off the internal loop at 1620, so it's pretty insensitive on 1710.
On the other hand, the 1936 Philco is really good on 1710, but that's on "band 2", as BC then ended at 1500.

The problem with 1710 is cutting off huge numbers of potential listeners, vs enjoying a clear frequency.
I'd like to see 10 watts into a 10 meter antenna from 1700-1790 for radio broadcast hobbyists.
Unfortunately, in AM, anything over a watt or two will start getting into phone landlines, intermodulating with other AM signals,
cause "unintended" operation of consumer electronics on the property. Not quite as bad at BC wavelengths as SW or citzens band,
but still more than I would expect the FCC to want to open up that can of worms.
The noise created by modern switching electronics (inexplicably permitted by the FCC) exceeds the intended design stated in FCC law,
written before "square wave" operation was considered a reasonable practice. Just like iboc, the switching noise created by pulses does
not exist on one frequency, but the "squarer" the wave corner, the wider the bandwidth in RF are the modulation products.
They are an animal too ugly to be conceived of when pt 15 was written.
The FCC should either begin enforcement of the pt 15 unintentinal radiator rules, :D, or modify something in the pt 15 AM hobbyist specifications to make it possible to use the service in a way that was as effective as it was before the current switching noisemakers came in the 1970s.
 
While it is true that some car radios don't tune 1710 kHz (I've got a couple of such myself), I don't think that druidhillsradio uses one of these in his car. The broadly-grinning smiley face that he used to punctuate his car radio comment suggests to me that he didn't intend to be believed.

Most of the "dead" zone between 1710 kHz to 2000 kHz is the 160 meter ham band.
 
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