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Author Topic: HF AM???  (Read 49069 times)

Posts: 1321

« Reply #30 on: October 04, 2013, 03:35:44 AM »


6146, 6146A, or 6146B? I suspect that if they are the B's, you got something that is appreciating in worth faster than a CD....probably even if they are 6146A, since the Collins rigs prefer those.

Posts: 218

« Reply #31 on: October 05, 2013, 07:51:34 AM »

They are B's. I chose them because they still are being commercially produced, albeit by our "friends" in China. However I have discovered over time they are well made, have consistent performance from tube to tube, and relatively inexpensive.

I do not see them appreciating anytime soon, at least not from scarcity. My supplier in Chongqing tells me he can fill an order of 10,000+ if need be. The prices I see them sold in the West is ludicrous considering the cost at wholesale. The fact that they are in current production, and are in no way scarce, tells me retailers here are taking advantage of people who think no tubes are being manufactured anymore or just satisfying the audiophile fools who think if its expensive it must be better.

Still with my project on hold (most likely until the recession effects slackens) I have all these tubes. Grrr ... I hate bankers; especially, when they take on high risks for personal profit that put us all in financial jeopardy.


Posts: 4546

« Reply #32 on: October 05, 2013, 08:01:13 AM »

But, but, but... Without the wealthy many of us would be poor, financially insecure, afraid of illness, and living from paycheck to paycheck......................

Uhhhhhhhhhhhhhh.  I suppose.   Tongue


Posts: 60

« Reply #33 on: October 14, 2013, 08:32:40 PM »

AM is not in the Privileges, of the Tech Class. Upper SSB 28.3 to 28.5Mhz. CW and Digital
 modes 28.0 to 28.5 Mhz. 200 Watts of power.On 10 meters you are granted the Novice Class
 Privileges. If you want to Operate  10 meter AM get your General.
                        Stan K6RMR

Posts: 218

« Reply #34 on: October 19, 2013, 07:06:40 PM »

Strictly speaking in regard to privileges set forth in Part 97, in addition to J3E - amplitude modulation telephony, single sideband, with suppressed carrier, Technician, Technician Plus and Novice can use R3E -amplitude modulation telephony, single sideband, with vestigial carrier within 28.300 to 28.500. Which is basically AM with carrier but only one sideband. The 200W PEP power limit still applies, which with R3E would be 50W carrier (as a vestigial carrier) with only LSB being suppressed.

Also RTTY and Data are limited to 28.000 to 28.300 and CW is 28.000 to 28.500 for Technician, Plus and Novice.

See FCC Rules Part 97.307 paragraph 10

The ARRL Band Plan does not reflect this; however, that is not the where the privileges are defined. That's done in the FCC Part 97.

And just to be clear, technically SSB (J3E) is AM. However, in J3E the carrier and one sideband is suppressed. So Stan, if you are upset by heterodyne on 10m between 28.300 to 28.500, go to another part of the band.  Smiley

John, W2WDX
« Last Edit: October 19, 2013, 07:45:42 PM by W2WDX » Logged


Posts: 218

« Reply #35 on: October 19, 2013, 09:24:48 PM »

A bit more specific information about R3E emission type...

§ 97.307(a) states, No amateur station transmission shall occupy more bandwidth than necessary for the information rate and emission type being transmitted, in accordance with good amateur practice.

Good amateur practice is considered by the FCC as adhering to, as a minimum, the emission and bandwidth specifications outlined in the FCC rules (Part 2.201 & Part 2.202). Experimentation can be an exception to this in the Amateur Service. In the FCC rules, emission type specifications for all services (including the Amateur Service) are defined in Title 47, Chapter I, Subpart C, Part 2.201.

In it it states that R3E is defined as R -Single-sideband, reduced or variable level carrier 3- single channel E - Telephony

In § 2.202(b) they go on to define necessary bandwidth.

(b) Necessary bandwidth. For a given class of emission, the minimum value of the occupied bandwidth sufficient to ensure the transmission of information at the rate and with the quality required for the system employed, under specified conditions. Emissions useful for the good functioning of the receiving equipment as, for example, the emission corresponding to the carrier of reduced carrier systems, shall be included in the necessary bandwidth.

In later subsequent sections they go on to state. "... for all services the term Communications Quality is used as reference to Commercial Quality as outlined in the table in § 2.202(g)"

This means that in the Amateur Service R3E is defined in the rules as Single-sideband, reduced or variable level carrier, single analog channel telephony using a bandwidth of Bn=M or 2.99kHz. Furthermore, the carrier is determined such as to be useful for the good functioning of the receiving equipment.

As a general rule the R3E carrier reduction is at least 16dB below the maximum peak-envelope-power as corresponding to 100% modulation. Where with J3E it is at least 40dB below the maximum peak-envelope-power at 100% modulation.

John, W2WDX
« Last Edit: October 19, 2013, 09:57:14 PM by W2WDX » Logged

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