K4KYV
| Joined: | Sat, Apr 4th 1998, 00:00 | Roles: | N/A | Moderates: | N/A |
Latest Topics
| Topic | Created | Posts | Views | Last Activity |
|---|---|---|---|---|
| HOAs have their own Union! | Aug 6th 2014, 15:31 | 7 | 9,326 | on 30/1/15 |
Latest Posts
| Topic | Author | Posted On |
|---|---|---|
| QST as Downloadable PDF | w4msl | on 28/1/18 |
| Why were the old CD-ROM versions of QST that used to be available from issue one on, and prominently advertised in QST, discontinued? I purchased a set several years ago that goes up to 1929 IIRC, covering pre-1925 issues missing in my collection. The quality is not the greatest, about on par with the microfiche magazine archives you see at the public library, but at least they are readable and browsable. $25 for a one-year CD set includes two other publications that you may or may not be interested in, is a bit much. |
||
| retransmission of frequency | n2nlm | on 9/8/14 |
| > It is my understanding that t is legal to monitor the frequency, but not to disclose what was heard to a third party. That may be true with commercial two-way communications, but it does not apply to amateur radio. AR communication has no expectation of privacy, and anyone is free to record, publish or re-transmit via internet, anything heard over the air without any restrictions. I would be more careful about re-transmitting the signal over the air however, particularly regarding callsigns and station IDs, and making sure it is clear what is being re-transmitted and what originates from one's my own station. Re-transmitting another ham's signal over the air might open a can of worms best left closed but I could see no problem re-transmitting it over the internet. |
||
| 40 meters SSB | K2ADK | on 6/8/14 |
| Try listening above 7200 some more. I have found that in the past few years the foreign BC stations are thinning out. Plenty of blank spaces with no broadcasters - or hams. Often a 20-30 kHz swathe of open space in the vicinity of 7230 around 8 PM. BC activity seems more heavily concentrated on 7300-7500 than on 7200-7300. Many of the former big ones, like Voice of Russia (ex-Radio Moscow), Radio Netherlands and BBC have either gone dark entirely, or no longer beam to North America. Many countries, including USA, have severely cut back their international broadcasting budget, since nearly every country in the world claims to be hurting for money, and listeners are increasingly receiving via internet steaming rather than over-the-air short wave, which remains popular in lesser developed regions like equatorial Africa. I think a lot of hams just assume 7200-7300 will be jam-packed with BC QRM during the evening hours and don't even bother to listen. |
||
| HOAs have their own Union! | K4KYV | on 6/8/14 |
| ...and their opposition to HR4969 is up and running: "...CAI opposes H.R. 4969 and we are speaking with Members of Congress to help them understand why H.R. 4969 should not become law. Further, we will be engaging membership around the country to let members of U.S. House of Representatives know that we oppose H.R. 4969 because we support the preservation of the community association model of allowing neighbors to create reasonable rules for their neighborhoods." http://www.caionline.org/govt/advocacy/regulatory/Pages/HamRadioOperation.aspx Call to Action: Protect Your Association's Rules and Standards, Tell Your U.S. Representative to Oppose H.R. 4969 http://www.caionline.org/govt/news/blog/Lists/Posts/Post.aspx?ID=112 |
||
| Hi Fi AM | 1000095588H80 | on 26/11/13 |
The FCC intended it that way. The Part 97 limits on bandwidth were left deliberately vague, defined in terms of "good engineering and amateur practice", in order to give amateurs the maximum flexibility for experimentation and self-instruction in the radio art. A few years ago, Riley reiterated that at the FCC forum at Dayton when someone posed a question regarding so-called ESSB, although for whatever reason, he went on to raise the issue of whether ESSB has any place in amateur radio at all. Just as variable selectivity is a desirable feature in a receiver, some variability in audio bandwidth is equally desirable in a transmitter. There are many ways of accomplishing this; in the audio chain that drives my transmitters I have incorporated switchable, passive, low-pass audio filters, something I picked up decades ago at a surplus store and at a hamfest. One filter has a very sharp brick-wall cutoff at 3400 Hz, while the other has a more gradual cutoff that begins just above 5 kHz with everything gone at 7.5 kHz. The third option is no filter at all, with the highs limited only by the frequency response of the audio transformers. Normally, the 3400~ filter is used under congested band condition or when there is a nearby adjacent QSO, and the 5000~ filter is used when the band is less congested. The no-filter option is rarely used except for testing purposes. Passive filters like mine are hard to find these days, and usually the ones that show up are expensive, but current technology allows one to easily build effective filters at very low cost using active circuitry. I have seen circuits published on websites, using nothing more than a handful of components, usually a couple of transistors and IC chips, plus a few resistors and capacitors. More sophisticated filter circuits can be found using digital technology, for those so inclined. There is little use in transmitting audio frequency response that would produce 20 kHz wide signals, since very few amateur receivers would be set to wide enough selectivity to receive such a signal in its entirety, and it would be poor engineering and amateur practice to deliberately transmit such a broad signal merely to keep the adjacent channels clear. But, OTOH, "wide" signals that cause harmful interference to adjacent channels are more often the result of spurious distortion products than the frequency response of the audio used to modulate. I would recommend first and foremost, a "clean" transmitter that is not pushed beyond its modulation capability, and then an appropriate low-pass audio filter in line to limit bandwidth as needed. Merely lopping off the higher frequencies beyond a certain point doesn't cut it; the overall audio response curve needs to be adjusted for balance to produce pleasant sounding audio that is still readable under adverse conditions. I often get reports that my audio is "broadcast quality" when using the 3400~ filter. A "presence rise" of some 9 dB in the upper mid-range seems to allow the articulation of consonant sounds to still pass through, and compensate for the limited high frequency response. Nevertheless, when running an A/B comparison under less congested band conditions, most reports tell me that the signal sounds better with the 5000~ filter. But they usually tell me there is little or no difference in audio quality between the 5000~ filter and no filter at all. An interesting tutorial on AM and audio frequency response can be found at http://www.amwindow.org/tech/pdf/eam.pdf Don k4kyv |
||
