Messages

91

Equipment / Re: Square or Bent Dipole for Transmit

« on: June 11, 2018, 1707 UTC »

I Have tried what you are talking about, I think. When I First got on HF ham radio, I was confined (or so I thought) to 40 meters and up, due to the size of my parents yard. I really wanted to get on 80 meters, and, not having any real experience, I tried almost everything. Bending the ends of the dipole in the same direction to make a 'C' shape, failed to tune, and I have no idea what the pattern was, as I was never able to transmit on it. After some reading, and help from a friend, I tried a 'Z'shape. The feed point was in the center of the 'Z', with each end bent in opposite directions. This was also somewhat of an inverted vee. I had the feedpoint about 40 feet up on some 1.5 inch steel EMT tubing which I had welded end to end, the bends in the 'Z' were about 20 feet up supported by trees, and the ends were about 10 feet up. The antenna was a little harder to tune than my 40 meter inverted vee, but would load up well, and seemed to work well in all directions. It was no larger than the "'C' shape, but significantly better. Something to keep in mind, the bending of the legs into a 'Z' shape will detune the antenna, so if you are operating on a single frequency, and wish to not use an antenna tuner, give yourself plenty of extra wire, and tune the antenna in its final position, also, the less bend you can get away with, the easier tuning will be.

92

General Radio Discussion / Re: Antenna 4 bedroom setup

« on: June 11, 2018, 1646 UTC »

I would try a tabletop magnetic loop, I ran a setup like this in southern california for several years. The BIG advantage of RX only is that you can use high Q, components without needing to worry about heating or loss too much, the big disadvantage is that a magnetic loop that works well for, say,10 to 30 Mhz, wont do well below that. If having 2 loops is an acceptable solution, go for it.
Some people build tabletop loop tuner boxes that do this, with quick change loops and ferrite loopsticks.
https://www.youtube.com/watch?v=q7PZpjEUKEk
unfortunately, I do not speak german, but even the demo itself shows this tabletop antenna. Building something like this is a good path to acceptable indoor reception. Of course, companies like AOR and Wellbrook make commercial antennas like this if one is willing to spend the money.
PS. Joshs suggestion of wire around the window also works quite well, and is far easier to implement, I have done this as well, but I found I prefered the selectivity of a tuned device.

93

Equipment / Re: RETRO RECEIVER REVIEW #12 -The YAESU FRG-100

« on: May 22, 2018, 1505 UTC »

That is what I was wondering as well Looking Glass, But I guess once one starts Listening to NDBs, its hard to stop

94

General Radio Discussion / Re: SHORTWAVE TRADING | PART I | THE WEST CHICAGO TOWER MYSTERY

« on: May 17, 2018, 2149 UTC »

it seems that the "the RF spectrum is full" arguments and the new-ish allocations for things like this are in contradiction. I don't think its a case of available spectrum they're not telling us about, but rather a case of the FCC saying "we'll make room" when they see a profit. The FCC is severely underfunded when it comes to actual field work and enforcement.  I really want to build a radiometer that measures the total power received between 3 and 30 Mhz, and look at the dip in the chart when there is a major power outage. I would be willing to bet a signifacant portion of the white noise is a summation of services like this too far away or weak to be heard.

95

General Radio Discussion / Re: LPAM proposals, studies, and map.

« on: May 17, 2018, 1829 UTC »

Glad to see I'm not the only one on here who reads this
http://www.engineeringradio.us/blog/

96

General Radio Discussion / Re: LPAM proposals, studies, and map.

« on: May 11, 2018, 1817 UTC »

I love the Idea of LPAM, but it is , unfortunately, a double edged sword. 
The AM broadcast band is clogged with hundreds of identical syndicated programs, and in major markets, only the strongest stations are listenable. As much as I would love to see small, local broadcasters making real shows run by real people, the AM band just cant hold any more. what needs to be done is a reduction in force. The FCC needs to lay down some stipulations for AM license renewal, stipulations such as the broadcasting of original, local content, which is not also being broadcast on FM.  This would allow receivers to be widened back up to a 10 Khz bandwidth, rescuing the audio from its current, telephone like, poor quality. The preference toward local contend would also favor low power over high power, and independent over conglomerate. and over all, would be a better "revitalization" of the AM band that any amount of deregulation. 

P.S, I don't have any objection to simply disregarding the FCC rules, and I am not saying pirate radio is bad, just that even pirates need to be stewards of the limited radio spectrum we have.

97

General Radio Discussion / Re: Broadcasters Cheer Pirate Radio Bill

« on: May 11, 2018, 1715 UTC »

As to what was mentioned about the big boys not playing by the rules either, Most commercial radio stations (especially the top dog stations in small markets) have countless FCC violations, most commonly poor EAS functionality and interference to other operations both broadcast and non-broadcast related. They will almost never directly report an FCC violation of a pirate or competitor station, as they themselves would then have to "clean up" I have seen many stations (mostly translators) which run at several times legal power, AM sites which are abhorrently in disrepair not meeting FCC regulations or even fire safety code, and a complete disregard for any other broadcasters in the market (unless of course they are owned by the same big company). 

To boot, most of the translators I have seen are sold in the community as the main market station, allowing the AM to become a more and more unreliable and poor quality signal. This is completely against the purpose of a translator, and yet, seems to illicit no negative response from the FCC or NAB.

on a second note, I wonder what would happen to a pirate operator who was caught if they had been running a sane and well controlled amount of power, with clean modulation, and monitored an EAS primary to actually participate in eas alerts and weekly tests? I am quite curious to whether the FCC could deem that pirate OPs action legally "harmful".

98

General Radio Discussion / gotta catch em all

« on: May 05, 2018, 0455 UTC »

90's throwback, perhaps this has been said before.
Non Directional Beacons are the SWL's version of pokemon.

1.they just say their names over and over.
2. enthusiasts will go great lengths to "catch" new and unsusual ones, including travelling to remote locations.
3. somewhat special equipment is required to hear them. and people will even get competitive about building special antennas, converters, etc.
4. the more you find, the more you know, the better you get at finding new ones.

i'm sure there are more,  and I also don't know as much about pokemon as I could. Anyone find the resemblance striking?

99

Equipment / Re: Looking for suggestions for a directional antenna for circa 8 MHz

« on: April 25, 2018, 1509 UTC »

I would also tend to say beverage, but unfortunately not one that would work at lower frequencies well, I built one a while back for the 40 meter ham band, and it was one wavelength and about 4 feet off the ground. The termination will probably be more touchy than a longer one, but once it was terminated right it worked quite well. I have never tried a beverage that small any higher off the ground, and I imagine that its performance would pretty quickly change near 1/4 wave up

100

Equipment / Re: Best broadband receiving antenna below 500khz (longwave, NDB, DGPS)

« on: April 04, 2018, 1827 UTC »

I haven't experimented much with active loops, but I am usually a fan of small (relative to wavelength) loops over wire antennas, even loops of the untuned vareity. I get a much higher noise floor on wire antennas, and switching to the loop does not lower the signals any more than it lowers the noise. That being said, I also have an ac powered receiver, and operate at my house. if you can get away from the city, the wire may preform better.  as far as active antennas go the best source of info I have ever found is this site
http://www.vlf.it/
it is pretty much devoted to stuff below 22 kilocycles, but almost all of their "receivers" are actually preamplifiers, amplifying audio range rf signals. these designs could probably be scaled up to higher frequencies. whatever you do, if you build a preamp, make sure it has a good rolloff in gain above 500 kilocycles, or even weak AM stations will clip and intermodulate your front end

101

FM Free Radio / Re: Low-power broadcasting at bluegrass festivals

« on: March 06, 2018, 0043 UTC »

My radio station (legal, commercial) dosent even notice pirate or part 15 stations most of the time, as long as they don't interfere with us. Thats the big rule. I actually cannot remember the last time we looked up and legal information that wasnt our own.
if you do it right, the big boys wont even know you are a pirate station, and will be more likely to compare their sound with yours just to see how theyre doing. Of course, I dont live in a heavily populated urban area, its way harder there, but the same principles still apply.

102

FM Free Radio / Re: Identifying Emergency Bands

« on: March 06, 2018, 0038 UTC »

Its good to see FM pirates who do there homework first, Good on ya.
Fm can carry farther than many people think. One of the broadcast stations I maintain only puts out 400 watts, yet I can hear it full quieting about 80 miles away. this result is unusually good, but it can happen.
with low power (less than 100 watts) and a 1/4 wave vertical or 1/2 wave dipole, you are unlikely to cause problems to a station 50 miles away, but I would strongly suggest you record your first show so you can drive around between your station and the licensed one while it is playing. the studio at the radio station wont hear you at all, but some of their listeners might, especially if they're close to you and farther from the station.  and picket fencing between your station will generate calls to the studio.

the FCC may be a toothless old dog, but paying spectrum users are not. a broadcast station will report you if you annoy them.

I suggest using a mild directional antenna and putting the nulls in like with the legal broadcaster.

and of course, I "cannot condone Illegal Broadcasting", but wish you the best of luck in your endeavors.

P.S make friends with your local broadcast engineer if you can, many of us arent against pirate radio at all, as long as it dosent hurt our stations, just tread carefully.

103

SDR - Software Defined Radio / Re: SDR receiver basic questions

« on: March 06, 2018, 0025 UTC »

Hopefully this post isnt too long, but I feel it may be helpful

The SDR can be divided fairly cleanly into three parts
the hardware
the operational software/firmware
the user interface. 

Most of the time, the lower end (<$1k) radios combine the software and user interface, and the higher end ones typically have some of the operational parameters written in firmware (one time code on an FPGA) and do only the second half of the radio operations on the host computer (the one you plug the SDR in to.)
          The ideal SDR (the one that is truly "software defined") would perfectly digitize infinite RF spectrum with no noise, error, or limits (not possible) and do all of the radio parts there.
          The real SDR usually has some form of down conversion, and always has some form of filtering. and then the remaining parts of the reception and demodulation are done in software. 

the fundamental point of all this is that an SDR cannot have any functionality that a traditional analog radio cannot have.
All parts, filters, mixers, local oscillators, multipliers, must be implemented in software just as they must be in hardware in an analog radio. 

That being said, there are many things that are possible in software that although technically possible in real hardware, are not practical, a 100 pole filter, fft, or fully adjustable equalizer for example.

so to put it briefly, no an SDR will not provide you with anything a traditional radio cannot. 

instead, what the SDR really gives you is the ability to model a "real" radio in a way that is infinitely alterable, and free from inaccuracies like component tolerance or stray capacitance.

that being said, the application that runs the SDR (of which there are probably over 1000) could be written to search the internet for whatever frequency you are tuned to and display that page in the database to give you a real time callsign readout.

P.S, I like the HackRF ONE, even though it has a poor noise figure, it can transmit as well as receive, and makes for quite a piece of budget test equipment.

104

Equipment / Re: Another source of QRM! This time from a KitchenAid mixer

« on: February 08, 2018, 1752 UTC »

If any of you guys have a neighbor down the street with that sweet ride from the 1950s, chrome bumpers, bright red, 600 horsepower, you know the one. well, it also has a totally unshielded/ unsuppressed ignition system, which will light up my spectrum analyzer noise floor about 20 db when he drives by. totally obliterates any chance of hearing DX below 500 Kilocycles. Even the close by DGPS beacons are gone

105

Equipment / Re: Grounding systems

« on: February 08, 2018, 1746 UTC »

 One of the other big points in the nautel article, the one that has helped me the most, is actually the part about all wires, coax, power, ground, signals, EVERYTHING, entering the shack at a single point. that way all interference and noise are common mode, and are very much easier to remove.

(p.s.  I actually only have a 3 ft ground rod at home, and I still manage to avoid RFI, but, admittedly, its not really up to spec)