Messages

226

Propagation / Re: Grey line map (real time)

« on: January 21, 2020, 1056 UTC »

I use one of the online ones. A solar propagation site has one that works.

http://www.spacew.com/www/realtime.php

While the grayline may be correct, don’t be fooled by the rest of the data at the map link above.  It has been a long time since we have seen a SSN of 86.

227

General Radio Discussion / Re: Reception based on East coast/West coast

« on: January 17, 2020, 1317 UTC »

An alternative to ground mounted/buried radials is to use elevated radials. The common lore is that 4 elevated radials will provide performance equivalent to 60 buried radials.

Things are usually not that easy though.  N6LF has researched this in detail, and his recommendation is for 12 elevated radials.  Still, you will need a boatload more buried radials for comparable performance to a vertical with elevated radials.  You can read his extremely detailed analysis here:

https://rudys.typepad.com/files/elevated-ground-systems-article-final-version.pdf

If you are using a vertical with elevated radials for transmitting, you also have to be aware that there will be high voltages at the ends of the radials.  You should also think about how you will address lightning protection for the elevated radial installation.

 

228

General Radio Discussion / Re: Pirate Act Passes Senate

« on: January 15, 2020, 1236 UTC »

At least one person at the FCC thinks this is good...

https://www.radioworld.com/news-and-business/business-and-law/senate-passes-pirate-act

229

SDR - Software Defined Radio / SDR.HU

« on: January 12, 2020, 1705 UTC »

The popular website SDR.HU, used to locate on line SDR receivers, has changed their policies to only allow access by licensed ham radio operators.

Other alternative sites exist for non-hams to find SDR receivers such as https://ve3sun.com/KiwiSDR, http://kiwisdr.com/public and http://rx.linkfanel.net.

230

General Radio Discussion / Re: Pirate Act Passes Senate

« on: January 12, 2020, 1521 UTC »

I read above someone said the FCC didnt want this...

I didn’t mean to say this was something the FCC didn’t want.  I meant to say they probably didn’t request it.  I am sure they would prefer Congress give them additional funding for enforcement rather than the potential for increased penalties.

This act places requirements for an annual report to Congress, and annual sweeps through the top 5 markets among other things.  I’ll bet the FCC will be told to do this within their current budget.

If this is in fact an unfunded mandate, I would think this is Act is not something they are happy with...but that doesn’t mean they won’t comply with it.  If you are a pirate in the “Top 5” markets (whatever they are) you should pay careful attention.

231

General Radio Discussion / Re: Pirate Act Passes Senate

« on: January 11, 2020, 1101 UTC »

I also find it interesting that they are so concerned with pirate radio that they feel the need to enact more laws.

I doubt this piece of legislation was something the FCC wanted.  As tailored as it is to the AM and FM broadcast bands, this looks like something a lobbyist pushed through for the benefit of his broadcast industry clients.  It takes little effort to get approved since no one is going to oppose it. This is another law that gives the illusion of accomplishing something while actually doing nothing.

Just be glad they limited the frequency range as they did.

232

The RF Workbench / Re: Power supply voltage

« on: January 10, 2020, 1302 UTC »

I agree that diodes would be the simplest way to do this...about a half volt drop for each diode in series.

If you need better regulation, another option would be a DC/DC buck converter (Similar to this: https://www.mpja.com/LM2596-Step-Down-Adjustable-15-37V-DC_DC-Converter/productinfo/30148+PS/ ).  These Chinese devices are available on eBay, Amazon, and other places for a couple of bucks.  You will need at least a couple of volts difference between the input and desired output voltage.  I would also be careful to filter the DC out of the converter to ensure it is clean and doesn’t modulate your transmitter carrier with noise.

You could also use a 7810 regulator chip, though if your input is 13.8 volts you might not have enough of a voltage difference for it to be reliable.

A fourth option might be possible.  Many power supplies have an internal adjustment to set the output voltage.  If your PR3 has this, you may be able to turn the output down far enough to meet your needs.

233

Longwave Loggings / TDF

« on: January 08, 2020, 0432 UTC »

Hearing TDF France on 162 kHz tonight, well enough to decode the time code information on my KiwiSDR.  TDF is much stronger than DCF77 was a few days ago. 

234

Equipment / Re: General Coverage Comms rxer down to 20KHz?

« on: January 06, 2020, 1313 UTC »

K1EL has abandoned efforts to revive the Palomar VLF converter.

https://www.hamcrafters2.com/VLFX.html

235

Longwave Loggings / DCF77

« on: January 04, 2020, 0426 UTC »

I was hearing DCF77 on 77.5 kHz tonight, well enough (in Midland, Virginia) that my KiwiSDR was able to decode the time.

236

Equipment / Re: What Radio Did you start your listening hobby with?

« on: January 01, 2020, 1553 UTC »

I started when I was in 5th grade with a Hallicrafters S-72 receiver that belonged to my Dad.  I enjoyed tuning around, but didn’t really know what I was doing.  The S-72 eventually died and I got a Hallicrafters S-120 for Christmas.  The S-120 was a bit better than the S-72, but not by much.  I had really wanted a receiver with an S-meter so I was a little disappointed.  Over the years I learned more about the hobby and got a few QSL cards.  Then one Christmas when I was in High School, I got a used Hallicrafters S-85.  The S-85 had an actual RF amplifier stage (the previous radios ran the antenna straight into the mixer).  OMG, what a difference.  I could hear so much more.  I added a Hallicrafters S-meter right between the dials (it looked just like a SX-99 then) and a Heathkit Q-multiplier.  Using an amplified loop antenna I built, I heard all sorts of AM BCB DX, including trans-atlantics. 

In one of Bill Orr’s (W6SAI) books he recommended not getting a top of the line receiver at first, but starting with an entry level set and learning to properly operate it.  Once you have squeezed out all the performance it is capable of, then upgrade.  I can see the wisdom of that, but doubt that anyone has the patience to do that these days.  Plus, today you get so much better performance with even the cheapest radios.  A $100 RSP1A is a zillion times better a receiver than that S-120 was.

I miss that S-85, but can’t stand to even look at a S-120.

237

SDR - Software Defined Radio / Re: New kiwiSDR Update

« on: January 01, 2020, 1128 UTC »

The DRM mode is disabled if the receiver is in the 20 kHz mode.

238

General Radio Discussion / Re: TDoA Questions & maybe an article?

« on: December 31, 2019, 1303 UTC »

The other factor I didn’t see mentioned is where some receivers are getting single hop reception and others are ground wave or multiple hops.  That will impact the position estimate unless the TDOA algorithm corrects for that.

The varying height of the reflecting ionosphere (which can be different for each receiver site) impacts the accuracy.  Picking receiver sites on either side of the day/night terminator could have an impact on accuracy. If you could get receiver stations that all heard the xmtr via ground wave then the position estimate could be very good...but you already have a good idea of where they are then don’t you?

Chris is right - modern day DF networks will spit out a lat/lon on a station in a fraction of a second. I imagine the biggest delay is just ensuring that all stations in the network are hearing the same station. All that is left at that point is to send a van through the area and find the specific house. If the FCC wants you, they can find you with little effort.

The biggest issue for pirates would be hobbyists doing their own DF work, getting a good location, publicizing their results, and drawing attention from the FCC. 

“The nail that sticks out is the one that gets hammered.”

239

Equipment / Re: Harmonics

« on: December 31, 2019, 1221 UTC »

If their fundamental frequency is 1160 and you are hearing them from 1010 to 1320, then “harmonics” is the wrong term.  Harmonics will be heard at integral multiples of the fundamental frequency (2320 kHz, 3480 kHz, etc).

It sounds more like InterModulation Products (IMP).  While it could be a problem at the station, it is more likely due to something in your receiver or your antenna system.  Is this the strongest station at your location?  Do you hear the same problem on different radios or using different antennas?  If you drive to a location further away, do you still hear the same problem?  Do you hear just that station, or do you hear other stations mixed together too?

240

Equipment / Consumer grade antenna splitters

« on: December 27, 2019, 1443 UTC »

KA7OEI has a good article on the use of consumer antenna splitters for ham/swl purposes.  I wasn’t aware of the problem with using “satellite only” splitters at lower frequencies.

http://ka7oei.blogspot.com/2019/12/using-tv-type-75-ohm-splitters-and-taps.html