Messages

1

Part 15 AM and FM Station Operation / Re: Walmart Parking lot movies using Part 15

« on: September 29, 2020, 2254 UTC »

..Personally, I still think using AM would be the better option for both Wa!mart and the churches. I wonder why they continue to focus on the FM option.

Because the AM in a modern car sounds like sh*t, and some don't even have it.  That coupled with the finicky nature of most LPAM antennas verses the 'set it and forget it' nature of a small FM setup.  I suspect the folks running these things are not engineering caliber people.

+-RH

2

Equipment / Re: DX Engineering Maxi-CoreŽ 20 Baluns and Feedline Chokes DXE-MC20-V4-1 TESTS.

« on: September 29, 2020, 2152 UTC »

You can get the same thing for less money from Balun Designs https://www.balundesigns.com/4/  I've used their 1:1 feedline chokes on all my verticals and dipoles, which solved most of my RFI issues.  DX Engineering makes good stuff, but it tends to be expensive for what it is.  Their sales staff also leaves something to be desired.

+-RH

3

Part 15 AM and FM Station Operation / Re: FCC vs God

« on: September 22, 2020, 0522 UTC »

I was later dismayed to find that local pastors prefer to hold services as usual, in spite of the risks.

Of course, much easier to guilt a donation out of a captive audience.

+-RH

4

General Radio Discussion / Re: Yet another potential massive RFI source - Wireless EV Chargers

« on: September 21, 2020, 0123 UTC »

I don't get it.  Is it really above the intelligence of the average soccer mom that drives one of these things to plug it in at night?  Wireless charging is horribly inefficient, and you think the point of all this in the first place is reducing one's energy footprint, not broadening it.

+-RH

5

Huh? / Re: Julian Assange arrested by UK police...

« on: September 15, 2020, 1254 UTC »

Hard to take the Brits seriously until they start driving  on the correct side of the street and lower their beer temperature another 10 degrees F.

+1

+-RH

6

The RF Workbench / Re: NOT A Replacement For Your Stretchy Audio Amp

« on: September 13, 2020, 2126 UTC »

It has crossed my mind, easy enough to drive a photocoupler/fet driver combination.  Then the sky is the limit, power wise.  Much cheaper too than a lot of the other solutions out there.

+-RH

7

The RF Workbench / Re: NOT A Replacement For Your Stretchy Audio Amp

« on: September 13, 2020, 1745 UTC »

Ya know, a lot of the problems with these amps stem from the use of a transformer in the first place.  Why not double the supply voltage, eliminate the transformer and drive the PA direct from one side of the audio amp IC?

I made a thread about this some time back...  https://www.hfunderground.com/board/index.php/topic,40717.0.html

*edit* I forgot that this is a 40W TX requiring 48V peak mod, and have not yet found an COTS audio amp IC that will run at that supply voltage.  Might be time to build a simple PWM modulator?

+-RH

8

General Radio Discussion / Re: Allan Weiner buys WHRI

« on: September 06, 2020, 0154 UTC »

"...I think he summed up intended programming for the former WHRI frequencies by saying...."we will continue to spread HIS word." Also in the final few minutes, he complained mightily about electric rates in Maine, perhaps a hint that the WBCQ operation will be heading south?

Sadly it's about the only format left that is self sustaining...that or conspiracy talk.

+-RH

9

Huh? / Re: Is Bomar Crystal the last one in USA?

« on: August 18, 2020, 1503 UTC »

It should be noted that Bomar does not make crystals.  They job shop their work to places overseas, which is why one-offs take 6-8 weeks to be made.

+-RH

10

Equipment / Re: The Best Active Loop Antenna 2019 = MLA-30?

« on: July 27, 2020, 0725 UTC »

...It could be set up as horizontal for omni directional antenna, but most BC stations on HF seem transmitting on vertically polarised antenna. But one could do some testing on that to figure out which polarisation works better.

FWIW every curtain antenna I've every seen at a shortwave broadcast station was horizontally polarized.

+-RH

11

Equipment / Re: DRM pirates

« on: July 24, 2020, 2043 UTC »

Most professional DRM exciters, like AM stereo, produce a phase modulated carrier signal and a envelope signal to feed the transmitter.  To produce a compliant signal of sufficient quality to decode, a lot of alignment has to be done in the exciter to compensate for the response and group delay in the transmitter.  I did one trial about 8 years ago.  The signal output by dream can be either I/Q or just the composite waveform.  In my case, the IF input on my upconverter was used to modulate the DRM signal as double sideband.  By the time it fought its way through the amplifier chain I had about 50-75W of DRM power and it was heard by one guy.  It does work, I'm just not convinced of the utility of it with the power levels that most of us play with.

+-RH

12

Huh? / Re: As if, AM Radio can't sound bad enough, then there's this!

« on: July 22, 2020, 0029 UTC »

Yup, you can hear it plainly on FM's too.  I described it as broadcasting from a broom closet, or talking through a paper towel tube.  Its one of the principle reasons I stopped listening to major market stations.  Often the streams are encoded as well.

+-RH

13

Huh? / Re: You Were In Radio, When!!!!!!!!

« on: July 14, 2020, 2339 UTC »

I walked into a small market station in 2000's and they were using alarm clocks to start Otari MX-5050B's to record satellite feeds.  By the time we rebuild their studios, they had a hard disk based logger to time shift things, and real automation.  They were nominated for a Marconi award the next year.

+-RH

14

General Radio Discussion / Re: Proposed Shortwave Station in Illinois Prompts an Objection

« on: July 14, 2020, 2330 UTC »

...In addition, I wonder how they got the approval for less than 50kW. That is the minimum power for SW broadcasting in the US. I actually looked into starting a SW station once and was turned off by the high minimum power requirement.

CFR 47 part 73.751;

§ 73.751 Operating power.

No international broadcast station shall be authorized to install, or be licensed for operation of, transmitter equipment with:

(a) A rated carrier power of less than 50 kilowatts (kW) if double-sideband (DSB) modulation is used,

(b) A peak envelope power of less than 50 kW if single-sideband (SSB) modulation is used, or

(c) A mean power of less than 10 kW if digital modulation is used.
[70 FR 46676, Aug. 10, 2005]

+-RH

15

General Radio Discussion / Re: Proposed Shortwave Station in Illinois Prompts an Objection

« on: July 14, 2020, 2031 UTC »

I'd like to see a microwave shot across the Atlantic...  My guess is that the accrued latency in passing through the various networks is longer than a direct HF circuit.  If they were smart, they would just run their own fiber across the pond and be done with it.

To me its all a reminder that the game is rigged, and those with deep pockets will find ways to screw the little guy.

+-RH