Messages

256

Equipment / Re: How high is that antenna rope in the tree anyway?

« on: November 27, 2019, 1140 UTC »

I think the zip ties would get tangled in the branches, leaving me with a piece of line that I can’t get up or down anymore. 

I have my wife stand at the base of a tree, holding a 10 foot piece of copper or PVC pipe vertically.  When I back away far enough, the 10 ft piece of pipe is used to guesstimate how tall the tree is.  This works reasonably well and is very quick.  For better accuracy I take a picture and then take the ratio of the pipe length to the tree length in the picture to get a more accurate estimate.

For best accuracy, back as far away as you can, while still being able to visually make out the pipe length.

257

General Radio Discussion / FCC approves all digital AM

« on: November 23, 2019, 1109 UTC »

https://radioinsight.com/headlines/181941/fcc-approves-digital-am/

258

Equipment / LF - HF Splitters

« on: November 18, 2019, 1122 UTC »

http://ka7oei.blogspot.com/2019/11/homebrew-construction-of-2-and-4-port.html

I’ve become a fan of KA7OEI’s blog - excellent technical content, concise, and frequently on a topic of interest to me.

259

VHF/UHF Logs, including satellites and radiosondes / Re: FRS/GMRS 463.725 MHz 2112 UTC 13 Nov 2019

« on: November 14, 2019, 1000 UTC »

Must be something different.   That callsign is for a licensee in Quincy, MA.

https://wireless2.fcc.gov/UlsApp/UlsSearch/searchLicense.jsp

260

General Radio Discussion / Garage Door Opener Interference

« on: November 08, 2019, 1152 UTC »

Some residents of Warrenton, VA started to have problems with their garage door openers this month.  The nearby government site denied having any new radio transmitters at first, but activities by the local amateur radio club showed there was a new P25 repeater operating near the frequency used by most of the openers.  The government then issued a statement saying they would suspend operation of the repeater for 30 days in order to give nearby residents a chance to replace their openers (this repeater was in the 380-400 MHz band the DoD uses now for their LMR sysyems).

The residents were not happy but got a lesson in the difference between being a primary user of frequency spectrum and using equipment operating under Part 15 of the rules.

More here:

https://www.fauquiernow.com/fauquier_news/article/fauquier-feds-admit-radios-interfere-with-garage-door-openers-11-5-2019

https://www.fox5dc.com/video/623173

261

Equipment / Copper Clad Steel

« on: November 03, 2019, 1438 UTC »

Owen Duffy points out that Copper Clad Steel (CCS) or Copper Clad Aluminum (CCA)  RG6, RG11, and CAT6 cable are becoming more prevalent.  I’ve also noticed that the only 450 ohm ladder line I can find anywhere is CCS.

Owen says that there are no specs on the thickness of the copper layer, and there are increased losses on these cables at lower frequencies compared to pure copper conductors.  He notes that losses of .03 dB/m at 1 MHz have been seen.  If you have a 100 meter run, this could be significant.

Is this really a problem?  The numbers seem to indicate it is something to pay attention to.

https://owenduffy.net/blog/?p=15974

262

General Radio Discussion / All Digital AM broadcast

« on: November 01, 2019, 1016 UTC »

https://www.radioworld.com/news-and-business/business-and-law/all-digital-on-the-am-band-the-fcc-might-allow-it-soon

263

Equipment / Re: Example Icom 718 Vs Icom R75

« on: October 28, 2019, 0941 UTC »

While their outward appearance is similar, the R75 has a superior receiver.  It has been a while since I compared the schematics, but I recall that they were significantly different.

The 718 is OK accept for one glaring fault: the receiver AGC is terrible.  I have a 718 I use on MARS nets and it is literally exhausting to listen to SSB for extended periods of time.   The hang time is far too short so the receiver just “pumps”.   I have found it necessary to ride the RF gain control to make it tolerable to listen to.

I haven’t seen any mods to fix this.  The nearest “fix” is one that turns on the AM mode AGC time constants while you are using SSB - this is supposedly better, but not perfect.

Other than the AGC, I’ve got no complaints about the 718.  It is a good value for the money (though my advice for anyone considering purchasing one today is to save up a little bit more and buy a IC-7300 instead - you will be far happier with it.)

264

Longwave Loggings / SAQ

« on: October 27, 2019, 1033 UTC »

I attempted to hear the transmission from SAQ (Sweden) on 17.2 kHz on the 24th but heard nothing.  I was watching the live stream on YouTube for the transmission, and I have started up enough large power plants to recognize that they were having problems.  Sure enough, they posted the following on their web site shortly afterwards:

“....No transmission on UN-DAY
We are sorry to inform that the “Old lady” was not able to start for the scheduled UN-Day transmission on October 24th, and therefore we will not be able to do any transmission. The overload protection for the main motor was tripping and we will start to investigate what is causing this.
The SAQ team at the Grimeton Radio Station....”

 
It was neat to see how much effort was necessary to operate the station. If you like things like watching someone start up an old steam engine locomotive, you will find SAQ fascinating.  I hope that whatever the problem is, it isn’t an “unobtainium” part.

265

Pirate Radio History / Re: The 1620 WJDI Story

« on: October 24, 2019, 1150 UTC »

For years I would see this out-of-state guy selling small parts at the DC area hamfests.  One day he told me the WJDI story.  I suppose this was Dave.  I haven’t seen him at the hamfests recently; I hope he is doing OK.

266

Equipment / Re: MLA-30 Loop antenna

« on: October 24, 2019, 1134 UTC »

I have one.  And I also have a Wellbrook.  I haven’t given it a thumbs up or thumbs down because I haven’t compared them side by side, in the same location.  My initial impression is that it seems noisy, but that was with it inside the house, so you can’t draw conclusions yet.

But my comments still stand.  The price is low.  And I don’t like their approach to providing power.  Putting a switcher right at the bias-t is nuts.  My own unit started having problems with the LED intermittently operating.  The schematic showed it is driven directly off of the switcher, so I suspect the switcher has failed.

There are a lot of choices out there for loop antennas - Wellbrook, DXE, Pixel, MFJ, and W6LVP to name a few.  The price for these tend to run in the $250 to 450 range.  For that money you get a huge step up in both the electronics and in the mechanical construction.

Everything about the MLA30 is cheap.  To sell at a $30 price point it has to be.  I seriously doubt it would last more than a year or two exposed to the weather.  If you look at G8JNJ’s posting, you can see that the circuit has some serious design mistakes.  I fully expect that the parts inside the unit are chinese counterfeits.  They would have to be at this price point.  I suspect the plastic enclosure will turn brittle when exposed to sunlight.  This is not something built for the long term.

That being said, there are uses for a $30 antenna, so it has its niche.  Just realize it isn’t in the same class as the other loops.  It may be good enough for your particular situation.  Or not.

267

Equipment / Re: MLA-30 Loop antenna

« on: October 23, 2019, 1205 UTC »

The schematic was reverse engineered here:

https://www.g8jnj.net/activeantennas.htm#MLA30

I haven’t been that impressed by it other than the low price.  The “power isolator” actually has an inverter in it to raise the 5 volts up to something higher.  I question the wisdom of putting a switching noise generator there! 

I might try it with a conventional power isolator at 12 volts to see if it works any better.

268

Software / Free Pactor Monitoring Software from SCS

« on: October 17, 2019, 0918 UTC »

 From the ARRL:

http://www.arrl.org/news/view/pactor-developer-scs-announces-monitoring-software

 

“....PACTOR Developer SCS Announces Monitoring Software

10/15/2019

SCS, the company that created PACTOR, has unveiled software that offers the ability to monitor the content of PACTOR 1, 2, and 3 transmissions over the air. The free PMON software runs under the Linux operating system. A software version to monitor PACTOR 4 is scheduled to become available next year. PMON will offer “thorough observation and documentation of all presently available PACTOR 1, 2, and 3 transmissions,” SCS said.

“PMON covers all PACTOR levels with the appropriate speed levels and packet variations,” SCS said. “PMON will read in parallel PACTOR 2 and PACTOR 1. The very wide receiving range (frequency offset ±200 Hz), as well as automatic sideband recognition, ease routine operation of PMON with PACTOR 2 and PACTOR 3 considerably.”

According to SCS, only minimal hardware is required to use PMON. The equipment complement includes a Raspberry Pi 3 Model B+ (minimum) computer and a USB sound device. SCS noted in an October 11 news release that all SCS PACTOR hardware modems include a command to allow PACTOR monitoring on the fly. The German company says PMON now makes this possible without a modem and adds the ability to decode B2F/LZHUF-compressed messages — Winlink email and others.

“This exciting new software development for Raspberry Pi complements and surpasses previously released SCS software that leveraged PACTOR modems’ ability to monitor PACTOR to read Winlink for meaning,” SCS said. The company also said the new software permits modem-less monitoring of all kinds, something that would be useful for monitoring Winlink email traffic.

The Winlink Development Team called the new software a “welcome contribution to the Amateur Radio community.”

The issue of message encryption arose in recent months with respect to renewed attention to ARRL’s so-called “symbol rate” petition for rulemaking (RM-11708) and the accommodation of automatically controlled digital stations (ACDS) — many of which employ Winlink. Some commenters on ARRL’s petition expressed concerns that PACTOR message encryption was a violation of FCC Amateur Service rules.....”

 

269

Equipment / Re: Yaesu FT-1000D repairs & parts...

« on: October 11, 2019, 1242 UTC »

“Fishfinder” LOL.  I like that.

270

ID and Translation Requests / Re: VLF and LF

« on: October 05, 2019, 0230 UTC »

I did check a nearby Kiwi and they weren't there.  I've pretty much come to the conclusion that they are EMI from somewhere in the shack.  Thanks for the idea.