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Messages - NJQA

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256
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.

257
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.

258
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.

259
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.....”

 

260
Equipment / Re: Yaesu FT-1000D repairs & parts...
« on: October 11, 2019, 1242 UTC »
“Fishfinder” LOL.  I like that.

261
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.

262
ID and Translation Requests / VLF and LF
« on: October 04, 2019, 1824 UTC »
I've been listening to VLF and LF transmissions today and I am trying to identify some of the signals.  NAA. NML, and NLK seem pretty obvious.  However I am hearing digital broadcasts on the following frequencies that don't seem to appear on any of the lists.  Is anyone else seeing transmissions on these frequencies, or maybe I am just hearing local RFI?

22.75 kHz
45.5 kHz
68.25 kHz
91.0 kHz

One list mentioned that there may be a station, WH2XBA/4, Stanfield, NC, on 45.5 kHz.


263
Equipment / Re: PSA: On Ferrites and their Brittleness
« on: September 28, 2019, 1005 UTC »
I have read that you can super glue them back together with little loss in performance (if they aren’t in too many pieces).

I wrap the larger cores in a layer of Scotch 69 Glass Cloth electrical tape before I add windings.  It protects the winding insulation from cuts on the sometimes sharp edges of the ferrite and provides a little impact protection.  You can also write the core type on the tape if you ever plan to reuse the core.

264
Equipment / Re: Inexpensive VNA
« on: September 18, 2019, 0958 UTC »
There is this case for those who have access to a 3D printer to make it:

https://www.thingiverse.com/thing:3673624

The creator of this case notes there are at least two manufacturers of the nanoVNA with minor variations in the mechanical construction of the VNA.

265
Equipment / Re: New AOR receiver
« on: September 15, 2019, 1129 UTC »
Video with a little more info.  They say it can search the entire VHF air band in less than 1 second.

https://youtu.be/Oh4taFRAL-Q

266
General Radio Discussion / Re: VOA Museum To Hold Anniversary Party
« on: September 14, 2019, 1701 UTC »
I remember a Western Auto store near where I grew up that had a new Hallicrafters HT40 transmitter for sale.  No other ham gear of any sort for sale - just that transmitter.  I imagine it was a special order for someone who failed to pick it up.

267
Equipment / Re: New AOR receiver
« on: September 10, 2019, 0856 UTC »
Yeah, I want one too.  I hope the price is reasonable.

268
Equipment / New AOR receiver
« on: September 09, 2019, 0955 UTC »
New AOR receiver announced for scanning the aircraft bands.  I expect that it won’t be cheap.  I wonder what market they are targeting this for?

https://www.universal-radio.com/catalog/scanners/1740.html

270
Can you provide a few more details on how you have the loops and transformer connected?  Why did you decide to remove the preamp?  Are you using RG6 feedline?

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