Messages

226

VHF/UHF Logs, including satellites and radiosondes / Re: FLTSATCOM

« on: January 30, 2020, 1319 UTC »

 FLTSATCOM uses geostationary satellites...there is no “pass”...either your location is in the footprint or it isn’t.  You will hear some clear voice traffic (mostly Brazilian pirates) but most traffic will be encrypted digital.

227

Longwave Loggings / Re: New to longwave

« on: January 30, 2020, 1304 UTC »

If you can’t find your LPF there are a number of designs available on the Internet.  They are very simple to build.  I agree with JFarley and Pinto - if you are serious about LF you need one.

I use one from rescueelectronics.com (though I am not sure if they are still in business - they aren’t answering email.)

One other thing I have discovered to be essential (at least for my installation) are common mode filters on the feedline, at both the antenna and at the receiver.  I was surprised at how much local EMI they cleaned up. They have to be rated to work at LF - your typical ham CM filter stops at 160M. (Palomar Engineering has models rated to go to 100 kHz, but they are very slow on shipping.)

You can build your own LPF and CMF for little cost...a fraction of what buying commercial products will cost.


If you build your own, make sure you use Type 75 or Type 77 ferrite for the CM filter.

228

Equipment / Re: Dual band vertical Vs Discone

« on: January 29, 2020, 1251 UTC »

I think a good discone is useful to have as a general purpose antenna.  You can never have too many antennas.

The Diamond D777 is an antenna for the VHF (118-136) and UHF (225-400) aviation bands.  You can find them at Ham Radio Outlet.  I have one but haven’t installed it so I can’t speak to its performance yet.

https://www.hamradio.com/detail.cfm?pid=H0-012019

229

General Radio Discussion / Re: The Ultimate Pride Of China Portable Shortwave Radio for $9.59

« on: January 26, 2020, 1426 UTC »

The solution is obvious, you buy glue from the "Department of Life" section: http://www.winningmart.com/category-362-b0.html

Oooh...blue and red glue...I don’t see that in my local box store...

230

General Radio Discussion / Re: The Art of Electronics: The x Chapters

« on: January 26, 2020, 1422 UTC »

Thanks for posting this.  I had the main book, but didn’t know about the “X Chapter” volume.  The chapter on transient supression devices alone was worth the price to me.

231

Amateur Radio / Re: Digital modes on HF... love it or hate it.

« on: January 26, 2020, 1414 UTC »

On  like note, the HAM repeater traffic I hear is always the same few people who know each other locally, not newcomers or even people driving past the area - however that does happen. I suppose this is to be expected among friends.

Many clubs, repeaters, or nets are not welcoming of newcomers.  I don’t think they are necessarily hostile, they just don’t take that extra step of creating a welcoming, fun atmosphere that makes people want to be there.  I am as guilty as the next guy of only talking to my friends and ignoring others.

The local club here has a reputation of being a fun place to be and we have a lot of new blood.  It wasn’t always that way - no one said a word to me the first meeting I went to years ago.  Today we have one guy who goes out of his way to greet all newcomers - whether on the repeater or at the meetings.  It’s not an “official” job...it is just his nature.  Another club I was once a member of was in an area with a transient population.  They went so far as to station a couple of guys near the front door to look for new faces and welcome them to the meeting.

It’s funny how a single individual can be the catalyst that makes a club successful...or a poison pill that drives people away.

232

General Radio Discussion / Re: The Ultimate Pride Of China Portable Shortwave Radio for $9.59

« on: January 26, 2020, 1345 UTC »

Mine rattles.  The speaker is loose.  And there is a crack in the case.  You can’t get a quality $9.59 radio anymore <G>.

233

Utility / Re: CIS Navy on HF

« on: January 25, 2020, 2048 UTC »

A posting on eham claimed that the Chinese CW decoder is based on this:

http://www.ik3oil.it/_private/qst_cw.pdf

I have not verified whether that is true or not.

234

Utility / Re: CIS Navy on HF

« on: January 25, 2020, 2035 UTC »

There is this:

http://www.f6hoy.com/cw/

Or this:

https://youtu.be/PnJTHTvBUPg

Is that what you were thinking about?

235

VHF/UHF Logs, including satellites and radiosondes / Re: UHF mil air

« on: January 25, 2020, 1951 UTC »

I hear mil-air stuff.  I am sure there is a lot of traffic Chris can hear.

The 225-400 band is big and it is easy to miss stuff.  Maybe start with some power surveys to identify good target frequencies?  Try this:

http://kmkeen.com/rtl-power/

236

Equipment / Re: Wellbrook help

« on: January 25, 2020, 1857 UTC »

The big advantage to the FLX1530 is that it is easy to transport and store.  I can just imagine him purchasing one of the regular Wellbrook loops and putting it in checked baggage for the trip back to Jordan!  Some helpful baggage handler will probably bend it in half to save room.

The regular Wellbrook just uses the entire tube as a conductor.  It is not a shielded loop design where the tubing has a small gap at the top to expose the inner conductor.  There is no inner conductor.

I’m guessing that the FLX uses the outer braided shield of the short piece of RG58/LMR400 as the conductor and ignores the inner conductor.

237

Longwave Loggings / Re: JJY Japan 40 kHz Time Station 1140 UTC 22 Jan 2020

« on: January 25, 2020, 1118 UTC »

It has been a long time since JJY was on SW but they may have used something like two beeps/second there.

You don’t usually see AM or CW keying on VLF though.  The antenna BW (because they antennas are so short compared to the wavelength) is extremely small and it becomes difficult to build an efficient antenna that has a BW wide enough to support AM modulation.

On-off keying (CW) is also difficult, particularly at power.  I think JJY is a 50 kW station.  Keying a large load on and off is hard on the electrical system and the power supply.  Still, from what I read JJY does send a CW ID, so they apparently do that.  WWVB uses a modulation scheme that raises and lowers power.

Most VLF stations today use a MSK.  It is efficient, has a constant carrier, and works with antennas with narrow bandwidths.  I don’t know what JJY uses but MSK would be my first guess (and I emphasize that I am guessing.)

238

Equipment / Re: Wellbrook help

« on: January 25, 2020, 1049 UTC »

The antenna he is talking about (FLX1530LN) is a version of the Wellbrook that doesn’t come with a solid metal loop.  You hook up a short loop of either RG58 or LMR400 in place of the loop.

Performance (using good quality cable) should be very similar for either cable type.  You might find the LMR400 holds a circular shape better though.  You can find variants of LMR400 that have either solid and stranded center conductors.  The solid will also help hold a circular shape better, but this may not be a big thing.  You can always build a simple frame out of pvc pipe to hold the loop.

As far as the feedline between the Wellbrook and the radio, LMR400 will have less loss, but you won’t notice the difference at MF and HF frequencies unless you are using lengths far greater than 100 ft.  RG58 will be fine for most cases.  Try to stay with name brand coax - there are many Asian knockoffs that have poor braid coverage.

239

Amateur Radio / Re: Digital modes on HF... love it or hate it.

« on: January 24, 2020, 1243 UTC »

Don’t get me wrong - I think what K1JT has done with weak signal detection is amazing.  His work with EME software has made moonbounce possible for small footprint stations.  Ditto his meteor scatter SW.

I have no problem with his weak signal algorithms.  My problem has been with automation of the QSO process.  His implementation has the operators involvement being nothing more than clicking a button to log the QSO...and modified code is available that allows you to run in full robot mode.  I saw one of Joe Taylor’s presentations where he had a slide of suspected “robot” stations (based upon the fact that they ran 24/7), and I have seen the robot SW for sale on eBay.  The days of fully automated stations working each other have already started. 

If you ever find a first edition (circa 1983) copy of W9KNI’s book “The Complete DXer”, it is worth reading.  He has stories in it of tuning through the bands searching for DX, and puzzling out the rare and not so rare stuff.  It took some skill to find and work a rare one back then, and it was very rewarding when you were successful.  Today, with DX spotting networks, etc it is much more like shooting fish in a barrel. Now full automation has removed the last vestige of necessary operator skill. 

Maybe this explains some of the renewed interest in learning CW.  Maybe these are operators that are seeking some of the satisfaction you find in doing something difficult and succeeding...

Its like I said before: People don’t value things that come too easily.

240

Longwave Loggings / Re: JJY Japan 40 kHz Time Station 1140 UTC 22 Jan 2020

« on: January 24, 2020, 1124 UTC »

Not a trace of a signal this morning.  What was new was a RFI signal that wasn’t present the previous two mornings.  The VLF spectrum was remarkable quiet until about 0600 local when a wandering RFI signal started up.  It went away for a little while, and then came back.  I suspect a neighbor has a grow light or something...