Radio Propagation Issues for the RV Service Net

During several months of observing the Eastern/Central RV Service Net and providing remote station access to W4BXI, the ability of net participants to communicate was analyzed.

The results of our study are presented in this document (PDF), which is focused on the 40 m band propagation during the time frame of the morning net on 7191 kHz. Marginal radio propagation at the current low point in the Solar Cycle makes it difficult for net participants to hear each other.

Our presentation combines observations of signal levels, net participant reports, ionospheric "soundings" and propagation modeling.

John WA5MLF
Dan KC4GO

RV Service Net - 11 April 2019

During the second hour of Thursday's net I captured some audio and screen shots of the activity. The net control station, Sam WA4ICK, was S9+10 to me (in Baton Rouge) and painted a strong image on my FLEX-3000 SDR waterfall/panadapter view as shown below.

Click on image for an expanded view.

Improved propagation noted by several net participants can be attributed to an active region (with sunspots) on the Sun that has rotated back into Earth view and is raising the solar flux. On April 11 the sunspot number was 13.

A sample of the audio recording from around the middle of the second hour illustrates the reception here of signals from WA4ICK and W3TOM. Below is a screen shot of a portion of the audio waveform. You can see how the signal-to-noise (S/N) ratio changes after the hand-off from WA4ICK to W3TOM at about 1/3 of the way from the left.

Click on image for an expanded view.

The first third has a narrow baseline between syllables, indicative of my receive AGC turning down the gain in the presence of the strong signal. The remainder of the waveform has a lower S/N ratio as indicated by the thick baseline. Some fading is evident. The signal improved after the first few seconds. In this later 2/3 of the waveform the AGC opened up to allow more signal, but the noise was also higher. Click here for a 47-second recording that includes the portion represented by the above waveform.

 I have two longer recordings that I can share with interested parties upon request.

73,
John WA5MLF

RV Service Net Reception at WA5MLF

During the last half-hour of yesterday's RV Service Net the signal from W4UOA was solid at Baton Rouge. The distance from my station to W4UOA is 430 miles.

Below is a screen shot captured at 0751 CDT, while W4BXI was transmitting on 7191 kHz  from W4UOA. Another strong signal can be seen below 7188 kHz.

Click to enlarge view.

A little earlier (0728 CDT) I recorded KB0BH checking into the Net and acknowledged by W4BXI. The recording (click here) was made from my Flex-3000 transceiver in Baton Rouge.

73,
John WA5MLF

Open Wire and TPARCA

Click above to enlarge image.

Here's the cover of the March 1989 issue of Open Wire, the news bulletin of TPARCA. Note that the dial-up bulletin board system was in use at the time. For a bit of nostalgia you might like to listen to the sound of a dial-up modem connecting on this YouTube video. It offers explanations and waveform views of each stage of the connection process, starting with dial tone -- something that young folks rarely hear.













Among the contents of this issue was the following certificate from the ARRL:

   

The back page of the issue includes the Telephone Pioneers emblem:

N4AHJ has provided a large volume of historical Open Wire and TPARCA material that I can make available to any interested members.

73,

John WA5MLF

Chat Room Tips

Here are a few tips about use of the new chat room:

Right after you log in, the window below displays briefly. Note the short-cut keys for quickly switching chat rooms. You can also use the 3-dot menu and click on the chat room that you want to use.

You can identify which chat room you are currently using by looking at the colored stripe at the top of the chat window. See the two cases below.

Also, note that the chat time stamps do not identify the date. If there a few entries on consecutive days it is hard to be sure when the date has changed.

John WA5MLF

CQ TP and CQ WE 2018 Results

CQ TP results are at: http://www.tpqso.com/2018/results-2018/

CQ WE results are at: https://cqwe.cboh.org/2018.htm

Chat Apps

Various free chat/messaging services are available for those who are willing to sign up for a free account. Examples include, but are not limited to: WhatsApp, Signal, Telegram, GroupMe, Wire, Skype, Twitter.

Google also has a chat app that can be used at https://hangouts.google.com/ by clicking on the MESSAGE icon. 

John WA5MLF

RV Net Stations and Remote Transceivers

Observations of received signal strength from various participants in the daily East Coast RV Net on 7.191 MHz has revealed a daily pattern of reception range during the 2-hour period of the Net. Below are map views that show distance (as a circle) from each remote transceiver site that is used by W4BXI. Click on any map for an expanded view.

500 mile range: During the early part of the Net, stations within about 500 miles of a remote are not readable from that remote, unless within ground wave range.
300 mile range: During the later part of the Net, stations within about 300 miles of a remote are not readable from that remote, unless within ground wave range. 

500 mile radius from W4UOA

500 mile radius from KC4GO

500 mile radius from WA5MLF

500 mile radius from W6SFG

 

300 mile radius from W4UOA

300 mile radius from KC4GO

300 mile radius from WA5MLF

300 mile radius from W6SFG