Saturday Net Operations

In response to John's (W4BXI) call to conference about possible ways to improve our Saturday Bell Ringers Net, the following Bell Ringers met:
John (WA5MLF), John (W4BXI), Carl (W4UOA), Gary (N4OLN), Jorge (KI4SGU), Larry (KB4LWT), and Phil (KB4XX). After discussing our 40 meter propagation problems, here are some ideas we thought might make our Saturday Bell Ringers Net better:

1. Use 75 m exclusively until sunspot activity enables a return to 40 m.
2. Use 75 m with optional Skype and/or phone patch connections for stations who are too distant from the core 75 m participants.
3. Use 60 m
4. Use 40 m exclusively, with the aid of relay stations. Remain on 7230 kHz while evaluating the effect of changing back to standard time on November 1.
5. Implement an RF bridge between 75 m and 40 m, enabling stations to select the band that gives them the best ability to hear and be heard.

We invite your feedback about these choices and any others that may be relevant. Please use the poll feature at the upper right corner of this blog to capture your votes for one or several of the choices. One of our goals is to resume a formal Saturday net with check-ins by member number.

The alternatives are listed in brief form in the poll to enable better visibility of the results after your votes are entered. You'll still need to use the horizontal scroll bar to see results. (The poll feature is one that I have not previously used.)

You may also post comments directly to this blog posting for other members to read.

An updated list of Net Control Stations is posted on our web site.

Thanks for your interest and inputs!
John WA5MLF

Map of 75 m Net: 1994-1997

Following yesterday's discussion of the Net's past operation on 75 m, I looked at my logbook records and found that the Saturday morning net used 3920 kHz in the 1994 - 1997 time frame. Making note of the member stations that checked during that period I produced this Google map showing their locations to reveal the Net's viability on 75 m during the low period of the sunspot cycle. The map supports our understanding of the membership as being concentrated mainly in LA, MS, AL, GA. The highest member number among check-ins at that time was 272.

Click on the link below the map to get a larger view with more navigation features. Many of the member locations shown are only at the city level of detail, not street address. It is interesting to compare this map with the one produced earlier this year that reflects participation in the 2008-2009 time frame.

John WA5MLF


View 75 m Net 1994-1997 in a larger map

VFO Controlled Low Power Transmitter

The Rockless, a VFO Controlled Low Power Transmitter, is featured in the November 2009 issue of QST. Jimmy K9JWJ contacted the author and was directed to The Rockless QRP web site for more info. Thanks, Jimmy, for the link.

ON8PO Radio Museum

See this amazing museum of radio equipment! Thanks to W4BXI for the link!

Early telephone multiplex systems & Bell Labs

During a recent morning QSO on 3968 we talked about early frequency division multiplex technologies for carrying multiple voice channels on individual metallic circuits. Probably the earliest example was the O-carrier system deployed on open wire routes. A few photos are shown at this web site.

Information about these FDM systems is sparse on the web. The above referenced article on FDM does include a link about L-carrier systems deployed on coaxial cable.

N-carrier systems were used on twisted-pair cables starting about 1950. According to two books in my library, N-carrier was used for routes ranging from 15 to 250 miles. They used two frequency bands: 36 to 140 kHz (low group) and 164 to 268 kHz (high group) in opposite directions, on two cable pairs. At successive repeaters the signals were translated between the low group and high group to promote equalization across the entire route. Depending on the version of the system, either 12 or 24 channels were carried on 2 cable pairs.

Searching the web for more information about these carrier systems also yielded a nice article about Bell Labs. Scroll down to find entries grouped by decades.

The Bell Ringers web site also includes some good historical links on the Links page.

Latest W4BXI System Audio Drawing

Here is a drawing of John's latest audio configuration. It makes use of a second PC to 'mix' a phone line caller via phone patch into a Skype conference call that connects to the transceiver.
Click on the image above for an enlarged view. Drawing is made using the OpenOffice Draw program.

With the drawing produced, one can make copies with overlaid features, such as the one below that illustrates the main flow for a regular phone patch. A series of these can be done to form a slide presentation, if desired.

Larry's Bees

Larry KB0BH sent me some additional photos of his bee keeping and honey production. Outdoor photos were taken by N4OLN. You can view the complete set in this album on the Bell Ringers web site.