February UARC meeting: DX Topics!

Mark, W7HPW

One of the facets of amateur radio that sparks the imagination of many hams (and would-be hams) is DX — the chance to work foreign countries in exotic places.

Our next meeting, Thursday, February 14, will feature Mark Richardson, W7HPW, telling us about some of the facets of DX. We hope to have more details shortly, but Mark is a seasoned DXer with some serious power and antennas and can fill us in on a lot of the secrets of the DX recipe!

We hope to see you there!

The room assignment for February:

Our February meeting will be in the Warnock Engineering Building, room L105.

For those who remember when we met in what was called the “Engineering and Mines Classroom Building,” down on the bottom floor, it's on that same floor, just a little ways down the hall - and all of it is now considered part of Warnock.

Getting there from the main (east) entrance:

If you enter the Warnock building on the main floor (e.g. through the east door), you need to get to the southwest corner of the building to find the stairway and elevator that go down to the L1 level. To do this, as you enter the open area on the main floor, notice some conference rooms along the far wall of the open area, left of the main corridor. Turn left along the pathway that goes past these rooms and follow it into a hallway that soon makes a sharp right turn. Follow the hall through the right turn and continue until you find the elevator and stairs near the end of the hall. The lowest floor accessible via the elevator or the stairs is your destination. Once there, look for room 105.

When are the UARC meetings held?

UARC meetings are held on the second Thursday of each month at 7:30 P.M., in the Warnock Engineering Building on the University of Utah campus. See the map for information on finding the building. Rooms for the remaining Spring 2013 meetings are as follows:

February:	L105 (Three levels down from the “main” floor)
March:	2230
April:	2250

Of course, the meeting will include the “standard” meeting features:

• Availability of ARRL books from Brett, the “book lady”
• An opportunity to join UARC or renew your membership
• An opportunity to join ARRL or renew your membership
• The chance to meet face-to-face the people you talk to on the air
• The “Meeting after the meeting”: A chance to enjoy pizza or other gastronomic delights with other hams. It happens at Litza's Pizza, 716 E. 400 South.
• The “Meeting before the meeting”: A similar get-together for those who can leave work early enough to get there by 5:15 P.M. The February get-together will be at “Charlie Chow's Dragon Grill,” 255 E. 400 South in Salt Lake City.

The UARC "Ham Hotline" is back!

The Utah Amateur Radio Club
Ham Hotline:  801-583-3002

After several months of absence, the Utah Amateur Radio Club's "Ham Hotline" is back in service.

The telephone number for the hotline is 801-583-3002.

If you have a question about any upcoming UARC events, events of note sponsored by nearby (Utah) clubs, upcoming sessions for amateur radio license testing or a technical or regulatory question related to amateur radio, this is a place to start!

Currently, this telephone number is directed to Linda, N7HVF and you may get an answering machine during business hours or when she is not home.  If Linda doesn't have the answer for your question there's a good chance that she can direct you to someone who does!


Why was it offline for so long?

We're not quite sure.  Several years ago this the ham hotline was "ported" to a VOIP service to reduce the costs and this worked fine for quite a while.  Suddenly - several months ago - we got word that it no longer worked and after some digging around we discovered that the VOIP provider had inexplicably cancelled the service and returned it to the pool of available numbers.  When asked why they had done this, we could not get any sensible answer!  (Yes, we'd been paying our bill on time!)

Fortunately, the number was still available so we obtained it through a different provider and, eventually, got it back into service!

IRLP/Echolink on the '76 repeater noise problem - "fixed" itself

Users and regular listeners of UARC's '76 repeater on Lake Mountain probably noticed that for a few days last week, the IRLP/Echolink node was unusable:  When the link came up, it would blast noise until it was taken down - either locally, or remotely.

Internet audio from the ground to the '76 repeater atop the mountain is conveyed using a UHF link and it was this link's receiver that was running "open squelch", causing the blasting of noise.  Since this receiver is active only when an IRLP/Echolink connection is brought up, there wasn't a problem otherwise.

Transmit antenna and UHF link antennas
of the 146.76 repeater.  The left-most of the
white antennas is the 146.76 transmit antenna
while the two UHF Yagi antennas are visible
near the bottom of the picture, just
to the left of center.
Click on the image for a larger version.

Analysis revealed that it wasn't really a problem with the UHF link receiver on the mountain, but that there was a signal present on its input.  In listening carefully to this noise, one could make out music and advertisements amongst the noise and by listening to the badly distorted audio, it was determined that there were two sources of audio:  That of FM stations on 107.5 MHz and 107.9 MHz.

As it turns out the 107.5 MHz transmitter is only a few hundred yards south of the repeater site, so it was understandable that audio from that radio station could appear in an intermod mix on the receiver:  This sort of thing can happen if anyone on this site - or another, nearby site - were to install a transmitter (or maybe even a receive system) without also installing the equipment necessary to "safely" operate in an "RF-rich" location such as Lake Mountain.  The sort of equipment necessary on these sites include isolators on the transmitters and bandpass and lowpass filtering on both transmitters and receivers.

But why was 107.9 MHz also in the mix as well when its main transmitter seems to be 10's of miles away?

We aren't sure, but here is our guess:

• Perhaps the 107.5 MHz transmitter was switched to a different, backup configuration and maybe it didn't have as much filtering between the antenna and transmitter.  It also could have been that something such as a filter or RF connection had "gone bad."

• With a large antenna system tuned to 107.5, it may have been that it intercepted a significant amount of energy from the more-distant but nearly frequency-adjacent 107.9 MHz signal, mixed within the final of the transmitter 107.5 MHz transmitter, and was re-radiated on many frequencies at a much lower level.

Years ago, a similar (but much more severe) problem was noticed with the 146.62 repeater's receiver on two separate occasions and in each case it was due to a malfunctioning or improperly configured transmitter!  In both of those cases the problem was identified - and corrected - in fairly short order!

In a valiant attempt to do a work-around of this problem, Gordon (K7HFV) and Brett (N7KG) drove to Utah County to gain access to the mountaintop so that they could turn the squelch up slightly, despite the noise problem.  In so-doing, they first attempted access via the south road (Mercer Canyon) but were immediately blocked by a gate so they went to the north side (Israel Canyon) and found a similar gate.

While they were prepared to park there and showshoe to the top, it was now about noon and a bit late in the day to make a start.  At about that time Clint, KA7OEI, did more testing and noticed that the interference problem was now gone and the system was working normally so Gordon and Brett were now off the hook and went home.

What "fixed" the problem, then?

We do not know at the present time, but it's suspected that the operators of the 107.5 MHz transmitter switched to their previous, "normal" configuration and the intermodulation source went away.  It may have also been that they discovered the malfunction and managed to fix it at that time.

While testing was being done on the UHF link receiver from the ground soon after the interference started, it was noted that it seemed to be much more "deaf" than expected - but this wasn't too surprising considering that there were spurious signals with FM radio station modulation on and near the receive frequency.  After the problem was resolved the apparent sensitivity of the UHF link receiver was re-checked and found to be 8-10dB better.

What this tells us is that it was very likely that we weren't the only users on Lake Mountain that were being badly affected by this problem and who knows if anyone else had complained and resulted in an expedited repair?

For now, we'll leave things alone and hold off on making another trip to the mountain until the spring unless some other pressing issue requires a trip sooner than that.  If this problem appears again, we should be able to do a work-around from the ground to restore IRLP/Echolink operation.

January UARC meeting: Formal Trafffic Handling differerent room!

Have you heard people on the air saying odd things like, “Please copy number 23, routine, from W7LID...” and wondered what was going on?

Well, UARC's January meeting will be a chance to learn all about it. There is a nationwide network of amateurs that operates every day of the year to relay messages (“radiograms”) from one part of the country to another.

Dick Leining, W7DML, will be telling us all about this operating activity including what form messages take, how they make their way from one place to another, and how you can participate. Traffic handling is one of the oldest activities in amateur radio. It's where the “relay” part of the American Radio Relay League name comes from.

With the new year, we're back to our regular schedule with UARC meetings on the second Thursday of the month. That puts the next meeting on Thursday, January 10, 2013.

Room Change!

The room in which we will be meeting is a little more complicated, though. It will be changing from month to month. The January meeting will be in room 2230, right above 1230 where our most recent meetings have been.

The meeting will start at the usual time - 7:30PM but you are welcome to show up earlier and meet new people as the wander in!

Of course, the meeting will include the “standard” meeting features:

• Availability of ARRL books from Brett, the “book lady”
• An opportunity to join UARC or renew your membership
• An opportunity to join ARRL or renew your membership
• The chance to meet face-to-face the people you talk to on the air
• The “Meeting after the meeting”: A chance to enjoy pizza or other gastronomic delights with other hams. It happens at Litza's Pizza, 716 E. 400 South.
• The “Meeting before the meeting”: A similar get-together for those who can leave work early enough to get there by 5:15 P.M. The January get-together will be at “The Sizzler,” 371 E. 400 South in Salt Lake City. 

See you there!