Calvert County ARES Emergency Coordinator

Earlier this month I volunteered to take over the position of ARES Emergency Coordinator (EC) for Calvert County. The previous EC had gotten busy in other areas and decided it was time to step down. I’ve held this position before but in a different location so while the job isn’t completely foreign to me, well, it’s been a while. I’ve been working on a new emergency operations plan (EOP) for ARES that’s more of an all-hazards plan than laying out specifics. Once that is complete I’ll start trying to get people to work on developing training and training topics.

At last night’s ARES meeting I was happy to have fifteen people join me in a review and feedback session on the new EOP. I’m hoping the momentum continues as I plan more training and exercises for the next few months. I’ll try to write about those events here when I get them complete.

ARRL Sweepstakes contest and LoTW

The ARRL Sweepstakes contest (phone) took place last weekend and I spent a few hours on the air making a few contacts. Although I didn’t have much time to spend on the event I did add twenty new contacts to my log. Since I’m working on my WAS from my new home in Maryland (contacts made before I moved up here don’t count since they were made greater than 50 miles away) working the Sweepstakes contest let me add a few more states to my log (I now have twenty-four states confirmed via LoTW). I wish I had had more time to devote to the event but I’m glad I worked the stations that I did.

I downloaded my LoTW QSLs today and found that fourteen twelve stations have already uploaded their contest contacts. That’s really great to already have those states confirmed so quickly. I wish everyone did this.

I’ll update this when the contest results are available.

Breaking the Arrow Antenna’s diplexer

The Arrow Antenna for satellites has an optional diplexer that allows easy operation of 2m and 70cm from a single feedline.  I’ve used this configuration for over ten years with no problems.  I’m not sure, exactly, what happened but the diplexer failed.  After ordering a new one I started digging into the hardware to see if I could see anything that was the matter.

Arrow Antenna diplexerLooks like one of the surface mount parts got a little warm.  The picture does not show the hole that had melted through the shrink wrap but the bottom right component definitely got too hot.  The solder is completely gone from one side which was definitely affecting the circuit.  I’ll likely try to repair this even though I have a new one in service right now.

What a difference 3.5MHz makes.

I was surprised at the difference  three and a half megahertz made this evening.  While chatting with my friend Emily, N1DID, we started trying different bands to check for a better signal.  Fifteen meters was okay but twelve was better.  We decided to try ten meters for the heck of it and the almost full-quieting signal of Emily’s was not heard at all just three and a half megahertz up the band.  Somewhere in that little bit of bandwidth the signal, instead of being returned to Earth via the ionosphere, was being shot into space with little hope that Emily would hear it.  I guess we found our maximum usable frequency!

What’s that noise on 20m?

Yesterday I was tuning around 20 meters and heard packet!  Wow, it’s been years since I’ve used packet (outside of APRS which is a different animal when compared to this).  Turns out I stumbled onto the Net105 frequency with all of their users.  It’s quite busy there and I’ve seen stations from Florida and Colorado and everywhere in between.

I still enjoy packet radio and even worked two stations, keyboard to keyboard, this morning.  I may try to put up something more permanent up for the network.  If I can find a KAM+ I should be able to hook an HF radio and a VHF/UHF radio together and provide a gateway for myself and anyone else that wants to join in.

We’ll see what happens in the future.

Results of the W4OTN/R UHF repeater test

As I mentioned a few weeks ago, I bought a UHF repeater and put it on the air at the Mt. Hope tower site here in Calvert County.  This was a temporary test which allowed myself and other CARA club members (and anyone else) to see what UHF would do in our area.  Turns out, the system did quite well.

We estimated ~3 watts was being seen at the antenna.  That’s not a lot of power and we weren’t expecting very good performance.  Turns out, that ~3 watts was enough to give us pretty good coverage, about a 15 to 20 mile radius with several longer distances seen.

We have now replaced the repeater with a Yaesu repeater and better duplexers.  We’re now seeing about 45 watts ERP and a better foot print (around 35 mile radius).

This has been a good experiment.  I’ll be moving on to stage two for my repeater project.

W4OTN/R on the air

W4OTN/R Installed at Mt. Hope

W4OTN/R Installed at Mt. Hope

Earlier today, Dave W3PQS and I installed my UHF repeater up at the CARA site in Sunderland.  The repeater is on the air on the TMARC shared, non-protected pair which makes the system quite portable.

In the short term, the repeater will be on the air at the Mt Hope site.  In the longer run, the repeater will be setup to be portable for special events, emergencies, and “family” use.

If you’re in the Southern Maryland area try it out and see if you can hear the system.  442.900MHz, + offset,  CTCSS 156.7Hz.

Update

As of 25 September the 442.900 repeater is off the air.  It has been replaced with a Yaesu System Fusion repeater on a frequency of 444.950MHz, + offset, CTCSS 156.7Hz.

FO-29 Success

Yesterday I had a broken QSO with K9?H?.  We were running CW and between the fading, the Doppler shift, and my poor CW skills I couldn’t quite get the full callsign and exchange. And then, of course, I was also chasing myself all over the transponder.  This morning was completely different, however.

The pass of FO-29 was going to be high.  Being that I’m still working on my antennas and not knowing what to expect I was just hoping to hear myself.  Tuning around the center of the transponder I clearly heard N8HM calling CQ.  I was able to find myself on the transponder and tune myself onto Paul’s frequency.  To my surprise he heard me and we were able to have a somewhat broken QSO.  I’m not hearing the downlink that strongly (clearly an antenna issue) but we were able to swap grid squares and have a short QSO.  Turns out Paul is just up the road in DC making this perhaps the closest distance satellite contact I’ve had.

I need to go back through my logs but I think this may be my first FO-29 QSO.  It is, at least, my first FO-29 QSO in many years.

First attempts at FO-29

I had a good pass of FO-29 this morning so I figured I’d give it a try with my 2m/70cm loop antenna.  I wasn’t expecting great things as this is not a gain antenna and I’m not sure how much of the signal is actually radiated up but I figured I’d give it a shot.  Turns out it does… okay.  I never heard the beacon but I was able to find myself on CW.  It’s been years since I operated a satellite much less a transponder satellite so I was having a hard time tracking for Doppler.  I’ll have to hook up with my satellite Elmer, again, and make sure I’m tuning the correct side (do I try to stay in the same place on the satellite transponder by adjusting my uplink or do I try to chase my downlink through the transponder?).

Another observation is that the loop doesn’t do very well.  I’m definitely getting into the satellite with ~10 watts but I’m not hearing the satellite that well.  A preamp might help here but I suspect getting some proper antennas would as well.

Parabolic antenna beamwidth calculations

Okay, I’m thinking about parabolic antennas right now.  I created a spreadsheet that would take care of all the formulas some years back but I can’t seem to find it now.  I’m trying to find all the formulas that I need to get the information I need to make my brain figure out the resolution at a distance based on dish size and frequency receiving.  So I don’t have to remember this, again, I’m writing it down here.

  1. The formula Ψ = 70λ/D creates an estimate for the beamwidth of half the power (to -3dB of the signal).
  2. A larger parabolic antenna will yield a smaller beamwidth which should result in a higher resolution.
  3. As frequency goes up the beamwidth goes down.

I’ll use a 1m [diameter] dish as a reference since that size isn’t too large for personal use.

[table “1” not found /]

This provides the basis of receiving a signal from a distance.  But the other question to look at is how big is that signal that you are looking for.  If you are trying to communicate with another terrestrial station, or even an orbiting station, then having equal footing is great as there is no waste.  This hardly happens and the antenna usually ends up trying to pull in a weak station and also gathering the surrounding noise.

But what if I’m not trying to communicate with another station but rather trying to hear a tiny “voice” in the middle of trillions of other voices?  I’d want a very tight beam to be able to not only pull out that tiny voice but also not collect the surrounding voices (and not overwhelming my receiver with a high noise floor).  The vocabulary escapes me at this point.  I’m sure there is a word for it but all I can come up with are words that describe optical reception (e.g. pixels and resolution).  When I can figure out the vocabulary and the formulas needed to put these two puzzle pieces together I’ll post it here.