NJDTechnologies

Radio: it's not just a hobby, it's a way of life

Current Operating Frequency and Mode

OFF AIR - but back tonight after dark for more CW

Listening on the road: SWL/K9/p’s summary of his receive activity on vacation in Branson

– Posted in: 630 Meter General Topics, 630 Meters
Below is a report by Ken, SWL/K9, normally located in Indiana but spending some time on vacation in the Branson area.  Like most of us addicted to this discipline, he took a receiver with him on the trip and below is his summary of the activity.  He was hearing very well in spite of the noise challenges he reports.  Enjoy!

 

Well, I’m back from my first vacation that included rx’ing 630m from a hotel room. Thought you might like to read about the “experience” of rx’ing from a hotel room.

The hotel was a hotel in the Branson, MO area. My room was on the 4th floor of the hotel. I had told my wife when she booked it to get the highest floor available. As I really had no choice of which room they would give us, it was the “luck of the draw” as to what compass direction the room window would face. As it turned out, the window was facing the NW. Unfortunately, the rooms have no balcony, as most newly constructed hotels don’t seem to have them any more. There was no way to mount the antenna outside, so I had to make do with that situation the best I could.

Here’s a pic of the rx installation on the desk:

hotel

Visible is the sdr, little Asus EeePC, and the large wall AC plug used as a system ground (ground wire brought out… the two AC prongs not connected). Notice the toroid used to keep pc rf out of the sdr. You can see the red ground wire and RG/174 coax at the sdr.

I had wrote you, mentioning using an eprobe on the window. That didn’t work out so well… didn’t deliver enough signal. I don’t know if the probe has a bad front end, or what…

I had brought another antenna… my resonant 20″ hula hoop. Setting it up, I saw it performed much better than the probe. Btw, the loop was used without a preamp.

pillow

The loop didn’t work well against the window, because the metal window frame detuned the loop. It worked best as shown. The loop is angled so as to be favoring the W-E direction. I did that to have a shot at the west coast and Canada. You can see the RG-174 exiting the loop over the pillows.

Well, as I previously mentioned, hotels are a really poor place to try to hear any LW-MW. First, the walls attenuate signals rather severely. Also, it seems that there are a number of noise-making devices all around you due to the proximity of all the adjoining rooms… above and below. I suspect that the AC line at the receptacles is also rf “noise plagued”.

Well, here’s what the sdr shows to be what the noise floor looks like at 630m on the sdr at the hotel:

interference1

Pretty ugly. Btw, the noise floor should be around the -140 level. Look at all the trash generated! This level stayed just like this all day until folks went to bed at around 10:00pm. reception was pretty much impossible until after this time.

Here’s what the noise floor looked like afterward:

inter2

Notice things got somewhat better late at night. You can see the broad resonance of the loop that peaks at 630m. Well, I would have had to live with this level of noise…

but fortunately, HDSDR has a software noise blanker that works to provide me this:

inter3

Well, this is much better! Yay! You can see the spike of WG2XXM transmitting. This is (fortunately) the final operating conditions that I had overnight.

I seemed to do OK on reception, considering this is an indoor installation with very strong RF noise problems.

I was pleasantly surprised to copy XBQ and XGP in a couple sessions. XZO was actually on the “wrong side” and had to plow RF through the building to be copied… surprised I did copy him. I never did copy anything from the NE guys… not surprising.

So, 630m rx’ing from a hotel has problems to overcome.

Strong RF interference from many nearby noise-makers Possible poor positioning of the hotel room in regards to compass direction.  In most cases, lack of outdoor access reducing the amount of desired signal reaching the indoor antenna.

I’ll be taking my rx equipment again on future vacations. This activity doesn’t take anything away from enjoying the trip… just adds to it. I’m asleep during the rx session while the equipment is “doing it’s thing”, I see the results in the morning …hi.

73,

ken   swl/k9/p