Messages

1

Equipment / Re: Regarding long wire antennas.

« on: March 26, 2016, 0113 UTC »

I'm about to embark on my first antenna project, a simple longwire. I have a 100' spool (suburban living means that's about the maximum I can make it) and thought I would connect it to my chimney on the far end and a tree outside my window for the near. That should give me around 50' of taught wire.

My question is this. In my research of longwire projects find that people often solder on the lead that connects to their receiver. However my unit (a Grundig Sattelit 750) has a place where you can connect a bare wire for the antenna in a jack like you find on a stereo speaker. Assuming that I get the length nice and taught, can I just trail the end of the wire down to the receiver directly? Or is there a compelling reason for soldering on a lead?

Thank you!

I have the same radio. the connection you refer to is a 600 ohm input and you should be able to connect your random wire to that directly. the other connection (bnc I believe) is for 50 ohm antennas.

2

Equipment / Re: Would an antenna analyzer be very useful w/ a mag loop antenna?

« on: March 26, 2016, 0111 UTC »

I'm still struggling a bit trying to maintain a low SWR on my recently built mag loop antenna.  Could be the feedline, the coupling loop, connection points to the cap...I'm not sure at this point but I continue to troubleshoot.  In any case, I've been starting to consider buying a dedicated antenna analyzer to see if that makes it easier to pinpoint the problem, but I'm not certain it would be of much use with my setup.  From my research, it seems like the way you'd use an analyzer with a mag loop is simply making tweaks (either by rotating your cap or making adjustments to your coupling loop) while watching for the lowest SWR dip.  But this is what I'm already doing from the comfort of my shack via remote control.  I watch the SWR on my meter while making fine tuning adjustments to the vacuum capacitor via DC motor control.  The only thing I have to walk 15 feet outside to do is make positioning adjustments to the coupling loop.  

I know some people swear by antenna analyzers and feel it's nearly impossible to design or properly tune a mag loop without one.  I'm not opposed to buying one if it'll help ferret out my problem, but I want to make sure it's going to do something more than what I'm already able to do.  Because from what I have managed to read so far, it seems all the analyzer would do is enable me to stand outside in the cold weather making adjustments I could be making from inside the warm house.  

I think having an antenna analyzer is helpful for troubleshooting issues. I have the mfj. i have used it to find resonance, reactances, shorts and opens on coax. They make it easier. your problem with the loop sounds very interesting. I have a mag loop. the bandwidth is very, very narrow. Move of frequency just a little and swr will change. Are you retuning after you move frequencies? is your transceiver frequency output stable, no drift?

3

Shortwave Broadcast / Re: CFRX Toronto CA, 6070 kHz, AM, 49m

« on: March 09, 2016, 2338 UTC »

One of the SW i regularly listen to here in midwest.

4

Equipment / Re: Magnetic baluns ... less noise?

« on: February 14, 2016, 1621 UTC »

I purchased a couple and have used them on long wires. I really didn't notice a difference. however, there are so many variable my results do not mean much. My location is probably a bit quieter than most. that said, from the research I have done, the best way to reduce noise and improve rx antenna performance is to eliminate common mode currents. The best way to do this is common mode chokes. Many shortwave and in particular mw listeners will also use some sort of balanced feed lines which i believe are inherently more immune to common mode currents versus unbalanced coax. Google search Dallas Lankford and Tom rauch. both and others have done much research and experimenting on this.

5

Equipment / Re: PREPARING FOR YOUR NEXT DXPEDITION - Part 1 article

« on: February 14, 2016, 1616 UTC »

Nice article. Look forward to part 2. I'm new to dxpeditioning. A few weeks ago, was traveling on business and was in Arizona for a week. I took the Elad SDR and Tecsun PL660 for radios. For antennas, I brought the quantum loop with mw and sw heads and the sony active wire loop. I was able to log a number of mexican mw stations. It was just interesting to listen to the content differences amongst the stations.

6

MW Loggings / Re: MW antenna ideas

« on: February 14, 2016, 1333 UTC »

Good morning! I have used and have 4 square, k9ay, and beverages. I have tried BOGs and Pennants. I also have Pixel Loop and good old dipoles. BOGs are easy to set up and work great. 200 feet is the optimum length. You can buy the transformers and terminations from dx engineering, as well as the wire. What I like about them is the simplicity. Just put them on the ground. That said, I spent the weekend building what is called a Misek micro SWA antenna. It is basically two beverages back to back fed in the center and phased with a variable phasor. Total length is about 60 feet. The antenna is amazing. You can steer a null through 365 degrees. This morning I was listening to CIAO on 530 and nulled it by 30dB and picked up another station on 530 (unid spanish and music). For such a small antenna is is really good. The version I implemented was designed by Dr. Lankford. He compared its performance to two phased verticals and said it performed just as well. You could make it longer and probably get even better performance.
Also try two long wires at 90 degrees phased through a variable phasor.