Any correlation between line of sight performance and 10-12M DX performance?

[RadioDaze]

I am wondering if there is a correlation between an antenna being high performance for line of sight.. or at least point to point surface wave (including the radio horizon) and F2 layer DX ?

Do low take off angles produce better signals or worse signals typically to point to point ground based stations that hear you? I think I read somewhere that in some instances higher angles can increase signal strengths locally. Let's call locally 5 - 100miles. (which could be typically "local" to stations anywhere from 0ft ASL to 600ft elevation above sea level)

 

[Moleculo]

am wondering if there is a correlation between an antenna being high performance for line of sight.. or at least point to point surface wave (including the radio horizon) and F2 layer DX

Sure, there are some basic correlations. As antenna gain increases, the line of sight and surface wave results will improve, as will performance due to F layer propagation. For example, think about the difference between a directional antenna like a yagi vs. a basic omnidirectional vertical.

Do low take off angles produce better signals or worse signals typically to point to point

That depends on where the station is that you're trying to communicate with locally. If the station is far off in the distance at the same elevation as you, then the lower take off angle will probably be better. However, if the station is at an angle of 45 degrees above you on a distant hill, the same antenna might perform worse.

So...the way to think about antennas is that everything is a compromise of some sort. You have to decide what you're trying to accomplish and then choose the right tool for the job. If you want to perform multiple jobs, you might need to use more than one tool.

 

[RadioDaze]

That makes sense. At the moment my longest surface to surface (line of sight) contact without any known tropo lift or Sporadic E (I checked the forecast and there was none forecast and the signal from this guy was uniformly extremely weak and a similar hard copy for him to RX myself) was approx 240 miles (S-0 R1) I had to work this station QSO in a manner that was considerably more difficult than any F2/Sporadic/Tropo DX skip contact I have worked. I said it was doing to be a very hard job to get this in the log so said we will both need to be patient....I asked him 5-6 times for just his call sign in phonetics. I am, glad we stuck with it.

It was especially nice for me as I had yet to break the 200 miles mark. Only 197.3 !! so this one blew that away by some margin. 100 miles copies are a fairly common occurrence for me. (almost every time I go out)

I think the guy at the other end had an Antron99 on the back of his vehicle up a hill - 26CI001 (David) St. Ives Cornwall UK. I was mobile static using the Gain Master. We were both mobile to mobile stations on high ground.

He is on Youtube...



Approx locations :

 

[222DBFL]

I know ol 001 David. One of my first logged entries a couple years ago. And that is a heck of a good distance for "local" talk, even at 100 miles, at 200 miles you are really making a good distance for sure. I am happy to get above 100 miles here. Ive made a few and I mean a few 100 mile contacts but man it has to be super quiet on the band for me to do so. You must be doing something right with that setup of yours!! Keep up the good work man. It's almost more fun making contacts like the one you made with Dave, as its really a challenge. I saw the radio you use, and not to intrude but how much power do you run?? If you wish not to speak about that I do understand. Just curious. Know a guy here that uses an A99/w GPK, with some sort of contraption he has added to the bottom of the antenna which is housed in 2" sch40 pvc. He has a very and i mean very sensitive receive and can hear stations that most others don't. He says the device he has built isolates the antenna from any metal. The antenna slides into the 2" pvc and he uses a single run of coax from antenna feedpoint to his radio, in which the coax is part of the device he has built into the pvc. He won't tell me all the details as he says he is trying to patent it. It seems to work pretty damn good is what is so funny. I know it sounds like BS, but whatever he has built inside the 2" pvc pipe is working. He wants to build one for me but I haven't gotten around to meeting up with him and such. He is almost 40 miles from me and he hits me with s3-s5 while guys in the same area within a couple of miles I can barely hear. And they aren't running crappy setups. His antenna is 36ft to the feedpoint so he isn't real high but can consistently talk across the state when others can't even against 3 element beams and such. Wild stuff but again don't know if it's snake oil or BS, or if the damn device really works. One of those gotta try one and see. But he says they aren't easy to build. So there is something to it. Anyway, again, keep up the great work and posts as well. And have a good day.

 

[RadioDaze]

Cool, radio makes the world small

What I lose in my cheap radio RX I make up in the height up hills and low noise level. (generally speaking) I do get something along the lines of arc welding interference at one QTH but on the whole I chose fairly quiet locations. Again height is the one for the long DX line of sight and I do pretty well on that side. It is definitely fun talking long line of sight. I bet you can get these kind of "export" Chinese radios for about $150.00 on your side of the pond. I paid £150.00 for mine, I am happy so far, it has not broke and works well enough.

I do not have access to all these cool DSP filters, low noise high quality RX electronics and noise blankers sadly like the Yaesu's, ICOMS and Kenwoods. (I question my RX a lot but one of my radio buddies has an awesome location on the coast with salt water and he seems to hear quite a bit better than me despite the hill. I expect a factor of being on salt water in a metal boat. (now that is a ground plane) Coupled with a better quality radio. But if I save my pennies who knows, I bet that would be a major upgrade in the RX side of my set up, no question. I just try to set up the best possible station I can given my ability and means.

In my limited knowledge I can only guess at your buddies magic pipe. I reckon on a couple of turns of coax through some very good quality ferrite cores, maybe ? That is all I could imagine that is not lossy and could quieten down the RX and keep the antenna pattern in check.

This kind of thing ? (and maybe he speaks to vertically polarized stations and does not lose on the cross polarization like those using the horizontal beams? Just guesses really.)

http://wsplc.com/t-4-plus-unun.html

 

[222DBFL]

Issues I have with vertical antenna at the moment is an outside noise source from the neighbors. It's not very noticeable on the dipoles as they are horizontal, but it's there. It's bad on the vertical like S3-S5 at times on SSB. S7 or more on AM. I've tracked it and it a neighbors house but what it is idk. Anyway, I will eventually get a new vert up soon. Just not sure what I am going to put up yet. At any rate I can still talk dx pretty well with the dipole setups so I am cool for now.

 

[RadioDaze]

This is exactly why I don't bother DXing from the home QTH. I have normally S4-S5 noise and sometimes S9 of pure, thick HISS when someone close turn something on it completely blocks the radio out.

I gave up at home.

But on the up side I see the countryside more often and get some fresh air/exercise lugging 20KG batteries and putting the antennas up.

 

[222DBFL]

That I would be nice for me as well. Just that my vehicle isn't practical for a mobile setup currently. Would look a bit funny as well on a 2008 Chevy Impala SS. Sunroof and antennas don't mix well!! Anyway. Like I said enjoying yourself is the most important thing IMO!! And being safe as well!!