Will Extra (open) Jacks Harm Performance

[Dewey]

I have been running multiple scanners through "common" TV splitters for YEARS (I bring the signal into the house with quality quad-shield 75 ohm coax). Since I'm in the DC Metro area, I am not at a loss for strong signals. I am thinking about upgrading my antenna system from the Sputnik (RS 20-176) to a Diamond Discone D130J. If I do further chase this thought (I'm in the homework stage right now), I'll probably upgrade the entire antenna system. On the inside, I'm considering going from the regular TV splitter to a passive or active Stridesberg. Here's where my question comes in. While I have several scanners from upgrading over the years, I normally only run two as base units... the others are portables anyway. While using a passive two port Stridesberg shouldn't hurt my signal too bad (actually, it should still improve when compared to the TV splitter), I have not totally ruled out an active Strideberg. BUT, if I shell out the $$$ for an active Strideberg, I'm thinking for just a little more, I can have four ports instead of two. Will two unterminated ports (for those "normal" times when I'm only running two scanners) hurt me in the signal department? I still remember an old argument from the 70's about using terminators on unused F-connector TV jacks to help with TV reception.

Thanks,
Dewey

 

[N_Jay]

Why do you think that any of the changes will help your signal?

How long are your cable runs?

As for the open ports, they do add a little random frequency and impedance issues to your system, but I doubt anything you can tell with a scanner.

 

[Dewey]

Why do you think that any of the changes will help your signal?

How long are your cable runs?

As for the open ports, they do add a little random frequency and impedance issues to your system, but I doubt anything you can tell with a scanner.

I have a habit of revisiting projects somewhere between three and five years later to see if "improvements" can be made. The current thinking process about the current antenna system is bourn out of just "improving" my reception with a "better" antenna (I sure hope that you're not going to tell me that the Sputnik is as good as the Diamond Discone). It's kind of like first time computer owners... most outgrow their first purchase, and try to improve on their "horsepower" the next time around. While I've already mentioned that I am not at a loss for strong signals, I would like to see what's "out there" further than I am currently hearing (I've been to the moon, now it's time to go to Jupiter). My current cable run is between 20 & 30 feet. While I am in DC's suburbs, I have not experienced any overloading from home, which is also why I'm thinking of reaching a little farther. BTW, while doing some of my homework, I think I may lean a little more towards an Electroline rather than a Stridesberg (I forgot to mention that in my OP).

Dewey

 

[N_Jay]

OK, a discone is a unity gain antenna. The RS thing is probably only down one or two dB.

As for cable, even at 900 MHz the difference between RG-6 and LMR-400 is less than 1 dB.

As for the splitters, I doubt that the Electroline or Stridesberg, are significantly different than the TV splitters. (as long as you did not go too cheap)

As for the "active Splitters, they are just a splitter and an amplifier in one package. Nothing special.

If you want an amp, you want it as close to the antenna as practical, and as high a gain and low noise as practical without it becoming overloaded. Anything else usually does little real good for weak signal reception.

Next you have to realize that with an FM receiver you will need a 6dB increase to get any significant difference. AND, 6 dB will take a noisy unreadable (but definitely there) signal and make it a noisy but readable signal. It will also take a noisy but readable signal and make it a fairly noise free signal.

SO, unless you are already hearing things that you want to make better, changes under 6 dB are usually worthless.

Now, if you want to REALY improve your reception, I would look at more height. That is the one factor that affects reception range the most.

 

[reconrider8]

how good is the 20-176 over a http://www.radioshack.com/product/index.jsp?productId=2103640 cause im thinking bout getting the 176

 

[N_Jay]

how good is the 20-176 over a http://www.radioshack.com/product/index.jsp?productId=2103640 cause im thinking bout getting the 176

I would bet a good bit.

Loaded antennas tend to have relatively narrow bandwidths.

Getting it outside and up high is even more important.

 

[reconrider8]

first off i think ima put it in my attic then if it does real good there i might move it up casue i have an old tv antenna pole like 13' then with like a 7-8 foot piece of pipe what wiould get it to like 20 ' thats bout as high as i want it to go right now

 

[kinfolk]

Dewey,

I use a Stridsberg active 4 port splitter with a Diamond Discone with fantastic results. The Stridsberg active splitter gives no loss as I have tried the antenna direct with no improvement. In my opinion, if you upgrade both your antenna and splitter you will see a very noticable difference and considering the area that you live in, you may have to deal with front end overload issues at that point.

 

[kinfolk]

Dewey,

I forgot to mention that I purchased 2 dummy loads for unused ports and they did not make any difference. Now I am running four scanners so I don't use the terminations anymore.

 

[Dewey]

how good is the 20-176 over a http://www.radioshack.com/product/index.jsp?productId=2103640 cause im thinking bout getting the 176

I'm very happy with my "Sputnik's" performance, I just want to see if I can get more at this point.

N_Jay
Thanks for the advise. I already knew that elevation is one of primary areas to increasing antenna performance. While I don't have a HOA, I do want to stay "neighbor friendly", which is why I selected the 20-176 in the first place. It is on the top of the house, but only on a 5-foot mast. I really don't want to increase the height as it would really stand out since my house "opens" into to a view as you come around a curve (could make the neighbors start "talking"). I also greatly appreciated the 6 dB rule as I had never heard that one.

Thanks again,
Dewey

 

[Dewey]

Dewey,

I forgot to mention that I purchased 2 dummy loads for unused ports and they did not make any difference. Now I am running four scanners so I don't use the terminations anymore.

Thanks for both posts. Somehow, I just don't feel that I will increase my chances of overload, and subsequent desensing. I sometimes run my Pro-96 off the current house antenna, and do not have problems. I would think that Pro-96 would definately start "balking", or maybe stop "talking" once hooked to the house antenna if I were too close to any RF alleys... and believe me, inside of DC is FULL of them!!!

Dewey