My First Antenna

[SharpNEO]

So, I'm thinking that this little coat hanger from RS looks great for an all-purpose antenna.
Outdoor VHF-Hi/UHF Scanner Antenna - RadioShack.com

I'm connecting it to BCT15X which will be just be used for some basic scanning. (I plan to get a BCD996XT sometime in the next month or so for listening to trunked and digital stuff here in Ohio.)

So, I'm thinking about mounting it (on the north side of the house) just a few feet above the peak (approx. 20 feet high) on my roof, which would give it a total height of approx, 25 feet. The nearest set of power lines coming to my house are on the south end of the house which is opposite of the potential mounting location. And from what I've read, that should be sufficient for catching most local traffic within a few miles or so.

However, that is where my confidence begins to dwindle... I do not know what type of cable I should be using to run the total 30 feet or so of cable that I need to reach my office/man-cave, how to make the connection at the antenna, or if the antenna should be grounded.

I'm reading and learning when I can, but I'm also a full-time student just starting my senior year for a bachelor's degree, so I often have a lot of other "reading and learning" that takes precedence. That leaves me just chugging along slow and steady for now.

Which is why I'm here asking for some guidance with my first outdoors antenna. I've read some things in the wiki (which is where I found the RS antenna to begin with) and some external links, but nothing so far that is giving me the basic info I need to actually purchase and assemble the right stuff.

I'd like to do this right the first time so I can focus on learning more instead of trying to figure out what I goofed up the first time I did something.

 

[K9WG]

I do not know what type of cable I should be using to run the total 30 feet or so of cable that I need to reach my office/man-cave,

For 30 feet any good qulaity coax would work.

how to make the connection at the antenna,

This antenna (according to the manual) has a standard PL259 connection. If you buy the coax already with the PL259 connector it will just screw into the base of the antenna.

or if the antenna should be grounded.

This would be good. Biggest concern would be lightning protection but even grounding will not protect you from a lightning strike. Depending on how you mount the antenna you might be grounded through the mount.

I would buy a pre-made 50ohm coax cable (PL259 on both ends). You will probably need a PL259 to BNC adapter for connecting it to your scanner.

 

[Awesomeman92]

I would recommend that antenna, I use it mounted on a random wooden pole in my room running into my Pro-197 and it works great. Just be careful, the metal pieces like to bend. I've got it running through 30 feet of RG8 coax (way more than I need) with a PL259-BNC adapter with very little signal loss and great reception. Although if you're after digital, I'd go with a wide band antenna, at least on the systems by me I get a lot of dropped digital signals (although I'm listening to a simulcast system fairly close to 2 towers, so it could just be multipath). For 800mhz analog trunking/conventional it does just fine, I listen to our town's analog trunking system with it no problem. Just don't expect to pull in a site over around 20 miles I'd say, that's my experience with it at least.

 

[SharpNEO]

Very much appreciate the advice, folks! Now for some fine tuning...

Biggest concern would be lightning protection but even grounding will not protect you from a lightning strike. Depending on how you mount the antenna you might be grounded through the mount.

Do you think (something like) this would might work satisfactorily for a grounding device? (Winegard GB-8100 Single Grounding Block for Coaxial Cable (GB-8100) - Winegard - GB-8100 -) Not necessarily that model, I just chose that one for illustrative purposes. But something along those lines?

I've got it running through 30 feet of RG8 coax (way more than I need) with a PL259-BNC adapter with very little signal loss and great reception.

This was also an upcoming question, what might be caused/lost with an adapter. With this set-up, I am assuming that any loss or interference is going to be negligible or unnoticeable for an amatuer system.

Although if you're after digital, I'd go with a wide band antenna...

I'm hoping to create a whole new beast for my digital scanning. I'm planning to pick-up a BCD996XT in about a month or so. And I'll definitely be asking about choosing the right wide-band antenna now that you've mentioned it.

 

[K9WG]

The grounding block is OK but it is only going to protect you from a direct hit. Best thing it will do is help ground the coax shield.

The PL259 to BNC adapter will not introduce a large amount of loss so I would not worry about it unless you have several attached together (otherwise know as a plumbers nightmare).

Performance really comes down to how far away you want to hear. I am receiving 800 P25 from the next county using a very simple Yagi antenna sitting on my desk inside the house. If all you are wanting to listen to is local 800 Mhz you probably won't need much. I would try the RS antenna first before looking at other setups. You might be surprised at the results.

Found this on www.AESHAM.com

 

[Gator596]

I'm very much in the same boat as Sharpneo. Am just going to set up my first antenna. I have the same model from RS. About the only difference is my scanner is a 396xt and my cable run is a little longer at 50'.
I thought the grounding talked about in the antenna instructions was for signal quality and NOT lightning protection. Now I'm not so sure...

 

[mass-man]

Antenna grounding of a ground plane antenna is for lightning protection!!!

 

[ka3jjz]

You don't ground the antenna - you ground the coax that leads from it (which is the attempted purpose of the 'Guardian Angel' pic below...), and/or the mast it's on. There are actually only a few antennas you actually ground to make work correctly- an example would be some 2 meter ham mobile antennas, that form a ground through the metal screws that hold a trunk lip mount in place.

Just remember there is no such thing as absolute protection against lightning. Disconnect all antenna leads (and preferably the radios from AC as well) when that's in the vicinity. Better safe than sorry.

Oh, and don't forget about sealing against moisture - no PL259, BNC or N connector is water tight. Use Coax Seal (available from many ham distributors) or a double layer of tape and silicone sealant (from Lowe's, Home Depot, etc.). Otherwise you'll have ruined coax due to moisture in short order

best regards..Mike

 

[Gator596]

Thanks for the clarification!

 

[jackj]

Allow me to stick my oar into these muddy waters too.

First, the antenna you have selected seems to be aimed at VHF/UHF frequencies. From RS's web site: "Covers 108-1300MHz with peak performance occurring in the 152-470MHz range." I don't think they would specify "peak performance" if the coverage was pretty flat up to 1300 MHz. You will need an antenna that covers 800 MHz pretty well if you plan on monitoring Ohio's MARCS towers.

Second, the height you are taking about will work fine as will the length of your coax run. Now for your selection of coax. Each type of coax has numerous grades. The two major factors are the shielding and the dielectric material. Cheap coax will work but will have less shielding, sometimes as little as 60% shield coverage. Better coax will have >95%. The dielectric material will determine the loss of the coax and how long it will last when exposed to weathering. It is almost impossible for you or me to verify these important specs but the best way to judge coax is by price, expensive RG-8 is better than cheap RG-8. The length of the run means that you should not use RG-58. You should consider RG-8 to be the least expensive coax you could use.

Third, the antenna will be out in the open and should be grounded. The best way to do that is also the cheapest. Use a stainless steel hose clamp that will fit around your mount. Get some no-ox from an electrical supply house, sand the mount where you will fasten the ground, coat the pipe and your ground wire with no-ox and clamp the two together. Don't use wire smaller than about #8 and run it as straight as possible to a ground rod driven about 6 to 8 feet into the ground. Your goal here is to bleed off static charges that will develop on an ungrounded antenna so #8 gauge wire is about all you need. You could use #000 welding cable but that still wouldn't be big enough to survive a direct lightning hit.

Good luck!

 

[Gator596]

Thanks Jackj
I'm going whole hog and use LMR400 cable. I'm hoping it will last a long time.
My antenna is going up on an old metal TV tower that is sunk in the ground - do I still need to do the grounding as you describe?

 

[jackj]

Yes Gator596, you do. The TV tower might or might not have a good ground to the top. Running a copper wire to the mast pipe is about the only way to insure that you have a ground that is good and will stay good. A lightning strike 1/4 miles away will induce pretty high currents and voltages in ungrounded antennas.

I wish I could afford LMR400.

 

[Gator596]

Thanks again jackj. Will ground as you described!

 

[Dewey]

Concerning the antenna itself, a lot of us refer to it as the "Sputnik". In my opinion, it is a very good antenna, dare I use the word "great" when you compare it's performance to its price. I replaceed mine last year with the more expensive and higher rated Diamond D-130, but I really miss my Sputnik!!! I plan on putting another Sputnik in my attic for use when the spring and summer storms hit.

Dewey

 

[mass-man]

Are u saying it is better in the attic than outside? Not so durable in the elements. ALL of my antennas are in the attic, and this might make a worthy addition to the arsenal.

thanks

 

[Dewey]

Are u saying it is better in the attic than outside? Not so durable in the elements. ALL of my antennas are in the attic, and this might make a worthy addition to the arsenal.

thanks

No complaints about my Sputnik when it was outside on a five foot mast above my roof's A-Frame. I was in the process of having my roof reshingled and I decided I wanted to "1-up" my reception, so I went out and bought the D-130J. When all was said and done, I REALLY MISS MY SPUTNIK!. I'm not having any type of intermod or desensing issues, I just feel that my Sputnik was just as good as my D-130J. And to make matters worse, my Sputnik was only operating with two of it's three radials because the tripod roof mount fell over breaking one of the Sputnik's radials when I was originally preparing it on the ground before mounting. So my "in the attic" statement was not about the Sputnik's outside durability, but more about I REALLY miss it, and know that it will make a good attic antenna for storms.

Dewey

EDIT: PS... if you do a search on "Sputnik" or "20-176" on RR, I think you will find that those of us who have used them are happy with them. Of course, YMMV.

 

[SharpNEO]

Well, Sputnik it shall be, then! Sorry I haven't replied sooner. However, I was looking at the roof a few days ago as I was pulling out of the drive and I stopped and decided I might be adding just a few more feet of cable so I can reach an old UHF/VHF antenna mount I seen on the side of the chimney. (I'm back in college after almost 20 years since I graduated the first time. And I am absolutely dying to find some free time to get some of this stuff done!) Anyways, I appreciate all the advice, as always, and the extra boost of confidence I now have in Sputnik as my first antenna choice.

 

[K9WG]

Yes Gator596, you do. The TV tower might or might not have a good ground to the top. Running a copper wire to the mast pipe is about the only way to insure that you have a ground that is good and will stay good. A lightning strike 1/4 miles away will induce pretty high currents and voltages in ungrounded antennas.

I wish I could afford LMR400.

jackj is correct in that lightning will induce voltage spikes in an antenna. I would theorize that the vast majority of equipment damage is done by nearby strikes and not direct hits. If you have a direct hit two things will happen

1. You radio will be toast no matter how well grounded

2. You will have much more urgent things to worry about at the moment then your scanner.

 

[Gator596]

jackj is correct in that lightning will induce voltage spikes in an antenna. I would theorize that the vast majority of equipment damage is done by nearby strikes and not direct hits. If you have a direct hit two things will happen

1. You radio will be toast no matter how well grounded

2. You will have much more urgent things to worry about at the moment then your scanner.

Thanks - My tower has a huge old TV antenna on it that was never grounded so I was going to skip grounding my scanner. For the couple of bucks it is going to take to do it right though - I will ground the sputnik antenna.
Thanks again,

 

[SharpNEO]

Rise, rise from the dead, you most useful thread...

My apologies for necro-posting, but I really want to keep this next post of mine in-line specifically with information found in this thread.

I still have not picked up my BCD-996XT, but it's only a few weeks away. I am, however, putting together a rig that will hold my BCT-15X and the BCD-996XT side-by-side on my desk. And I am ready to run my antenna(s) so that part will be done already.

So, as I am preparing to order my antenna gear tomorrow or the next day (depending on the answers I get to this post) I have a final preparation question or two that will decide the sizes and quantities of my orders.

1) If I mount the Sputnik (Radio Shack antenna mentioned above) on my roof, can I safely (and decently) run both scanners off the one antenna or do I need one for each unit?

2) Can I safely use the same grounding unit (as mentioned above) if both units are hooked to that single antenna?

3) Just in case I am not asking the right questions about this, is there anything I should know or should do (or not do) while considering this single antenna idea?

4) I'm thinking of ordering pre-assembled coax cable from Universal-Radio. I'm thinking about #0497 (50') and #3849 (12') of the RG-8X cable to run from Sputnik on my roof down to the grounding unit and then on in to the spare room (currently our ad hoc office). The prices look fine to me, but I'd sure like to double-check that this cable is suitable for my basic scanning needs based on the units listed above and the antenna(s) I would like to use.

As always, your insight is much appreciated!