Need antenna advice.

[woodyrr]

I finally got so tired of my lousy reception of the DPS Norman site and Norman TRS, I replaced the “bell wire” cable from my scanner to the antenna with an uninterrupted 20’ length of Belden 9913 coax with Amphenol PL 259 connectors.

Very much to my displeasure and dismay, I noticed an improvement on VHF using the weather broadcasts as a guide, but had absolutely zero improvement at 800 MHz.

Toward that end, I’m looking for a high quality dedicated 800 MHz antenna though not necessarily industrial grade or frightfully expensive, and certainly not huge. Do any of you have a clue as to an antenna model or brand that might work?

 

[benjaminarthurt]

Not familiar with the system/slights you referenced. However in a similar situation I did some asking and someone suggested I use rg-6 75ohm tv cable. They explained that it acts more like a 50 ohm cable in that range. I tried it... and much to my surprised It improved my reception noticabley. I am not sure of the science behind this but it worked for me. I just used cheap RS brand rg-6 quad shield. Just my $0.02

 

[dward42586]

Antenna for trunked systems

I use this antenna, I have two. I'm about 35 -40 miles from the tower I monitor and reception is excellent. Same coax as you mentioned but will need to change the connecters. Look at this link http://www.ccrane.com/antennas/cell-phone-antennas/wilson-trucker-cellular-antenna.aspx
Cost about $75.00.

Hope this helps.

 

[car2back]

if you are willing to try directional antennas, I found this great deal on Fleabay: 3 element beam

EDIT: Found a nicely priced omni-directional 800mhz antenna as well!

 

[freqscout]

Here is a good antenna system from Austin Antennas. It is a little pricey but is worth saving for if what "KK5FM", "D_Stew" and "KX5MOT" say is true of the mobile version. It is really a multiband antenna offering gain at many common frequency ranges.

Base:
http://www.rfwiz.com/AustinAntenna/AustinAntennaFerret.htm
Mobile:
http://www.rfwiz.com/AustinAntenna/AustinAntennaSpectra.htm

 

[woodyrr]

Thanks for the ideas. I've been looking them over.

Replacing the cable made a big difference on VHF as I am receiving NOAA WX radio from Clinton and Stillwater at least well enough to hear clearly.

For all intents and purposes, I'm line of sight to both Norman and Edmond so unless I'm expecting too much out of 800 MHz, it has to be the antenna.

I have a self imposed limitation in that I am very leery of installing an antenna on a mast above the roof. Many years ago, I had one about 20 feet up and one night I suffered a lightning strike. I had one of the first Uniden Trunktracker base scanners, BC 896 or something, and the brightest, whitest, stream of sparks that I have ever seen came squirting out of the back of it. Most of the energy went gown the ground wire, I guess, and the house didn't catch fire, but most of the electronic items in the house were destroyed. With the antennas in the attic, I can blame the big steel air handler that is up there if I get hit again!

 

[crayon]

For all intents and purposes, I'm line of sight to both Norman and Edmond so unless I'm expecting too much out of 800 MHz, it has to be the antenna.

You might be expecting too much ..

http://www.qsl.net/kd4sai/distance.html

 

[dward42586]

Lightning

Antena cables should be unattached from radios during lightening storms, which I'm sure you have figured out by now.

 

[woodyrr]

Antena cables should be unattached from radios during lightening storms, which I'm sure you have figured out by now.

Actually, I knew it then and I religiously disconnected the antennas at my first inkling that there was a lightning storm which entailed being rousted out of a very, very sound sleep at 1:00 AM by the loudest crash of thunder that has ever been and will ever be, concurrent with a shower of sparklies. I then turned the power off at the service entrance and climbed into the attic to look for smoke.

 

[Tulsey]

antenna

woodyrr: It sounds like you might have some of the classic scanner problems in dealing with 800 coverage.

1. The Belden web site shows 9913 as 50 ohm RG-8 type cable with a loss of 1.8 db per 100 feet at 200 Mhz and 4.1 db loss per 100 feet at 900 Mhz. Rule of thumb is 3 db is a loss of half. Of course, your 20 foot length is not going to be that great a loss, but you can see how much more 800 is affected by long or even not so long cable runs.

2. You mentioned you are using Pl-259 connectors. I suspect that means you are using a female PL-259 to male BNC adapter on your scanner. I don't remember the exact amount of loss, but those adapters at 150 Mhz don't bother much, but at 800 Mhz can make a huge difference.

I once ran a long length of cable to get out of a building and found the VHF greatly improved, but because of the cable length the 800 was worse than a back of set antenna.

You might check some of the cell phone sites for a cheap little yagi type beam cell phone antenna. You might find one of them and a short length of RG-58 with a BNC on the scanner end works better than even an outside antenna. Or by trial and error you might try putting the antenna you have with a 800 beam. It appears you might have the easier need to fill in that what you want on 800 is from one direction.

Of course you can have lightning arrestors on outside antennas, but they do cut down performance and a nearby lightning hit can cause damage by going through the power lines if you don't have surge protection on the AC to the scanner.

Good luck with your project.

 

[freqscout]

Very well put Tulsey.

You should remove all adaptation to the coax if possible. I think that you are using a 596 so that would mean that you are using a PL-259 to BNC to SMA (most likely) if you are. If so you are absolutely destroying your signal strength.

HOWEVER you might just be expecting too much out of what you have. If you were using an actual trunking radio then your reception would be different since it a designated radio and not a high speed cruiser of the airwaves. I can be in my car and hear a certain EDACS system with incredible clarity while listening to it on the scanner it cuts in and out. The radio antenna is a 1/4 wave (no gain). The scanner antenna is a super large gain antenna and the reception is still affected. So take that into consideration.

I would also suspect that you have the ability to install multiple antennas. You might consider putting a better antenna ("Big Papa") in your attic to take care of it and installing a low cost discone or other scanner antenna ("Lil' Boy") on the outside. You could run two sets of coax and only use the one you select. You could plug in the outside one on fairweather days or days that you pay particular attention to your antennas. You could use your inside antenna for regular day to day listening. This would spare you from having to switch your coax in the middle of the night.

As far as coax I would say go with the LMR- series of coax. It is a slightly more expensive but usually gives better performance in the higher range frequencies and forgoes the effort of installing hard heliax type coax.

 

[woodyrr]

This antenna is for the Uniden 996 so there is one PL259 to BNC adapter at the scanner end. The local supplier where I bought the cable and connectors did not have any RG-8 / BNC connectors, so I got what they had. Radio naive as I am, I took one look at that 12 gauge conductor in the center of that cable and figured that no signal could ever get stuck in there. If there is a local supplier that has connectors of that type in stock, I'd go buy one. I buy cat 5 supplies at Synergy Datacom on Classen and since they had the cable and connectors, that's where I bought them. Trying to avoid connections and adapters is why I ran an uninterrupted cable rather than using the Leviton "Quik Port" system that I use for audio / video / and datacom which allows for aesthetic plates and ports to plug things into. I've been reading the replies and searching the web and have received some good ideas to try. With this new cable, I drilled a new hole in the top plate of the wall so that the run could be as direct as possible and installed the plate where the cable exits the wall directly behind the radio. Once I change out the antenna, I can shorten the cable run by maybe one or two feet - maybe - and If I can purchase a RG8 / BNC connector locally without having to mail order one tiny item, I'll change that out. Once that's done, I'll live with the result. I've been getting just a little intermod on VHF -some of the old Tinker stuff. I haven't heard intermod in ages!