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Message |
    
Chad
Advanced Member
Username: Chad
Post Number: 880
Registered: 11-2004
| | Posted on Wednesday, May 31, 2006 - 2:21 pm: | 
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I was presented a deal I could not refuse. I bought a RS PRO-2051 for dirt cheap in like new condition, really cheap. Since I have this shiny new tower to litter with antennas I was thinking of installing a scanner antenna on it. Very few of the freqs are in the 800 MHz range but there are some. Most are below 465 MHz. What antenna is recommended on a bang for the buck basis. Then what coax is recommended sans heliax. I am expecting and willing to spend more on the coax than for the antenna. If I put it up 20' on the tower I will need about 65 feet of length maybe 75 to be safe. I know line loss starts to play an important role here. Would the buryable cable from copper be adequate for this venture? I want to bury it but will use PVC if I need to go with a different cable that will not like soil contact.
Are homebrew antenna's out of the question? Anyone have any homebrew plans that are wide-banded? How about a wire running from the base of the tower up to the top? Is that lossy? Wide banded? Bad idea and I should be smacked?
Please feel free to add comments, insults, and suggestions 
Chad |
Bruce
Senior Member
Username: Bruce
Post Number: 3893
Registered: 9-2003
| | Posted on Wednesday, May 31, 2006 - 2:51 pm: |
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ok on 450
I use a dualband JTB3 JETSTREAM 4.5DB/7.2DB 144-148/440-450 ( under $50 ) for my pro - 2052 scanner with very good results. im feeding it with lmr-400 coax and the top of it is at 25 foot. NO PROBLEM hearing highband VHF / UHF within 30 miles .... |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1245
Registered: 6-2004
| | Posted on Wednesday, May 31, 2006 - 3:33 pm: |
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I like discone antennas for scanners. If you just want to listen to 450MHz signals, I'm sure you can find a gain antenna for that frequency, but I've never had issues with my discone antenna.
The great thing about a dedicated receiving antenna is that you don't need to worry about transmitting, so a variable preamp at the antenna will easily overcome cable loss. RG6 is used in DSS installations, so it handles high frequencies fairly well, and it's inexpensive. |
Bruce
Senior Member
Username: Bruce
Post Number: 3894
Registered: 9-2003
| | Posted on Wednesday, May 31, 2006 - 11:05 pm: |
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Discones are very good for wideband radios HOWEVER they are neg gain antennas. I used this cheep diamond clone because it has gain and can be used as a 2 and 440 BACKUP antenna |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1735
Registered: 9-2004
| | Posted on Wednesday, May 31, 2006 - 11:29 pm: |
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well, you know what im going to say; i think LMR400 is the way to go.
my only thought is; since line loss is an issue at these freqs., would the benefit of having the antenna up high on the tower be outdone by the line loss from having to use so much coax?
would an antenna on a five foot mast right above the shop (im guessing thats where the scanner will be) be better, since the coax run would be ultra short?
just some thoughts, not too experienced with VHF/UHF.
for the record, i also like discone antennas, the one i had from rad shak years ago was the best ive ever used.
here is a homebrew antenna that looks easy enough and fun to build.
http://www.sentex.net/~mec1995/ham/scanant.html
if you dont see it, email me and i will give it to you.
matt |
Chad
Advanced Member
Username: Chad
Post Number: 883
Registered: 11-2004
| | Posted on Thursday, June 01, 2006 - 10:00 am: |
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Bruce, What is your total coax run? See, my tower is away from the house so it comes down the tower, under ground, up to a grounding point, in the house and across the bench, it's a decent run but by far probably not the longest out there! Thanks for the heads up on the antenna, I'll certainly include it in my research.
HP, the Discone is another I am researching, this preamp at the antenna you are speaking of, whaere can they be researched or purchased? Is power supplied via the coax in a Phantom Power type config?
KV, The bury flex I am using now has similar loss properties as the LMR400, I could just use more of that, wish I could find another 80' "remnant" on internet sites again! I've been looking like mad! As for mounting it just outside the shop. Come-on-man, you are making too much sense And it would look cooler on the tower Actually i live in an area that is very un-populated, there won't be much in the way, but as I have learned height is important IMHO. I'm still kicking around Ideas.
This scanner thing is a whole new world, I have never used an electronic device that I have had to refer to the manual so much to use, I hope I get used to it. I imagine there are many features I will not use. I did download, and install the scancat software, very cool stuff, WAY easier then poking the freq's in by hand!!!!!! The boy and I were poking around in the shop and made a simple Coax antenna so I could mount it along side the other gear, it works for now. That boy can strip wire like it's nobody's buisness, and he's 5, He can't wait to use the soldering station, ADA BOY!
Chad |
Bruce
Senior Member
Username: Bruce
Post Number: 3897
Registered: 9-2003
| | Posted on Thursday, June 01, 2006 - 12:24 pm: |
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all my runs are 75 - 125 foot antennas are 20-40 foot up but are not near the drop point to the shack window.
COAXS here are for scanner antenna 75 foot
6 meter beams 100 foot
2 meter beams 125 foot
horz 2 meter ant 75 foot
vert 6/2/440 75 foot
75-10 dipole 125 foot
ALL use LMR-400 and past lighting aresters use a good MINI - 8 into shack. |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1248
Registered: 6-2004
| | Posted on Thursday, June 01, 2006 - 9:47 pm: |
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Yes, the amplifier is installed at the antenna and is powered/controlled from the radio end of the coax. That way any coax loss is easily overcome, and you can use less expensive cable as long as it's well shielded - RG6 quad shield for example. There are or at least were some made specifically for scannists, but in looking around online, it appears they're not made anymore. The good news is that TV antenna amplifiers are nearly as good (probably why the others went away) and cheaper too. |
Bruce
Senior Member
Username: Bruce
Post Number: 3899
Registered: 9-2003
| | Posted on Thursday, June 01, 2006 - 9:57 pm: |
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if your running long coax a TV amp does work |
Chad
Advanced Member
Username: Chad
Post Number: 885
Registered: 11-2004
| | Posted on Thursday, June 01, 2006 - 10:07 pm: |
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Right on! I'll look into the TV amp thing. don't know why i did not think of that... THANK YOU! I have one at the house here with the power supply waiting.
FYI all, I downloaded (paid for) scansat, it's software for programming Scanners. It is sooo slick! I also paid 5 bucks a county (10 bucks total for me) for ALL the pertinent scanner freqs, like 600 of them came for my area. I touched up state police and added the baby monitor and some others I wanted. I had over 800 entries in it in less that 30 minutes including the time to figure out the software and diagnose a com port error. That ain't bad at all IMHO!
I'm getting into this, it's fun. Put on a little reggae music and it's like watching "Cops"
Chad |
Bruce
Senior Member
Username: Bruce
Post Number: 3900
Registered: 9-2003
| | Posted on Friday, June 02, 2006 - 6:27 am: |
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Chad i use it for my 2052 ....... NOW BE GOOD and don't program in the 46 mhz PHONE channels .... and be carefull on thoes baby monitors you NEVER know what you might hear ....
I had one back years ago at our other house that was 1500 foot away but with my outside antenna was very strong! You could hear EVERYTHING going on in that houes ....... EVERYTHING .......
So tring to be a good guy I put a note on their door telling them what it was doing and please turn it off ...... It stayed on ......
SO ........
I taped them is a ( PERSONAL ) moment and put the tape on the door ....... It got turned off ....
lissen for a ( a very ) few hobbiests and monitors on .... 49.815, 49.830, 49.845, 49,860, 49.875 and 49.890 mhz are the most common frequencys and they are PART 15 so do not have sec 605 protection ..... and is LEAGAL to lissen too ... |
Chad
Advanced Member
Username: Chad
Post Number: 888
Registered: 11-2004
| | Posted on Friday, June 02, 2006 - 9:18 am: |
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Yeah I know. There would only be 2 monitors in my range. Mine and my best friend/neighbor, nothing is sacred between the two families It's nice for me to have mine programmed because my radio room/shop is thru a breezeway and in the back half of a garage sectioned off. It is COMPLETELY isolated from the home. I can run out there to get something done quick and listen in by just punching in the preset. There's so much out there to be heard that someone's personal moment is a moot point to me But if my kid falls out of bed (talk about an active sleeper) or has a nightmare I can fly in right quick. Also saves me from having to buy battereis for the receiver intended for it's use. It's not the buying I guess I hate, it's the DARN SCREWS they use to hold battery covers on EVERYTHING these days, Grrrrr.
I have someone getting me a Discone for FREE! I plan to look into inline amps today. Not having to buy Buryflex/LMR400, yadda is going to save me A TON of money. (like a Gieco commercial) They make some great RG6 type cable for cheap, it's buryable, and has 100% shielding.
You mean people still use 46Meg phones?!
Chad |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1249
Registered: 6-2004
| | Posted on Friday, June 02, 2006 - 9:33 am: |
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Why wouldn't it work? Some of the more powerful amps have over 20dB of UHF gain and only 3dB of noise - that's quite a lot of gain and would more than offset losses for 200' or so of decent RG6 coax.
Belden's RG6 shows 4.26dB loss per 100' at 450MHz. While that's a lot of loss, amplification right at the antenna will offset it quite well. If you use several hundred feet of RG6, you can still overcome most of the loss with an amplifier that boosts the signal 20dB or more. |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1250
Registered: 6-2004
| | Posted on Friday, June 02, 2006 - 9:37 am: |
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I've got another antenna suggestion if you're going to buy a new antenna just for scanning - the Scantenna. It's a double discone design, and I've heard nothing but good things about them. It comes with 50' of RG6 coax and a balun. I wish I had room to install one, but my discone works just fine for my purposes. |
Chad
Advanced Member
Username: Chad
Post Number: 891
Registered: 11-2004
| | Posted on Friday, June 02, 2006 - 10:37 am: |
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I notice that most of the cable recommended is 75 Ohm, the scanner has a 50 Ohm input. It this important for receive on these? I found a preamp made by the same company that looks really cool. I could see me ordering this rig really soon if my discone falls thru
Thanks HP!
Chad |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1252
Registered: 6-2004
| | Posted on Friday, June 02, 2006 - 10:58 am: |
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The difference is negligible on transmit, and on receive a mismatch that small won't matter at all.
Have you tried using your CB antenna with your scanner yet? It should really bring in those low band VHF signals. |
Chad
Advanced Member
Username: Chad
Post Number: 893
Registered: 11-2004
| | Posted on Friday, June 02, 2006 - 11:26 am: |
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Not yet, all the coax is buttoned down and I'll need to make a short adaptor, I may try that tonight. I spent last night programming, etc.
Chad |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1253
Registered: 6-2004
| | Posted on Friday, June 02, 2006 - 11:40 am: |
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I have an old version (DOS - believe it or not!) of Scancat that came with an AOR2500, but I've never used it.
I'm not familiar with the PRO2051 - does it do anything more than autoprogram with the software? Data logging, searching for new frequencies, that sort of thing? |
Chad
Advanced Member
Username: Chad
Post Number: 894
Registered: 11-2004
| | Posted on Friday, June 02, 2006 - 12:24 pm: |
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Just programming, and reading. Reading is nice because if you lock out in the radio it will load up into scansat as locked. You can really keep tabs of things. When the data cable is attached it will not scan, it's for data transfer only. Still a HUGE time saver when paired with a service that provides frequencies. I could not imagine programming it with the front panel!
Chad |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1265
Registered: 6-2004
| | Posted on Monday, June 12, 2006 - 11:56 am: |
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Did you get that discone up on the tower yet Chad? |
Chad
Advanced Member
Username: Chad
Post Number: 918
Registered: 11-2004
| | Posted on Monday, June 12, 2006 - 2:06 pm: |
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Nope, I'm leaning towards the Scantenna now After reading and research it looks like the best option. I'll probably order the goods tomorrow/Wednesday! The same company also makes (what looks to be) a robust antenna mounted preamp. I'll do that too.
Chad |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1268
Registered: 6-2004
| | Posted on Tuesday, June 13, 2006 - 11:44 am: |
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Cool. Let us know how it works. |
Navyrebel782003
Intermediate Member
Username: Navyrebel782003
Post Number: 195
Registered: 12-2004
| | Posted on Tuesday, June 13, 2006 - 1:35 pm: |
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Hollowpoint, you mention a cb antenna for scanner, I had a bearcat BC350A in high school in my truck with a 102"SS whip and let me tell you, I could hear everything with that set up, i could listen to the police over 100 miles, no joke. had a magnetic scanner antenna I used until I knocked it off the roof and it broke, used the 102 and never looked back...LOL
James
CEF#590
CVC#49
Va Beach |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1269
Registered: 6-2004
| | Posted on Tuesday, June 13, 2006 - 9:37 pm: |
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I used a Wilson 1000 (tuned as far away from 27.375 as I could) on my car as a scanner antenna for a long time. It worked much better than the 1/4 wave whip cut for 155MHz that I had used previously. Of course it's biggest gain was on VHF LO frequencies - which we have quite a few around here for fire dispatching.
I had to stop using it because even though it was tuned as far away from my normal operating frequency, it interacted enough with my 102" whip to cause a VSWR issue. I could have cut the whip, but I thought it better to use the normal 1/4 wave whip cur for 155MHz. |
Chad
Advanced Member
Username: Chad
Post Number: 984
Registered: 11-2004
| | Posted on Wednesday, July 12, 2006 - 10:30 pm: |
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So I bought the Scantenna today after many favorable reviews and recommendations.
The thing sits Vertical and is 102" long total, it is in the shape of a "t" so it's 52" up and 52" down (Dipole) I plan to hang it off the side of the tower BUT to get it as high as possible it will be in Parallel with the Imax 2000. But only for like 2-3 feet. Is this a bad thing? shoudd I plan to mount it lower so that it will not be in the outward pattern of the Imax?
Will the transmitting antenna damage the input of the Scanner from overload?
I CAN mount it lower. I'm in a remote area so even the homebrew coax made one werks pretty darn good.
Chad |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1297
Registered: 6-2004
| | Posted on Thursday, July 13, 2006 - 9:09 am: |
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I don't think it'll matter where exactly it's positioned relative to the Imax2000 because it'll still be in the near field of radiation so the 11 meter signal will be very strong.
I don't think you have to worry about it damaging the scanner, but I suppose it's possible depending on how fast the AGC attenuates the signal. You'll certainly have lots and lots of intermodulation when transmitting. You could use a filter or an attenuator to deal with that, and maybe use a switching scheme to make it convenient. You could also wire up a relay to ground the coax when you transmit - just a thought. |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1477
Registered: 6-2004
| | Posted on Friday, April 13, 2007 - 9:17 pm: |
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How did that scantenna work out Chad? Did you try the TV preamp?
Aack! - Bill the cat
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Chad
Senior Member
Username: Chad
Post Number: 1288
Registered: 11-2004
| | Posted on Wednesday, April 25, 2007 - 11:51 am: |
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The scantanna is great! It has held up well and receives very well. I did not need a preamp at all, no receive issues, everything comes in quite nicely!
Chad
CEF 433
HAM 212
not an ego thing, just keepin' the mods happy
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