Help me pick a base antenna for 150 MHz and 800 MHz on Uniden SDS200 due to Topography

[downeydigs]

@prcguy @jonwienke @nmelfi @Ubbe @JoshuaHufford @doctordialtone

Just to be sure that I am understanding:
First preference would be a discone due to its wide band performance and low price. However, 800 MHz reception quality may not be as good as other options.
Second preference would be the tri-band mobile antenna with ground plane due to it being tuned specifically to the narrow frequency bands that I am most concerned with receiving. However, it will not receive well outside of those three ranges.
Third preference would be the OmniX antenna that @JoshuaHufford recommended. No one provided a case against this option, but the price (relative to the other options) makes this my least preferred option.

 

[jonwienke]

The most important consideration for 800MHz performance is going to be your coax. If you have a 20-meter run, the difference between cheap stuff and LMR400 could be 6db or more; more than the difference in antenna performance.

I haven't tested the Omni-X antenna, so I have no opinion on its performance. Just by looking at it, I would guess that it won't be as wideband as a discone, but more wideband than a typical 1/4- or 1/2-wave vertical. It looks like a bicone antenna with most of the radials removed, and for that reason, I suspect that it's going to have an odd radiation pattern--performance will be different between north/south and east/west.

 

[Ubbe]

I would probably get 50ft LMR400 with connectors which is $60-$70 incl shipping from ebay, that's only 2dB loss at 900MHz.
And get a discone like a Tram for $60 incl shipping and if you can sacrifice a little loss of reception below 150MHz you can cut all the element a little shorter to make the lowest frequency of 90MHz-100Mhz to raise to 150MHz that will also make it receive better at 800MHz.

LMR-400 50 FT BNC Male / UHF Male PL259 COAX CABLE CB,HAM,SCANNER | eBay

US MADE 50 FT LMR-400 (CNT-400) BNC Male to UHF (PL259) Male Ham CB radio Antenna cable.

www.ebay.com

Tram 1410 Scanner 25MHz-1,300MHz VHF/UHF Super Discone Base Antenna | eBay

Find many great new & used options and get the best deals for Tram 1410 Scanner 25MHz-1,300MHz VHF/UHF Super Discone Base Antenna at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Discone Antenna Designer

Free Online Engineering Calculator to quickly estimate the geometric Size of the Parts of a Discone Antenna

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/Ubbe

 

[prcguy]

Your first and second preference are simply facts, its up to you what order you place them in. I do not own nor have used the Omni-X so I can only offer opinions and not facts on that. I believe it might work sightly better than a Discone at the three discreet frequencies the dipoles resonate at which appear to be around the VHF air band, VHF high band and UHF. Not sure on its 800 reception as I do not see any specific elements for that and it could rely on lower frequency elements working at an odd multiple harmonic.

I know and trust a Discone for a certain level of performance across a very wide range, although not very high performance. Your 800 signals are sure to be all from elevated repeater sites and if they come in at a reasonable level at your roof top, then the DIscone should have no trouble there and will give you good reception across everything else. If you are going for really weak distant 800 stuff, then a Discone may not be the best choice.

@prcguy @jonwienke @nmelfi @Ubbe @JoshuaHufford @doctordialtone

Just to be sure that I am understanding:
First preference would be a discone due to its wide band performance and low price. However, 800 MHz reception quality may not be as good as other options.
Second preference would be the tri-band mobile antenna with ground plane due to it being tuned specifically to the narrow frequency bands that I am most concerned with receiving. However, it will not receive well outside of those three ranges.
Third preference would be the OmniX antenna that @JoshuaHufford recommended. No one provided a case against this option, but the price (relative to the other options) makes this my least preferred option.

 

[MisterLongwire]

A Tram antenna? Seriously? Save yourself your hard earned money and get RG6 coax...prob Round 40 feet to start with...a Diamond discone...and a connector adapter for the coax. Trams are junk!

 

[jonwienke]

A Tram antenna? Seriously? Save yourself your hard earned money and get RG6 coax...prob Round 40 feet to start with...a Diamond discone...and a connector adapter for the coax. Trams are junk!

You'd gain 2dB on the antenna and lose 6dB with the coax, especially given the impedance mismatch loss at BOTH ends of the cable.

 

[prcguy]

So tell us exactly what the difference is between the Tram and Diamond. Is there a difference in gain that you know of? What is it?

A Tram antenna? Seriously? Save yourself your hard earned money and get RG6 coax...prob Round 40 feet to start with...a Diamond discone...and a connector adapter for the coax. Trams are junk!

 

[wowologist]

Many speak very highly of this antenna as an alternative to a discone,

OmniX Scanner Base Antenna

Specs Gain: 3 VHF 4 UHF dBi Pattern: Omni-directional Wavelength: 1/2 Elements: 3 Tuned: 118-137, 148-175 & 225-900 MHz Band: UHF & VHF Connector: N Female Cable: RG8X Cable Length: 16 Inches Height: 45" Width: 30" Weight: 2 lb Features Multi Band-Wide Coverage: The uniquely...

dpdproductions.com

Make sure you don't go cheap on your coax, at 50 Ft. at least use LMR-400, if you can afford it, maybe even larger, signal loss is pretty severe at 800MHz.
[/QUOTE]

I'd love to see a VNA plot on this antenna...with 100' of a quality LMR coax and mounted at 20', because the sum of the elements should throw this thing for a loop.

 

[captainmax1]

I've posted this in other antenna threads over the years but I have always had a discone antenna as part of my antenna arsenal for the last 40 years. I currently use a Diamond D130J discone on a 30' mast with 50' of LMR 400 going to my shack and get great results on all frequencies. I use a Stridsberg 8-port multicoupler in my shack with one port daisy-chained to a Stridsberg 4-port in my bedroom. I also use a 4-port Stridsberg in my vehicle with my 800 MHz scanner antenna but use other mobile antenna's also.

 

[MisterLongwire]

OMG....are you sure? Tram quality is junk! I recommended to my neighbor to buy quality and immediately he goes to Amazon and orgers the Tran discone. Flimsy a d screws missing. 40 feet or less is fine with RG6. I have no need to have a tower or extend it beyond the clouds. If you want to compare....especially about loss...then go ahead and use a novelty 12 inch paperclip. One can even use a TV antenna for receiving. Seriously.

 

[downeydigs]

So, I have a couple more (maybe really dumb) questions.

I plan to buy a pre-made LMR-400 coax cable with PL-259 or N connectors. Thus, I will be routing the cable with the connectors attached, which will require larger (3/4 inch?) holes be drilled. I will have a penetration on the exterior siding, in the interior wall top plate, and through the sheetrock.
Of course the exterior will need a drip loop, and the siding will have to be sealed with silicone or something to prevent water from getting in.
My scanner (Uniden SDS200 w/BNC Connector) will be in my living room on my chair-side table, so I’d like for that part to look neat and clean. Do I use a low voltage gang box with some sort of pass-through face plate, or is there some sort of coax face plate that I can use and then have a short jumper cable between the wall and radio? Can I use a right-angle connector at the back of the radio?

Any advice on best practices to make the whole installation neat and clean looking and have all penetrations properly sealed is greatly appreciated.

Additionally, what are best practices to protect my radio and my home electrical wiring from lightning strike to the antenna and visa-versa?

 

[Ubbe]

There are different kinds of connectors from ebay or amazon you can use that you install to a metal plate and then use a standard 10ft RG58 bnc coax to the scanner. There are also angled bnc-bnc adaptors for the scanner if you don't order a special made coax with an angled BNC at one end.

/Ubbe

 

[prcguy]

Instead of an electrical box I like to use a low voltage bracket which gives you a lot more room for large cables to bend, etc,. Just cut a hole and it will grip the inside of the sheetrock and hold your wall plate. Carlon 1-Gang Non-Metallic Low-Voltage Old Work Bracket-SC100RR - The Home Depot

Wall plates with an appropriate good quality connector are hard to find so I just get a stainless steel wall plate and drill a hole for a bulk head feedthrough SO-239 or N type. You mentioned a drip loop which is good and drill the entry hole slightly below the centerline of the outlet box so the coax has a downhill run to the outside wall.

If your running coax down an outside wall prep the entry point first and attach the coax to the wall with the drip loop there using a cable clamp, then pull it tight to the top of the wall at roof level making it plumb with a bubble level and put another cable clamp there. Then go back and add any additional clamps last. This will leave you with a very straight coax run instead of the typical leaning zig zag runs most people have. It will also save you from forgetting about the drip loop, running the coax down the wall centered with the entry hole and now you have to make a question mark shaped drip loop to compensate.

I used to use through the wall cable tubes but don't any more, they are usually cheap plastic and the outer ring falls apart in the sun over time and they don't handle large cables with connectors. Same with outside cable entry grommets, I don't find them in sizes to handle cables with connectors installed, so I carefully goop the entry hole with silicone and preferably the same color as the wall.

So, I have a couple more (maybe really dumb) questions.

I plan to buy a pre-made LMR-400 coax cable with PL-259 or N connectors. Thus, I will be routing the cable with the connectors attached, which will require larger (3/4 inch?) holes be drilled. I will have a penetration on the exterior siding, in the interior wall top plate, and through the sheetrock.
Of course the exterior will need a drip loop, and the siding will have to be sealed with silicone or something to prevent water from getting in.
My scanner (Uniden SDS200 w/BNC Connector) will be in my living room on my chair-side table, so I’d like for that part to look neat and clean. Do I use a low voltage gang box with some sort of pass-through face plate, or is there some sort of coax face plate that I can use and then have a short jumper cable between the wall and radio? Can I use a right-angle connector at the back of the radio?

Any advice on best practices to make the whole installation neat and clean looking and have all penetrations properly sealed is greatly appreciated.

Additionally, what are best practices to protect my radio and my home electrical wiring from lightning strike to the antenna and visa-versa?

 

[jjlongworth]

For what it's worth, one of my favorite antennas was a Channel Master Monitenna. It was an omni broadband that worked well for me. They stopped producing them about 20 years ago, but I just wrote plans and posted them for building one over at Antennas and Associated Hardware.

 

[Ubbe]

For what it's worth, one of my favorite antennas was a Channel Master Monitenna.

They sold one at an auction site recently for $19. It seemed to be unused still in the box. So they can still be found at reasonable prices.

/Ubbe

 

[downeydigs]

Just to update, I went with the Diamond D130NJ Discone and 50’ of LMR400 coax. I have it (temporarily) installed in my yard mounted at roughly 7’ elevation on a t-post. I am quite pleased with it thus far, and can’t wait to see if there is any significant improvement once I get it mounted at 30’+ elevation on my tv antenna mast. Now just to figure out how I’m going to get it up there. Have only been up there once since my metal roof was installed, and it is near the peak of the gable end and was very slippery. The mast telescopes, but it is attached to the eave at about 18’, so I can’t scope it down past that point. Guess I need to buy or borrow a taller extension ladder.

 

[JoshuaHufford]

Just to update, I went with the Diamond D130NJ Discone and 50’ of LMR400 coax. I have it (temporarily) installed in my yard mounted at roughly 7’ elevation on a t-post. I am quite pleased with it thus far, and can’t wait to see if there is any significant improvement once I get it mounted at 30’+ elevation on my tv antenna mast. Now just to figure out how I’m going to get it up there. Have only been up there once since my metal roof was installed, and it is near the peak of the gable end and was very slippery. The mast telescopes, but it is attached to the eave at about 18’, so I can’t scope it down past that point. Guess I need to buy or borrow a taller extension ladder.

Glad to hear it is working well for you, should be even better up in the air.

Be very careful, it isn't worth taking a fall over, hire it done or rent a lift if you need to.