800mhz antenna scanner outdoors

[BorisG]

Hello wonderful forum,
I am looking for an 800mhz scanner antenna (listening only)
The device I am using (if relevant) is the unication g5 && sdr dongel
The antenna should be external and give me a circumferential range I want to hear sites at as great distances as possible
I'm outside the US

The length of the cable from the antenna to the device is 15 meters

1. I would love to get a recommendation from someone's experience

2. I saw a recommendation for 3 antennas

A. 800 MHz UHF Vertical Outdoor Base Antenna (851-869 MHz)
B. 800 MHz Double 5/8 Mobile Antenna
C. RadioShack 800 MHz BNC Scanner Antenna

3. Is there a significant difference between A and B? And what about using C outdoors will give similar results?

4. Regarding the cable if there will be RG58 is it significant regarding attenuation?
5. I will probably need a BNC TO SMA connector if I buy from ebay is it quality enough or is there something else recommended?


Thanks in advance

 

[dlwtrunked]

Remember that height of the antenna above average terrain is most important.
Antenna A. above leads me to think this is for a base station. If only interested in 800 MHz, it is far the best among your list.
eBay sold adapters vary. This type has always cause me trouble with the center falling out un-noticed and me then thinking my receiver was dead.

SMA Male Plug to BNC Female Jack RF Coaxial Adapter Connector | eBay

Connect your handheld Ham or GMRS radio effortlessly with the SMA Male to BNC Female RF Coaxial Adapter Connector. This premium adapter allows seamless connectivity from your radio's SMA antenna to a BNC male antenna or RF cable, ensuring reliable performance. Crafted from high-quality...

www.ebay.com

But this design, though not as pretty has always worked well

Pardon Our Interruption...

www.ebay.com

 

[BorisG]

Regarding the quality of the cable at such a distance - significant?

 

[popnokick]

Yes, 15 meters of RG-58 coax is going to result in "significant attenuation". In fact HUGE loss of about 9 dB for a 15 meter run. For a similar size, flexibility, and cost you should consider RG6. For scanner receiving usage the difference between 50 and 75 ohm cable is insignificant. But the attenuation of RG6 at 800 mHz in 15M of cable is much less at about 2.8 dB.

 

[WA0CBW]

Don't forget the mobile antenna will need some kind of ground "plane" if mounted outside on a pole.
BB

 

[popnokick]

I just looked at all three of the antennas you are considering, and your only choice among them for an outdoor base station antenna is "A" (the DPD antenna). You do not want to use "B" or "C" as they are both mobile antennas and as WA0CBW points out will not work without a proper RF counterpoise / "ground plane".

 

[BorisG]

Can anyone tell me if this product will do the same job?

47.57US $ 10% OFF|868MHz אנטנת omni סיבי זכוכית אנטנת 10dBi חיצוני גג צג משחזר UHF IOT RFID LoRaWAN הליום כורה 915mhz אנטנה|אנטנות לתקשורת| - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

he.aliexpress.com

Sorry for the unprofessional question but high dbi increases the absorption intensity?

 

[WA0CBW]

DBi and dBd are two scales for measuring the receive and transmit gain of an antenna. 10dBi and 7.85dBd are the same gain.
BB

 

[AM909]

Can anyone tell me if this product will do the same job?

47.57US $ 10% OFF|868MHz אנטנת omni סיבי זכוכית אנטנת 10dBi חיצוני גג צג משחזר UHF IOT RFID LoRaWAN הליום כורה 915mhz אנטנה|אנטנות לתקשורת| - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

he.aliexpress.com

Sorry for the unprofessional question but high dbi increases the absorption intensity?

Note that is an 868–915 MHz antenna, not 851–869, so you would want one for the lower range.

DBi and dBd are two scales for measuring the receive and transmit gain of an antenna. 10dBi and 7.85dBd are the same gain.
BB

To explain, dB is a measure of one thing in relation to another. In the case of antenna gain, there's the idea of an isotropic antenna, which is a hypothetical radiator with the same radiation in all directions. dBi gives you the theoretical gain (or loss) relative to that theoretical radiator.

A dipole is considered to have 2.15 dBi gain (2.15 dB over the isotropic antenna). dBd gives the gain over a dipole. If you add 2.15 dB to a dBd value, you get the equivalent dBi value. So, antenna manufacturers may be naturally inclined to publish dBi numbers because they are larger, and theoretical.

The more dB gain the antenna has, the better you will receive or transmit some signals, but it usually comes at a cost of something:

• Bandwidth – the frequency range over which the antenna gives that amount of gain. The higher the gain, the narrower the bandwidth is usually. Getting just the 850–870 MHz LMR base station frequencies should be fine with most antennas, though.
• Vertical beamwidth – higher gain antennas tend to "squeeze" more signal toward the horizon, which is usually a good thing.
• Directionality – directional (non-omnidirectional) antennas "squeeze" more signal into a "main lobe" (the direction in which they are pointed) at the expense of less signal in other directions. The higher the gain, the narrower in azimuth that "main lobe" will be.