Amazon 800Mhz beam review

[batdude]

purchased one of these: Amazon.com: XHTECH 11dBi 824-960MHz GSM CDMA Outdoor Yagi Antenna for Cell Phone Signal Booster: Cell Phones & Accessories

$16. INCLUDING SHIPPING.

Arrived in about 2 weeks.

Construction is old-school style tubular aluminum. Not super robust (certainly not hurricane rated), but decent enough.

Bottom line - my reception for several 700-800mhz p25 systems in the 40-60 mile range went from "marginal" - to "pretty damn good".

worth the $16.


doug

 

[RFI-EMI-GUY]

hmmm; might solve my simulcast troubles..

 

[W8RMH]

Your reception would be even better with a 760-870 MHz. Yagi. I use one (that I received as a gift from a family member) which greatly improved the simulcast issues on my feed.

 

[marksmith]

hmmm; might solve my simulcast troubles..

It will help with simulcast issues in that if you receive multiple sites and this antenna is highly directional, you could cause your radio to only receive one site and eliminate the source of the signal distortion.

On the other hand it may reduce your reception of other non-simulcast signals not in the antennas directional path.

You can accomplish the same thing by putting a lousier antenna on the radio so only the strongest site is received, or by attenuating that system to reduce signal strength.

If it works, attenuation of that one system is the best option because it does not effect reception of other systems you might also be monitoring.

Mark
SDS100&200/536/436/WS1095/996p2/996xt/325p2/396xt/psr800/396t/HP-1/HP-2 & others

 

[RFI-EMI-GUY]

I have actually tried removing the antenna. One of the odd things, that bears investigation, is that plenty of 800 MHz signal is coupled into the radio via external connections.

I have a wifi module and speaker plugged in along with the normal DC power. So if signal is getting in via those routes rather than the antenna, they can be mixing with other noise making circuitry inside the cabinet.

There are a bunch of things wrong with the design of these Uniden scanners.

When I get time, I will try some ferrite on the external devices.

 

[scanmanmi]

I was ready to throw my radio out until I bought a 15 element 900MHZ beam at a ham show for $15. I couldn't pass up this huge yagi just to try and it worked. The elements must make up for the band.

 

[RFI-EMI-GUY]

With simulcast, in an overlap zone, the multiple signals can only be discriminated by using a directional antenna to seek a stronger signal.

When using an omnidirectional antenna, if you attenuate one tower, you attenuate the other. Using the attenuator in the receiver to attenuate a tower won't work, as they are all the same site from the receivers point of view. You still have the same signal to interference level and same time differential. In theory, I suppose you could drive the weakest tower into the noise, but then you have additional Gaussian noise added to the channel.

I have worked on simulcast systems since the late 1980s during my career. The analog systems simply sounded bad in overlap, the digital ones fail to decode properly if at all. The BCD536HP relies on sorcery to decode P25 CQPSK and it does so marginally.

The system I listen to has painfully different audio quality depending upon whose radio and who is talking. When the same system was analog, using same towers, it sounded excellent.

I have some tweaking to try.

I really only listen to this one system on this radio, so directivity is not an issue.

Sent from my SM-T350 using Tapatalk

 

[Joe_Blough]

I got the 9 element 13dBi version from AliExpress for $16 and change shipped free and received it in 10 days. The one like yours was $13 and change. They also have a 5 element 8dBi version for $11 and change.

 

[Anderegg]

I got improved reception using some cookie cutter eBay China antenna...by cookie cutter, I mean it is a flat piece of aluminum cookie cut int he shape of a yagi with some thin 314 coax. Improvement of signal of the target tower went from -55dBm to -45-50dBm, but I think the main advantage to the yagi is the off axis attenuation. A 6db 3-4 element yagi would have about a 70 degree RX cone, 6 element around 40 degrees. I just ordered a replacement Larsen 6 element for $35 brand new on eBay.

Paul