Poplar Bluff PD/FD New System

[RF23]

I don't remember how the point radius for mobile areas of operations is calculated but if it was "real" it wouldn't be a perfect circle with the same radius in all directions. Sometimes they are a county or state.

If you have a perfect circle, then you have an omni directional antenna. If you are against a mountain range, large body of water, a very oblong city, or you must constrain your RF footprint due to other agencies that could be interfered with; then you will need to use an antenna with directivity. Tiis will result in a symmetrical shape to the RF field but not a circle. Real RF fields are seldom symmetrical in actual use, except under the conditions I previously posted.



The FCC Map for this NXDN system appears to be three overlapping circles.



At least this is my present understanding, this kind of activity was not my line of work. Therefore, I may be missing a lot of important details.

 

[crippledchicken]

Nah, I had it vertical all along. You don't want to know, what I thought vertical meant on this type of antenna LOL! You can probably guess though. I thought about maybe getting a BCD536HP thinking maybe it might perform a little better at those frequencies. The other radio is a Whistler WS1065 so it doesn't receive the NXDN. Being no Simulcast I probably would have been better off getting the 536 to start with. I'm sitting on steady 5 bars now. But still have warble in the voices a lot of the time. I'm thinking, a 536 might have a little better receive. I've been thinking about saving up for one.

 

[buddrousa]

Have you played with the filters with the SDS200?

 

[crippledchicken]

Yeah, they definitely make a difference just not quite enough. Clearing user data and formatting the sd card took me from 3 to 5 signal bars. The high RSSI and Digital Error so high, the audio is too garbled a lot of the time. I'm guessing it's my location more than anything. Where we are at, we get 1 bar signal on our cellphone. I had to get an antenna/ booster to use our phones.

 

[buddrousa]

You said -92Db to -98Db on P25 my SDS's 100's and 200 decode good to about -112Db.

 

[crippledchicken]

I'm guessing it's this hole in the ground I live in. This valley has always been terrible for getting signals. They valley and the 800mhz frequencies I don't think are working good together. I can pick up pretty much everything on my Diamond 3000N excluding the 800mhz NXDN frequencies I've been trying to receive. The highway next to me is probably 30ft above the top of my antenna. The antenna is between 25 and 30 ft high. Pretty much all directions around me is hills. Those particular frequencies can't seem to make it through all the obstructions.

 

[nd5y]

I had to get an antenna/ booster to use our phones.

What kind of booster? That could be causing 700/800 MHz scanner reception problems.

 

[crippledchicken]

Not sure about the bands or frequencies but I'm on T-mobile. They also told me I'm in a poor signal area. Their Cell towers are a lot higher than the site antenna I'm trying to receive.

 

[crippledchicken]

I tried to find the booster online but, I think this has been discontinued. The brand is Solid RF. It's antenna is outside on a pole. The inside unit has a walwart unit with a small antenna on it.

 

[crippledchicken]

I'll experiment by moving the inside booster unit around. Thanks!

 

[nd5y]

I would unplug the booster first instead of moving it and see what happens.

If you didn't get the cellular booster from the carrier and installed by them then there is no telling what kind of crap it puts out. See the threads about BDAs (bi-directional amplifiers) in large commercial
buildings, tunnels, etc. causing problems when not installed and calibrated properly.

 

[crippledchicken]

I already tried unplugging it, moving it around so far hasn't made any difference. Replacing the booster antenna with the 14dbi Yagi has made a dramatic improvement with our phones. With the booster antenna all I could receive was the nearest tower. That sucked when the tower went down for 2 or 3 days with no phone. Now, I get 3 towers no more doing without phone. That's the exact same antenna I'm using on my scanner. That antenna I'm trying to receive is only on top of a water tower about 5.5 miles from me. Of course there's hill after hill between me and the site. If the site antenna was as high as the cell towers, I could probably receive the signal a lot better. Early morning or late at night it clears up sometimes.

 

[RF23]

Do you have one or two Yagis?

Your cell phone boosters appear to have the same antenna polarity as your scanner. Cell phones themselves have the reverse antenna polarity of scanners and a Yagi made to work with them normally requires a reverse polarity adapter to work on a scanner. Unless this has changed in the last 8 years.

How did you point your Yagi antenna? It does not take much of a signal to get 5 bars on the SDS200. Then you must use the RSSI readout to point the antenna more precisely. Normally, this requires two people or one person with a portable radio with an RSSI readout. You might want to consider pointing the Yagi between Sites 1 & 2 (if the signal is strong enough) so if one Site goes down you can monitor the other Site. You can keep Site 2 avoided until needed.

Also, you might want to look at Sentinel & see if any Attenuation is enabled in the new system.

Good to see you are making some progress at least on one front.

 

[crippledchicken]

I have 2 Yagis identical. Any recommendation on the polarity adapters? I'll try anything at this point I'm running out of ideas. Thanks! Also, I've checked for attenuation.

 

[RF23]

The place you bought your 2 Yagi antennas from did it say they were for Cell Phones?



When I bought my Wilson 11 element 800 MHz Yagi from Amazon it said it was for cell phones. However, the other 3 different yagi I bought did not say they were for cell phones and they do not need an adapter to work on scanners.



What kind of connector do you have on the coaxial cable from your Yagi that goes to your scanner?

 

[kruser]

Cell phones themselves have the reverse antenna polarity of scanners and a Yagi made to work with them normally requires a r to work on a scanner. Unless this has changed in the last 8 years.

WHAT?

You can change the polarization of a standard antenna by mounting it horizontal or vertical but AFAIK, there is no such thing as a reverse polarity adapter for an antenna.
All the cell phone boosters around here on rooftops are all mounted with a vertical polarization. Just like a yagi or log periodic would be mounted if using for typical scanner use.

Are some cell phone boosters using circularly polarized antennas? Those can have a left and right handed polarization but I don't think any adapter could change that.

 

[RF23]

WHAT?

You can change the polarization of a standard antenna by mounting it horizontal or vertical but AFAIK, there is no such thing as a reverse polarity adapter for an antenna.
All the cell phone boosters around here on rooftops are all mounted with a vertical polarization. Just like a yagi or log periodic would be mounted if using for typical scanner use.

Are some cell phone boosters using circularly polarized antennas? Those can have a left and right handed polarization but I don't think any adapter could change that.

This is not the kind of polarity I am referring to; sorry I was not clear on exactly what I meant.

The reverse polarity adapter reverses the center & shield of the antenna when it attaches to the radio.

 

[crippledchicken]

These are the 2 antennas I bought. https://www.l-com.com/824-mhz-960-m...-black-n-type-female-connector-hg914ye-nf-blk

 

[RF23]

A very good antenna, but I think it is not performing as well as it should.

The description of the antenna does mention cell phones & the adapter is only around $10.

What kind of connector is on the coaxial cable that will attach to the radio?

This Yagi has a female N type connector, so, the cable should have a male N type at both ends. This assumes no adapters are being used, like a PL-259 or F type to N type adapter.



Your SDS200 has a female BNC connector on the back so, the adapter will need to have a male BNC at one end & a female N type at the other end.

I will check Amazon to see what I can find. I think the adapter is under RF Reverse Polarity adapter.

 

[RF23]

I visited Amazon & they have a new search AI that is ridiculous, no matter how I worded the search term I got camera adapters, car antenna, etc.

I would recommend visiting the place you bought the Yagi antennas and they will help you safely. Google will give to many dangerous sites, but they were able to show me many RF Reverse Polarity Adapters.

Let us know how this turns out!