Antenna Setup

[lu81fitter]

A regular "T" type splitter will reduce the amount of signal going to each radio. If you are using 2 radios, and monitor different bands on each radio, look in to a diplexer. This is a better option then just a "T" type splitter. The diplexer acts like a band pass filter and separates out the signals to different ports. You can get various types depending on how you want to split up the frequencies going to each radio.

 

[ltginrage]

Basically I would run the antenna to the diplexer and it would split the VHF signals to the feed scanner (Its all FDs so there all VHF) and UHF (400-900) to the 325p2 for trunking?

 

[lu81fitter]

Try one of these.

www.theantennafarm.com/catalog/comet-cf-4160j-1638

You'll need the appropriate adapters and jumpers to go to the radios. I know it says 540.xxx MHz on the high side, but it passes my 800 fine. I use one in my car.

 

[ltginrage]

Ok, I'll have to wait a little bit on that. If theres anything I learned over the process of building the antenna is that this hobby is not cheap.

 

[lu81fitter]

Your radio is only as good as your antenna. It takes some time, but quality stuff will most likely outlast your radio. Just a little minor antenna maintenance is required for good NMO mounts. Drill that antenna in when you get a chance. You won't be disappointed. Just the look of a good install makes you feel better, and it will serve you well.

 

[digitalanalog]

Drill that antenna in when you get a chance. You won't be disappointed. Just the look of a good install makes you feel better, and it will serve you well.

The antenna is not mounted on a vehicle.

 

[lu81fitter]

I thought this was the antenna in question.......

Can you recommend a good sturdy magnet mount for vehicles? I would definately use this antenna on a vehicle when I go somewhere with the BCD325P2.

Maybe I'm confused!

 

[ltginrage]

I thought this was the antenna in question.......

No I built that and have it running already. lol

 

[Ubbe]

Ok, I'll have to wait a little bit on that. If theres anything I learned over the process of building the antenna is that this hobby is not cheap.

A capacitor at 4,7pF will have 50 ohm at 450MHz and 200 ohm at 150MHz. Put that in series with your UHF scanner and it wont' affect your VHF scanners reception when you connect both scanner to the same antenna coax using a standard bnc T-connector.

You can cut the coax and splice the ends and then tie wrap the coaxes together and connect their braids and then solder or screw the capacitor between the center leads in series. Put that in a shielding box of some sort or put some electrical tape around it and then some alumium foil around it and you'll have a high pass filter that will isolate that scanner from the 150MHz band. You can't do it any cheaper than that.

/Ubbe

 

[lu81fitter]

No I built that and have it running already. lol

Sorry about my confusion. I didn't see any posts about that. They all ran together.

 

[ltginrage]

https://www.theantennafarm.com/catalog/laird-technologies-mbcn-7531

A few questions about the antenna base....
Does this comes with the F to N and N to NMO in a diffrent arrangement?
Also does it still need to be grounded or does the pole act as a ground rod?

 

[mmckenna]

https://www.theantennafarm.com/catalog/laird-technologies-mbcn-7531

A few questions about the antenna base....
Does this comes with the F to N and N to NMO in a diffrent arrangement?

No. You either need to use a cable with a male N connector on the end (preferred method), or use an adapter. F connectors are 75Ω and don't have a lot of value in the LMR industry, so no point in producing a product designed for commercial antennas to use a connector like that.

Also does it still need to be grounded or does the pole act as a ground rod?

It needs to be grounded, but if you are using a metal pole as the support, that would be OK.

 

[ltginrage]

No. You either need to use a cable with a male N connector on the end (preferred method), or use an adapter. F connectors are 75Ω and don't have a lot of value in the LMR industry, so no point in producing a product designed for commercial antennas to use a connector like that.

So he would need a F to N?

It needs to be grounded, but if you are using a metal pole as the support, that would be OK.

That pole is metal right?

 

[mmckenna]

So he would need a F to N?

Ideally, you should be running cable that has an N connector on the end. Adapters are often failure points. But if none of that is an option, sure, a female F to Male N adapter would do the trick.

That pole is metal right?

I have no idea what the pole is made out of. Ideally, yes, metal, and make sure it's grounded.

 

[ltginrage]

Hello all,
I am back with an update. My setup did survive the winter madness. I've had no issues with it until about within the last month. I noticed the reception is getting worse day by day. I did expect it to get worse over time but not as fast as it is now. For example I could reach the county fire repeaters 2 counties away from me a month a go and now I'm barely reach the county I live in. I realize that it being exposed to the elements could also have some effect on it getting worse. At this point I'm wondering if I should've went with a discone in the attic. My attic is probably 25-50 ft higher then my shed (the current position). And I can get a discone for about the same price I got the Larsen for?

Whats your guys opioion? Should I wait to see if it keeps deteriorating then go from there or is it normal for it to go down that fast?

Thanks

 

[mmckenna]

Whats your guys opioion? Should I wait to see if it keeps deteriorating then go from there or is it normal for it to go down that fast?

Thanks

I think you need to look at your coax and the antenna mount. Slow deterioration sounds like water intrusion. It's likely water got into the mount or into the coax connector. You may need to take it down, clean it all up and try again. If water entered the coax, you'll need to cut enough off to get down to good coax. Make sure your waterproofing is spot on.

Other option could be that the weight of the coax pulling on the connectors resulted in them separating. Strain relief is important.

If the antenna was working well, and it sounds like it was, I'd figure out what was wrong and fix it.

 

[ltginrage]

I think you need to look at your coax and the antenna mount. Slow deterioration sounds like water intrusion. It's likely water got into the mount or into the coax connector. You may need to take it down, clean it all up and try again. If water entered the coax, you'll need to cut enough off to get down to good coax. Make sure your waterproofing is spot on.

I never thought about that. The snow was just melting for the final time about a month ago so that would make sense. I will go check that out.

 

[lu81fitter]

Also remember, the leaves are growing on the trees now. They may be blocking some of the signal. But mmckenna is right about strain relief and water intrusion.

 

[mmckenna]

Also remember, the leaves are growing on the trees now. They may be blocking some of the signal. But mmckenna is right about strain relief and water intrusion.

Unlikely to be an issue on low band or VHF. It can be a minor issue on 800MHz and up.

 

[ltginrage]

Unlikely to be an issue on low band or VHF. It can be a minor issue on 800MHz and up.

I should've mentioned I was noticing this on VHF Fire Dispatch channels and the one UHF freq I have near me. No major change for 700/800 P25.