Antenna and Setup Help

[ch1158]

Hello, I was wondering if somebody could help me with some equipment recommendations. I am pretty new to this and looking to buy some solid equipment so I don’t have to upgrade in the future. I currently have a BCD436HP and am adding an SDS 100 soon as well as a scanner solely for VHF bands which I will gladly accept recommendations on.

I am looking for some advice on antennas and a splitter to go to these two scanners. These scanners will be monitoring my local P25 trunked systems but looking to scan as far as I can. As far as I have read, the Diamond Antenna D-130J seems like a good choice for a multidirectional antenna. Are there any others that are superior for monitoring LMR-400UF seems to be the best cable option as well but looking for recommendations on all of this. Planning on mounting the antenna on my roof and running the lines to my basement which will be around 75 feet. I am also wondering if that antenna will be good for the VHF scanner or if I should look into getting a separate one for that?

Since the LMR400 seems to be very heavy, any advice on what I should run from the cables after they split to the radios themselves? Something not as strong that is movable so my radios do not get damaged. I am looking to build a very small portable stand for the radios that I can move back and forth in my basement around 10 feet from my desk to the couch. On this stand, I was thinking of mounting the splitter on the back or should that be a further distance? Basically does there need to be LMR400 running after the splitter to the radios or can my homemade stand hold the splitter and run the less bulky wire to the radios? This may be confusing so I can clarify as much as need be.

For the separate radio solely monitoring VHF which one would you guys recommend and would I need a separate antenna for it that is more tuned for VHF waves? If so what cable would I need for it as I would rather not buy double the amount of LMR400 as it gets pricey but I am looking to make this a permanent setup and not have to make upgrades in the future so any recommendations will be great.

Any help would be greatly appreciated, thanks!

 

[mmckenna]

A discone is an interesting antenna as it covers a large slice of the radio spectrum and can be a good choice if you want to listen to all the bands your scanner will receive. However, they also have the benefit of being equally crappy across all those bands. Their benefit is the wide bandwidth, the drawback is they are zero decibel gain antennas, and can have funky radiation patterns that don't work so well on higher frequencies.

On the other hand, using a band specific antenna for VHF will give you some gain fairly easily in a small package and a known radiation pattern that can be better designed for you needs. If I was doing this, I'd use the discone for one scanner and a dedicated VHF antenna for the other. That'll give you better performance on the VHF bands.

As for coaxial cable, LMR-400 is a good place to start, but there are better coaxial cables out there, and which one is best really depends on your exact need and budget. No way anyone could rightfully tell you if it's the correct solution without knowing more about your installation. Things like budget, total length, and routing path would help us give you a good recommendation.

And, you are correct, you don't want to connect anything but a very thin/flexible coax directly to your scanners. The antenna jacks on top are a known failure point if they get stressed. It's usually a good idea to use something like RG-58 to make the last few feet to the scanner. That'll save you some costly repairs.

 

[ch1158]

A discone is an interesting antenna as it covers a large slice of the radio spectrum and can be a good choice if you want to listen to all the bands your scanner will receive. However, they also have the benefit of being equally crappy across all those bands. Their benefit is the wide bandwidth, the drawback is they are zero decibel gain antennas, and can have funky radiation patterns that don't work so well on higher frequencies.

On the other hand, using a band specific antenna for VHF will give you some gain fairly easily in a small package and a known radiation pattern that can be better designed for you needs. If I was doing this, I'd use the discone for one scanner and a dedicated VHF antenna for the other. That'll give you better performance on the VHF bands.

As for coaxial cable, LMR-400 is a good place to start, but there are better coaxial cables out there, and which one is best really depends on your exact need and budget. No way anyone could rightfully tell you if it's the correct solution without knowing more about your installation. Things like budget, total length, and routing path would help us give you a good recommendation.

And, you are correct, you don't want to connect anything but a very thin/flexible coax directly to your scanners. The antenna jacks on top are a known failure point if they get stressed. It's usually a good idea to use something like RG-58 to make the last few feet to the scanner. That'll save you some costly repairs.

If I went the route of two separate antennas what would the best in your opinion? One to solely monitor P25 systems and another for VHF? I have been saving for a while now to make a great setup so I would like to consider the best options. If I went the two separate antenna route would they both need a separate dedicated cable or is there some type of splitter I could attach from two antennas before running the wiring down? And then some type of 1 to 4 way splitter before reaching the antennas?

My installation will be roof-mounted antennas running cables from there to my basement at three stories. All together around 50-75ft to the door plus another 15 feet to the furthest point it would need to go in the basement. What other cables would be best for this besides the LMR400, and how much of a difference would that make do you think?

As far as the last couple feet and wanting to build a small docking station to hold the scanners would it be best to connect the splitter to the back of that docking station then run the RG-58 from there? It would need less than a foot as I plan to have them wrap around the top to further decrease the stress. Hope this helps narrow it down and thank you for the response.

 

[mmckenna]

If I went the route of two separate antennas what would the best in your opinion? One to solely monitor P25 systems and another for VHF? I have been saving for a while now to make a great setup so I would like to consider the best options. If I went the two separate antenna route would they both need a separate dedicated cable or is there some type of splitter I could attach from two antennas before running the wiring down? And then some type of 1 to 4 way splitter before reaching the antennas?

I would run one VHF antenna and one multiband antenna.

The dedicated VHF antenna will give you better performance than the discone will.
The discone will give you some level of wide band performance for listening to other bands.

Combining antennas like that gets tricky. You'd be better off running two separate runs of coax. Something like a diplexer will combine different band antennas, but you won't get what you want going that route.

My installation will be roof-mounted antennas running cables from there to my basement at three stories. All together around 50-75ft to the door plus another 15 feet to the furthest point it would need to go in the basement. What other cables would be best for this besides the LMR400, and how much of a difference would that make do you think?

For VHF, the LMR-400 would be a good choice.
For the discone, if you plan on listening to 700/800MHz stuff, LMR-400 would be the minimum I'd run. I'd probably run LMR-600. But that costs a bit more per foot, and is a stiffer cable, so routing it will be more difficult.
If receiving is the only thing you'll be doing, then the LMR-400 and maybe an amplifier at the discone antenna might be a good option. If you plan on ever transmitting with the discone, then the LMR-600 would be a better option.

As far as the last couple feet and wanting to build a small docking station to hold the scanners would it be best to connect the splitter to the back of that docking station then run the RG-58 from there? It would need less than a foot as I plan to have them wrap around the top to further decrease the stress. Hope this helps narrow it down and thank you for the response.

I'd run two separate coaxial cables, one for VHF, one for the discone. Terminate the LMR-400/600 and transition to the RG-58, (or LMR-195, LMR-200) to make the final connection to the two scanners.

 

[ch1158]

I would run one VHF antenna and one multiband antenna.

The dedicated VHF antenna will give you better performance than the discone will.
The discone will give you some level of wide band performance for listening to other bands.

Combining antennas like that gets tricky. You'd be better off running two separate runs of coax. Something like a diplexer will combine different band antennas, but you won't get what you want going that route.

For VHF, the LMR-400 would be a good choice.
For the discone, if you plan on listening to 700/800MHz stuff, LMR-400 would be the minimum I'd run. I'd probably run LMR-600. But that costs a bit more per foot, and is a stiffer cable, so routing it will be more difficult.
If receiving is the only thing you'll be doing, then the LMR-400 and maybe an amplifier at the discone antenna might be a good option. If you plan on ever transmitting with the discone, then the LMR-600 would be a better option.

I'd run two separate coaxial cables, one for VHF, one for the discone. Terminate the LMR-400/600 and transition to the RG-58, (or LMR-195, LMR-200) to make the final connection to the two scanners.

Is there specific antennas you recommend for each? Or just the discone I mentioned earlier should work well? Just seems to be a million types out there.

Transmitting is probably something I will be interested in eventually so I will definitely go with the LMR-600.

For splitting the 600 to two scanners from a discone or other antenna type are there any splitter brands you recommend? I’ve read it cuts the signal down significantly so was wondering where to go on that. Also for splitting the signal should I take the 600 as far as it will go inside to my stand then split to the other type of cable or just use the secondary cable to run on the inside?

 

[mmckenna]

Is there specific antennas you recommend for each? Or just the discone I mentioned earlier should work well? Just seems to be a million types out there.

The Diamond is a pretty decent discone. I scored one for free many years ago. I put it up at my home as a temporary solution, and just never got around to replacing it. It's been working fine for 10 years, maybe more. Occasionally I'll bring my good analyzer home from work and sweep it, and it still checks out just fine. It's on LMR-600, about a 35 foot run, and connected to a VHF Motorola for some ham and work stuff.
The antenna has been through some good storms and it's been fine. Unless they changed the way the antenna is built, it's probably a good solution.
Be aware that there are/were two models. One had a UHF connector, one had an N connector. The N connector is preferred model as the N connectors perform better as you go higher in frequency.

As for the connectors, make sure you seal all your outdoor connections well.

For splitting the 600 to two scanners from a discone or other antenna type are there any splitter brands you recommend? I’ve read it cuts the signal down significantly so was wondering where to go on that. Also for splitting the signal should I take the 600 as far as it will go inside to my stand then split to the other type of cable or just use the secondary cable to run on the inside?

I don't use any splitters with my stuff, so I'll avoid making a recommendation, but I'm sure you'll find some good suggestions on this site. Strideberg seems to be a well respected brand.
A two port splitter will result in something around 3.5dB of loss on each port. 3dB is half your signal. That may not be an issue if you have strong signals to work with, but if doing weak signal stuff, you'll want an amplified splitter to make up for that loss.

Yeah, run the LMR-600 as far as you can, as that's good low loss stuff. Split it out to the two scanners closer to the radios.

 

[Ubbe]

You can use a $20 diplexer at the antennas to combine them to use a common coax. You can even transmit thru it.

Diplexer 2m 70cm for Ham Radio Transceiver | eBay

If you have three receivers you will probably want some type of amplifier to compensate for the loss in a 1-3 splitter. In the RR forum there are several users that suggests some good TV amplifiers that have a max of +6dB gain. You can also get a more expensive Stridsberg multicoupler that will do the same job.

/Ubbe

 

[ch1158]

The Diamond is a pretty decent discone. I scored one for free many years ago. I put it up at my home as a temporary solution, and just never got around to replacing it. It's been working fine for 10 years, maybe more. Occasionally I'll bring my good analyzer home from work and sweep it, and it still checks out just fine. It's on LMR-600, about a 35 foot run, and connected to a VHF Motorola for some ham and work stuff.
The antenna has been through some good storms and it's been fine. Unless they changed the way the antenna is built, it's probably a good solution.
Be aware that there are/were two models. One had a UHF connector, one had an N connector. The N connector is preferred model as the N connectors perform better as you go higher in frequency.

As for the connectors, make sure you seal all your outdoor connections well.



I don't use any splitters with my stuff, so I'll avoid making a recommendation, but I'm sure you'll find some good suggestions on this site. Strideberg seems to be a well respected brand.
A two port splitter will result in something around 3.5dB of loss on each port. 3dB is half your signal. That may not be an issue if you have strong signals to work with, but if doing weak signal stuff, you'll want an amplified splitter to make up for that loss.

Yeah, run the LMR-600 as far as you can, as that's good low loss stuff. Split it out to the two scanners closer to the radios.

Awesome thank you so much for the help!