Mountaineer304
Member
Hey everyone so I just purchased me a new Uniden SDS 100 and a ProComm Home Mount Antenna kit with 100 feet of RG6 what connector will I need to connect my scanner to the base antenna?
Hooking up ProComm Home Mount Antenna to my SDS 100
- Thread starter Mountaineer304
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You are going to have fairly high signal loss from RG6 - especially 100' of it.
RG6 is used for high-bandwidth, high-frequency applications like cable TV, internet, and satellite TV.
And, it is 75 Ohm
RG8 is used for radio frequency applications, radio antennas, and wireless transmission.
And, it is 50 Ohm - which is what you want (the antenna is almost certainly 50 Ohm)
Better yet is LMR.
RG6 attenuation chart.
(Remember, every 3dB is HALF)
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Mountaineer304
Member
Oh well that's jusy what zip scanners sells with there kits I jusy wanna know how to connect a so-239 to my scanner and a decent base antenna lol
Mountaineer304
Member
It's actually rg58 they include sorry
Mountaineer304
Member
Coax is rg58 sorry
Mountaineer304
Member
It's actually rg58 sorry
Mountaineer304
Member
What about rg58
mmckenna
I ♥ Ø
Question:
Do you -really- need 100 feet of coaxial cable to get from your radio to your antenna?
As cable length goes up, losses go up, so less cable = less loss.
What frequencies will you be listening to?
As frequency goes up, losses go up.
Ideally you want just the length of coax you need to get from your radio to your antenna. If the antenna is going to be outdoors, also remember that you should have a lightning protection device where your coax enters the home.
High grade coaxial cable can be expensive, difficult to route, and may require a shorter whip of more flexible cable to make the final connection to your radio. Stiff cable like RG-8, LMR-400, etc. will put a lot of strain on the antenna connector on your scanner and risk breaking it.
Do you -really- need 100 feet of coaxial cable to get from your radio to your antenna?
As cable length goes up, losses go up, so less cable = less loss.
What frequencies will you be listening to?
As frequency goes up, losses go up.
Ideally you want just the length of coax you need to get from your radio to your antenna. If the antenna is going to be outdoors, also remember that you should have a lightning protection device where your coax enters the home.
High grade coaxial cable can be expensive, difficult to route, and may require a shorter whip of more flexible cable to make the final connection to your radio. Stiff cable like RG-8, LMR-400, etc. will put a lot of strain on the antenna connector on your scanner and risk breaking it.
Mountaineer304
Member
Yeah I have multiple hf,vhf and uhf antennas just new to scanners… i may be able to make 50 feet work i wanna be able to monitor vhf/uhf and 7-900mhz
mmckenna
I ♥ Ø
You are going to lose a lot of your received signal on those higher bands with that much RG-58. At 900MHz, you'll be losing 80% of the signal just to coax losses.
That may be OK if what you are listening to is close by and has a strong signal. If you are trying to hear traffic from further away, it's going to be a major problem. That antenna isn't going to have any gain on those higher frequencies, so no benefit there.
Try it out with the RG-58 and see if it's working well enough for what you want. If it's not, you'll need to look at improving the cable. I'd look at some LMR-400 as a starting place, maybe some good RG-8 if your budget is tight. Don't try connecting either of those direct to the radio. Use a short whip of RG-58 or similar small diameter cable to make the final connection. That'll reduce the stresses on the antenna jack.
Mountaineer304
Member
Okay I want to hear traffic far I’m at an elevation of 3000 feet so I’ll go lmr I know a ham who makes quality lmr. Now the whip that’ll need to be so-239 to a male correct ? Any recommendations on a antenna I’m on the second floor 25 feet up I have a 5 foot mast I never used I was gonna utilize and may only need 50-75 feet if I mount there
mmckenna
I ♥ Ø
Use what ever fits the antenna. Looks to be a SO-239 on the antenna base, so you want a PL-259 (UHF male) connector on one end of the new coax. Make sure you properly seal the outdoor antenna connection. You don't want water getting inside.
On the radio end it's not super critical. N connectors are a bit better for higher frequency work, but since you've got a UHF at the antenna, keep it simple and use that.
Then use a 2-3 foot long piece of RG-58 or similar small diameter cable to make the transition to your scanner.
Finding good multiband scanner antennas can be a challenge. So many trade offs.
Discone antennas are good if you want a lot of useable bandwidth. Problem is, they have zero gain, so not much benefit for weak signal work. Also, on higher frequencies the radiation pattern starts going up above the horizon, which makes things worse.
There are some whizz-bang antennas on e-Bay/Amazon that will claim all kinds of things, but they rarely do much better.
Band specific antennas are always a good option, but then you have multiple coax runs, mounting challenges, etc.
Kind of have to find the happy place in between all of those. I have a wide band receiver at one of my high sites and it's connected to a commercial discone antenna with LMR-600. Works well for what it is, but it is not a stellar performer when compared to the band specific antennas.
Mountaineer304
Member
I keep seeing this ham on eBay who makes these pvc antennas he has some good feed back but idk
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mmckenna
I ♥ Ø
Feedback is something you need to be careful with. You would need to know the experience level of the one leaving the feedback, what they were comparing the antenna to, and if they are legit or not.
Most of those magic PVC pipe antennas are just a couple of ~somewhat~ tuned lengths of romex wire stuffed inside a piece of Home Depot PVC pipe.
Will it work? Yes, so will a paper clip stuffed in the antenna jack of your radio.
Is it going to work well? Depends on how strong the local signal is. You said you wanted to hear weak signals. This isn't the antenna for you.
Mountaineer304
Member
Your correct but some of thise hams on ebay make amazing antennas,Nelson antennas are amazing he made my end fed half wave
Mountaineer304
Member
So since the sds 100 is a female I'd been a pl259 to male or female adapter?
mmckenna
I ♥ Ø
Absolutely, there are some good antennas out there.
Some of these PVC pipe antennas are just a twin lead J-pole in a pipe. Or 1/4-ish wavelength pieces of THHN wire, or sleeve dipoles made out of RG-58, and stuffed in piece of sprinkler pipe. Somewhere, someone had a photo of one they took apart, and it really was just lengths of solid copper wire soldered to the coax. About 15 minutes of work a few bucks in parts. Probably something you could make yourself fairly easily.
The beauty of those is that they are inexpensive and will easily outperform a stock antenna mounted on the scanner inside the home. Getting any antenna outside will really help performance. As always, you have to balance budget and needs.
mmckenna
I ♥ Ø
If the other guy is going to make you custom cables, get the LMR-400 made with UHF connectors on each end. Then use a short piece of RG-58 with a female UHF connector on one end to attach to the LMR-400, and an SMA male on the other end to attach directly to the scanner. Try to not use adapters as they add leverage to the connection on top of the scanner and can easily snap it off.
