Outdoor base antenna for handheld/signal loss w/ UHF connectors vs. N type connectors

[Bubbles35053]

Am erecting a discone antenna for my handheld Pro-106, am using an 85 foot run of LMR-400, I have a few concerns/questions:
1. Using the thick/rigid LMR-400 coax was curious if there is a "jumper cable"? smaller in diameter that I can run from the LMR-400 to the actual radio and if so what all would be necessary to do this with no signal loss(if possible?) I would truly like to split the signal coming off the LMR-400 down to another room (an approx. 30 foot run) built on to house and noticed a splitter advertised for just that purpose from Grove: 2 Way Splitter this is something (the design) that would solve both problems only most splitters I've looked at are much more expensive like the sp-1300? @$49( this splitter' would be fine only I would have to use several- guessing 3-6 extra connectors(more signal loss) to make it work for me?) on up to splitters that cost close to $400. Perhaps these other more expensive ones are for transmuting or are multi couplers- I wouldn't know the difference? After enlarging the photo of this particular splitter I noticed it was simply a Radio Shack splitter- please correct me if I'm wrong as my goal is absolute minimal signal loss as possible considering I live in the boonies down a huge hill w/ almost a mountain on one side of me surrounded by trees- would this cheap splitter not mean more than a 1-3 db signal loss for me. Figured if I'm going to put all this $$ into quality coax- I def. don't want to skimp on a splitter, yet for now def, can't afford anything more than $50 for one.

2. Keep in mind as is evident by my first question/questions when it comes to the tech part of this I'm def. LOST-yet have done a lot of research and have gotten a lot of mixed results regarding the use of UHF connectors (PL-259, SO-239,) vs. N type connectors and signal loss. Have read a lot of folks claiming that the UHF connectors are extremely "lossy" and shouldn't be used on antenna systems anymore. Just how much loss is involved with a UHF connector, there are a couple of antennas I'm still debating on one has an N type connector the other has a SO-239, the N type is a bit more expensive. Was simply trying to get some input on how big of a deal this is when I'm trying to hang on to every db I can. From what I have read some seem to be very passionate about the amount of loss w/ UHF connectors? Thought I'd throw it out there and see if I could get some good solid information about just how much loss these folks are talking about, and one last thing which I also know their are many opinions on crimping on connectors or soldering-which is truly best? Anyone with information on any of these questions or topics that would be kind enough to take the time to share their opinions/answers would be GREATLY appreciated- THANKS, B.C.

 

[Daniel_Boone]

Discones doesn't really exhibit any gain, except that it carries it's own ground plane.

For a scanner application, there is no need to use RG8 cable.

Your scanner does not care what the line impedance is - and as a matter of fact the line impedance changes as the frequency goes up or down from the center tuned frequency of the antenna.

Your best bet is to use a good piece of Belden 1829 AC - Rg 6 Quad Shield coax and a unilateral splitter.

Since I do not know which frequencies you desire to receive, I will take a guess and guess that it is mostly 440 - 470 mhz - the public service bands.
At those frequencies or below - there is not a lot of line loss.

If you wanted to DX the UHF bands - you could add a Channel Master CM 7777 pre amp.
Put the mast head amplifier up next to the antenna and the power injector down in the basement someplace and use a unilateral splitter after the power injector and more RG 6 cable after the amplifier to both rooms.

They make an adapter to go from the Crimp on style RG 6 connector to the BNG which is probably the style antenna connector on top of your radio.

The money that you save by not buying the more expensive wire can be applied to a good base type scanner for the other room such as a Uniden BC 890 / 895 XLT scanner....

A even better piece of coax is the silver stuff the tv cable people uses between the poles.
If the cable company does a repair job and has less then 120' left over, they throw it in the garbage - because it is too short for what they need it for and you could probably get it cheap if you know the right person.

 

[n5ims]

There are several choices for your jumper cable depending on what you want to accomplish. None will provide you with "no loss", but nearly all will do so with only minimal loss, as long as you keep the jumper short. Some good choices would be:
* RG 8 - nearly the same size as LMR 400, but more flexable and least loss
* RG 8X [or RG 8 Mini] - much more flexable than LMR 400, but smaller and a bit more loss than RG 8
* RG 58 - Much more flexable than LMR 400, but not quite as flexable as RG-8X, close to the same RG-8X. You may find premade lengths with BNC connectors on each end.
* RG 6QS [also called quad shield] or RG 6 [non quad shield versions] - 75 ohm coax (not really an issue for scanner use) and not as flexable as RG-8X. Easy to find, cheap to get and install (even for high quality coax), easy to install F and BNC connectors available. Good shielding from external noise (especially with the quad shield versions).

Splitters allow you to connect more than 1 radio to a single antenna, but normally introduce loss. If you want the splitter to allow you to use the single radio in either location, a coax switch may be a better choice since unterminated connections add noise and distortion to the signal. Often you get what you pay for with them, but often the standard cable-TV versions (with F connectors) are much less than the scanner versions (with BNC connectors) for similar quality splitters. Since the CATV ones are so low cost, it's good to try one and if it works out, great! If not get the high cost one then and you're only out a few bucks (and you'll probably use it sometime on your TV anyway).

N connectors aren't easy to install (not really hard either after some practice) while it's easy to install a UHF connector (especially if done badly). There aren't many bad brands of N connectors, but a bad UHF connector is easy to pick up. These two facts have given the UHF connector a bad name (especially when they weren't really designed for UHF frequencies, despite the name, while the N connector was designed for use into the low GHz range. The loss between a properly installed good quality N connector and a properly installed good quality UHF connector is visible using the correct instruments, but probably isn't noticable by listening to a typical scanner. Given the choice (and minimal price difference) between an antenna with an N connector and one with a UHF connector, I'd go with the N, but would easily go with the UHF version if the difference in price was too much or the N version was out of stock. The N connector is also more water resistant than the UHF, but since the connector is often protected or at least standard water protection methods used when outdoors (hopefully both!), this generally isn't an issue in real life as well.

 

[prcguy]

A good quality 2-way power divider or splitter not of the TV type will have a minimum of 3dB loss (half your received signal) and maybe a few tenths of a dB more loss on top of that. Mini-Circuits is a fairly inexpensive commercial supplier of good quality power dividers.

I've measured some 2-way TV splitters at 4 to 5dB loss.

I like the idea of using high quality low loss cable like LMR-400 and I'm not a fan of using RG-6 coax except for TV and Satellite use, although I consume a few miles of RG-6 on projects every year.

Quad shield RG-6 generally has no advantage for scanner use over single shield, if there is interference it will usually be picked up by the antenna rather than through the coax shield. Quad shield is useful when cables are bundled together carrying L-band satellite signals where the leakage between cables is much worse at 1-2GHZ.

Good quality PL-259s are fine up through about 500MHz where they generally have less than .2dB loss and I've measured about .25dB loss for a pair of connectors and a double female barrel adapter.

I'm also not a fan of using a preamp at an antenna unless its preceded by a narrow band filter for a specific frequency range to keep the preamp from causing more problems than your trying to cure.
prcguy

 

[Bubbles35053]

Thanks everyone, I assumed a simple TV splitter would result in a good bit off loss, way too much for my liking. So what am I looking at for a decent radio splitter RXing only, and forgive my ignorance but if I go w/out a splitter how do I go from my LMR-400 to a jumper cable are there connectors on the jumper cables- I'm guessing- if so I need to know all this before I have cable made up. Don't get me wrong money is an object but considering I'm going w/ good coax, a good antenna, and as much height as I can I'd like to know what my best choice is for a jumper cable is and how long is too long 3-4 feet?? Or does cable within mini-8 or 8x even maybe rg 58 just ones preference- keep in mind signal loss as w/ everyone else here is my enemy I can handle .25 db for a PL-259 adapter vs. N type but preferable not much over that if a jumper cable of even 2feet is going to cost me ore than 1 db then I'll skip it as I'll already be loosing close to 1.5 db's in my coax run @ 155 Mhz ad another 1db that's 2.5 it adds up quick-any more info on these topics would be greatly appreciated-Thanks, B.C.