HF or VHF / UHF.


Other than just getting the best / lowest loss coax you can get - what else is to be done?


Run an amp and accept the losses?

That's about it. You could spend some bucks on hardline but won't offer that much benefit. Would lighten your wallet a bit

For HF, also consider running a remote tuner so that coax losses are minimized if your antenna is non-resonant.

This is why cellco's use remote radio heads.  
Feed the RRU with fiber+power and go straight to the antenna, while all the big equipment sits at the bottom of the tower.

How long are we talking here?  Hundred ft or so, or like thousands?
Not sure if there's amateur transmitters that can do something remote like that, but maybe box something up and control it through wifi/ethernet/etc?
100-200ft I wouldn't worry about.  500's where I'd start thinking "Maybe we could do something different".  

You can run a preamp at the antenna which is powered via DC that runs on the coax.

Couple hundred meters ish.

Looking at a loss calculator, a 100 foot run of LMR-400 will be about .488db total loss.  A 100 foot run of RG-8X will be 1.2db loss.  Personally, I don't think you will be able to detect the difference in the losses.  If it was me, I would put the money into your antenna instead of coax.

FWIW, I tend to use RG-8X for HF and short distance runs of VHF/UHF with our go kits.  I use LMR-400 for VHF/UHF at our base station.

or 600 ohm open feeder with a .072db loss.

You've got it, OP.

50' run here, high quality coax, inline amplifier/booster.
Pulling in stations here from 50+ miles away with one of those flat antennas folks stick to the inside of a house window, the $ savings is glorious and picture quality much improved from the cable TV service we used to have.

There are several different ways to go about it depending on what you are wanting to accomplish.

In microwave (anything above 1 GHz), there are three main types of setup. A traditional setup where the radio is located at the bottom of the tower and then RF is transported up the tower either via corrugated hardline or nitrogen purged waveguide (but waveguide is dependent on the operating frequency). A hybrid setup split mount popularized by the Motorola PTP800 where an base unit would convert Ethernet to an IF frequency and then transport it via braided copper coax to an outdoor unit to upconvert to the proper giga-squiggles but these days these are falling out of favor. Finally, radio on tower setups where power and data are sent up the tower to a radio either interfaced via short (24" or less) coax jumpers or waveguide connector interfaces to the antenna which has really become quite popular over the last decade or so.

In LMR typically you would just push some power with appropriate coax. As an example in 7/800 MHz trunking, 100W repeaters are pretty much standard as it's pretty much assumed you'll be running through a transmit combiner (2 dB loss for cavity, 8 dB for hybrid) and then at least 250 ft of tower (so 1/2", 7/8" and 1-1/4" hardline are common place here). In some situations, may also see the use of Tower Top Amplifiers (TTAs) where a pre-selector and pre-amp are placed just behind the RX antenna to help overcome the line loss back down the tower. The other approach is move the RF equipment closer to the antenna system. Two examples of this are towers more than 800 ft tall tend to have platforms where equipment can be placed at various heights in outdoor enclosures to reduce feedline length or using UTP to transport audio through a building or up a tower where it is interfaced to a remote control station as it is easier to manage UTP through a building than it is to manage coax.

Open feeder would be sorta difficult.


Situation is this.  Off grid cabin at the bottom of a draw.  Could go straight up the bluff and be at the top with a view to the horizon with a run of 200 meters or so.


Taking the calc from above and rule of thumbing it at 0.488 db for 100 feet, 1000 feet would be 4.88 db.  So figure 8 ish db loss to overvalue it.



Sounds like there isn't much to be done without doing something really esoteric like building a small doghouse at the top of the bluff and remotely controlling the transceiver.

For VHF / UHF i guess a crossband or true repeater would work (with the aforementioned doghouse).  But that's not really conducive to spinning the dials and  'playing radio.'

Remote station. Run power/ethernet (or wifi) up to your ridge line and control it from the cabin.

You could probably even get away with solar if you're not running things 24/7 and just wifi into it.

I use a 5 watt 2 meter HT with a 100 ft RG8X to the attic.  Thats hooked to a 50 watt Motorola amp and about 6 to 8 ft out to the antenna.

Or rg6qs, accept the slight missmatch, and use cheap/free coax. I got 250' for $7.

I have an 800 ft run of 75 Ohm cable low-loss hardline from my cabin to the ridgeline above it with a 5BTV up there.

I have to manually tune using a BIG MFJ tuner.

I have measured the losses at about 3-4dB depending on the band (I only use it on 80/40/20).

I do have an ALS600, so I figure I can easily get 200 watts to the feepoint, and at 1800 ASL that is a lot.

The neat part is the noise floor is non-existant.  You hear everything.

I'd love to put a small connex up top with a genny, but I am not there often enough to warrant it.  Maybe when I retire.

How do you like the 5BTV? I'm contemplating a 4BTV on my metal roof.

40 and up it is a fine antenna.

80 it is very finicky to tune.

I have changed my primary QTH to a simple 1/4 wave vertical wire for 80/40/20 and would instantly replicate that at the cabin if the 5BTV ever fails or gets smashed.

I am done with fancy antennas.

I'm not nearly as educated on antennas as others here - but i get the impression many of these antennas are much like fishing lures.  Designed to catch fisherman, not fish.

Similar to why I mainly run 1/4 wave antennas for VHF/UHF in mobile application. Yes I can pull out some fancy test equipment and show that it's a better antenna...but doesn't mean I can actually hear the difference with my own ears.

Before spending any money, calculate your feedline loss, remembering that a power increase or decrease by a factor of 4 results in a change of only one S-Unit on the other guy's receiver.
Then ask yourself if it's worth the extra $$$.

A 5 db. loss on 160 through 20 meters won't be as noticeable on the RX side, as on 10 meters or worse - VHF/UHF frequencies. You may be able to compensate the TX losses with an amplifier. Yes, it's not optimal but you will be able to enjoy most HF bands.
Obviously, like others mentioned, an open air balanced transmission line is a good choice to long runs on HF bands. If it's not practical, buy some hardline, if you can afford it. Buy once, cry once.

You know, back in my early days, low loss coax was unobtanium. I ran about 250' of crappy, lossy 75 Ohm TV reception cable. I never measured the losses but I worked several hundred DX entities with a home made transceiver, single output tube with about 40-50 watts output. It worked just fine. The antennas were on top of a 5 story apartment building. Balanced transmission lines were impractical.

Also, try to get the best antennas you can afford. This hobby is all about antennas if you really want to really enjoy it.