A few comments, amateur radio vs CB

[Moleculo]

having accurate swr readings and tuning antennas are two totally different things,so the purpose of having an impedance repeater isn't just for use when tuning,it allows accurate readings after tuning too

Yes it allows for accurate measurements. Other than the measurement aspect, it serves no useful purpose and doesn't affect the performance of the station at all.

why do you use half wave repeaters to tune your antennas on every band if you don't think it makes any difference? your contradicting yourself.

No contradiction. You can use 1/2 wave multiples to MEASURE if you want finite accuracy. That has nothing to do with what length you ultimately end up using for operating the station. MEASURING and OPERATING characteristicts are two entirely different animals.

if your trying to tell me your a ham and therefore a superior intellect on radio theory then i'm not impressed.if you were that knowledgeable about radio,antenna's and transmission lines you wouldn't even allow crap like rg8x in your shack

Two things: 1. QRN is a broadcast engineer and has put together AM/FM broadcast radio stations much more complicated than anything you or I will ever assemble. But he doesn't need me to defend his credentials. 2. RG8x has perfectly good places to be used in a shack. It's just a tool. Every tool has a purpose. If you use the wrong tool for the job, that's where you have a problem. It's quite common and perfectly acceptable for people to use smaller coax for jumpers between equipment, especially when the power levels aren't very high and then use coax with less loss for the long run to the antenna. The loss of smaller coax isn't even a consideration under that scenario. I can probably come up with a 1/2 dozen other reasons to use rg8x that are perfectly fine.

 

[Captain Kilowatt]

Yes it allows for accurate measurements. Other than the measurement aspect, it serves no useful purpose and doesn't affect the performance of the station at all.



No contradiction. You can use 1/2 wave multiples to MEASURE if you want finite accuracy. That has nothing to do with what length you ultimately end up using for operating the station. MEASURING and OPERATING characteristicts are two entirely different animals.



Two things: 1. QRN is a broadcast engineer and has put together AM/FM broadcast radio stations much more complicated than anything you or I will ever assemble. But he doesn't need me to defend his credentials. 2. RG8x has perfectly good places to be used in a shack. It's just a tool. Every tool has a purpose. If you use the wrong tool for the job, that's where you have a problem. It's quite common and perfectly acceptable for people to use smaller coax for jumpers between equipment, especially when the power levels aren't very high and then use coax with less loss for the long run to the antenna. The loss of smaller coax isn't even a consideration under that scenario. I can probably come up with a 1/2 dozen other reasons to use rg8x that are perfectly fine.

That's pretty much what I would have said Mole if I had been here first.

As for what my credentials are all I will say is that with my 22 years of being a commercial broadcast engineer and having put both AM and FM radio stations on the air literally from the ground up as well as installing and maintaining VHF/UHF STL repeater systems (Studio-transmitter link) and dealing with transmission lines up to 5 inches in diameter as well as multi station FM power combiner units, I do not need YOU to lecture ME on what is best for measuring or maintaining a proper transmission line and antenna system. If you had read what I said you would have noticed where I said I use Belden 8214 or Heliax,specifically Andrew LDF4-50 half inch to be exact, for my transmission lines. The RG-8X is only used to interconnect a couple pieces of gear such as switches or meters and is also used with my antenna analyzer for tuning antennas.Oh,and on top of that YES I AM A HAM SO SUE ME! :angry:

 

[74IN]

What's wrong with 8X?

I use it, along with RG-213 and LMR 400.

It has it's place.

 

[jazzsinger]

hams ain't called amateurs for nothing,rg8x has its place,yeah right,your having a laugh.only place fit for rg8x is in a dustbin/trashcan next to all those crap cobra 200's and antron 99's.:headbang:headbang:headbang:headbang:headbang,i'm sure qrn doesnt need back up moleculo,after all he's a broadcast enginner.,just out of curiosity if he doesn't need you to defend his credentials,then why are you doing so?want him to swr your antenna

and i never said it did affect station performance,i said it allows you to monitor the ongoing state of an antenna system reasonably accurately,big difference.

 

[Justme]

When you really want to know what your antenna does, measure directly at the antenna, what i do, and use an good antenna analyser.

Then get the coax on it, making sure it is watertight, and done according spec's
No need to monitor antenna systeem, some antenna's been up here for 10+ years and have the same results as the day they were put up in a yearly check up.

For coax, beeing it HF or 70 cm's i use the Ecoflex 15 1/2 inch coax, wich is better as LMR 400.
Why? because i can do it, and low loss hi quality cable UV resistent will last almost forever when taken care of.

I just cut the cable as long i need it.
I don't use an swr meter in line, trusting my abilieties to mount the antenna's correctly and the same goes for coax and connectors.

Trying to insult professional people here shows your lack of understanding the antenna theory.

Have a nice day

Cor

 

[Captain Kilowatt]

jazzsinger is probably one of those that couldn't pass the amateur exam and is bitter over it hence his attitude towards hams. I guess he does not realize that if you are not a professional,ie paid to do something, then you are an amateur. The only differance between the two is payday. In the early days of radio commercial radio operators looked down on hams and called them amateurs because they were the snooty ones that made a living off of radio.

jazzsinger,just what do you use for transmission line and please enlighten us on the pitfalls of RG8X when used in short runs and low power applications. I tried using LDF4-50 for jumpers to my meters and switch boxes but it started to get real expensive real fast for the connectors and it was taking up far too much room in order to get it all to fit behind the console.

 

[Peddler]

I feel you only need what will do the job at hand. RG8X works just fine for me. I'm not a Ham, Broadcast Engineer, or radio shop operator... Just a lowly CBer that know what works for his situation:angry:.

 

[W5LZ]

The general opinion that RG-8X has it's uses is certainly correct, it does. It isn't limited to use as a 'jumper', reasonable lengths for feed lines is typically something it does pretty well.
Just like any of the other 'sizes' of coax, there are different grades/characteristics with RG-8X. Ran across some that was intended for use as audio cable, and it probably worked just fine as such. As an RF feed line, you wouldn't believe how bad it was. Wish I could remember the 'name' of the stuff, but can't, I definitely don't want anymore of the stuff. Buying a name-brand, reading the specs to make sure I'm getting what I think I'm getting, has worked for me. I've used RG-8X (Mini-8) for antenna feed lines for years. Honestly couldn't tell any differences when changing to another type of cable. The radio couldn't either so it was happy too. It has some physical characteristics that I do appreciate. It's size and flexibility are nice compared to some others. The same can be said for RG-58 coax too (gasp!), the 'trick' is that 'reasonable' part.
Having the "best" possible thingy to do something with is nice, but it's also not that important, you'll never know the difference in most cases.
As for the typical 'hardline' for CB/Ham use, ain't no way except for VHF/UHF stuff. What's the point, that stuff is over-kill on HF. My deciding factor on that is cost versus improvement. Sorry, just ain't enough to justify it for me. (Yes, I've used some.) The largest users of hardline in this part of the country are cable TV companies. Some of them even have people working for them that know what they are doing ('nuther hard to believe thingy, huh?). They aren't all that 'thrilled' with it either, by the way .
Oh well. Just my opinion, has validity as far as I'm concerned.
- 'Doc

 

[Captain Kilowatt]

I have to agree 100% with what Doc just said. Just to clarify, the ONLY reason I use LDF4-50 Heliax cable is because I was able to acquire several hundred of both new and used cable for free along with the connectors.I have also collected almost 500 feet of various sizes of 75 ohm CATV main trunk hardline. Being in the business has it's fringe benefits. If not for that there is NO WAY that I would ever have used it even on 2m.

 

[Justme]

Getting a better Q coax on your HF antenna can have its merit depending the antenna setup, SWR you have on some bands etc.

Normally in resonant systems RG213 will do fine if you don't use 100's of meters.

Using an OCF for multiple bands where on some bands your swr can be a bit higher a good Q coax will give less loss.

The Ecoflex 15 i use is compatible with LMR 600 but has a multiple core and is quite flexible.

Now used on 2/70/6 meters. runs vary from 18 to 23 meters.
Aircom plus, the european LMR400, is used on HF for the OCF and Imax 2000 wich is used for 10/12/15, as the OCF is run from 160 -10
The OCF has an added coil and wire for the 160 meters.

From 6 meter and up the N connector is standard here.

The antenna system, antenna connectors, feedline should be your main concern, specially on the higher frequencies.
Any signal lost in that system cannot be heard, even using the best reciever with dsp etc.

Even the jumper coax cables are Aircom plus, just because i can do it, trying to keep losses at a minimum.

Most people spend mega bucks on a transciever and skimp on the antenna department/system.
Then the new tranciever gets the blame if the results are not what they expect.

Just make your choice.

73,
Cor

 

[loosecannon]

oh yes jazzsinger, please enlighten all of us on exactly why we should not use RG8x. LMAO! as if there is something inherently wrong with it.

how much does anyone want to bet that this guy heard something somewhere on the CB band, believed it, and is perpetuating it here? LOL

the only thing worse than a pompous ham op is a cb'er who believes what they hear without checking it for themselves, and then repeats it as if its a proven fact.

cant wait to hear the explanation. LOL
LC

 

[W5LZ]

Justme,
I have no idea how the coax you use would compare to the types made/used here, so, I assume what you are saying is true.
There are a few things that are common to any type coaxial feed line. One of those is that the SWR you see with one particular type is going to be about what you see with another type assuming that the characteristic impedance of both are the same. That also assumes that the particular length used isn't important for some reason (phasing/timing).
Different types of coax have different losses, nothing unusual about that. Selecting one that has lower losses than another is a nice idea if the amount of loss really amounts to much. On HF, those losses usually don't amount to that much for the 'average' length of feed lines (something less than 100 -150 feet). Until those losses amount to something more than about 3 dB, they just are not noticeable.
Foam type dielectric insulation tends to have less voltage/current tolerance than the 'solid' types of dielectric. As long as you keep that in mind, and don't 'push' the coax's limits too far, either will work well. That goes for all brands/types of coaxial cable, 'hardline' included.
After sorting though all that, the 'right' coaxial feed line to use is almost never limited to just one brand or 'type'. The 'average' 100 watt level of 'station' can use almost anything if the length of that feed line isn't hugely long, or your feeding something that's not really 'off'. Even that nasty 'Radio Shack' RG-58 stuff.
- 'Doc

 

[74IN]

I'll not notice the loss on 10M with my 8X.

85 of 100 watts make it to the antenna.

WTF do I care if it was 90W instead?

 

[Justme]

For VHF and UHF i work mostly SSB and try to keep the system losses to a minimum, hence the Ecoflex 15 coax and N connectors both ends.
For 6 meters and the 5 element beam it goes the same, trying to get the last bit out of the antenna system.
DDS Antenne kabel. Verkoop van super low loss antenne kabels, zoals CLF, clf400, CELF400, Aircell, Aircom, CLF400, Ecoflex, RG, 50 en 75 Ohm Coax Antenne kabel
Scroll down to bottom of the page.

Ecoflex 15:
Loss in db per 100 m
Frequency ECOFLEX 15
5 MHz - 0.60
10 MHz - 0.86
50 MHz - 1.96
100 MHz - 2.81
144 MHz - 3.40
200 MHz - 4.05
300 MHz - 5.0
400 MHz - 5.9
432 MHz - 6.1
As stated, all losses per 100 meters.
My lengths vary from 18 to 23 meters.
When installing a new antenna i measure directly at the antenna, MFJ269 antenna analiser, and when the coax is mounted a new measurement is taken in the shack.

From 6 meters and up every dB loss counts, specially in SSB and long range communication.
For HF it might be overkill, but i can make 1 KW and don't want to make power and then loose 50 or 100 watt in the coax, even if it is not noted on the other side.
Loss in coax works both ways reception/transmitting.
The power made on 2/70 is just 250 watts from a few homebrew amps, 6 meter is standard 100 watts and HF max 1200 watts, far within the max power rating of the coax.

Since i bought a full roll of the cable i just replaced all coax for the new one, I'd rather spend money on the antenna system as the transciever.

The same cable is used for our repeater 2/70/23 here one reason i bought a full reel of it.

Have fun,
Cor

 

[W5LZ]

Interpolating/extrapolating from your figures and the 100 Meters thingy, it certainly sounds like you made the right choice for VHF/UHF, and it certainly shouldn't hurt on HF.
I haven't checked, but I'm willing to bet that we have the equivalent here. Unfortunately, I certainly don't have the equivalent locally. Buying by the 'spool' is certainly one way of getting around cost, but I'm too cheap (also just don't use that much coaxial feed line).
- 'Doc

Just for 'grins', where in the Netherlands?