Commercial Transmission Feedline, Hardline And Waveguide

[@mike95826]

Just an FYI on the prices that we are talking about for elliptical wave-guide for 6 Ghz. The wave-guide itself is about $35.00 a FOOT. The connectors are about $250.00 each. The tool for installing them properly is about $800.00 used. Also the connectors are tuneable and a calibrated signal generator, spectrum analyzer and return loss bridge are needed to do it right. Then, as you said, an air dehydrator or nitrogen bottle is needed to keep the wave-guide dry and pressurized. If the system is installed, like most of them are, on a mountain top somewhere then an alarm system is needed to notify personnel when there is a problem. I worked for about 30 years for an electric utility where we had about 20 sites and about 35 end-to-end paths. Most at 6 Ghz and a few short paths at 10 Ghz. When I started in the early 1980's there were about a third of the sites and everything was analog. The interesting tidbit is that we can do with 500 milliwatts with digital what required 10 watts with analog (two synchronized transmitters).

[@albert7ii]

Mike.... thank you vy much for that info. Very useful indeed to know,. The highest I ever went was when I got my hands on some surplus 3/4 Andrew Heliax.... but as you rightly said, those connectors are NOT cheap ! But... on 440 MHz the loss was very low indeed.. Thanks for giving some extra info to this video from Eric, while I am unlikely to ever embark on those freqs it is still nice to know. Albert EI7II.

[@louiewhite1922]

Thanks for showing that and bringing back some memories from my commercial radio days. During my military career, I had limited experience with antenna lines as I was mostly an inside telecommunications technician. At least until I became attached to a Combat Comm Group. But most of my experience with the lines you were showing came from being a Microwave Field Technician with Motorola. Where I was assigned to the Norfolk Southern Railway Project where I was responsible for maintaining about a dozen or so sites running from just south of Tuscaloosa, AL to just north of Laurel, MS. Each site employed, Microwave and VHF radios for Dispatching and Signal Controls. A Train Engineer or Signal Maintainer in New Orleans, LA talk to the Dispatchers located in Atlanta, GA as the VHF was tied into the Microwave which brought the signal to/from and also in/out at all the hundreds of sites along the route. I also maintained their Data Systems and a small Redcom PBX (Telephone Switch) at my main site in Meridian, MS. That is until I was promoted and moved to be a Lead Tech in the Atlanta Facility. Norfolk Southern has the largest private microwave system in the world. Stretching from Chicago to New York to Florida to Louisiana and all states in between. This experience paid off following Hurricane Katrina, where I was the Network Operations Manager for T-Mobile, I directed the deployment of unlicensed Microwave Transceivers to bypass AT&T T` lines as AT&T switches were buried under six to fifteen feet of water. This allowed T-Mobile to 90% restoral their Louisiana and Part of Mississippi Cellular Service within 30 days of Katrina hitting New Orleans. One thing to note is that we used a Vacuum Pump connected to Desiccant Dehydrator to keep the moisture out. And when the desiccant began to fade, we would seal off the Dehydrator by closing a valve and replace with fresher desiccant. I would then take to wet desiccant home and bake in the oven until it was dry and bluer again. Seal in a can until needed again. Unfortunately, I am now retired due to medical conditions but enjoy doing what I can with ARRL, ARES, Storm Spotting and our local Crescent City Amateur Radio Group (CCARG). Louie General Radiotelephone Operators License # PG-GB-01126 Ham Radio License KG5EFQ

[@markbolin6651]

Along time ago I was in the Air Force and worked on airborne radars. The frequencies that were being used were all in the gigahertz. All of our packages used waveguide that were square or rectangle. They were all pressurized. The inside of the waveguides were plated with precious metal, either yellow or white gold because of the velocity factor and conductivity of the gold. After we finished a repair, we were required to pressurize the system and perform a leak check to ensure that the system remained pressurized. To do this we carried a small bottle of “Leak Detector” which was essentially a bottle of water with some dish soap mixed in it. If it is sprayed on a fitting that is leaking air, bubbles would form to indicate the area of the leak. My experiences working on radar system has help a lot with understanding Ham Transceivers. But in Ham Radio we use much different test equipment. I never had to tune a microwave transmitter to the microwave dish... I guess the design engineers took care of all that before the Air Force bought the systems. Field modifications were never allowed. That’s one of the fun things in Ham Radio... experimentation!

[@rumsin300]

Very good information!! Thank you for putting this all together. Not many of us get to see this type of feed line everyday

[@wecontrolthevideo]

When TV was still analog, we ran a 50kW visual transmitter and a 5 kW aural transmitter, through a diplexer combiner, into 6 inch transmission line to the antenna. The transmission line was basically a 6 inch pipe with another smaller pipe suspended in the center and pressurized with nitrogen.

[@dougtaylor7724]

Have you seen the old video about a huge transmitter station in the UK about the WW2 time frame. It is a huge amount of copper pipe all done by hand in a swamp. Tower construction, line soldering, trench digging and the whole smear. Construction people today would laugh at the prospect of such a project. Those men were like, ok not a problem.

[@davidhuffman4013]

Thanks Eric for the great video. I had two jobs where I worked with wave-guide. One in marine radar where the common freq. was around 9-10 gig (X band) radar and less common 3 gig (S band) X band wave-guide is 3 cm rectangular and long runs were less common as most new radars would have the tx & rx in the base of the antenna. Usually 3 to 12 kw transmitters with the receivers using the same antenna with circulators and rf limiters to protect the receivers. All this in wave-guide and a rotating connector to connect to the antenna. I did install one long wave-guide radar on a government boat in the 1970's and that was the last one. The other Job was for an Oil company big in southern Calif, who had the "largest private phone system in the world" as I as told. We maintained their systems in 3 counties but the main work was just in one, I helped install a site on a new platform and maintained the sites on the others. Some were only a mile apart so the transmitters were 10 - 100 milliwatt with a 10db attinuator. to not overpower the receiver at the other end. the whole system was 100% redundant so any failure would not shut it down as some of the info being sent was the telemetry for the oil pipelines, they had to keep and accurate count of barrels in to out of the pipeline for leak detection.

[@JDDupuy]

I have 8 - 150 foot runs of 1 5/8 Cell Flex hardline to 3 towers. Then reduced down to 3/8 hardline to the antennas. I run an H-Frame with 4 antennas on 2/432/1296, 2 antennas on 222 and 902 and 2304 Ghz. Two Moon bounce antenna arrays for 2/432. This system has been in operation for 19 years now. I had a old ham friend who ran wave guide on 1296 and 2304 and 10 GHz. Its was something to see.

[@kb6dxn]

I use 1/2" hardline on 430 for satellite communications for the run to the antenna from the transmitter. I also use the 1/2" hardline to my 18HT high tower vertical too, it's a 100 foot run..

[@mikesimpson7748]

Radar waveguide is rectangular and the weather radar is transmitting at around 65 kilowatts.

[@utterden]

500Mw to a Watt for line of sight. I worked on high power troposcatter microwave in the US Army where we had 10Kw watt power amps. It had be much higher transmit power as on the receiving end we would typically see 500Mw of signal coming back down after the bounce back from the troposphere. This is over the curvature of the earth. Kinda blows the mind as this was a multi channel signal carrying a multiplexed 48 voice channel signal and we were able to put it all back together from that 500Mw received signal. John KI5ASO

[@nateo200]

White Alice always makes me smile. Have always wanted to play with one! Couldn't they do like 10-20Mbps broadband like Internet?!

[@FStewartIII]

I worked at a radio shop years ago and when we would get trained on installing those large connectors we had a connector that had a trainer model exactly like the real one to practice with.

[@mikemcdonald5147]

uses 7/8 inch Andrews hardline for vhf uhf on my 72 foot tower with n connectors. Probably overkill but it works LOL :)

[@villiersman951]

yeh ive been using 7/8 and 1/2 on vhf and uhf for years as you say overkill but gee it works

[@Skullfocher]

Why not DIN connectors?

[@nateo200]

I wish remote radio heads were more common in amateur radio! Cellular sites have been using them a lot to get that UHF or even SHF signal out more. That way you aren't wasting power on the transmitter on the ground, rather, you put it as close to the antenna as you can up top.

[@Skullfocher]

^ Exactly what he said!

[@timothystockman7533]

The first transmission line looks like it might be foam dielectric Heliax made by Andrew. When I set up a 950 MHz studio-transmitter link system for a local FM broadcast station, I used 100 ft of 7/8 foam Heliax at the studio end and 160 ft 1/2 inch foam Heliax at the transmitter site. The main transmission line at the transmitter was 1 5/8 air dielectric Heliax. At my amateur station, I'm using a 9913 equivalent cable for VHF/UHF and DXE-400MAX (LMR 400 equivalent) for HF. For the comparatively short runs at my QTH, these feed lines are close to lossless when properly matched.

[@samgrieg]

Very interesting. Thanks for making this video. Excellent material.

[@W1RMD]

I can remember going down the Merrit Parkway when I grew up in Connecticut to see my grandparents and passing what was then "Times Fiber' later to have an "Amphenol" sign on their building. After becoming a ham, it's cool to see that this is what they made. I must say the quality of Ct. made goods rival the Germans in precision . Winchester, Colt, Pratt and Whitney, Sikorsky, about ten different clock companies, the ARRL just to name a few cool places.

[@jimlanigan7298]

Excellent video Eric. The best one I’ve seen.

[@rcambrj]

"Let's see if this will focus... yep, there it is" Do you even have eyes?

[@rkaag99]

That 1.25" line could be a mast! lmao

[@patrickbaer3742]

Cool beans man that is one badass section of coax or transmission line thumbs up

[@tubalcain1]

I have tons of these waveguide connectors... they make great shelf brackets and parts for steam punk projects!!!

[@TheHamNinja]

Great vid. You mentioned that you did an episode on how COAX works etc. Can you link to those. Thanks & 73, N1CLC

[@DeltaWhiskeyBravo13579]

That's awesome stuff Eric.

[@kylesnavely6165]

Very awesome!

[@Perspectologist]

Very interesting. Thanks for sharing this with us.

[@buzzsah]

I ran 100ft of 7/8HL on my 2m repeater back in the early 80's it did have a solid center, and it did cost an arm/leg as did the connectors. I transferred ownership 5 years later and it was still running great. lol.

[@catalinalb1722]

Could you please do a video about microwave guides? I use to work in the GSM industry. Would like to know more about the link between the tower sites

[@chucksayers1248]

thanks Eric I learned a couple things today so it's good. keep up the good work

[@lenperkins5724]

Enjoy your enthusiasm

[@donaldsmith3048]

I have seen the cable, if that is what you want to call it, that is 8 inch copper pipe with about a about 3 inch with spacers to keep it centered. It is used for TV stations output.

[@coreyn0st159]

Thanks for sharing that . I found it very interesting.

[@Heathfx5]

Would a pinched waveguide reflect the power back at the transmitter and burn it out or would it try to burn the pinched section?

[@donh5794]

Very interesting and educational topic and lesson. Do the ridges in the elliptical waveguide help move the frequency through the waveguide? Any situations where it would be smooth on the inside?

[@radiosification]

Very interesting, thanks for sharing your knowledge

[@bruehlt]

I bought some 3/4" Heliax (Commscope brand) for my 2M/70cm coax run. Antennafarm has great prices for this stuff. You can order it with whatever connectors you want on it (better for me since I don't need to spend a ton of money on Heliax crimpers). I spent about $150 on a 100 foot run - but for sake of putting out as much power to my antenna as I can it works fantastically! Plus I'm future proofing my shack for when the IC-9700 comes out :)

[@kenrangen]

Good video. I actually learned something new.

[@donaldsmith3048]

The wave guide is about 1/2 wavelength to get one to work on 40 meters it would not be easy to work with something 1/2 wavelength wide.

[@Skullfocher]

Why would anyone in their right mind use waveguide on 40 meters? 7/8" heliax only has 0.19dB loss at 7.299 MHz for a 200' run and 99.9% of amateurs will most likely never need a 200 foot run. Besides, the size of waveguide you'd need for 40 meters is completely ludicrous, if not straight up impossible.

[@MET90LX]

You were talking about CB radio... lots of big power stations using heliax

[@northbetrue]

I’m looking at my RG8 after watching this video and it looks like a strand of hair!

[@robertklinger2000]

Always informative!

[@DBruno]

What about using 75 Ohm coax? I work for a cable provider and have access to anything from rg-6 Quad shield to 1" hardline.

[@MrRepeater]

All Star! Great video

[@mktwatcher]

The antenna is never in the shed ! The Antenna / RF Radiator is always up in the air especially for commercial applications. If anything the continual shrinking of hardward has seen the transfer of the transceivers somewhere up the tower and the RF Signals are processed there and taken down the tower as data via ethernet or optical. AC power is taken up the tower to the hardware.

[@antidecepticon]

i think the inner conductor is using the insulation and a capacitance push this gives the ability to shove current like a rod long distances. The Ridges are so you can bend the pipe.

[@AlexandreJasmin]

I don't know the first thing about these microwave transmitters. But since the power is not that high, can't we put the transmitter in the tower directly and dispense with the expensive waveguide?

[@swashington942]

What is recommended for attaching the hardline to the tower? I (stupidly) used big zip ties and now my line is hanging loosely only being held up by the connector.

[@LegacyLost]

Did u go to cocoa off 520?was asked to go help yesterday but was too windy for my liking

[@jamesratay4141]

That is very interesting. Thanks for the infomation. Really cool. Wish we had .01db cable... lol

[@jamesratay4141]

Man, that microwave line wave guide is interesting.

[@w8lvradio]

What are the ridges for? Could you as a ham fabricate something similar with some pipe and insulation for a long run?

[@chriswynn5910]

The ridges are just congregation that helps the line bend without kinking. Similar to corrugated gas line for a gas grill or logs.....

[@nateo200]

Our local 6 meter repeater is on an old Channel 4 low band VHF Batwing array TV Antenna fed with this stuff. It REALLY get's out there. KD2SL 6m repeater, look it up! I believe Kevin only puts about 75watts into the thing. I can pick up that repeater with a damn paper clip and 1watt! LOL. It goes all over the place even when Sporadic-E isn't that great.

[@Gravelbomber]

I've been using 1/2" LDF4 Heliax for years. My buddy runs a company that builds and maintains commercial towers, and he hooks me up with whatever I want. He had 6 spools of 1 5/8" that he wanted to sell, but couldn't find anyone that wanted it. He ended up scrapping it for copper. He got $2/foot and scrapped over 6000 ft!

[@sergiocavazos8963]

tks! learned a lot

[@cobrasvt347]

This is a good vid 👍

[@brontoab1]

Good vid!

[@izzzzzz6]

I run 9ft of this 1" 1/4 straight out the back of the radio and directly to the feed-point. I don't need a mast as the coax works like a mast.

[@FStewartIII]

We had an accidental overage on an order of 1/2 hardline just under 250 feet. I was able to purchase that roll for pennies compared to the actual cost. I believe I paid $100. I never used it and stored it for years and moved it with me the 4 times I moved. I eventually donated it to another ham for his tower. I knew the value of it at the time, but never thought to sell it, or use it for the short runs I had in my radio shack.

[@stargazer7644]

Hams operate microwave too. Some run up to 240 GHz. 122 GHz is not unusual. 10 GHz is the most popular band in the ham microwave world. 1, 2, 3, 5, 10, 24, 48 GHz and others are all used. You could run waveguide at HF, but it would be big enough for your house to fit inside. Not all microwave is point to point. You can have omni antennas at microwave, which are often used on beacons.

[@catalinalb1722]

My former colleagues used to burn the leftovers and sell it as pure copper. I would have buid a nice magloop out of it. Didn't know back then much about amateur radio.

[@johnadams9558]

Not sure why it’s called microwave when the wavelength is not micro at all! If my math is correct the 2.4ghz a microwave oven uses is 120ish mm. I think a 1 micrometer wavelength translates to almost 300 terahertz....right?

[@antidecepticon]

So Basically you are saying wave guide is designed to be resonant with the freq of the signal feed. It is designed to ring like a bell. The window i believe is made of cellophane

[@Skullfocher]

I'm actually in the process of replacing my soft coax with LDF4-50A for VHF and AVA5-50 for HF and UHF. Why the big stuff for HF? Because 7/8" heliax has 0.09 dB loss at 29.6 MHz and less at lower frequencies and handles full legal power much better than LMR-400. I work a lot of weak signal DX, even on VHF/UHF, Satellite, and EME. Minimal loss in an absolute must! As for microwave, direct transceiver/transverter mount to feed horn is necessary at 10ghz+ and instead of coax, you run CAT-6 data for PTT/Audio. Waveguide if used should be kept to a minimum, like PA to Feed horn which should only be a few inches.

[@jhettish]

Not bad. I would suggest that you take your razor knife and cut the heat shrink off the type-N connector then get a couple of wrenches and remove the connector. Then remove the center pin. Much of the cable these days requires special tools but that has not always been the case. Many connectors, exactly like the one you showed on the 7/8 can be put on and taken off using regular (if not large) common tools. The O-Rings might get damaged but often are reusable. With foam coax (not gas type) the o-ring is there to keep water out. Of course we use electrical tape to protect the connector, mastic to keep the rain water out, and additional wraps of electrical (vinyl) to protect the mastic from sunlight. If you are interested in what I suggested you might like the final result from what you've learned. You can see all sorts of broadcast and LMR tower work on my channel, kzbin.info You've given me the idea of doing another video concerning broadcast "rigid" coax, 1 5/8 and up. There is a lot of video of us replacing 3 inch and 4 inch rigid. Another simple thing. You may be familiar with RG-58 (1/4") coax. It's used in mobile installations these days mostly. The ratio of the braid to the center conductor is determined by a formula. The ratio of 4" coax to it's inside connector is governed by the same formula, both matching 50 ohms. I have 48 years in the two way radio business and a similar amount of tower time. Haven't climbed higher than 770 since January 5, 2021. Nice day with 30 degree wind chill. As old as I am it's time I stopped doing that. :-)

[@medaharmoud8594]

The window called pressure window.

[@zuckertube]

You have two outside skins there

[@antidecepticon]

if you want to know who makes any cable 99% its on the side. This is great if you bought a nice cable at 50' but want to make many, you can source the cable and put your won ends on.

[@ggem8125]

FYI all this radio equipment at broadcast facilities is or has been scrapped for the metals. IP has completely replaced radio in my business. Stations save on all the roof leases for antenna and they don’t need a radio specialist on the payroll for maintenance. Point to point radio is over in broadcast even the microwave 2ghz live shot is over bonded cellular has replaced it. No more traditional news van with microwave mast and antenna, just waiting for the vans to wear out. It is amazing how technology can render years of knowledge useless.

[@beachstreet5970]

So when there is a major earthquake and all the cell services are offline, are you still maintaining some backup systems?

[@dougtaylor7724]

You know why they call it hardline? It’s not about the line, it is what happens to a ham when you talk about huge coax and extremely low loss. Well, that’s me anyway. 👍

[@HamRadioConcepts]

Lol

[@Genii69]

I hate when my signal gets kinked, lol... :)

[@quadrant2005]

HELIAX Hardline

[@ggem8125]

All you need to know is how to set up an IP address

[@casanova419]

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