HF Repeaters

[ladn]

I was pondering radio topics while consuming Mongolian Beef at lunch this afternoon and the rather arcane topic of HF repeaters came to mind. Ten meter (still, technically HF) FM repeaters exist at the upper end of the band. I know there are various ways (remote base, IRLP, Echolink, Allstar, etc.) of bridging/linking different bands and systems, but I've never heard about any SSB or AM repeaters in the amateur HF bands.

I can think of a number of reasons why this isn't practical, but lack of practicality used to be considered a challenge for hams. Maybe not so much today among "appliance operator" level licensees, but still potentially interesting conversation fodder.

 

[buddrousa]

Duplexers that are made out of 55-gallon barrels

 

[dlwtrunked]

Decades ago, the FCC direction finding network used an (poorly)encrypted Baudot FSK RTTY system where the repeater site used several frequencies to transmit out at the same time. The bit-inverting encryption key changed daily by a predictable pattern and for under $1 in parts, I was able to regularly watch it. That system long ago disappeared.

 

[prcguy]

I do HF repeat occasionally using three remote control Icom 7100s, one in So Cal and the other near Dallas, TX and another north of Boston, MA. I have all the control heads to the remote radios in one location and have a special repeat cable that plugs between two control heads and completes the repeater function.

When I get a few people on both sides of the country on HF to agree to a repeat function I'll enable it and usually on 10m SSB. Then we announce the repeat function is active and people who hear it start chatting across the country when there is no skip conditions. I believe its legal but who really knows. But it sure is fun. I've also enabled it on 146.52 simplex on both ends and have confused a few on why they can talk "simplex" from Dallas to Los Angels on 2m.

 

[ka3jjz]

There are also 10m FM repeaters, and even SSTV repeaters on 10 as well

Mike

 

[prcguy]

A repeater is usually at one location and serves a particular area except when skip conditions are in. I call my repeater thing a "worm hole" since its spread out across the US.

There are also 10m FM repeaters, and even SSTV repeaters on 10 as well

Mike

 

[Lauri-CoyoteFrostbite]

A wonderful topic!

Enuff so I texted my father about it ... he has been a ham since 1963, his father (my grandfather was a 'ham' since the retreating of the last glacier of the pleistocene epoch)--he and my father were "there" during the rise of the repeaters in the 1960's. (My grandfather was a friend of the man who we regard as the "father of repeaters"-- Wayne Green, W2NSD-- publisher of 73 Magazine.)

If my father wakes up his nap I am sure he will text me full of interesting historical repeater stuff .


Whats the term?...."Stay tuned ?"

Lauri



.

 

[RFI-EMI-GUY]

Many of the International HF broadcast stations use "Relay stations" to accomplish global coverage.

 

[RFI-EMI-GUY]

Then, there is this if you can print your own money.

High Frequency Global Communications System - Wikipedia

en.wikipedia.org

Joint Chiefs of Staff HFGCS Network - Update

There is a lot of old frequency and callsign lists that float around the internet. One of these old lists involves a U.S. HF military netwo...

mt-milcom.blogspot.com

 

[prcguy]

If your father or grandfather were in So Cal they would have probably used the first known amateur repeater K6MYK which was 2M AM and built from WWII surplus aircraft radios. It first went on the air in 1956. This first repeater K6MYK currently lives on as W6MEP on Mt Wilson in So Cal and is owned by a good friend of its original owner who was Art Gentry, a famous LA broadcaster and uses his old callsign. A version of this repeater has been on the air continuously since 1956.

Parts of the current W6MEP repeater were built by its present owner in the early 1960s and are still on the air today. Just last week this repeater moved from a compromised location on Mt Wilson to a different building and the antenna is now at the top of a 175ft tower and clears the highest part of the mountain. The current owner is a delightful man 81yrs young and seems to have more energy than I've ever had.

If you look at the picture in the upper right of this link, thats the current owner Burt standing next to the repeater. The big box in the rack with a meter and lots of knobs is the portion that was built in the early 60s. Part of the audio chain of this repeater is an Orban Optimod FM broadcast audio processor, which is an unlikely piece of equipment to see in a radio repeater, but it provides really good repeat audio.

I've been working with the repeater owner and have a nice Motorola Quantar to hopefully replace the aging repeater in the near future.

W6MEP Callsign Page

W6MEP personal biography

www.qrz.com

A wonderful topic!

Enuff so I texted my father about it ... he has been a ham since 1963, his father (my grandfather was a 'ham' since the retreating of the last glacier of the pleistocene epoch)--he and my father were "there" during the rise of the repeaters in the 1960's. (My grandfather was a friend of the man who we regard as the "father of repeaters"-- Wayne Green, W2NSD-- publisher of 73 Magazine.)

If my father wakes up his nap I am sure he will text me full of interesting historical repeater stuff .


Whats the term?...."Stay tuned ?"

Lauri

View attachment 124327

.

 

[mass-man]

A wonderful topic!

Enuff so I texted my father about it ... he has been a ham since 1963, his father (my grandfather was a 'ham' since the retreating of the last glacier of the pleistocene epoch)--he and my father were "there" during the rise of the repeaters in the 1960's. (My grandfather was a friend of the man who we regard as the "father of repeaters"-- Wayne Green, W2NSD-- publisher of 73 Magazine.)

If my father wakes up his nap I am sure he will text me full of interesting historical repeater stuff .


Whats the term?...."Stay tuned ?"

Lauri

View attachment 124327
NH
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Ah Wayne-O...he flew me to the offices of 73 decades ago to talk of producing videos for ham radio. We had done the same thing, albeit briefly for CQ, 4 shows I think, and they dropped the idea. It was a fascinating trip and evening talking with he and Sherry! Oh I how I wish it had worked out...

 

[trentbob]

I was pondering radio topics while consuming Mongolian Beef at lunch this afternoon and the rather arcane topic of HF repeaters came to mind. Ten meter (still, technically HF) FM repeaters exist at the upper end of the band. I know there are various ways (remote base, IRLP, Echolink, Allstar, etc.) of bridging/linking different bands and systems, but I've never heard about any SSB or AM repeaters in the amateur HF bands.

I can think of a number of reasons why this isn't practical, but lack of practicality used to be considered a challenge for hams. Maybe not so much today among "appliance operator" level licensees, but still potentially interesting conversation fodder.

Good fodder for conversation indeed Rodger. And you got Lauri's attention, it's been a while.

 

[AK9R]

Duplexers that are made out of 55-gallon barrels

That's why you build your repeater as a split site system. Transmitter in one location, receiver a few miles away. Link them using a UHF frequency, microwave, Internet, tin cans and string, etc.

 

[k7ng]

Awww... I was just imagining tuning a 6-cavity HF duplexer (the 55-gal drums would have to be welded 2-high for each cavity, I think). Would have made a great YouTube video.

 

[jhooten]

For a 160 repeater duplexer what, old grain silos?

 

[prcguy]

You don't necessarily need full size 1/4 wave cavity filters to make a duplexer. A friend of mine had a famous CB repeater in the 80s and he used home made multiple section helical filters that were smaller than a shoe box. At one time this repeater ran about 300 watts and worked well.

 

[ladn]

Thanks, all for you comments. I thought this would make a fun summertime discussion.

In terms of (amateur radio) practicality, the split site model is probably the most practical, as @prcguy and @AK9R suggested . It eliminates the oil drum-sized "cans" and linking can be accomplished in a number of ways.

It would still interesting, in an antiquarian sort of way, to see a traditional repeater on 40, 20 or even 60 meters, big cans and all!

 

[Lauri-CoyoteFrostbite]

"............they would have probably used the first known amateur repeater K6MYK which was 2M AM and built............" prcguy



Awesome !! ---Where to start ?....

This morning I got a call from my dad who has lately turned into a morning person and who doesn't seem to care that there is a two hour time difference between us (he's on east coast.) I am worthless at 5.30 AM. But that aside, I took some drowsy mental notes, with his promise of more historical pearls later (and at a better hour.)

The AM repeater was one of his gems mentioned and I am pleased to see it here.

My grandfather and his friends were quite aware of how niffty VHF repeaters were as far back as hams were aware of VHF. He told of listening to police calls on the high end of the AM broadcast band that were repeating traffic from the squad cars transmitting on low band VHF. The headquarter's station was high powered, approximately on 1700KHz .... an AM station that broadcasted to the cars..... they would responded on low power VHF. No details on the equipment but what ever it was it sparked ideas.

Mobile FM equipment was available in the 1960's-- which is the time frame for my grandfather's VHF experiments-- but it was prohibitively expensive. It would not be until the FCC required VHF system to go "narrow band" that there would be a phethora of surplus FM radios to spark a radio revolution--- but a lot more on that to come later.

Back to the AM repeaters.

One of the things necessary for repeaters is to have something to repeat. There were plenty of Technician class licensee's-- Six Metre AM was a very hot band back in those days... a fertile ground to experiment upon.

Drawing on the experiences of listening to those police radios, my grandfather and friends set up a simple AM repeater system. He built the repeater- which basically was a modified CB transceiver as the IF --using a TV tuner tuned to some frequency in the low 50MHz range. Using a "nuvistor" (Remember those cute little metallic tubes - 6CW4's, 6SD4's? They were the hottest things until V/UHF transistors) --preamp made it a 'hot' receiver (or so I am told.... but Hey ! this was 1960's standards, in the days of true home brewing.)
The CB radio had a squelch and its audio fed a a low power AM transmitter operating in the high end of 53MHz. What made this interesting was they squelched the audio, but not the carrier. It was left on continuously. In the days before crystal control that allowed even regenerative receivers to find the repeater and stay "tuned in" - and it provide a beacon of sorts to adjust your equipment to (no mention of Channel 2 TVI however--- ignored ?).

The repeater used separate antennas and some sort filtering to keep the 53MHz out of the receiver. Supposedly the low power and frequency separation was not a big de-sensing issue.
____________________________________________________________

These hams played with the system for "awhile" according to my father; This was in the Washington DC area-- he said they covered a "several mile radius of Andrews Air Force Base/ Camp Springs/ Clinton area."

But other than a novelty this repeater went nowhere---- and now is just part of my family's ham history. It wouldn't be until the FM Sweep later on, that serious VHF repeaters would take off.


.



Lauri

.

 

[prcguy]

Very nice story, thanks!

The very first 2M AM repeater built by Art Gentry shown in my link above still exists and I've been begging the owner to refurbish it and put it on the air at least temporarily. It might be worth contacting the ARRL and make it some historical event. But the owner says its in real bad shape and would require way too much time and labor to pull that off. I'll bug him again about it and see if a crew could be assembled to do the work.

Some things like this and your grandfathers repeater should live on somewhere so the young'uns can see how things were done back then.

"............they would have probably used the first known amateur repeater K6MYK which was 2M AM and built............" prcguy



Awesome !! ---Where to start ?....

This morning I got a call from my dad who has lately turned into a morning person and who doesn't seem to care that there is a two hour time difference between us (he's on east coast.) I am worthless at 5.30 AM. But that aside, I took some drowsy mental notes, with his promise of more historical pearls later (and at a better hour.)

The AM repeater was one of his gems mentioned and I am pleased to see it here.

My grandfather and his friends were quite aware of how niffty VHF repeaters were as far back as hams were aware of VHF. He told of listening to police calls on the high end of the AM broadcast band that were repeating traffic from the squad cars transmitting on low band VHF. The headquarter's station was high powered, approximately on 1700KHz .... an AM station that broadcasted to the cars..... they would responded on low power VHF. No details on the equipment but what ever it was it sparked ideas.

Mobile FM equipment was available in the 1960's-- which is the time frame for my grandfather's VHF experiments-- but it was prohibitively expensive. It would not be until the FCC required VHF system to go "narrow band" that there would be a phethora of surplus FM radios to spark a radio revolution--- but a lot more on that to come later.

Back to the AM repeaters.

One of the things necessary for repeaters is to have something to repeat. There were plenty of Technician class licensee's-- Six Metre AM was a very hot band back in those days... a fertile ground to experiment upon.

Drawing on the experiences of listening to those police radios, my grandfather and friends set up a simple AM repeater system. He built the repeater- which basically was a modified CB transceiver as the IF --using a TV tuner tuned to some frequency in the low 50MHz range. Using a "nuvistor" (Remember those cute little metallic tubes - 6CW4's, 6SD4's? They were the hottest things until V/UHF transistors) --preamp made it a 'hot' receiver (or so I am told.... but Hey ! this was 1960's standards, in the days of true home brewing.)
The CB radio had a squelch and its audio fed a a low power AM transmitter operating in the high end of 53MHz. What made this interesting was they squelched the audio, but not the carrier. It was left on continuously. In the days before crystal control that allowed even regenerative receivers to find the repeater and stay "tuned in" - and it provide a beacon of sorts to adjust your equipment to (no mention of Channel 2 TVI however--- ignored ?).

The repeater used separate antennas and some sort filtering to keep the 53MHz out of the receiver. Supposedly the low power and frequency separation was not a big de-sensing issue.
____________________________________________________________

These hams played with the system for "awhile" according to my father; This was in the Washington DC area-- he said they covered a "several mile radius of Andrews Air Force Base/ Camp Springs/ Clinton area."

But other than a novelty this repeater went nowhere---- and now is just part of my family's ham history. It wouldn't be until the FM Sweep later on, that serious VHF repeaters would take off.


.
View attachment 124353


Lauri

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[jwt873]

Repeaters use carrier operated switching to turn the repeat function off and on.. The presense of a carrier turns the repeat function on.

With no carrier, single sideband is difficult to 'repeat'. The linear SSB amateur satellites use crossband transponders. Transponders blindly up-convert or down-convert one frequency to another. Using crossbanding eliminates the need for extensive filtering. Linear Satellite Frequency Summary – AMSAT

This could work on HF.. Go in on 20 meters and get transverted out on 40.. (And vice-versa). But what would be the point? HF by its very nature is capable of covering long distances without the need of a repeater. Just use the frequency that provides the best propagation for the job at hand.