Any idead how far a 10 watt lsb radio would tx ?

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Satelite
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Joined: Sat Aug 12, 2006 10:43 am

Any idead how far a 10 watt lsb radio would tx ?

Post by Satelite »

Hello:
Several years back while on a canadian hunt I saw a radio that had really intriqued me and always thought bout its capabilities.
We were dropped into camp by a bush pilot and camp quide was one person for the week.
During that week the quide was many times out helping retrieve .
During hisabsence several times during the week a radio signal would be called into camp from im assuming base checking in to see if things wereok and if anything needed picked up or dropped off by float plane.
Anyway I responded with the notes found on the radio camp quide wanted ect.
Ive always wondered how far that signal might have come and how far I was possibly talking in miles.
It was pretty much open flat country with a bare copper wire strung between 2 poles id estimate 25ft tall and obviously above ground obstructions that the tx wire connected in the center of the wire with a balum as I recall now.
Coax wasn't 1/2 inch heliax but looked a bit better quality than cb rg8 1/2 inch coax as I recall.
The radio was a 10 watt lower side band at 4529 khz .
I do recall needing to adjust the clarifier on side band to hear the other better and reallydid sound fairly good for a sideband whiny reception.
Without all the hype on skip or enhanced atompherics conditions what would the aprox tranmit range be for day and is it same for night without storms ?
Thank you
Satelite
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Astro Spectra
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Re: Any idead how far a 10 watt lsb radio would tx ?

Post by Astro Spectra »

I have talked over 500 miles on similar equipment and frequencies with the antenna (a wire half wave dipole) just stretched over bushes 6' above ground. 4MHz is good usually late evenings.
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Astro Spectra
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Re: Any idead how far a 10 watt lsb radio would tx ?

Post by Astro Spectra »

I have talked over 500 miles on similar equipment and frequencies with the antenna (a wire half wave dipole) just stretched over bushes 6' above ground. 4MHz is good usually late evenings.

Day time might be just 100 miles depending on ionosphere conditions. Coax at that frequency doesn't matter much and with a good base at a low noise site a 1W HF packset can do much the same. This stuff is regularly used by wildernesses SAR teams.
Karl NVW
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Joined: Wed Sep 03, 2003 7:13 am

Re: Any idead how far a 10 watt lsb radio would tx ?

Post by Karl NVW »

My first question would be "Where do you plan to use this equipment?" both from a geographic and a spectrum perspective. Not all countries permit that type of communications or have HF channels speciallly reserved for such usage. Range also depends on the equipment at the other end - talking to your pickup aircraft flying at 5,000 feet is much easier than talking over a 5,000 ft mountain to a base camp on the other side.
Karl - WA8NVW AFA5VB
SHARES + NCS
Satelite
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Joined: Sat Aug 12, 2006 10:43 am

Re: Any idead how far a 10 watt lsb radio would tx ?

Post by Satelite »

Hello Karl NVW
Answer to your first question : I don't plan on using this type of equipment geographicly or in any spectrum. ( Couriousity interest only)
Response to not all countries allow this freq = Yes that was also one thing mentioned way back in camp that it was intended for northern Canadian quide use and wasn't likely legal in the usa.
I am now anyway wasn't way years back then a ham operator but id assume without looking that usa hams have a similar spectrum that usa can use but as a tech license only I seriously doubt id have legal access. ( Eric KC0SZS )
Yes true I agree and was aware the opposite radios specs as in how high and db gain wattage ect would affect the total tx distance.
But unfortunately at 5 ft 8 inches I wasn't able to see the other radio at base coms so didn't have that info to add. :-) (You can kick my butt for that smart a$$ comment = Just funning with ya )
I really never saw the need to have that kind of range as I do own my own repeater that transmits aprox 35 miles on biz band and covers my coms needs nicely just always thought it was a neat radio and always wondered at that low freq what it might do for tx range on average.
I did take a picture of that radio back then and it was a cute orange in color radio that was lower side band at 10 watts 4channels and used 9 c batteries I found out later.
In picture I can make out info : Tag placed on radio- Comunications Electronics / Radio itself said = Spillsbury comm. systems Model SBX-11A
I ran across that pic again and it peaked my wonderings of its capabilities again so posted.
During a google search I was surprised to see a few for sale where others had purchased one or two and that the radio was able to do 1 to 10 khz freqs with a color coded component if one of 4 different freq ranges in the 1 to 10 khz area.
Even looked like you might have been able to install one of each in the 4 ch radio and tune to one freq each if for some reason you wanted one freq in each 4 segments of 1 to 10 khz.
Couriousity kills the cat they say.
Luckily im not a cat :-)
Satelite
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Astro Spectra
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Re: Any idead how far a 10 watt lsb radio would tx ?

Post by Astro Spectra »

One Spilsbury SBX-11A in orange:
Image
Also available in green. These were often used in Antarctica by field parties with the antenna just laid out on the ice.
Made in Canada, eh.

And the brochure:
Image

Here a little SAR radio from my collection dating from the seventies:

Image
1W Australian made AM portable fitted with international SAR channels of 3023 and 5680 kHz (note AM is not used on these frequencies today)

This is what I use:
Image
This is a Australian made Codan 6924 Mk II 20W SSB with a CCIR selcall mod (the thumbwheels) for phone calls. This doesn't show the outer case of the radio as I took the picture after fitting the selcall board. This radio is USB only (despite the switch) and is fitted with various commercial channels between 2 and 6 MHz for back country SAR use.

Here a web site for a mountain radio service in New Zealand that uses portable 5W HF SSB radios for serious hikers:
http://www.mountainradio.co.nz/
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