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Has anyone been able to duplicate these results?
- Thread starter rabbiporkchop
- Start date
I guess due to the lack of response, but instantaneous 70 video views, that nobody else is capable? Either that, or everyone is enjoying their Memorial day weekend.
I guess I'll check back in a week or so.
I hope everyone enjoys the holiday weekend.
I guess I'll check back in a week or so.
I hope everyone enjoys the holiday weekend.
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Some radios lend themselves better than others when it comes to sensitivity both by design and quality of parts. In addition, while a radio is made to be extra sensitive to weak signals (getting to the ~ .1 uV range) - can be done - it also tends to get overload on the stronger signals. A trade off with no remedy, other than turning the RF Gain knob to accommodate.
As far as changing out with hotter receive transistors, using matched schottky diodes, and aligning the receive circuit, there are trade-offs as previously mentioned. Tends to have a higher noise floor - even when using low noise replacement parts. Overload vs sensitivity vs noise floor is why the standard method is used to align receivers when employing these mods. In fact, it was the first lesson I'd learned about doing a receiver alignment - tough lesson at that. Even seen factory out of the box radios go for sensitivity and overload on the strong signals. Something to avoid at all costs when aligning - IMO . . .
As far as changing out with hotter receive transistors, using matched schottky diodes, and aligning the receive circuit, there are trade-offs as previously mentioned. Tends to have a higher noise floor - even when using low noise replacement parts. Overload vs sensitivity vs noise floor is why the standard method is used to align receivers when employing these mods. In fact, it was the first lesson I'd learned about doing a receiver alignment - tough lesson at that. Even seen factory out of the box radios go for sensitivity and overload on the strong signals. Something to avoid at all costs when aligning - IMO . . .
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No overload problems with this tune.
Still hoping to find someone else that can master the technique whatever that might be.
Still hoping to find someone else that can master the technique whatever that might be.
Picking up a signal 135db down when connected directly to an RF generator doesn't prove a thing. If this guy really wanted to show how good his work is, he should hook up 2 of the same model radios (one stock, the other modded) to an antenna through a switch box and do an A/B comparison. If his stuff really works, it should pull in signals that the stocker can't hear. A real world demo is what I want to see. Notice his disclaimer at the end of the vid: "YOU WILL NEVER HEAR WHAT I SHOWED YOU" if you don't have QUALITY coax, solder joints, blah, blah blah.
- 399
- 399
RatsoW8
Supporting Member, W9WDX ARC Member - WD8T
unit 399 I had a hard time watching the video myself for all the blah blah blah in it, was not impressed at all. think he said it was a 50.00 mod also.
A good communications receiver will have a noise floor less than -125 dBm but the antenna noise is usually well above that level.
that goes on 10 meter as well.
The jitttery unprofessionally made video showed me nothing else as the claim of the maker.
On H.F. sensetivety isn't the holy grail, since atmospheric noises and antenna noise will be higher as what you could archieve in front end building.
2 meter or 70 cm's yes it has a reason to go for a good front end with low noise.
On H.F, 160 - 10 meters other demands are at play,
Here in Europe other situation arises.
The demands made on a short wave receiver when used in the western hemisphere, and particularly in Europe, are great indeed. Such a receiver has to be capable of resolving weak signals in a welter of almost unbelievably strong transmissions, and provide high sensitivity at the same time as high immunity to overload.
Most CB transceivers have the double conversion receiver which all don't differ that much from each other.
I wasn't impressed to be honest.
that goes on 10 meter as well.
The jitttery unprofessionally made video showed me nothing else as the claim of the maker.
On H.F. sensetivety isn't the holy grail, since atmospheric noises and antenna noise will be higher as what you could archieve in front end building.
2 meter or 70 cm's yes it has a reason to go for a good front end with low noise.
On H.F, 160 - 10 meters other demands are at play,
Here in Europe other situation arises.
The demands made on a short wave receiver when used in the western hemisphere, and particularly in Europe, are great indeed. Such a receiver has to be capable of resolving weak signals in a welter of almost unbelievably strong transmissions, and provide high sensitivity at the same time as high immunity to overload.
Most CB transceivers have the double conversion receiver which all don't differ that much from each other.
I wasn't impressed to be honest.
The fact that the person did those mods on an export radio is just a waste. At least do it on a CB radio.... you're taking a radio that is designed to operate from 28 to 29.7 mhz and modding it to perform in an area that's better than a full 1mhz BELOW its designed parameters (Channel 1 starts at 26.965). A CB radio has better sensitivity stock than a stock export radio has after modification into the CB band. That's in real world testing and comparisons that I have performed.
I've said for years that if you want best performance on the CB band, get a CB radio. They're designed to run in the CB band. Even if a person wants to run in the "freeband", such as 27.555, that's far closer to CB territory (150khz) than it is to 10M territory (750 khz, since 10M voice starts at 28.300). Again, a waste if you do all those mods on an export.
~Cheers~
I've said for years that if you want best performance on the CB band, get a CB radio. They're designed to run in the CB band. Even if a person wants to run in the "freeband", such as 27.555, that's far closer to CB territory (150khz) than it is to 10M territory (750 khz, since 10M voice starts at 28.300). Again, a waste if you do all those mods on an export.
~Cheers~
Which is exactly why tbe last thing you want is a preamp on th3 lower HF bands like 80m and 40m. They do no good due to atmospheric noise and can overload a receiver.
Has your "real world testing" Involved one of Marks radios?
I've also done "real world testing" and have yet to meet someone capable of hearing what I can hear without giving someone a 10,000 foot elevation advantage or the benefit of an 8 Element
Beam.
I use a SINAD program on a dedicated computer , an Hp sig/gen, and a o-scope to do RX alignments. Which is typical to use and the factory protocol. Nice to have some of the gear used in these vids; but necessary? Not really; doubtful one could tell the difference with the end product.
Want/need a better receive?
Use a better antenna with some real gain working for you.
SINAD = signal vs noise vs distortion.
http://comtekk.us/sinad.htm
Want/need a better receive?
Use a better antenna with some real gain working for you.
SINAD = signal vs noise vs distortion.
http://comtekk.us/sinad.htm
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