• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
  • Click here to find out how to win free radios from Retevis!

What is this mod? Stryker 955

The most surprising thing to me is that this feels like something new to so many people. That is likely due to the fact many have become accustomed to completely disabling the AMC limiter in radios. This circuit not only prevents distortion on word peaks but it's also a very effective way to hold PEP output, within a well defined limit. That feature alone can be invaluable when trying to set a rig to properly drive a linear amplifier. The same holds true for ALC on HF rigs and SSB use.

If you don't like the setting or range of the existing circuit, consider adding resistance to the "trigger" or sensing diode in order to increase range, long before you just hack the circuit out of line.
And unfortunately drail is pumping these out to people who arent going to use them as a ghost watt producing bench test unit. These will be used by brainless idiots on the air. Another reason to get my ticket. Next month...
 
  • Like
Reactions: freecell and NZ8N
I didn't put much thought into the fact this was a test bench radio. Being able to limit PEP power could prevent many transistor failures, where other amplifier protection is not available.
 
  • Like
Reactions: Tokin
I probably shouldn't mention this but in an effort to get more people to at least use some level of audio limiting, I'll explain a way to "satisfy" the customer, while only giving them half of the distortion created by a complete AMC bypass...

The most common complaint from the customers I use to see was that with the AMC intact, the radio simply could not swing to the same level as it did without it. They just could not be convinced to give up the stronger positive peaks associated with over-modulation.

The distortion this creates is twice as bad if you can't at least "overdrive" the RF stage, with a clean AF signal! Without some feedback loop to control the gain of the mic pre-amp, you will often have cases where every single stage is driven into distortion from the mic amp, to the final RF output. When AMC is active, it fixes that problem but will not reach full PEP output on AM at a reduced carrier.

If your customer demands the full PEP be retained at reduced carrier, change the location that the AMC detector diode senses distortion, from the RF output section, to the AF output section. Now, all AF stages can be held just below the level of distortion, regardless of where the RF carrier is set.

This does not prevent over-modulation but it does eliminate all distortion created in the audio stages, prior to the RF stage. The reduction in distortion this makes is noticeable even when driven into extreme over-modulation. This is especially true if you have audio with a lot of bass, since these are the frequencies that tend to distort the AF stages first.

This type of modification, obviously defeats the ability of the AMC circuit, to limit PEP output but, it's much better than defeating the entire AMC circuit.
 
Last edited:
I didn't put much thought into the fact this was a test bench radio. Being able to limit PEP power could prevent many transistor failures, where other amplifier protection is not available.
Heres 1 of 2 more. I see the Hispanics around Tampa running these 955's and other high power exports and they're very dirty radios the way theyre being tuned.


 
Heres 1 of 2 more. I see the Hispanics around Tampa running these 955's and other high power exports and they're very dirty radios the way theyre being tuned.



Hack the garbage wack pack "High Power" option, out of the radio and much of that dirt is probably absent in the stock radio chassis.
 
Drail also has a "variable bird" mod that is just an NPC mod with the value of the resistance in the "NPC" circuit (a diode and resistor) variable. Of course mucking with how much avg/rms swing vs. peak swing with an NPC changes the audio frequency response of the transmit audio - so I don't know why this would be desirable. Seems to me if you wanted to use NPC you'd pick a fixed resistor value that provided reasonable peak/avg power & audio frequency response and stick with it. Maybe to let people tweak the compression ratio of the NPC based on what kind of PA stage(s) they are using. I've heard a "fully built" 955 from Drail costs about 800+$ and he's supposedly got a 1 year waiting list, so apparently people dig it.

I will say the hifi mods he does to the 955 coupled with the right audio going into them sound pretty amazing though. I heard a gate (youtube video) of one the other day where the guy was only running an e-bay special / Ukrainaian EQ/Compressor with a Shure SM7b driving it and it sounded great. Not many people are willing to change out as many tiny surface mount parts as he does to get them "hifi" on the rx and tx. For that kind of money though, just save a few more bucks and buy a previous gen Apache Labs Anan or something, unless you needed a CB platform for mobile.
 
Last edited:
Drail also has a "variable bird" mod that is just an NPC mod with the value of the resistance in the "NPC" circuit (a diode and resistor) variable. Of course mucking with how much avg/rms swing vs. peak swing with an NPC changes the audio frequency response of the transmit audio - so I don't know why this would be desirable. Seems to me if you wanted to use NPC you'd pick a fixed resistor value that provided reasonable peak/avg power & audio frequency response and stick with it. Maybe to let people tweak the compression ratio of the NPC based on what kind of PA stage(s) they are using. I've heard a "fully built" 955 from Drail costs about 800+$ and he's supposedly got a 1 year waiting list, so apparently people dig it.

I will say the hifi mods he does to the 955 coupled with the right audio going into them sound pretty amazing though. I heard a gate (youtube video) of one the other day where the guy was only running an e-bay special / Ukrainaian EQ/Compressor with a Shure SM7b driving it and it sounded great. Not many people are willing to change out as many tiny surface mount parts as he does to get them "hifi" on the rx and tx. For that kind of money though, just save a few more bucks and buy a previous gen Apache Labs Anan or something, unless you needed a CB platform for mobile.
I run the same compressor on a cobra 29 with a mosfet mod and a home modified dynamic low z d104 ug8 base and i bet my station sounds just as good. It's the eq/compressor that makes it sound so crisp. I get those reports all day long since i hooked that ur6qw unit up. 1598744133405333710408790649508.jpg
 
Cool, Tokin. Thanks for sharing. I've heard people rave about those little EQ/Compressor units. Do you have any cap mods to widen the TX up a bit on your 29 or running it stock audio bandwidth?
 
  • Like
Reactions: Tokin and Slowmover
Cool, Tokin. Thanks for sharing. I've heard people rave about those little EQ/Compressor units. Do you have any cap mods to widen the TX up a bit on your 29 or running it stock audio bandwidth?
I dont believe any tx mods have been done but its possible. Just the fet, variable and echo as far as i know.
 
  • Like
Reactions: FredTx63
You guys sure do talk a bunch of smack. D-Rail builds some of the best radios out there! Super loud and proud unlike some of you stuffy old ham guys who REFUSE to accept anything out of your comfort zone. You can bash this radio all you want, however it will out talk anything you have guaranteed! Tune into channel 6 one day when the skip is going and you'll hear how D-Rail sounds. People pay nearly a thousand bucks for some of his radios for a reason. You can either build bad ass radios like D-Rail or you can talk smack on your keyboard. BBI wouldn't have purchased one unless it was bad ass. He uses his D-Rail Stryker 955 to show high average watts when compared to his other radios. Not everyone who mods CB radios lives in a trailer or in a meth lab. Some of you are just idiots.
 
You guys sure do talk a bunch of smack. D-Rail builds some of the best radios out there! Super loud and proud unlike some of you stuffy old ham guys who REFUSE to accept anything out of your comfort zone. You can bash this radio all you want, however it will out talk anything you have guaranteed! Tune into channel 6 one day when the skip is going and you'll hear how D-Rail sounds. People pay nearly a thousand bucks for some of his radios for a reason. You can either build bad ass radios like D-Rail or you can talk smack on your keyboard. BBI wouldn't have purchased one unless it was bad ass. He uses his D-Rail Stryker 955 to show high average watts when compared to his other radios. Not everyone who mods CB radios lives in a trailer or in a meth lab. Some of you are just idiots.
If BBI bought one then it must be legit.:whistle:
 

dxChat
Help Users
  • No one is chatting at the moment.