Rocketbox info thread !!! Made in the USA with a reasonable pricetag !

[WINKDOGG]

Hey Shockwave do you think that's as simple as say , "borrowing" the biasing circuit from an RM Italy or similar box ? Will the surface mount board make this extremely difficult (I imagine a tight fit regardless) And by simple I mean can someone draw me up a solder by numbers biasing circuit I can just replicate lol This is basically what I was talking about when I was saying Im sure some guys will put "their own spin" on the kits ! I never claim to be a tech but what you said makes perfect sense to me I just lack the skill to design the individual biasing circuits . Im willing to be the Guinea Pea once I get 1 assembled and operational , that's the best way for me to learn . I thought I had a great understanding of antenna theory until I started building them and Im still learning as I go , but I can string up and tune just about anything to acceptable spec (on 11 meter at least) .

Man I love these forums , Happy New year to All I wish I was in the shack reading the mail right now

73's 4-2-ZERO Winkdogg aka Brian Winks in The Garden State . Your long distance radio friend

 

[WINKDOGG]

With a gate threshold that can vary between 2 and 4 volts between any two devises, it is important to provide individual bias controls for EACH transistor otherwise, matching will not occur. The lack of this is likely to cause noticeable distortion in the carrier sinewave at the crossover point.

I was also considering heat waste and poor harmonics bc of the lack of a tight match , but I suppose biasing them individually would also bring them into "harmony" for lack of a better word . As always feel free to tell me if Im way off base , Im not just a random "screwdriver hack" but based on the first stripped down ebay 2 pill I ever built (or assembled) I remember matching being the biggest issue and my local buddy Rooster tinkered with it for a few days but I wasnt around to see his process and I cant find that lil sucker amist my stacks and totes of goodies . But Im guessing thats what he did was biased them to get them to match . Ill look for it later and post pics . That kit came bare bones and I built it on an old motorola suitcase cell phone heat sink , so its extra "pretty " lol

Thanks again as always , Brian

 

[2NC995]

Nah but I wish I could source the parts myself lol he must be buying bulk in China ‍
Still gonna try 1 lol

73’s

I like your posts on the topic. Maybe not be the best amp ever (at $100)..but whatever. I’ve still enjoyed the posting.

 

[ENC Pirate]

I like your posts on the topic. Maybe not be the best amp ever (at $100)..but whatever. I’ve still enjoyed the posting.

and ******Winkdogg said :"The smds are actually easier in my opinion if you have a steady hand and a tiny tip on a high wattage iron . I dab flux on the pads and the components will actually stick in that tiny swipe flux and you juts flow solder off the tiny tip and touch it for a second . I love solder work and re-work with full size components too but if you have the right tip and iron take apart an old cell phone and give them a chance the smds will surprise you . I really was worried about ever touching one until I gave it a shot" ****** I say: unless you have access to The Hubble Space Telescope to work on that stuff avoid it,lol. I have dabbled in the SMD stuff, without Conductive Wire Glue I would have two radios asking me " what have you done? I lucked out this time, no more SMD work or SMD MODS. Lots of small amps out there that are just fine and pretty cheap. Wishing everyone a Happy New Year. Ocean One Cape Hatteras

 

[WINKDOGG]

and ******Winkdogg said :"The smds are actually easier in my opinion if you have a steady hand and a tiny tip on a high wattage iron . I dab flux on the pads and the components will actually stick in that tiny swipe flux and you juts flow solder off the tiny tip and touch it for a second . I love solder work and re-work with full size components too but if you have the right tip and iron take apart an old cell phone and give them a chance the smds will surprise you . I really was worried about ever touching one until I gave it a shot" ****** I say: unless you have access to The Hubble Space Telescope to work on that stuff avoid it,lol. I have dabbled in the SMD stuff, without Conductive Wire Glue I would have two radios asking me " what have you done? I lucked out this time, no more SMD work or SMD MODS. Lots of small amps out there that are just fine and pretty cheap. Wishing everyone a Happy New Year. Ocean One Cape Hatteras

Thanks a lot guys ! I am never afraid to try anything 1 or 100 times lol . I just recently ordered a rework / 100 watt iron combo , Im looking forward to tearing into some really small stuff with the heat gun/rework flame thrower lol I couldn't believe that hot air doesn't damage ICs and other tiny components ! Its all fun to me , I look at it like this .. I have wasted a TON of money on things that never pay off like oh I don't know ..going to bars and clubs 5-7 days a week , staying up for 3 days (without coffee ) and women haha So if I can build an Amp Kit for $100 and actually key it and talk on it I feel like a winner I might not have the highest goals in life but once I hit 40+ I have learned just to say "go for it " very few regrets ever since ! Thanks for keeping with the thread everyone , I have learned so much on this forum Im glad I can at least entertain folks if not even help them learn along with me lol


Happy 2020 and 73's to all

CHECK OUT MY NEW LOW BUDGET 1KW LDMOS THREAD!!!

 

[WINKDOGG]

I like your posts on the topic. Maybe not be the best amp ever (at $100)..but whatever. I’ve still enjoyed the posting.

Thanks a lot 2NC995 ! That's how I feel , I never claimed this was anything super high end or even put my hands on one yet but well worth the conversation and learning experience! The holidays beat up my wallet but my NOS Texas Star 12G is almost ready to come back home and I WILL have a Rocket Box inline soon so we can kick the tires and have some fun ! I read a review about the Rocket HD500 swinging 650 watts with a 40 watt driver , now Im guessing that's Dosy watts but who cares its new affordable and interesting to me and apparently others !

See you gents in DX Land !! 4-2-ZERO WINKDOGG aka Brian Winks in NJ

 

[9C1Driver]

Agreed a kit is a kit however knowing this forum …..
I simply meant mosfet swaps different ways of altering the input side and the different ways we decide to wrap and flow the chokes . No two will produce the exact same results and some of the resident geniuses will certainly find the necessary tweaks to get their moneys worth IMHO lol
Also I can only find the preliminary spec sheet for the 2 x Palomar 9530 FET transistors?? Who knows but have fun boys !!

73.

The 9530 FET is the only final made at this time that works/fits in those amplifiers. The previous final that was used was the discontinued 7530. There is nothing to swap or upgrade to.

These boards are pre-stamped and mass produced, there really is nothing to mess with or change. The style of amplifiers that you can fiddle with if someone wanted to try a design change or up-grade would be the X-Force, Fatboy, Davemade and so on comp style amp. These are all assembled on a large copper board and everything is hand soldered. That would be the "kit" of choice for what you are talking about.

 

[WINKDOGG]

The 9530 FET is the only final made at this time that works/fits in those amplifiers. The previous final that was used was the discontinued 7530. There is nothing to swap or upgrade to.

These boards are pre-stamped and mass produced, there really is nothing to mess with or change. The style of amplifiers that you can fiddle with if someone wanted to try a design change or up-grade would be the X-Force, Fatboy, Davemade and so on comp style amp. These are all assembled on a large copper board and everything is hand soldered. That would be the "kit" of choice for what you are talking about.

Thanks for the input 9C1Driver !

73's

 

[WINKDOGG]

The 9530 FET is the only final made at this time that works/fits in those amplifiers. The previous final that was used was the discontinued 7530. There is nothing to swap or upgrade to.

These boards are pre-stamped and mass produced, there really is nothing to mess with or change. The style of amplifiers that you can fiddle with if someone wanted to try a design change or up-grade would be the X-Force, Fatboy, Davemade and so on comp style amp. These are all assembled on a large copper board and everything is hand soldered. That would be the "kit" of choice for what you are talking about.

Also I do ask basic straight forward questions , not only for myself but for other novices and beginner or inspiring tuners lol . I have a good grasp on the basics though haha ! I would love to order some 4mm copper sheet , heat sinks , fiberglass sheet and start tapping and building and etching my own heavy copper traces but I have only scratch built a Lego Car that could follow a strip of red tape on the floor haha and that was 20 years ago in technology lab ! So I understand the limitations but with some of the smart dudes like yourself I have met on here so far I'm sure there are some tips tricks and mods to help refine these kits ! We were talking about a individual biasing circuit for each transistor to ensure they match cleanly ! Someone else brought up some simple mods to improve the input circuit . So I have faith that even if its a pig we can get it lookin pretty

73's Buddy ! Stay tuned lol

 

[Shockwave]

Hey Shockwave do you think that's as simple as say , "borrowing" the biasing circuit from an RM Italy or similar box ? Will the surface mount board make this extremely difficult (I imagine a tight fit regardless) And by simple I mean can someone draw me up a solder by numbers biasing circuit I can just replicate lol This is basically what I was talking about when I was saying Im sure some guys will put "their own spin" on the kits ! I never claim to be a tech but what you said makes perfect sense to me I just lack the skill to design the individual biasing circuits . Im willing to be the Guinea Pea once I get 1 assembled and operational , that's the best way for me to learn . I thought I had a great understanding of antenna theory until I started building them and Im still learning as I go , but I can string up and tune just about anything to acceptable spec (on 11 meter at least) .

Man I love these forums , Happy New year to All I wish I was in the shack reading the mail right now

73's 4-2-ZERO Winkdogg aka Brian Winks in The Garden State . Your long distance radio friend

None of the 11 meter equipment is going to have individually biased transistors and the board has to be planed for that in advance. You must isolate the DC path to the gates of the transistors from the input transformers secondary winding. That requires low inductance chip capacitors being installed between the transformer and gates before you can even add the individual bias parts to the existing circuit. On a board like this, your best bet is to try and match your own transistors using one of the testers found on eBay for testing gate threshold.

 

[WINKDOGG]

None of the 11 meter equipment is going to have individually biased transistors and the board has to be planed for that in advance. You must isolate the DC path to the gates of the transistors from the input transformers secondary winding. That requires low inductance chip capacitors being installed between the transformer and gates before you can even add the individual bias parts to the existing circuit. On a board like this, your best bet is to try and match your own transistors using one of the testers found on eBay for testing gate threshold.

Thanks as always for the thorough explination ! I suppose there certainly is nothing simple about that then lol

Thanks again , 73's
Winks 4-2-ZERO

 

[Shockwave]

From a technical viewpoint, independent bias is not a difficult circuit to construct. It only becomes difficult when you have to physically install it in the existing space on the board. If I had to do this modification, I'd probably break the DC path at the back center tap of the input transformer and build a separate multi channel bias board to inject the bias through chokes or resistors, to the gates.

 

[Shockwave]

Another thing to consider about bias is that many of the test circuits given in transistor data sheets are simplified to the point of allowing the transistor to just produce good results under a specific test. Bias was considered just long enough to show the transistor having good gain. Not that it will hold the transistor in class AB operation over a wide range of drive or temperature fluctuations.

If the impedance of the bias supply is too high (excessive series resistance), the RF drive can now modulate the DC bias level. High quality designs will hold this impedance below 100 ohms and usually require a buffer transistor between the bias control and the gate input to do this.

The diode and two resistors Palomor is using as a "companion" part on the gates of their transistors is interesting too. It appears to intentionally maximize the effect of modulating the DC bias by rectifying RF and applying it as additional bias. The gain on these parts is so low at 30 MHz. that I suspect this setup is done to improve swing or PEP output. You'll also notice they add a 1000 ohm resistor to the back of the input transformer feeding the fixed DC bias in and supplying the RF ground to the center tap.

The "sponginess" of that 1000 ohm resistor on the input transformer is about the only thing keeping these switch mode transistors alive in "not so linear" use. They have hidden the guts of their companion part in an effort to make you think it's required. True, their FET will burn up if you leave it out but that's only because it forms a voltage divider leg to ground, with that 1000 ohm resistor in series. Now if you leave it out, the anticipated voltage drop across the 1000 ohm resistor is no longer present and you apply too much bias voltage!

The added RF rectified bias in driver stages can sometimes kill final stages by applying too much peak drive. RM Italy gets around this problem by leaving the RF bias diode out of their companion circuit on driver stages. They still keep all of the extra resistors intact in an effort to protect the gates with bias applied to them. Something you do not have to do with linear rated RF MOSFET's.

 

[WINKDOGG]

Another thing to consider about bias is that many of the test circuits given in transistor data sheets are simplified to the point of allowing the transistor to just produce good results under a specific test. Bias was considered just long enough to show the transistor having good gain. Not that it will hold the transistor in class AB operation over a wide range of drive or temperature fluctuations.

If the impedance of the bias supply is too high (excessive series resistance), the RF drive can now modulate the DC bias level. High quality designs will hold this impedance below 100 ohms and usually require a buffer transistor between the bias control and the gate input to do this.

The diode and two resistors Palomor is using as a "companion" part on the gates of their transistors is interesting too. It appears to intentionally maximize the effect of modulating the DC bias by rectifying RF and applying it as additional bias. The gain on these parts is so low at 30 MHz. that I suspect this setup is done to improve swing or PEP output. You'll also notice they add a 1000 ohm resistor to the back of the input transformer feeding the fixed DC bias in and supplying the RF ground to the center tap.

The "sponginess" of that 1000 ohm resistor on the input transformer is about the only thing keeping these switch mode transistors alive in "not so linear" use. They have hidden the guts of their companion part in an effort to make you think it's required. True, their FET will burn up if you leave it out but that's only because it forms a voltage divider leg to ground, with that 1000 ohm resistor in series. Now if you leave it out, the anticipated voltage drop across the 1000 ohm resistor is no longer present and you apply too much bias voltage!

The added RF rectified bias in driver stages can sometimes kill final stages by applying too much peak drive. RM Italy gets around this problem by leaving the RF bias diode out of their companion circuit on driver stages. They still keep all of the extra resistors intact in an effort to protect the gates with bias applied to them. Something you do not have to do with linear rated RF MOSFET's.

WE NEED "STICKY NOTES" ON THESE FORUMS . On other forums they have sticky notes you can apply to any post or thread and that particular post goes on a board for all to access .

My point is Shockwave thank you , there is tons easy to understand information right there ! I hope lots of people read this stuff guys like yourself , kopcicle , shadetree and 2nc995 (and lots of others) make this stuff not only understandable but also exciting. I along with other novice tuners read things like your post and a lightbulb goes off ! I know more about biasing mosfets right now then I ever would if I tried reading googled crap lo!

Also thanks to all the Hams on here that dont bust my/our stones for being CB operators , I have been treated like a second class citizen on other forums for not having my HAM ticket and not knowing morse code(I know a little) haha I respect Hams I have never bothered any 10 meter operators I know many local Hams quite a few 10 meter ops with tickets (IM SURE THEY WOULD LET ME KNOW!) I am still really satisfied with 11 meter even without DX I have tons of nice locals . I live 2 miles from Philadelphia 4 miles from I-295 1 mile from I95
and there is always someone on the band .

Ill go for my ticket eventually but I have some serious bucks in all this CB gear so I may have to liquidate to get myself a decent ham setup !!




Im pumped about some new projects for the new year. Im going to setup a decent camera and lighting on the bench and make more videos on some of my fun mods and repairs and you guys THEN can start busting my balls lololol


Shockwave thanks again for the great info !!

73's to all and to all a good night , Im really rambling now lol

Stay Tuned ….. Brian

Winkdogg 4-2-ZERO in NJ Waving

 

[TIN_CAN]

WE NEED "STICKY NOTES" ON THESE FORUMS . On other forums they have sticky notes you can apply to any post or thread and that particular post goes on a board for all to access .

My point is Shockwave thank you , there is tons easy to understand information right there ! I hope lots of people read this stuff guys like yourself , kopcicle , shadetree and 2nc995 (and lots of others) make this stuff not only understandable but also exciting. I along with other novice tuners read things like your post and a lightbulb goes off ! I know more about biasing mosfets right now then I ever would if I tried reading googled crap lo!

Also thanks to all the Hams on here that dont bust my/our stones for being CB operators , I have been treated like a second class citizen on other forums for not having my HAM ticket and not knowing morse code(I know a little) haha I respect Hams I have never bothered any 10 meter operators I know many local Hams quite a few 10 meter ops with tickets (IM SURE THEY WOULD LET ME KNOW!) I am still really satisfied with 11 meter even without DX I have tons of nice locals . I live 2 miles from Philadelphia 4 miles from I-295 1 mile from I95
and there is always someone on the band .

Ill go for my ticket eventually but I have some serious bucks in all this CB gear so I may have to liquidate to get myself a decent ham setup !!




Im pumped about some new projects for the new year. Im going to setup a decent camera and lighting on the bench and make more videos on some of my fun mods and repairs and you guys THEN can start busting my balls lololol


Shockwave thanks again for the great info !!

73's to all and to all a good night , Im really rambling now lol

Stay Tuned ….. Brian

Winkdogg 4-2-ZERO in NJ Waving

What about this cheap kit dude?
https://www.ebay.com/itm/180W-Linea...388472?hash=item547bbf50b8:g:AC8AAOSwkdld-JFw