inexpensive/cheap cb amps . palomar/cobra vs. rm/kl

[DXman]

I wasn't too happy after I had sold my Cobra 350XL and heard how nice it sounded on SSB. It was a 11 yr old amp, brand new, I only used it to see what the output was (285) and then sold it to a local.
Bad mistake on my part.

Hey dd18, is that you David from Indonesia??

 

[dd18]

CQ DX !!!

Yup tis me, I think we spoke the other day on the radio. KP178?
my morning and your evening....
you were coming through all day!!!
Have not had conditions that good for a while now...
Good to catch up on this band too!!!
73,
Dave

 

[BOOTY MONSTER]

i called H&Y and asked about the palomar and cobra amps .
i asked if any of them were class AB biased and was told "they are all class C biased"

 

[Toll_Free]

RM Italy the money goes to Europe.

Galaxy / Palomar / etc. the money usually goes into someones pockets here in the USA.

Somethin to think about. Of course, if you shop at Wal Mart, then who cares (and that REALLY FUCKING PISSES ME THE FUCK OFF, since they MADE their reputation on MADE IN AMERICA)

--Toll_Free

 

[GLR]

Galaxy / Palomar / etc. the money usually goes into someones pockets here in the USA.

You sure about that?

 

[mackmobile43]

RM Italy the money goes to Europe.

Galaxy / Palomar / etc. the money usually goes into someones pockets here in the USA.

Somethin to think about. Of course, if you shop at Wal Mart, then who cares (and that REALLY FUCKING PISSES ME THE FUCK OFF, since they MADE their reputation on MADE IN AMERICA)

--Toll_Free

Lots of people sell their souls to the Devil and then some sell their soul to China.

 

[Seven01]

The KL503 is a 9 Mosfet transistor amp with 1 transistor driving 2 sets of 4 transistors...or 1x8.
With this type of layout it appears that a single final radio (25W PEP) would
be best......dual final (40W or more rigs) will easily overdrive the single driver.

This is also a class AB amp, which should give clean, biased SSB.

I will post a full test of this unit in the next coupla days....

 

[443]

Would like to see more about this. Notice in the 503 schematic that it uses the mosfets in parallel groups (2 on each side of the transformer) more like you would "normally" use a mosfet. I tried building a prototype very similar to this about a month ago, not such good luck, been thinking about it and have some new things to try.

The biggest drawback with the mosfet amps that I have seen so far is:

1. Heat makes them "put out" way less power.... They need to be kept cold for full output

2. They suck at "gain". About 1:3.5 ratio. i.e. You put in 100 watts you get 350-500. not so much if you think in terms of "s-unit" gain. However due to the $price of mosfets, not so bad, ultra cheap power.

I have a pair of Palomar mosfets here and they do rated power. 1 of them I blew the original ERF7530 mosfets... So I went to the cabinets here and found some ultra low gate charge fairly cheap $1.53 each mosfets and stuck them in the Palomar and retuned. It works great so far. Only about 15-20% less power for WAY less money, and I have beat the crap out of these mosfets (decent 400V mosfets) and they have not given out yet. I drive it with 125 watts (it uses 4 mosfets) and it puts out 500-600 watts depending on temperature. What I don't know is how much of it is "on band", I need to send it to someone with a Spectrum Analyzer to see wtf it's doing. I just can't afford a SA right now, times are too tough.... I would like to have one though, and if I did, I'd be doing ALOT of mosfet RF amplifier experiments...

TollFree is right, the Palomars are built in USA and money goes to pockets of americans. RM it goes to Europe, so DO think about that.....

 

[Toll_Free]

You sure about that?

As I now the owner(s) of Galaxy, Texas Star, Messenger and the original Palomar... Yes.

Notice, I DID qualify my statement with usually....


--Toll_Free

 

[Toll_Free]

Chris,

check out a SDR unit. You only need a receiver. That will get you Spec An, for cheap.

The EASIEST way is a Softrock, centered on 455 Khz. THEN, take the output from your flavorite radio and stuff it into the softrock, and use powerSDR to take a snapshot of the RF spectrum you're occupying.

Barring that, drop a few thousand on a decent HP spec an


--Toll_Free

 

[-=PEAKABOO=-]

RM Italy the money goes to Europe.

Galaxy / Palomar / etc. the money usually goes into someones pockets here in the USA.

Somethin to think about. Of course, if you shop at Wal Mart, then who cares (and that REALLY FUCKING PISSES ME THE FUCK OFF, since they MADE their reputation on MADE IN AMERICA)

--Toll_Free

Very true about the amps. And also very true about walmart. They suck bigtime.

 

[NorthStar]

I wish people would buy more American made products so that their would be more american made products. I second TollFree on the amps.

 

[Transister]

I agree, but look around what is made here anymore besides auto's. Just go to a department stores and look at the labels on clothes, there are no US products....D--- shame...transister

I wish people would buy more American made products so that their would be more american made products. I second TollFree on the amps.

 

[triple nickel]

I agree, but look around what is made here anymore besides auto's. Just go to a department stores and look at the labels on clothes, there are no US products....D--- shame...transister

Tell me what is actually 100% made in the USA ??? Not a whole lot that i know of. For instance a lot of the steel we use here in the US comes from Japan. They say it's cheaper to buy outside the US then to make it right here, Like they used to. OK enough said, I will leave this alone now.

 

[223texas]

PIC

I found this on the web. Better late than never I guess.