amp choice for newbie

[varmonter]

Hi
I have a pres lincoln 2. (freq mod done )am thinking about putting an amp in my vehicle to increase the out put..But i am a complete newb in this realm.
i was looking at this mosfet amp.. xforce MF400-292 ..but don't really know if this would be a good match for my radio.?? would love your input...i use a wilson 5000 mag mount.
i like the idea of mosfets..they seem a bit more forgiving. mostly i would be on the 11 meter side of things but would also use 10 meter ssb ..this amp has "auto sideband delay..
does that mean i can use it on usb/lsb?? it only draws 45 amps so would io need to modify my car 09 vw jetta sport wagon tdi thanks...

[silvereagle1]

I have the president lincoln 2 and a KL 503 mosfet amp and they work good together. I keep the power turned down to 1.5 watts on AM. I've always had good SSB reports with this amp. It's a solid 250 watts of good clean sound and only cost around $150.00

[MDYoungblood]

Just because it has a SSB delay switch doesn't mean it is biased for SSB. I'm not sure but I believe a mosfet has to be biased to work. That would be a question to ask before buying it. Not a lot of operators like "mosfets" but they are the future, look through what is online, with the radio you have I would look at HD (High Drive), save a lot of smoke time if you forget to turn the RF down. Mosfet's also like premo SWR, it needs to be under 1.3 all the time and watch the long "queso's", they do heat up quick. IMO, look at the Palomar HD250 or 450, sold by GI Joe's.

3's

Greg

[yota167]

I couldn't agree more with what MDyoungblood said. High Drive amps are a bit tougher, and despite what people say you can run a stock low power radio into them. I ran a 4wattdk swinging to 13 pep into a Palomar250hd for years and years. I loved my lil palomar 250hd. The Texas stars are awesome too. I've tried to blow some 2879's up and it's really insane how tough the toshiba 2879's are but they draw a lot of amps compared to other amps with different transistors. Anyhow I just wanted to share....I'd reccomend a Texas star 250hd or the palomar.

[Mkymse1]

One thing I will tell you don't get hung up on watts, if you can be heard, you have enough. The "more watts" virus can be very detrimental to your wallet and once you catch it, its VERY hard to find the cure.

You'll be very surprised just how far a DX250 will talk.

[Crusher]

Since it is a MOSFET amp that you are looking at. That amp will be biased. Since the mosfets need to be biased in order to turn them on. They are not like a standard bipolar device. Without bias, they could blow as soon as you key. Keep the SWR at antenna as low as possible. Also keep in mind, as mosfets Heat up the power will drop off. They are the opposite of a bipolar transistor that will go into thermal run away. Usually. I haven't messed with 7530 fets. Just the bigger stuff.

[DB_Cooper]

Texas star 500 v. Keep dead key down. It's a 4 pill so it would be tough to hurt it as long as the dead key is kept fairly low.

[chewy78]

get a 2sc 2879 transistor 2 pill high drive amp or 4 pill amp

[kskev]

I couldn't agree more with what MDyoungblood said. High Drive amps are a bit tougher, and despite what people say you can run a stock low power radio into them. I ran a 4wattdk swinging to 13 pep into a Palomar250hd for years and years. I loved my lil palomar 250hd. The Texas stars are awesome too. I've tried to blow some 2879's up and it's really insane how tough the toshiba 2879's are but they draw a lot of amps compared to other amps with different transistors. Anyhow I just wanted to share....I'd reccomend a Texas star 250hd or the palomar.

So, If I understand.... A Texas Star or a Palomar amps are a high drive amps compared to a MOSFET amp like RM Itally KP 203, 503?
So you can run more DK watt in them compared to what should be ran into the MOSFET amp which everyone says no more than 1 to 2 watt DK?

[yota167]

I set the radio so when it keys the amp the amp has a carrier of 1/4 of the amps peak output. Whatever you need to do to your radios dead key to make that happen is how I have always ran my stuff. I haven't blown anything up yet and people like how I sound on air. I don't know much compared to most guys on here but Ive been keying mobile boxes for over 10 years and haven't seen any 10ohm smoke yet. Far as mosfets go, I'll let someone else chime in there.

IMO, your VSWR, power leads, grounding, and properly installed coax is more important than anything. As close as you can get the antenna system to 50ohms, the more efficient your entire system will run and will therefore be much more forgiving if you do happen to key too much carrier for too long. The whole goal in a mobile is to try and fool the radio transmission output wattage into thinking it has an infinite run of coax so it never makes it to the end, because if your 27mhz output finds the the termination point abruptly (bad antenna or mis tuned) it instantly does a complete 180 and comes back down the coax back into the amplifier generating heat.

[varmonter]

well lots of good info here thanks..the lincoln has an rf power knob..so if i keep this low will it keep me in that magic 1/4 area.? I am looking for an amp i would not have to do any
alternator modifications on so nothing too big..do these amps mentioned above require a beefed up alternator. ??

[Crusher]

Since you do plan on using this radio for 10m SSB. I would recommend something like a TS dx400 or 500. Or get something from XForce or one of the others that has at least class B biasing. The MOSFET amps are biased as well. They have to be in order to be turned on. They don't work the same as a standard bi polar transistor that you can run class C. And use carrier to turn on.

[silvereagle1]

I can only speak for the setup that I use I have no experience the others But I know it sounds good on AM and It puts out good clean SSB audio and you don't need to upgrade your electrical system. My Lincoln 2 keys 1.5 watts on low and drives the amp with no problems with heat either. it might get a littler warm but it's never got hot. just my two cents.

[varmonter]

silvereagle since we are using the same radio i would definitely want to look at this 503?? these are made in italy.who sells them in the states? where is your rf power set to drive this amp in setting 3?
sorry about all the questions... just don't want to fry my lincoln.

-- Tuesday, 27 January 2015, 3:08 AM --

well i found one and dropped the dime on it..i will let you know how it works out..any tips on the install..I know swr has to be below 1.3:1...deadkey down low too.