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[KC6RWI]

I looked around he net and tried to find some info first, I have been listening and talking to some fm stations on 10 meter 29.6.
It would seem to me that FM Hf amps a few and far between? I searched and I didn't find any except for kits from chinese sellers.
I don't need one for home, I think a 7300 is just fine, but I have a little 10 11 meter radio that does fm, it would sure be nice to
be able to have an amp for that.
So most amps are for cw, ssb maybe Am and rarely for fm, does that make sense?

[K1KIM]

RM Italy KL35 is 1-5w in 35w out for HT's

RM Italy KL503 I believe is 12w in 250w out on FM  450w on SSB

They have several 10M FM capable amps.

Buy here in the US

One place to buy. https://www.andradsupply.com/amps.php
There are several others

[KC6RWI]

I saw some of those but the ones I saw where $800 and no mention of FM,
 I must have been looking in the wrong place,
I have a very old solid state amp in the van, its ssb and am,  I wouldn't try it for fm.
I wonder if the fm signal would pass thru it if it was turned off.

[AD0AR]

If it works for AM, it will work for FM. Most likely use it at a lower power or duty cycle.   AM and SSB amps are class AB or better to reduce unwanted harmonic generation.  FM can even be used to class C without harmonics since it is a carrier that simply varies in frequency.  The big problem is heat generation.  If you are using a class AB AM or SSB amp with a FM carrier there is the potential to generate copious amounts of heat the amp has to deal with dissipating. 
My Mercury III amp has no problem pushing out carriers of 600 continuous watts and the heat dissipation is all automatically controlled as in most modern solid state amps.

[W1VT]

Amplifiers are much more cost effective for low band SSB than 10M FM.
The duty cycle of SSB voice is low so you don't need an expensive heavy duty power supply.
And you can take other liberties to reduce costs as well.

Sort of like the difference between pro golf and pro football.
I can do some of the things pro golfers do on the golf course like hitting the ball out of a sand trap.
I can't do anything a pro football player does on the football field in terms of athletic ability.

[K7LZR]

If you can find a good quality CB amp i.e. quality construction, low pass output filter etc. then it should work on 29.6 FM. Such things are few but do exist. Or you could buy a good quality 11m amp and add your own filtering etc. if you don't mind doing some work to make it worthy.....

[AI5BC]

So most amps are for cw, ssb maybe Am and rarely for fm, does that make sense?

No reason for anyone to make one. A linear AMP does both AM and FM modes. An amp made for FM would be class C making it a uni-tasker, it can only do FM.

[K1KIM]

I saw some of those but the ones I saw where $800 and no mention of FM,
 I must have been looking in the wrong place,
I have a very old solid state amp in the van, its ssb and am,  I wouldn't try it for fm.
I wonder if the fm signal would pass thru it if it was turned off.

Look again.

$300-$400 gets you exactly what you are looking for.

[VE7RF]

So most amps are for cw, ssb maybe Am and rarely for fm, does that make sense?

No reason for anyone to make one. A linear AMP does both AM and FM modes. An amp made for FM would be class C making it a uni-tasker, it can only do FM.

No brainer here.  Just increase the bias when using FM. A simple toggle switch on the rear apron will do that job.  It's it's for FM only, no switch required.  I used a spdt-center off miniature toggle switch  on my L4B's...to provide for 3 x bias positions.

[PE1HZG]

A SSB amplifier can do FM. All of them. HOWEVER...

A SSB / CW amplifier is typically constructed for lower duty-cycle, hence lower load on the transistors/tubes and the power supply.
You can overload a tube for a little bit and many amplifier designs do.
With transistors, brief high-load may not cause a lot of heat, extended high-load (as FM does) may cause things to overheat if the cooling isn't designed for the sustained high load.
And the power supply is typically not intended for continuous operation at high load.

So you will need to check the design and the specs. And perhaps de-rate the amplifier significantly. The well-known SB200/220 are made like that: OK for low duty cycle, smoke if the high load is constant.

People are finding out these things. Check for amplifier complaints from people running FT8, which has the same characteristics.

"it depends on the amplifier design". And, does the amp switch off if it finds an overload / high temp situation?

Geert Jan

[VE7RF]

A SSB amplifier can do FM. All of them. HOWEVER...

A SSB / CW amplifier is typically constructed for lower duty-cycle, hence lower load on the transistors/tubes and the power supply.
You can overload a tube for a little bit and many amplifier designs do.
With transistors, brief high-load may not cause a lot of heat, extended high-load (as FM does) may cause things to overheat if the cooling isn't designed for the sustained high load.
And the power supply is typically not intended for continuous operation at high load.

So you will need to check the design and the specs. And perhaps de-rate the amplifier significantly. The well-known SB200/220 are made like that: OK for low duty cycle, smoke if the high load is constant.

People are finding out these things. Check for amplifier complaints from people running FT8, which has the same characteristics.

"it depends on the amplifier design". And, does the amp switch off if it finds an overload / high temp situation?

Geert Jan

This is where a SSB/CW  (hi-low B+) setting really helps.  If using 10M  FM,   I use the lower CW (1900 vdc) on my drake L4B amps...(and also increase the bias vdc / reduce the idle current to almost nothing).  Then 600 watts out using 10M FM works just fine. Nothing overheats at all.  Later on, I replaced the oem drake blower with the ebm papst blower used in the ameritron AL-82/1200/1500 amplifiers.

[W3SLK]

I did 1K FM on 160M with my RCA SB-1K amp. It uses a pair of 3-400Z's. However, since it is a commercial marine amp, it was designed for high duty cycle.

[KO4JPZ]

Saw the link on the Italy amps and checked those out. Thought to myself this would be fantastic for POTA.
I go to a place with 5300 feet elevation every August and it's great opportunity for DX.
Then I scrolled down the page and saw the message in red. Hmmm, what to do?

[K1KIM]

Saw the link on the Italy amps and checked those out. Thought to myself this would be fantastic for POTA.
I go to a place with 5300 feet elevation every August and it's great opportunity for DX.
Then I scrolled down the page and saw the message in red. Hmmm, what to do?

What message in RED?

[KO4JPZ]

There is absolutely no warranty applied or given on these items. No factory support either.

These units are for industrial, scientific, medical, or export use only. It is a violation of US FCC regulations to operate these units on the Citizens Band or Amateur Radio Services in the United States. Please check regulations in your country before operating these unit.

This is on the bottom of each item description.