70cm Power Amplifiers?

[VK4GHZ]

Hi all

For the first time, I am considering a 70cm PA, and currently only run an IC-910 barefoot on 432 MHz.

This is something I have not looked into before.
What practical 432 MHz PA choices are currently there out there?
(No point recommending something that is not available)

Solid State, valve.
Don't care.

Ideally in the 200 - 400 watt output class.
Even higher if it can be throttled back to legal limit, so it isn't working "as hard".

Considering all options.
Kits, plug n' play, modified ex-commercial.
Don't have the time to be etching PCBs and scrounging difficult to get parts.

I'm aware of the W6PQL 500 watt amp using the Freescale LDMOS device, but are there other alternatives to consider?

Suggestions please!

[VK4TI]

Several options
The GS35B is cheap and very powerful http://vk3nx.com/files/432_MHz_PA.pdf , join freescale buy direct or buy a commercial amp from the states and import , cci do sme basic amp kits which are very affordable and easy to get going

[VK4AMG]

Adam,

I am currently building a W6PQL kit for VK4FLR.

Frank has a 28V Power Supply and the ancilliary stuff. I estimate he will get 200W + for under $400.

With switching supplies, case, meters, control board, change over relays etc. The total will most likely reach $700 for the full gallon version packaged as per my 2m SSPA.

It does avoid the bad guy HiV! ==== ONE FLASH & YOUR ASH. =====

73s

George

[VK3BJM]

G'day Adam,

Just a bit of fine detail on the Freescale option. I'm building two pallets, as I have long term grand designs... The first pallet I've built using the RFHam kit; the second will be one of Jim's kits. As Jim mentions in his description, the kit from RFHam - well, the PCB specifically - is not much more than the Freescale experimenter's board. In comparison to Jim's kits, it's a bit... Er, amateurish? In short, I think I'll have a bit of tweaking to do with Pallet 1; I don't expect this so much with the W6PQL kit.

US$650 for a completed & tested 500 w pallet looks pretty good. Especially with the benefits of (1) small size and (2) 50 v working, instead of 12 v high current or HV heart-starters/stoppers.

Happy shopping!

73,
Barry
VK3BJM

[VK3QI]

Adam,

I'd go with the W6PQL amplifiers any day.

Jim has the happy knack of foreseeing problems with production and dong something about it in advance to overcome the problem.

What is not generally known is that Jim has been designing and marketing amplifiers since the late 1970's having cut his teeth so to speak on the MRF600 series transistors on 2 and 70 up into the 100 + watts class. With all that experience, his projects are always well designed and documented.

Not to mention the fact that switchmode power supplies in the 28 and 50 volt range are now generally available at quite reasonable prices, including surplus supplies from the phone services, making solid state amps the preferred way to go.

There are always those who will argue that valve amps are more forgiving of bad antenna matches and can easily be "tuned" to compensate for these mismatches, but I would argue that that just forces one to look more closely at the antenna matching, which in the long term is the best way of improving the overall system anyway.

Cheers

Peter VK3QI