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RM Amplifiers


#1

Morning all. Has anybody any experience with RM amplifiers? They appear quite reasonably priced and could give the 817 the boost it needs.
Found them here http://www.rocketradio.co.uk/vhf-356-c.asp

Cheers

Tim


#2

In reply to G4YTD:

I have converted several of the CB ones for use on 40/30m. They are cheap, in part, because they have no output filtering. No idea about the VHF ones but would suspect that they may be equally poorly designed.


#3

In reply to G4YTD:
Hi Tim,
Before switching to an 857 from a 817 for SOTA, I used an RM KL144 amplifier on 2m.
It provided a conservative 25 Watt output, when driven by the 817, and seemed to be reasonably ‘clean’ and linear. Amplifier weight is 400 gms.
I switched to the 857, after weighing the 817 plus amplifier and connecting leads combination, and finding that the 857 weighed only a pound more. The 857 had the added benefit that it permitted high power on HF, if needed.

73,
Frank


#4

In reply to G4YTD:

They are cheap, nasty CB junk. As Richard says there is no filtering on them.
You can add your own filtering to them either by completly rolling your own design or using the filter designs and kits that are available for amplifiers like the HF Packer kit or from Communications Concepts Inc.

Personally, if I wanted some QRO for the 817 I’d build a complete kit. There’s more satisfaction to be had.

Or you could buy an amplifier chassis from me (I have several)… ~0.5W from the 817 gives 150W out on 5MHz and that’s with an input and output filter!

The same applies for VHF except building the filters requires more metal work.

Andy
MM0FMF


#5

In reply to G4YTD:

A possible alternative. The kit is easy to build and a similiar price to the RM vhf amp.

http://www.spectrumcomms.co.uk/amateur.htm#TRANSMIT_AMPLIFIER

Regards,
Nigel. G6SFP/P