Adaptive Predistortion sampler

John Watson W4JCW

What sampler is recommended and/or is everyone using with success?

Mr Radio

OM John,

vk-amps.com offer - 55 dB sampler. Also sometime ago TAPR.org listed a sampler in their on line store.

Tom

David Decoons, wo2x

CleanRF makes one also.

I am using the two sample outputs of the Power Genius.

KD0RC

I have a CleanRF sampler on order. I expect it next week. I will report back here on how it works with my KPA 500 amp. It provides -60 dB at HF and -50 dB at 6 meters.

Russ Ravella

Hi Len,

Something that was discussed back when Flex first announced their APD was the ability for samplers to auto-switch between inputs for the radio connector's original purpose, say "RX1 during receive, and the sampled input during transmit. That would seem to involve another input on the sampler FOR the displaced radio input, in this case "RX1".

From what I can see the CleanRF doesn't have that capability ? If that's right do you have a game plan for doing that ? I know you're been using DIV a lot lately, perhaps using the RX inputs ?

Thanks, Russ KR6W

KD0RC

Hi Russ, no the CleanRF is just a sampler. Flex talked about a sampler / TR switch combo so that you don't lose a RX port to APD, but nothing has been announced yet.

I do DIV using several antennas (only 2 at a time) connected to my Antenna Genius and to a loop-on-ground connected to RXB.

I am saving RXA for the RF sampler. So in my case, I don't need the second RX port for anything else. I am guessing that you will also be able to use a XVTR port if you already have your RX port(s) in use.

Russ Ravella

Hi Len,

Thanks as always for the response ! Ok, understand.

Seems Flex's thinking about adding dedicated ports to the 8000 was that, like you, most of us won't be using at least two of the aux ports so why add expense/cost for additional ones. It was probably a good decision though I still wish they had; even if it were an extra expense option. But the sampler / TR switch will solve the problem when it arrives for the few who need it so all good in the end I suppose.

Quick loosely related question: were you ever able to get the new ESC function to work ? I did a fair amount of experimenting and could never convince myself it was doing anything. Hoping there's a big fix in 4.2 for it. I note they didn't list anything specific in the "bug fix" category so far so finger's crossed.

Thanks again, Russ KR6W

KD0RC

Hi Russ, no, ESC is not doing anything yet. I too was hoping to see it in the release notes as a fix. Hopefully soon…

Mr Radio

Sampler with a switch

https://www.vk-amps.com/collections/hf-amplifier-kits/products/ldmos-amplifier-2kw-tx-rx-relay-with-55-db-sampling-port

David Decoons, wo2x

I tested my friend's Clean RF sampler. Looking on a tracking generator/spectrum analyzer, the sampler was pretty flat with the knob all the way in one direction (forgot if it was clockwise or counter clockwise)