[amsat-bb] Flex radio for satellites

Edward R Cole kl7uw at acsalaska.net
Fri Nov 27 19:46:41 UTC 2015

I guess I should reply to comments by several:

When I investigated the Flex-5000 when it first came out, there was 
no U/V transverter available and no duplex Rx function.  I contacted 
them regarding that and also about their second Rx regarding another 
project (eme) which does not concern satellite users.  After 
consideration over a couple years I decided on the Elecraft K3/10.  I 
still had my FT-847 and FT-817 at that point.

Apparently,Flex subsequently added duplex operation and came out with 
V/U transverter for the 5000.  So maybe you can find a used one if 
building a satellite station.

Now addressing Rick's assertion that one can save money buying a Flex 
6000 series radio coupled with Rx downconverter and buying another 
VHF/UHF capable radio as transmitter.

I checked the prices on new Flex:
6300 ... $2399
6500 ... $4099
6700 ... $7199

Not sure where you find VHF or UHF Rx converters these days.  price ...?
One of the used IC251or 271 (451 or 471) could be used but you would 
need two to cover both 144 and 432
Or buy a used IC910, FT-847, or TS2000 (but then you do not need the Flex).

A couple FT-817 with amplifiers would be cheaper.

Compare with Elecraft:
K3s/10 ... $2099
K3s/100 ... $2649
KX3 ... $899
2M transverter for KX3 ...$199

DEMI transverters:
L144-28 ... $479
L432-28 ... $499

Cheapest Elecraft combo:
KX3-2M = $1099
KX3+L432-48 = $1398
total ... $2497

or my proposed sat station:
KX3-2M = $1099
KX3s/10+L144-28 = $2598
total ... $3697

both dual Elecraft sat combos are less than a Flex6500.

Of course if you also want mode VU then you need a modest power 2m linear.
I have RF Concepts 2-30 linear which produces 30w for 2w 
input.  Granted they are rare to find these days but you can 
substitute the Mirage equivalent.

Of course if Flex6700 will have full duplex with second Rx all you 
need is VHF/UHF amplifiers.

I'll leave the comparing to the reader.

In my case I have already voted with my dollars:
K3/10 (bought in 2010)
KX3-2M (bought in 2012)
L144-28HP (50w)
L432-28 (with Apol synth)
1296-28H2 (with A32 synth)
[no you don't want to total that] ;-)

Currently, I mostly do eme:
144: 4x M2 2mXP20 yagis + 8877 PA
1296: 4.9m dish + W6PQL 150w PA
3400: 4.9m dish + 50w Toshiba PA
50: 6-elem yagi + 1000w Harris PA

73, Ed - KL7UW
still have all my AO-40 antennas and mw gear.

Subject: Re: [amsat-bb] Flex radio for satellites

In answer to your questions, yes the Flex 5000A could be fully equipped with
2 rcvrs and the V/U module, however they discontinued it with the release of
their 6000 series radio. For satellites I've used the FT736f,
Ts2000 and ft847 and none compare to the ease of operation and rx quality of
the Flex5000A, which is why I'm holding on to mine.

But you could do what I'm now doing which is to use another radio capable of
V/U transmission on all modes as your uplink radio and use a 6000 series
radio with inexpensive down converters for rx. I then built a USB relay
controlled box that drives antenna switching relays. I found this to be much
cheaper than the other alternative which is to buy DEMI transverters or
possibly Elecraft. And you also end up with another really useful radio as a
backup for HF and other purposes at less cost than the 2 DEMI transverters.
I've used this arrangement before (minus the automated relay switching ) I
got my tricked out Flex5000. At that time I used the
TS2000 as uplink with a Flex 5000A for downlink wth converters and it worked
great! Stay tuned for exciting articles by Ron Parsons, W5RKN, and Dave
W0DHB in the AMSAT Journal about all this. What I'm doing is a spin off of
their ideas and working with them.

Rick, W2JAZ

73, Ed - KL7UW
     "Kits made by KL7UW"
Dubus Mag business:
     dubususa at gmail.com

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