Using a Yaesu FL-2100B with my Flex 6400 via Ameritron ARB 704?

Barry Young

Can somebody give me the wiring diagram and / or instructions for connecting and using the Yaesu FL 2100B with a Flex 6400 using an Ameritron ARB 704?  I have read that it is possible I hope.

Neil D Friedman N3DF

Wow!  Havn't used a Yaesu FL2100B in nearly 50 years.

Barry Young

Anybody have any ideas? Thanks!

PeteP

Hey Barry, any info? I find myself in the exact situation as of today:
Flex-6400
Yaesu FL-2100F
Ameritron ARB-704

Pete KL7IS

Barry Young

Hi Pete,

I purchased a 1.5 KW dummy load. I have had the amplifier for about 8 months. I feel like I want to test this with an another less expensive radio, in case something goes wrong. One concern I have is the amperage draw, the Flex draws 18-22 amps. The FL-2100F can draw up to the same. And My radio room is on a 20 amp fuse wired in series.. I’m concerned that running the amp and radio simultaneously will obviously overload and **** the breaker. I may solicit a ham fried of mine to see if he has a 40 amp circuit for his radio room.

The ham that I bought the amp from said he had his radio and amp connected to the same circuit and it worked fine...

Not sure what to do. I don’t want to damage the radio or amp. I am kind of walking on egg shells right now.

Thanks

Barry Young

Hi Pete,

I purchased a 1.5 KW dummy load. I have had the amplifier for about 8 months. I feel like I want to test this with an another less expensive radio, in case something goes wrong. One concern I have is the amperage draw, the Flex draws 18-22 amps. The FL-2100F can draw up to the same. And My radio room is on a 20 amp fuse wired in series.. I’m concerned that running the amp and radio simultaneously will obviously overload and **** the breaker. I may solicit a ham fried of mine to see if he has a 40 amp circuit for his radio room.

The ham that I bought the amp from said he had his radio and amp connected to the same circuit and it worked fine...

Not sure what to do. I don’t want to damage the radio or amp. I am kind of walking on egg shells right now.

Thanks

David Decoons, wo2x

The Flex current is DC, not AC. The amp is AC current. For SSB a 20 amp house circuit should be OK for the amp and DC supply.

To be safe it probably would be better to have a separate 120 volt 20 amp circuit installed for the amp. You can have the electrician install 3 conductor wire for the new circuit in case you ever upgrade amp to a 220v amp, then the electrician will only need to change the circuit breaker and outlet. For 120 volts the extra wire in the cable from wall socket to electrical panel would not be used.

Also for the amp keying it is recommended to use a relay buffer such as the Ameritron AR-704B

Dave wo2x

PeteP

Thanks David, but the original thread start was just that...how to connect the Flex-6400 to the Yaesu FL-2100 using the 704 buffer.
I.E.- What actual physical connections to make. We are still researching.

Barry, I think I may tackle this this weekend...if I don't smoke the units I'll let you know. Wish I could paste a diagram here.

PeteP

Think I may have inserted the diagram I want.
On the 704 there are 3 RCA connections. Left to right- 'Amp, ALC, Radio'. The Amp goes to the RY and E of the Yaesu (E is the ground/shield). ALC goes to the ALC and it's E on the Yaesu.
Since there is no DIN cable for the Flex must use the 3rd connector 'Radio' then to the Flex. This connection I'm not sure to which Flex connector yet. This for experimentation this weekend.
Lastly, since no DIN cable to carry power a separate pwr wall wart must be employed.

Barry Young

Hi David,

So if the radio draws 18 -20 amps DC,

how much AC amperage is the power supply drawing to generate the required DC amperage?

Thanks!

ka9ees

Throw the ALC cable away. Just don’t overdrive it. Relay to RLY. Radio to TX 1, 2, or 3 You don’t need the DIN cable either. I don’t know what the 2 e’s are. I don’t think they are used unless you are driving the thing with an FT-101 series rig. And I don’t mean the current version. The one built around 1976.

73,

Ed KA9EES

David Decoons, wo2x

Yes ARB704 amp center to RLY and outer to amp E. No ALC needed but set radio to proper output power.

ARB704 radio rca to Flex TX1.

If using Flex software 2.6.2 or newer go into TX band settings and enable TX1 for bands you want to use the amp on. You also can set drive power needed per band.

Dave wo2x

PeteP

Like the convo all, thanks. Haven't gotten to it yet, hope to soon.

Barry Young

In my case, I have a 1.5 KB dummy load that I plan to use. I am just concerned about AC amperage load on powering the radio plus the amplifier on the same AC circuit.

Pete, look forward to hearing about your results and how it worked out. And how you connected the radio to the amplifier.

Thanks!

Ronald Panetta

Let's take a shot at this.

1) download the FL2100 manual if you don't already have it. I found it via Google at rigreference.com. BTW also download the 704 manual available on MFJ's web site.

2) do NOT connect the ALC line. Please compare the amp specs with the Flex specs for ALC voltages. If not compatible you could let the smoke out of the Flex. For initial setup and if properly driven you will not need ALC. I do not use it with my AL80B and my 6600.

3) the 4 **** terminals on the amp are paired. "E" terminals are ground if you check the schematic in the amp manual. So no connect to ALC and it's ground.

4) RCA to spade lug cable from 704 "AMP" jack to amplifier RY (hot) and E (ground/shield).

5) make sure internal 704 jumpers set for Radio(TX send)=Low per the manual.

6) with amp on dummy load and NO connections to radio, short the 704 "Radio" RCA center conductor to ground. The amp should key if in operate mode.

7) connect RCA to RCA cable from 704 "Radio" jack to one of the Flex "TXn" RCA jacks. Flex 6400/6600 TX ports good for 40V at 140mA max.

8) in the Flex band settings, configure the "TXn" for amp capable bands. Also suggest a Flex Transmit profile with reduced drive power for amp.

9) start with very low flex drive power and test.

Good luck, Ron

Barry Young

Hi Ron,

9) start with very low flex drive power and test.

You have to drive the amplifier with 100 watts min, correct? Are you saying start the amplifier output maybe starting with 200 watts?

The previous owner said the max wattage from this amplifier is 600. I don’t remember why that is the case.

Thanks!

KD0RC

Hi Barry, the amp requires 30 - 100 watts to produce full output. Start with 10 watts from the Flex to see what you get out of the amp. Slowly turn up the power from the Flex until you get the desired result. Be sure to to carefully read the Yaesu manual to be sure that you don't over drive it.

This amp is old enough that it is rated as 1200 watts input which will translate to around 600 watts out. In other words, it will be somewhere around 50% efficient. 1200 W / 120 V = 10 A, so a 15 or 20 A circuit is plenty. I would guess the Flex and a power supply at full output would draw a couple of amps at 120 V, so this amp and radio combo should play fine on a 15 amp circuit. You can always run it at a little less output if you are concerned about tripping a breaker.

Ronald Panetta

Barry, As KD0RC said, 30-100 watts input from the Flex is what is required to drive the amp. You'll get full output from the amplifier with 100 watts from the Flex. So start with 30 watts from the Flex.

Just to be clear, with KD0RC's comment "This amp is old enough that it is rated as 1200 watts input which will translate to around 600 watts out." When he talks about 1200 watts input he is NOT talking about input from the FLex. He is talking about 1200 watts input to the tubes inside the 2100. That is the internal plate voltage times the plate current (power=volts*amps) to the tubes in the amp. so if the amp is 50% efficient, to get 500W output to the antenna the 2100 internal power supply will have to source twice that or 1000W. Again, to be clear, that is not the drive level from the Flex. That remains at 30W to 100W.

Ron

Barry Young

Thanks Ron! I have a 1.5 KW dummy load I was going to test with.😄👍

Barry Young

Hi Pete...

Any luck getting your FL2100 to work with your Flex?

Any issues?

Thanks!

PeteP

Hi Barry, yes! Putting the document together now and will post in a few.

Barry Young

Hi Pete,

You are awesome!

Can you let me know what tuner you are using? I may have to buy a new one.. I have the LDG AT 200ProIi, which is only rated at 200 watts max.

Thanks!

PeteP

Radio.Amp.ARB set-up.pdf

My apologies if not clear, but here is the setup that is currently working for me.

Received some pretty rave reviews on 20 meter for sound from here in Alaska to CA and AZ so far.

Rather pleased with the results, sorry it took so long...like you I was hesitant.

Good luck,

Pete

PeteP

I'm running everything to a SteppIR that has it's own controller/tuner rated for full power so that's what's happening for 40-6 meter. I use a SG-230 on a wire for 80 meter but only to 200 watts...want to get away from that and probably put up an AlphaDelta fan that's real length, full power and resonant, so no need for a tuner.

If looking for a tuner, you may look toward Flex ATU Kit? Just a thought but I have no experience with it. Appears to be a cheaper solution than anything else ($299).

Hope this helps Barry, take care and cheers,

Pete KL7IS

Barry Young

Thanks Pete...

With the tuner,

Radio>Amplifier>Tuner>Antenna

Or

Radio>Tuner>Amplifier>Antenna

Thanks!

Ronald Panetta

Radio>Amplifier>Tuner>Antenna

In most cases it is the antenna that does not present a perfect 50 ohm load so that is where the tuner is required. Most amplifiers present a good input load back to the exciter so no tuner required there. The Flex, or any exciter for that matter, will display the SWR it sees into the amp. The amp will show the SWR into the tuner. Of course that is when the amp is in operate mode (aka not standby).

Ron

Barry Young

Thanks Ron!

So if that is the case, how does the Flex internal ATU be connected before the amplifier?

My tuner is rated 200 watts. Obviously I can’t run the full 600 watts....

I may have to purchase a new tuner.

Thanks!

David Decoons, wo2x

When using an external amp you should NOT use the Flex internal tuner. The amp input circuit should provide a good match to the radio.

If your antenna is not resonant then you will need a tuner between the amp and antenna and rated to handle the power of the amp.

Dave wo2x

Dave Skinner

You should not use an internal tuner when using an amplifier. This can damage the Amp. The tuner should be on the output of the Amp.

73, Dave WA5IMF

Dave Skinner

You should not use an internal tuner when using an amplifier. This can damage the Amp. The tuner should be on the output of the Amp.

73, Dave WA5IMF

PeteP

Thanks all for the help with the Flex ATU info, don't have nor plan to probably.

Barry, let me know if the config I sent helps.

73