Tuned input question

[Jerry-n5ugw]

I'm feeding a AL-811 with a TS-430, If the tuned input between the TS-
430 and the AL-811 do not match could that cause a reduced Grid Drive
input??

The reason I ask, The TS-430 will not drive over 30mils of Grid drive
current no matter how high the input wattage on any band. So I poped
open the case and found two of the tuned input slugs backed all the
way out until they were touching the heat sheild behind them. The AL-
811 came from a SK.. via his CB'er son. I suppect someone tried to
retune the inputs for 11m. I hope I can still find the tuning sticks
for alen head slugs. Thanks

[W1RKW]

Jerry,
 I'm building a 813 AM rig and had a problem with getting sufficient grid drive to the 813 grids. My input tuning network was the sticking point in getting the drive to be were it needed to be.  I had an issue with one of the capacitors that gave me all the grief I was getting.  Although my issue was with a cap it was in the tuning network.  You maybe having a similar issue where it may not resonate where it's supposed to. 

I wouldn't think if the slugs are backout as far as they are that they are in their normal position.  Are the slugs backedout for all bands or just the 10m band?

Isn't the AL-811 a grounded grid amp?  Not sure if that matters or not.

[N3DRB The Derb]

get the GC hex head tuning tool offa ebay and I think you will find that adjusting the input for maximum grid drive while keeping it under the tubes maximum rating will fix that. probably adjusted the 15 and 10 meter slugs, right?

[Jerry-n5ugw]

Yes the amp is a GG three 811a tube amp. It's the 15/20m and Aux slug. Found a green wire cut to the Aux position. This my be the 10M mod for the AL-811. Not sure. I think this CB'er monkeyed with all of the slugs trying to get this amp to work on 11m.
So if you don't mind my asking? What would be the procedure for re-tuning this to A Ham band tuned circuit with the TS-430.

[WD8BIL]

Jerry... in the GG amp you don't want a lot of grid current. The AL-811 is probably biased class AB2 so when properly LOADED it should have minimal grid current.

When you find your diddle stick tune the inputs for best swr 'tween the radio and the amp.

[Jerry-n5ugw]

I understand that but I'm only getting 30ma grid drive with 70W drive in and that will not drive the 572B nor allow proper loading and not more than 100W out. So I need more drive to get around 200w carrier. In SSb i don't get more out than the 430 itself on peaks.
I'll get the meter inbetween the rig and AMP when I get the tuning tool and set that. Then I can see what else the Boo-zoo did. Thanks

Now if I'm barking up the wrong tree on this let me know... or anyone needs more info on the issue. Thanks

[W1QWT]

Found a green wire cut to the Aux position

Yes that is the mod for getting 10 meters. I just bought one.


Regards
Q

[Jerry-n5ugw]

Have you looked inside at the tuning slugs. Was the 20/15 and Aux slugs backed out against the heat sheild???

[W1QWT]

I never really noticed but I seem to think I remember that I could see much of the slug out the end.
I just opened it to cut the green wire to enable 10 meters.
Regards
Q

[WA1HZK]

Put a SWR meter on the input. Tune the slugs for the best match. If you still cannot get much drive look at the tubes. Did one or more of the grids get smoked by the diddler?
Keith
WA1HZK

[WD8BIL]

Grid current in a grounded grid amp is NOT a priority drive parameter. AB1 draws virtually no grid current and AB2 draws very little when tuned properly. It is more a measure of loading not drive. Plate current is the major measure of drive in a GG amp.

Keith is correct. Tune the inputs for best match. Lack of proper PLATE CURRENT indicates a drive issue. Those issues usually break down into drive not getting to the cathodes or soft tubes. If the bias is developed by a zener in the cathode line check the zener and it's bypass cap. Don't worry about low grid current until proper plate current is present. When it is grid current can be primarily controlled by loading.

[Jerry-n5ugw]

Will do.. on the swr meter, I get about 150-300 mils max with 25-75 watts input.

[Ralph W3GL]

You are using a TS-430 as the driver.  That radio should have a built in "swr" position on the meter switch!  At least my TS-440 does and also all the other Kenwood radios I'm familiar with.

No need then for an external SWR meter! Just turn up the carrier control, switch to the swr position and go with the diddle stick...

[Jerry-n5ugw]

430 is not that complex.. Pwr/Alc on same switch no swr..

[WD8BIL]

Jerry, what's your plate current with the amp keyed and NO drive?

[Jerry-n5ugw]

idle current is 60ma. on the plate with 1600vdc

[W3DBB]

.

[Jerry-n5ugw]

That's how I do it Doug, but when i load max in CW I still only get 100W-150w output. Not near the expected. I think the Power Supply will only handle 400w total carrier. So Am swings included a 100-150W carrier is it. I have this station in my RV so Boatanchors will not fit. The 430 does ok, I'm not trying for BC or Plate Mod audio. That won't happen. I may have more than one issue masking each other. So knock them down one at a time. Thanks

[W3DBB]

.

[KI4NR]

The AL-811 has an excellent tuned input circuit easily getting the input SWR down to 1.5 or less. Unless it has been tampered with as might be the case here, Do this. Put an SWR meter between the radio and amp input, connect the amp to a dummy load. Power everything up and put the TS-430 in CW mode medium output key her up and adjust the Amp's plate and load for max output. While keying up check the SWR meter to see what the input SWR is. If it is high over 1.5 adjust the coils to bring it down. Once you do that readjust the plate and load on the amp again, then check input SWR. Keep doing this until you get the lowest input SWR to the radio and maximum out from the amp which will be approximate 600 watts if the tubes are ok. Of course let the amp rest between testing key up's and sneak the power from the 430 up to max gradually in doing all this adjusting. I also wanted to add you obviously have to do this for each band.

Once you get all this situated, Here's how to run the TS-430 on AM .....Run the 430 with max power of 30 to 35 watts if you run it barefoot or with the amp set the power at 125 to 150 watts. The key to getting a good sound is to run the speech processor on AM. The TS-430 (and the TS-440) has an audio compressor that works very well on AM. I used a D-104 on mine back in my early days and it sounded great. The audio curve is good for this radio. Use the amplified version for best results. Turn on the speech processor, then set the Mic control on the 430 at about 10 o'clock and adjust the D-104 audio pot for best modulation, you might have to put a resistor attenuator in the D-104 audio lead because the 430 has a hot mic Preamp. The TS-430 like almost all Japanese radios use's the SSB balance modulator for AM in an unbalanced mode. This makes it a four quadrant multiplier modulator with all it's faults, But running the audio processor makes the audio input stable to it and it works fine. Much better than you would think. The ALC circuit on the 430 is not sensitive and at 35 watts or less it will have No ALC at all , This is because the 430 does not have a SSB power control that adjust the ALC threshold like the newer radios do. Hope all this helps you out.

73 John KI4NR

LPC Wireless
http://www.qsl.net/ki4nr/

[WD8BIL]

Jerry, what wattmeter are you using ??

[Jerry-n5ugw]

Thanks John and the rest for the input. I will exactally what you have suggested as well as others and once that is done i think all will be well. Had i known the CB'er had monkeied with the amp I would have done this first, but it was not on my mind as a posibility. It is way out of tune and I am awaiting the tuning sticks to be able to adjust the coils. I am going to rework the coax as well to ensure i have real good sheild path and center isolation to the inverted vee. Thanks to all for your input. Here you in the static down the road.

[Jerry-n5ugw]

I'm using a HM-102.. Not the best but close enough. Surprisingly enough and Jim W5JO can chime in her. This 430 does a fair job on AM. It does have a tendensy to downward modulate if given to much audio and you have to set the audio real close to to much or not enough. I'll try working on that after I get the Amp on it's feet. right now the testing shows a 2:1 or better SWR on all bands. Monkeyed with pretty bad. I am awaiting the tuning sticks to arrive and then get to adjusting. Once that is done I'll look real close at the coax and make sure I don't have any breaking down at higher wattage heat disapation. I'm trying to use RG-58 due to access to the outside.
After that I might see if I can bypass the mic amp stage and drive the Balenanced Mod. with 600 ohm audio.