Bliss Tuner Sick

[K1JJ]

...2) Big coil is 40 turns to cover 160M. Less for 75M. NOT critical. Any coil will work if it has enough inductance. The bigger tubing diameter, the better for losses. 1/4" - 3/8" is FB.  6" high X 15" long is typical.  Wind it on a quart paint can as a rolling  form and suspend on stand off insulators. [remove can... ] Many ways to do it...

I'll play the newbie and ask: What value for C1?

Whoops, I forgot to mention it.

Well, it depends if you want to cover 160M or just 75M as the lowest band. For 160M I wud suggest about 300pf or so. For 1500W I wud also suggest a 4-5kv capacitor spacing.  1/4" minimum. An old BC-610 cap with the two sections in parallel wud make a great cap. Or, a vacuum variable that's the common 500 pf at 7-10KV is even better.  Remember that only a single section is needed, so makes the choices easier. Remember to mount the cap on standoffs and use an insulated shaft for the knob. The coil also gets mounted on standoffs and floats.

You will find that with the four alligator clip choices, you can match about any load. The 50 ohm link tuning cap is a nice addition if you find you have wide ranges of various antennas, tho it is often not needed cuz of the versatility of the four variables and the cap tuning.

Dave, W2APE is building one up. He does real nice work and will hopefully post a picture of it.

They are so simple and require so few pasrts, I really like the idea of having a few pre tuned and connected to various antennas. Quick band hopping.

A good system might be a 160M open wire fed dipole that uses one tuner- used on  75M too.  Then a 40M openwire dipole that uses another tuiner- use on 20M too. And finally an openwire dipole for 15M that covers 10M and  6M.  The idea is that the antennas wud show a nice pattern [figure 8] on both bands and be easily tuned to either band. A coax switch cud get you on the next antenna/system. Fast.

I can envision having them preset on your favorite bands, like 75M, 40M and 10M ready to go with a coax switch.

T

[N5RLR]

FB, Tom...I've added this to my "reference library."   Thanks.

[flintstone mop]

GOOD BYE BLISS TUNER,
Hello my friends
I just wanted to say that the K1JJ tuner really does work!!!. I'll take a pix and you can see. Not the prettiest thing around BUT it plays very nice. Very slight warming of the coil. It was a breeze to find the 1:1 match using the MFJ 259 for 160,80 and 40M. Able to get 50 Rs and a Xs of 8.
 40M was a long time finding, but it handles legal limit with no arcing. The 40M taps were :::::Feedline, last taps in center of coil and the Vac cap 1 tap behind the feedline. Like I say,  full power and no arcing. I'm in heaven.

NOW the damned T/R relay crapped out on receive. It's a high power Magnecraft used in a Motorola FM base. I guess the contact was fryed from lightning in it's 2-way FM days at my former place of work.
Thanks for all the help a Pix is coming tomorrow.
Fred MOP radio

[WA1GFZ]

Fred,
 you worked for Mot? I did also for the worst year and a half of my working life. There were two possibes ways to get termianl sick working for them. 1. Mouse piss. 2. Terminal JSer's disease

[K1JJ]

GOOD BYE BLISS TUNER,
Hello my friends
I just wanted to say that the K1JJ tuner really does work!!!. I'll take a pix and you can see.

Wonderful....wonderful...  as Laurence Arc used to say.

That's good news, Fred. You now can see the joy of total versatility and control of a perfect match. Now that you've found the right taps, put the little bulbs on the feedline legs and fine tune each feeder leg in or out a turn to get equal brightness. Use low intensity for better eye sensitivity.

Once you get these coil taps marked, you can change bands in seconds.  Welcome to a small group of guys who have built and are using the tuner... and congrats on doing it homebrew, OM!

Can't wait to see the pic of your own implementation.

73,
Tom, K1JJ

[flintstone mop]

How I remember my parents watching those distorted black and white TV pix and the 4kc audio from the networks. The bandwidth hog was the video, even though sent by "coaxial cable" through the telcos or microwave, the audio was telephone quality from the networks, EVEN if the show originated in the city where you lived. Everyone heard the same crap.

OK on some bulbs to balance the system. Thanks for sharing the diagram and the "white paper"

The pix are the inpoot coil, which was a nice ceramic job laying around, I guess 3 inches and 6 turns. The beaded stuff was stolen from the Bliss tuner inpoot circuit. It gets very warm for an old buzzard.

The last pix is the actual tuner in all of its glory. Gotta find a better way to clamp onto the taps. I had some clamps from an edgewound coil. The local home store didn't have any manly aligator clips.
G'day..............MOP radio
Fred

[flintstone mop]

Sorry,Here's the inpoot pix
Don't know what happened

fred

[K1JJ]

Looks FB, Fred.

Please explain about the "Beaded" thing from the Bliss tuner??  You want to use regular wire for the input leads. You don't want to choke anything off there. You say the beaded lead gets warm?  Maybe I misunderstood.

Try to score a turns counter for the vac variable and pre mark a little card with settings. EZ and FAST.

Looks like you laid it out right and should work FB, OM.

T

[flintstone mop]

OK Tom,
I was just copying the input circuit from the Bliss Tuner. It was the length of coax you see that connected to the "built-in" wattmeter. It's a number of the small iron cores you see there. I cannot figure out what this is for, just threw it in coz it was on the Bliss tuner. Maybe someone can figger what is going on. Would it be like a 1:1 un-un??
Just throwing something out there. You know, empty barrels make a lot of noise.
The tuning of the variable is mainly 3/4 full PF for 160M and 80M and almost no PF for
40M.
I'm gonna nail things down and mount it on the concrete wall later today

Fred

[ve6pg]

...fred...the input coil..is it just sitting in there,or bonded in place? btw,how much copper toobing did ya use?..tim...sk..

[K1JJ]

Fred,

Yes, take those ferrite beads off the coax. You see, normally they wud be OK, but in this case, they are inside the main coil and are heating up due to coupling energy from this big coil.  Remove them and you're OK.  If you want them, then use them OUTSIDE of the big coil, at least a foot away.

The 40M taps being close to the inside... that's a pot luck thing... so happens that you are near a current max and are feeding it low impedance by tapping closer to the center. You can always add 10' or so [or subtract 10'] from the total feedline length, and hope that the other bands stay nicely positioned at the same time. When running one tuner configuration like that, there is always one band that is right near the voltage or current max... probability. Find a way to lengthen the feedline somehow while still maintaining a nice fedline run and your problem will be solved.

Another possible way is to JS clip lead in a 1200 pf cap in series with the input link to ground for a test. Try various settings of that. This will alter the transformation ratio and may let you get away with bringing the taps out a little more on 40M. 

Let me know what you come up with. BTW, maybe even getting rid of the ferrites will help if they somehow were sucking too much influence on 40M.. but just a wild chance on that.

T

[flintstone mop]

OK Amers
Tom what number bulb can be used to fine tune balance??

Here is a little recap I sent to Tim.
Hi Tim,
I bought 50 feet of 1/8 inch copper from Lowes.I wound 39 turns on a 4 inch OD PVC. For my antenna system, I am using about 4 turns INTO the coil for my first capacitor tap for 160M. The input coil is on a ceramic form, maybe  3 inches and 6 turns there.
I removed the beads and just have RG213 coming to a PL259 to interface to my transmission system. It slightly changed 40M settings, but I'm happy.
The hassle is that I have to leave the shack and walk 25 feet to the tuner if I want to change freq.
The proof will be throwing AM power to it and gathering signal reports.
I haven't found time to look in the MFJ manual for the Xs and Rs readout. I know that when I see a perfect 50 ohm match 1:1 SWR that the Xs = 0. So, I always try to play with taps and move the input coil slightly to get the Xs lower. My three bands are all siingle digit Xs and very near 50 ohms.

Fred

[K1JJ]

So, you're moving the input coil a little to get a better match? That's interesting - never heard anyone doing that. But, it will certainly have an effect, just like a link coupled final.  Whatever works but maintains balance is OK.

For the bulbs, any flashlight bulb will do. Solder 2" leads to each one and take one bulb and bridge it onto ONE feeder. Spread the connections, maybe 2" apart. Farther apart for a brighter bulb at a given power level. Be careful not to blow it out... start with QRP and ramp up.  You want the bulb to BARELY glow. Just get the filament to glow slightly.  Do this for the two bulbs. Put them at the same distance down the line.  Look at them together and compare brightness.

Tap OUT one feeder one turn to make the dimmer bulb brighter or vice versa.

Make sure the tuner is sitting at least 6" above any metal tables, etc, or you may be introducing an inbalance. Remember that the components are floating, just like the feedline. The only thing unbalanced is the 50 ohm coax coming in... and it is link coupled into the balanced tuner, thus no problems.

73,
T

[w3jn]

#48 or #49 bulbs are the most sensitive, if you wanna use lower power - 2V@60 mA.

[David, K3TUE]

I have to say, I am confused as to how to wire the bulbs for the balance indicator.  I understand you start at low power and increase until it is a useful low brightness for comparison.  But...

Are they in series or parallel with each leg of the feedline?

And if they are in parallel, where does the other lead of the bulb go (to ground?)?

[flintstone mop]

There is no direct connection to the feedline.
Solder 4 or 5 inches of insulated solid #24 wire to the bases of the bulbs. Has to be a quick tack solder.
Then wrap the wire around the feedline. You are going to induce the RF voltage on the feedline into the wire and that voltage will light the bulbs.
Hope this helped

fred

[K1JJ]

There is no direct connection to the feedline.
Solder 4 or 5 inches of insulated solid #24 wire to the bases of the bulbs. Has to be a quick tack solder.
Then wrap the wire around the feedline. You are going to induce the RF voltage on the feedline into the wire and that voltage will light the bulbs.
Hope this helped
fred

Fred,

That's an interesting way to do it, OM. I never thought of that type of RF coupling to light the bulbs.  It will work FB.


David,

The other way is to take two 6V bulbs and solder leads to them. Then take one bulb and spread the leads about 3" apart and solder them to ONE feeder. ie, one bulb on one feeder leg. The distance apart will determine the RF pickup from this single feeder wire.  Then do the same thing for the other leg.

By varying the wire distance you will vary the bulb intensity. As little as one inch or as much as 6" will work depending on if this is a voltage or current point, the resistance of the bulb and the power you run.

Just to be clear... the bulbs do NOT go across the two feeders... each one spreads itself out on one feeder and simply senses the voltage drop (IR) drop on one wire at a time.  Set the bulbs up so that they barely lite to give your eye the maximum sensitivity for balance measurements.

OK now?

T

[David, K3TUE]

Ah, I get it now.  Your suggestion implies open wire feedline.  Or at least stripped ladder line.

I was thinking insulated ladder line.  For this I see how Fred's RF induction would be better, but I am not sure what the other leg of his bulb is connected to, or is it the same deal for his, except both ends of the bulb are induced, and not direct connected?

[K1JJ]

David,

Yes, I believe Fred's idea  means a single wire across the bulb connections with the other end as a closed loop and wrapped around the single feeder wire. Picture the lead like the secondary of a transformer and the bulb is the load. (And the feeder wire as the primary)

That would be a better technique for insulated feeder wire...

T

[David, K3TUE]

Picture the lead like the secondary of a transformer and the bulb is the load. (And the feeder wire as the primary)

Boy, do I feel stupid for how long this took me.

[David, K3TUE]

Does anyone have a good source of affordable (what do you consider affordable?) 500pF @ 5kV breadslicer air variable caps?

This is all I can think of:

• Hamfests ($(deals can be found))
• eBay ($(sky high))
• TenTec ($69, UK site (http://www.aoruk.com/tentec/kits/1207/1207.htm) has specs that the US site (http://radio.tentec.com/kits/Accessory) does not have)
• Palstar ($110, (http://www.palstar.com/c600.php))

[flintstone mop]

Hello from MOP radio,
I have had good deals buying vacuum variables from E-Pay. Believe it or not!

Fred

[David, K3TUE]

Well, I have procured a sizable varfiable cap from ebay at a reasonable price.  But now that I have received it I see there is notable white corrosion on the plates (both rotor and stator).  Is this likely aluminum oxide or perhaps something else?  Is there some way I can clean it without removing all of the plates?  Or should I just leave it alone?

[flintstone mop]

Steve THE HUZMAN,
Gave me some advice to clean a bread slicer..........cook in tomatoe sauce for a few hours and it will look like new!!!!
You will have to lube the pivot points and give it a thorough drying.
Has anybody tried this???
It worked for me.

Fred

[David, K3TUE]

cook in tomatoe sauce for a few hours and it will look like new!!!!

Just drop it in a pot of bubbling tomato sauce?