AM Phone in Canada on 75-80 meters?

[VE3GZB]

Here's a schematic of what the whole transmitter, power supply and modulator are about.

Upper portion is power supply and modulator, including relay.

Lower portion is master oscillator (switchable 40/80 meters, switchable Xtal/VFO) and power amplifier. Tubes are British Cossor 215P (Master oscillator) and Cossor 220PT (Power amplifier).

Temporarily I've removed the 220PT and patched in a 6BQ6 to see if I get better results.

[K1JJ]

I'm not sure I can quite picture what you're describing? Can you link to a jpeg or something on the internet to illustrate what you mean by "running two legs"?

It's just a standard dipole, but with the two legs running out into your yard instead of in opposite directions. Use what you have set up now. Get rid of the auto transformer stuff and feed it directly. On the side of the feedpoint insulator where you have no connection, add another 63' wire like the first one.  Feed the two with coax or open wire.   

If you can't fit in 63' per leg, it's OK to let some wire at the end insulators hang straight down towards the ground 10' or so.  If using open wire, the length is not critical and will work on all bands  (ant tuner needed) -  but using coax will mean fussing with the legs lengths for 1:1 swr for one band only.

How far you can get the end insulators apart (and high) will dictate how well it works.


T

ie, Put up a 1/2 wave dipole and stretch the legs out any way you can to keep the end insulators as far apart as possible.

[VE3GZB]

Hmm....well I have no more wire. I used all that I had to make this antenna that's running now. Ditto for feedline.

For the sake of length, because the back yard is rectangular and our house is right next to the village's power lines, I'd have to run the wires parallel to each other, over to the far end clothesline pole.

If I run them parallel, wouldn't they cancel each other out?

[K1JJ]

Hmm....well I have no more wire. I used all that I had to make this antenna that's running now. Ditto for feedline.

For the sake of length, because the back yard is rectangular and our house is right next to the village's power lines, I'd have to run the wires parallel to each other, over to the far end clothesline pole.

If I run them parallel, wouldn't they cancel each other out?

Yep, they will cancel if run too close to one another. Can you use the extreme edges of the propery as anchors, if it will help to spread out the legs?  Even the ends 8' off the ground will be OK.

Sounds like you would have a good installation if the XYL let you hang the feedline in the middle of the span - but maybe the system I've described will be a good compromise.


Home Depot (or equiv) has wire cheap.

The problem is when using only 3 watts, you need a good antenna system or it will continue to be frustrating to make contacts on 75M.

T

[VE3GZB]

On the opposite end of the property? It would have to cross over the power lines that run to the house, through a tree, over the garage, over the Cable TV feed - plus at the opposite end or anywhere near by, there is simply no mounting point that's elevated from the ground that's on our property. There's the village's hydro pole but I wouldn't be permitted to anchor to it without violating some bylaw or something. The old defunct TV antenna tower and the other clothesline pole is all I have to mount my antenna from.

I've been trying this evening (4:30 to 5:30) to see if there's anything I can receive on 80 or 75 meters - not much activity, only static and a few stronger commercial SW broadcasters. I'm next to power lines and a Cable TV feed so I'm not surprised that I get lousy reception....plus there's a reason why this village is called "Grand Valley" - it's because it's in a valley, so even if I put 100 foot antenna up, I'd only be at ground level compared to other terrain.

I'm in an RF noise pit I guess!

[KX5JT]

May be time for a camping trip to a nice campground with electric hookups underground and plenty of trees to string up a temporary dipole! 

[ve6pg]

..geo..i was on, with jim, ve3brl, and al, ve3ajm from 5pm until 6:50 this evening...al was 40/9, jim was 30/9, in hanover...i'm very surprised you did not hear us, on 3725...

..sk..

[K1JJ]

On the opposite end of the property? It would have to cross over the power lines that run to the house, through a tree, over the garage, over the Cable TV feed - plus at the opposite end or anywhere near by, there is simply no mounting point that's elevated from the ground that's on our property.

....plus there's a reason why this village is called "Grand Valley" - it's because it's in a valley, so even if I put 100 foot antenna up, I'd only be at ground level compared to other terrain.

I'm in an RF noise pit I guess!

Geo,

OK, I get the picture now.

Well, there's still hope, but you will need to stretch.

It appears you are limited to a 50' flat top. That will be OK on 40M, but lossy on 75M unless you do a few things. 

1) Build up a K1JJ "Super Tuner" for the shack.
http://amfone.net/Amforum/index.php?topic=18054.0
(For more info do a search for "K1JJ Tuner" on this site.)


2) Get some #10 wire (Home Depot) and make up some high quality open wire and use the rest for the 50' flat top.  Use any open line spacers you like: Plexiglas, Teflon, Lexan, ceramic, PVC, etc.

3) Beg the XYL to let you feed the flat top in the middle with the openwire. If not, feed it as a Zepp like you do now using the existing tower. Connect the openwire directly to the flat top without any network. (Just use the shack tuner)


The 50' flat top will work great on 40M fed at the end or in the middle using the tuner and openwire. On 75M you neeed to use the tuner in the series mode and the #10 wire will reduce the losses greatly. 

BTW, being in a giant moon crater like you are is a good thing for local work. The bowl acts like a big dish and enhances your take off pattern in the higer angles, though will reduce it for DX.  I've modeled this with "Terrain Analyzer."


Put up the low loss flat top and openline and build the tuner and I guarantee you will make contacts on both 75M and 40M with 3 watts.  If you get the XYL to let you feed it in the middle, then you will do even better.

The biggest risk here is having you give up in frustration cuz of an antenna system that is lossy.   Give it a good go first with the stuff I mentioned above.

Later -

Tom, K1JJ


Build This:  (A standard variable bread slicer capacitor is OK instead of the vacuum cap.)

[VE3GZB]

Geez, that's an amazing tuner!!

Well, I know what my wife will say about messing up the backyard so I won't even go there!

This is rapidly turning into some kind of hideous monster......I did find something - my receiver is really whacked out! Calibrations are totally off, linearity across the tuning scale is also very bad. This is on the 1.6-4 MHz band as well as the 4 to 10 MHz band.

I have a frequency counter and signal generator (I have my own home electronics lab where I also do some work for my employer but I'm also heavily laden with work-related projects - I work in RFID - I have to attend to as well).

I got the receiver last year at the first hamfest I ever attended, I got it for $40. Fellow said he re-tubed it but I see now that the calibrations cannot be trusted. Sensitivity is still good though, I can pickup radio Ukraine on it.

That, plus the internal circuit hacks, it's gross nonlinearity, it's very queer spurious responses and the non-functioning BFO make it a worthy candidate for replacement as soon as I can afford it because figuring out what someone did to the poor beast will take more time and waste than it should.

Not sure how I'm going to afford that however. $40 is still a lot of money for me and I'm mad at knowing that I was gypped by a ham who knew what the inside of this receiver was, since he did the retubing himself, he sold me a "good" receiver but it turns out to be something of a wreck. Shame on him (don't remember who he is or his callsign).

I did make an old-time homebrew regenerative receiver, it uses one turned RF stage, one regenerative stage and one audio stage. It's not calibrated except for a dial that's 0 to 100, so frequencies are a big guessing game. But being a non-conversion type of receiver, I'd probably not be as plagued with spurious responses which cause me to mistune the receiver to some noise or other stuff radiating from the transmitter.

Imagine...all of this time it's possible people could have been replying to my CQs but I would never have heard them because I have probably been tuned to some odd receiver spurious response to my transmitted signal.

Funny that I was able to nail 3.880 this morning but I guess that's because I first found their signal, they identified their frequency, then I was able to use my freq. counter to tune my transmitter. Dial was not pointing at 3.880 when I received their signal but it was between 3.5 and 4 MHz on the dial so who knows what it's doing or responding to.

So thanks for the antenna advice but at this time I'm not going to change anything on my antenna system until I verify that my reception is fundamentally consistent and repeatable. To jump into changing the antenna system when I have measured such faulty performance from my receiver would be very wasteful of time and resources.

The energy my transmitter is developing is going through the feedline and ending up somewhere. I Ohm out the line and there are no shorts to ground or anything else, so the energy must be radiating into space as it ought to. Perhaps not at the best efficiency yet.

Once I have the receiver sorted out, then I can start looking afterwards at changes to sort things economically and in a sensible step-by-step process so I can reuse as many materials as I possibly can.

To make something good out of something badly vandalized as this, I'll probably salvage parts out of the Hammarlund, parts such as Xformer, tubes, varicaps, whatever passive components there are, so I can continue to build on budget (next to nothing is my budget).

[Steve - WB3HUZ]

If you are going to put the matching LC network out at the antenna, there isn't much advantage using open-wire line. Lots of designs out there doing just this. Check out the works of G6XN.

Thanks, I'll look into what times of day might work best. Will be too busy today with other family stuff, getting my car fixed, etc...to have time to play but I'll have more time on Sunday.

Here's a drawing of what my layout looks like.....minus the proposed tuned autotransformer idea I have drawn (but not yet tried so my antenna is just about 60 feet of wire attached to the transmission line).

What do you think? If I attached a tuned autotransformer to my Zepp to try and match it's apparently high impedance to the 450 Ohm transmission line, would there be any merit? Has anyone tried something like this?

My wife won't hear of me stringing ugly transmission line into the middle of the backyard, she's worked so hard to make it nice looking and she doesn't want the middle of the yard looking like some lab experiment, so my layout has to remain with the transmission line near the house (it's about 1 foot from the TV tower, held in place with a plastic coathanger and tape).

[ve6pg]

..geo...i'm here to help...what do you need?...tubes, loan of a receiver, wire...name it...i'm only about 45 minutes away...
...email me,
  ve6pg@wightman.ca
 

....sk..

[VE3GZB]

ve6pg - you have e-mail, thanks!

[k4kyv]

Here is some information you might find useful.

http://www.aa5tb.com/efha.html

http://www.g4nsj.co.uk/zepp.shtml

http://www.qsl.net/vk5br/MeritsOWLine.htm

http://books.google.com/books?id=f3asJreno0YC&pg=PA208&lpg=PA208&dq=end+fed+zepp&sour (scroll to p. 208)

[VE3GZB]

Very useful indeed! Thanks!

That Practical Antenna book looks wonderful! I wonder if my local library has something like it.

[VE3GZB]

Very miserable tests tonight, in fact my carrier was barely audible even when feeding 20 watts into a 6BQ6 final, quite a difference from a couple of months ago when my previous transmitter only got 3 watts into the final (1.6 watts out) and Lou picked me up at S9.

My friend VE3AWA and I did a phone thing. He monitored while I keyed the mic and tried to modulate. My modulation was not audible but my carrier on 75 meters was just audible above the static.

We switched over to 40 meters to see if anything could be had? Nope, not even a carrier, even though it was clear that I was pushing even more energy into the feedline (by the brilliance of the 5W 0.5A lamp in series with the feedline, it was glowing a VERY very bright yellow, almost white hot filament whereas on 75 or 80 meters it glows "normal" yellow).

Just how much input power do you really need to be heard on either 80 or 40 meters?

Bear in mind that I live right next to the village power line, it runs right by the house, and we're in a valley too.

This is really frustrating and getting depressing.

What if I tried constructing a loop antenna for the system to resonate at 80 meters? Has any Ham had any kind of success with loop transmitting antennas on 40 and/or 80 meters?

At work, we specialize in loop antennas (resonant and non-resonant) so if there's any chance I could use a resonant loop for long distance communication with just a few watts input (or a few more watts than a few), I'd like to hear about it?

My brother-in-law might have some old scrap clothesline at the farm in the junkpile, if so then maybe I could make some kind of backyard hidden loop antenna and resonate it from within the house?

[N3DRB The Derb]

geo,

I am going to send you some things that will be very useful. look for it via Canada Post.

we call it a care package around these parts. I have gotten many and it's time I sent out one.

You obviously can homebrew and build, so we'll send you some goodies along those lines.

Derb

[VE3GZB]

Holysmokes, thanks! 

I slept on it and I'll try making in antenna into a dipole. I'm out of leadin (I currently have this 450 Ohm stuff) so I'll ask my boss if he can spare any 16 ga stranded wire (like 150 feet of it).

I'll do like they did in the old days, twine it up, twist it and make a balanced feedline out of it.

A dipole runs about 72 Ohms, hopefully twisting up some number 16 will give me a characteristic impedance closer to the antenna's own impedance. Hopefully my boss says yes....he's a good guy, he got me some vintage tubes for Xmas!

I can probably run the leadin under the deck and up the railing.....as long as the colour and thickness are such that it remains nearly invisible, my wife will hopefully have no objections. The big chunky stuff I'm currently using resembles train tracks and there's no way she'd let that dangle in the middle of the back yard!

It's clear to me that my Zepp installation has major mismatch issues! I'm dumping 20 watts into my final and barely getting a signal out, yet the 450 Ohm feedline is drawing 1/2Amp (because I'm making a 24 V 5W lamp in series glow so very brightly, almost white hot)!

I tried something last night after the sunset made it possible - I put the transmitter on and examined my antenna for corona or arcing at either 40 or 80 meters. Nothing.

Thanks for the help!! It's a huge challenge and a struggle to try to get stuff going on a budget of nearly zero (as little as possible anyway).

[N3DRB The Derb]

One of the things I'm gonna send you is a hot wire rf ammeter so you can tune for max blowsmoke into a given load. Also a Grundig Yacht Boy 300 Rx that I was told to pass on to someone who needs it, and you need it more than I do.

some other stuff that wud be helpful. 

[VE3GZB]

Gee, thanks!!!!!! 

[KX5JT]

I just want to say that I LOVE this thread!  Don't give up George, you WILL make some QSO's.  80 meters is BRUTAL during the summer here.  But your project is inspiring.  I had been tossing ideas around for my first homebrew project and I kept thinking I need to start with an aluminum chassis.  Well now I think that is just DUMB!  I need to start with a WOODEN breadboard-type chassis like you and get the circuit working FIRST!  I am looking close at how you have the tube sockets on standoff screws and I wonder if you drill and bolt those with nuts are are they woodscrews?  Also I see some components seem to be simply tacked down with glue. 

This forum and a few other sites and by extension, all you guys are my Elmer.  I don't know anyone in my area into homebrewing anything larger than qrp rigs in altoid cans.  When I finally get around to trying out a project, I'm going to need lot of guidance! 

John KX5JT

[VE3GZB]

Thanks....the screws are just woodscrews and I used solder flux and solder and my good old Weller gun to solder the tube sockets to the tops of the screws.

The wood? Got at at Home Depot, their cull section, 51 cents each.

Glue? Almost. It's RTV Silicone. I'm using a lot of it to hold things down which aren't meant to be surface mounted.

I've been trying all winter and I'm frustrated but not going to give up!

73s
geo
VE3GZB

[VE3GZB]

My boss let me have a couple hundred feed of #16 insulated. I laid the pair out on the ground, tied one pair's end to a tree and put the other end in a drill. Then when that was done I put tape every 12 t o16 inches to hold it in place.

I measured my antenna, it's 45 feet long. I cut it at 22ft 6 in, installed an insulator, ran the homemade twisted pair under the deck (cut and drilled some wood, fastened them below the deck so I could run the homemade twisted pair twinlead through the holes and not have it lay on the ground), then ran it into the insulator and made the connection, then hoisted the antenna back into the air via an old clothesline I'm using on one end, fished through the old TV mast.

I wasn't able to remove the "old" 450 Ohm feedline from where it runs through the wall, it's in there REAL strong and even I couldn't pull it out (I've got some heft to myself)!! So I cut it as close as possible and left only about 6 inches of the 450 Ohm line in the wall and just soldered the homemade twisted pair to it on both the inside and the outside, then sealed the outside up (got a PVC pipe Siliconed on the outside wall to fit into the cutout I put into the Aluminum siding).

I ran a quick test on it this evening.....it tunes up differently on my transmitter and I'm able to hit maximum current (very bright, white hot filament) on both 40 and 80 meters! But I only tried for a few minutes because it's not 11:04 and I'm just finished up about 10 minutes ago!

I'll turn in now but try again tomorrow.

[VE3GZB]

Wow, 80 meters is so cluttered, also noisy where I am.

But I noticed that 40 meters doesn't seem to be as bad, in fact from where I am there's only a few broadcasts happening and those are spread far apart (commercial SW stations).

Is there any activity on 40 meters in the evenings? I tried calling for about 10 minutes but received nothing in reply.

(My antenna is 45 feet long and it's a dipole now so I can use my homebuilt antenna tuner to load it up on 40 as well as on 80.)

[W3RSW]

After reading the whole thread, between your wife, your manacured back yard, your receiver doubts, your signal strength and the rotten QRM/QRN laden bands in this part of the 'cycle' and just about everything, you have a real challenge. 

But you do have a nice looking breadboard in the classic sense and have obvioulsly had a lot of fun building up an "older" fashioned scheme of modulation.  A contact or two may be a miracle; why not try feeding your signal into a linear amplifier to make an intial contact then turn it off and see if the QSO can continue?  I'd sure like to hear your rig.  Such a work of art needs a name too; well... two names, one for the RF board and one for the modulator.  Shirley and Harley?  heh, heh.

[VE3GZB]

Heehehehe!!! YEa funny!!

Well, I don't have any factory made transmitting gear......the notion of paying a CEO for something I ought to do on my own, well that just goes against my grain.

I'm not giving up though!