Proud Mary wrote ...

A long wire antenna made of 'magnet wire' - i.e. enamelled copper wire, will work well, if it is thick enough and strong enough and resilient enough, though I wouldn't recommend it. But if it's all you can get just now, it will work for you in the short term.

As for your superregen, just connect the antenna directly to it for the moment. You'll get better results if you have an Antenna Tuning Unit (ATU), between the receiver and the antenna, but this is by no means necessary to start off with.

The EL84 power-oscillator transmitter design is truly awful, Alf, for the following reasons:

1.) In the key-up position, you will have HT on the key itself. This kind of dangerous cathode keying is not acceptable.

2.) Oscillator cathode keying will cause chirp. Chirp is a condition where the oscillator takes a small time to find its feet and settle onto its design frequency - which it will have to do at the beginning of each dit and dah since the oscillator will only be running when you depress the key. At receiving stations, this frequency change mixed with their BFO will sound like a chirp, hence the name. Chirp will be much worse with a keyed VFO.

4. The circuit will destroy most modern crystals, as discussed.

5. A valve oscillator driven hard like this one will produce abundant strong harmonics, which will not be attenuated very much by the output tuning arrangements in this circuit. It will probably interfere with your neighbours' televisions - TVI. Valve oscillators will get up to all kinds of tricks unless you take a very firm hand with them from the outset, from the design stage, where you must specify all the things they must not be allowed to get up to and take account of them.

6. The output matching/tuning set up is unsatisfactory. Besides doing very little to attenuate harmonics and other spurii, it won't make a good job of loading random wires, or anything else outside its obviously limited range.

Sulaiman wrote ...

I had a dipole for 20m band (2x 5m) using 0.8mm dia. 'magnet wire' which stayed up for several years, it finally broke so now I use 1.5mm dia 'magnet wire'
The dipole is over 8m high mounted on fiberglass fishing poles which sway easily >30 degrees each way in high wind ... no problem.
So I'd recommend 'magnet wire' for it's cheapness.
I've had trans-atlantic contacts with 50W ssb so it must be ok.
IF you have the space 1/2 wavelength dipoles are the best as no earth is required.

P.S. too thin wire breaks easily and birds may crash into it being unable to see it,
too thick makes an attractive birds resting place,

P.P.S. IF you have conductive soil and make a reasonably good earth then a vertical is good for 80m .. preferably 20m vertical, or less with a matching circuit (AMU/ATU)
If you use a 'long wire' antenna you will also need a good earth for 1/4-wavelength wire, or a good balun for an end-fed 1/2 wavelength, try to get the antenna 1/4 wavelength (or more) above earth or most of the power goes up, not horizontally.

Sulaiman wrote ...

That's why I said 'preferably 20m vertical, or less with a matching circuit (AMU/ATU)'
16m and 18m fishing poles are available via eBay
mount an 18m pole on a fence post and voila!

More economical 11m and 13m poles are a good choice with an AMU.
and easily made portable.

Since the requirement is an efficient antenna.. (far-field V/m per watt)
1/4-wave vertical or 1/2-wave dipole would be hard to beat.
Don't forget, the launch angle has a really significant effect on long range hf comms (skip etc.)

radiotech wrote ...

If you can get something metal to rise about 10 meters from a terminal insulator
you can bring it into resonance at 80 meters by connecting a variable coil in series
(variometer) with the bottom.

What is the output configuration of the transmitter? Single terminal, coax connector?

Sulaiman wrote ...

As you have the possibility for a full 1/4-wave antenna go for it,
being near a building will
- de-tune the antenna .. probably less than 20m required for resonance
- potentially cause rfi to your neighbours
- be a little lossy.

If some horizontal space is available mount the bottom of the antenna as far from the building as practical, sloping up towards the top of the building with insulating line (I use fishing line) at the top
Use co-ax (whatever impedance you can get cheaply) to feed the antenna from your rig.
Some means of easily putting the antenna up and down is very helpful for adjusting the length to resonance and repairs.
An AMU/ATU would mean less critical adjustment of antenna length and a wider tuning range.
You will need a good rf earth, a single stake will work but cause losses
an underground metal pipeline (water, sewage etc.) would be much better.
It's quite difficult to make a good rf earth
.... ideally many radials but in practice compromises are required..

1/4 of the fun is the antenna system ... trial and error in my case.