2m and 70cm antenna

Many years ago a local amateur G0LRD very kindly erected my big-wheel omni antenna which I use on 70cm SSB/FT8 and 2m SSB/FT8. Although a 2m antenna it seems to work really well on 70cm although I have no idea about polar plot on 70cm,

The big-wheel is a horizontally polarised antenna with some gain. It is an array of half-waves, suitably matched.

It is ideal for this and regularly gets a long way even with my QRP.

End fed halfwave antennas

These antennas are popular as they cover many bands and are easily erected. Especially with high power, RF in the shack can be an issue.

At the end of a halfwave the impedance is high so they are usually fed via a wideband transformer to bring the impedance closer to 50 ohms.  Wideband transformers are usually 1:49 or similar. On their harmonics the radiation pattern can be very odd.

They can be useful antennas, but are a compromise.

Multiband HF antenna

 

Last week I ordered an antenna from Aliexpress. It has just arrived from China by airmail. It will get erected soon. I am amazed they can do it for the price.

HF antenna

I think this steerable HF antenna is for a broadcast station.

I am sure the neighbours would complain it I had it!!

Wet string antennas

Yesterday I mentioned using the coax to my 2m big-wheel antenna on 80m. It worked remarkably well. 

I came across this video on YouTube showing someone using a coat hanger antenna on 10m. As long as the antenna is properly matched to the rig with an ATU, you may be surprised.

If you do not have an antenna for a certain band do not give up. I am sure such compromise antennas would be down on a "proper" antenna, but do not be too surprised if it works quite effectively.

Some have used wires in their plastic guttering down-pipe or a flagpole. You may be amazed just how well such hidden antennas work.

10m antenna

 

At the moment 10m is excellent and there are some 10m only rigs at bargain prices. Many will have a go on 10m only where antennas are small and they do not have to be far off the ground to be effective. 

I know this has been on several times before, but it is worth reminding folks of my 10m antenna that can be made from easily obtainable material, is small and really works. If you are after a simple 10m antenna, this may "fit the bill".  It was in Practical Wireless many years ago and is on my website.

See https://sites.google.com/view/g3xbm4/home/antennas/homebase10-10m-halo .

Antennas and amateur radio

My latest RadCom arrived yesterday.

One major dealer is advertising widely (the RSGB must really value this income) and I could not help noticing a major antenna manufacturer selling antennas (on the centre pages) via this dealer for £3899.99 and £4199.99!

If this major UK dealer decided to "hang up his boots" and leave the amateur market then RadCom would have to radically change. It would probably have to shrink and come out less often.  The only amateur radio magazine remaining on newsagent's stands would really struggle.

Now, I am not able, nor wish, to say how you spend your money. However, for me, these antennas are not amateur radio. A fan dipole covering all the higher HF bands could probably be made for the cost of a few coffees out. So you might be a few dBs down on a big tower with one of these antennas on the top, but you will probably save a 4 figure sum in the process.

In the end, we have to understand what our hobby is really about.  To me, there are 2 major sorts of radio amateur: (a) those who just get out their credit card and (b) those that experiment. I prefer the latter.

In my view, the writing is already on the wall. I personally see a battle looming between the credit card operators and experimenters.  In my view credit card operators will merge with CB. Experimenters?

Amateur radio?

We have to be grateful for "big" stations with "big" antennas, who sometimes hear us when others might not. 

However, this is not my idea of amateur radio fun. I prefer to see how far my QRP signals reach with very modest, low, antennas. 

Each to their own.

8m antenna repair

For reasons I do not understand my 8m dipole has gone to resonance at about 49MHz. It is simpler to replace the antenna and coax. Assuming the weather is OK, I may try doing this in the next week. 

At the moment I am inclined not to apply for an 8m TX permit again, but instead concentrate on ISM rules and WSPR. In the UK this means 10mW ERP and compliance with IR2030. In the UK this is totally free (no licence needed) and I believe open to all. As long as there are people monitoring, much of Europe should be within range on 8m WSPR in the Es season.

V2000 vertical omni

On 6m, 2m (vertical) and 70cm (vertical) the V2000 is used. This photo was taken some years ago. On 6m with 1W CW the USA has been worked with this antenna. 

Multiband antennas

Quite a good multi-band antenna is the end-fed via a 9:1 balun. At the end of the wire it presents a high impedance and the 9:1 balun drops the impedance to a low SWR, certainly less than 3:1 that can be tuned via the auto-ATU in many modern rigs. On many radios an ATU will not be needed at all. With QRP, RF on the coax is not usually an issue. With high power, more care or a counterpoise may be needed.

At the moment I am using an end-fed antenna. I have not found a counterpoise necessary.

Commercial versions are available (e.g. from Moonraker), although many make their own.

Bicone antennas

Sometimes people want a wideband antenna covering several bands. One to consider is the bicone. these can be quite large, but can cover several bands.

See https://en.wikipedia.org/wiki/Biconical_antenna .

23cm antennas (again)

At one time, a very popular 23cm antenna, for ATV I think, was the bow tie designed by G8GML (now SK). As I recall it was 2 diamond shaped elements with a solid reflector. I think it had a useful (not high) gain and a fairly broad forward lobe. 

For DX contacts, a decent beam with lots of forward gain is usually essential, but such an antenna might be better for me than the PCB HB9CV that, I believe, is supplied with the 23cm transverter that should come next month.

What I am wondering is does anyone make this commercially and at what price?

Such an antenna might be useful on 70cm too.

UPDATE 1907z:   As David says in the comments, Wimo make such an antenna. It looks expensive.

23cm antennas?

As regular readers will know, I am buying a 23cm 2W transverter from SG-Labs in Bulgaria. I think at one time they supplied a small 23cm PCB antenna with it. I have to check if this is still the case.

Looking around, 23cm commercial antennas look very expensive. As the majority of QSOs would be local(ish), I am wondering what you would recommend? As my fine motor skills are not good these days, I don't think I could make one. In the past, I would have made one! Is there one that would be ideal for me?

23cm antennas?

Next year, all being well, I hope to try some /P 23cm operation in some of the RSGB organised activity contests (UKAC). I am wondering if there is a popular antenna used in these contests?  

Clearly very high gain antennas will give good signals, but will miss stations that are out of the very sharp beamwidth, whereas smaller antennas will have broader beams, but less gain.  Perhaps, stations use one antenna for hunting, then a sharp, high gain one when on beam.

It is a very long time since I was on 23cm and then only RX.

Is there a favourite antenna?

ICOM AH-5000 antenna

This antenna has just come to my attention. Like all things ICOM it is expensive. It is meant to cover all HF bands (maybe with a tuner on some frequencies). I have no idea how it performs. 

It looks like a Rybakov style antenna, but I have no idea. 

There are other, similar commercial antennas around which are far less expensive. 

Of course, you can roll your own and save a packet!

See http://g0kya.blogspot.com/2009/02/rybakov-vertical.html .

See https://amphenolprocom.com/media/pdfdocs/hf-5000.en-GB.pdf?timestamp=1660739714.

2m halfwave antennas

Most people opt for 5/8th wave antennas when they want better ranges on their 2m handhelds. Some years ago now I made a half-wave antenna for 2m. It was widely used on my many 2m rigs. It was first used in the 1970s, so must be about 50 years old! 

The idea was simple: the end is a high impedance so I just added a tuned circuit tapped at the 50  ohm point to match to the rig. It got me across the English Channel with a 10mW AM handheld (160km), so it must work! The antenna was actually on the Fredbox.

Clearly this would work on 70cm if scaled.

One photo shows the matching arrangement and the other the full whip.

4 element Yagi for 70cms

Some years ago I was looking for an antenna for a 70cm contest to take out portable. It performed well with QRP SSB. Like similar antennas of mine, it was fabricated from an old metal coat hanger. It was a good match and used with my FT817. I still have this antenna in the back of the garage.

See https://sites.google.com/view/g3xbm4/home/antennas/70cm-4el-yagi .

8m antenna erection

In the next 48 hours, I hope to erect a wire dipole for 8m. Years ago this would have been trivial, but I am not good on ladders since my stroke in 2013. 

Putting this up requires a minimum of 2 ladder climbs. Luckily, both are not very high, so I hope to manage these.

I am really looking forward to experimenting on 8m TX.

My floored loft has not been visited by me in 8 years!! There is quite a bit of amateur gear in one of the boxes.

UPDATE 1352z:  Small steps! As I get very tired these days I am doing this is small steps with rest in between. So far I have (1) cut the 8m dipole to length, (2) drilled the hole from the outside into the shack for the coax, (3) lowered the 10m antenna so I can attach the 8m dipole to it and (4) shortened the length of the nylon insulator that holds the 10m antenna in place. Now I need a rest!

10m antennas

One of the beauties of 10m is antennas are small. A half wave dipole is only about 5m long. A halo is even smaller. 27MHz CB verticals can work very well too. 

Some years ago I wanted a simple antenna for the band and the Homebase-10 was born.

See https://sites.google.com/view/g3xbm4/home/antennas/homebase10-10m-halo.