President Lincoln 10m

The President Lincoln has been around for years, but still makes a good little monoband rig for 10m.

I was first introduced to the range when I went to Florida on holiday and bought a Uniden HR2600 for about £50. This is a 10m-only rig with repeater shift and about 10w FM/25W SSB output and I loved it.

However, it didn’t get too much use in the sunspot minimum years and I decided to sell it – what an idiot!

Anyway, I have never been able to find another one to buy, so settled on the President Lincoln. There are loads of these on eBay for around £120 - £180.

The Lincoln covers 26-30MHz in eight bands. It is very similar to the HR2600 but doesn’t have repeater shift.

Unlike the Albrecht AE 485S I reviewed earlier it does have continuous 100, 10 and 1kHz tuning. You don’t get the memory feature of the Albrecht, but you do get a built-in SWR meter and a scan button. It also has an RIT, mic gain button and RF gain.

Switching to the ham band (28-29.7MHz) I was able to hear everything that my Yaesu FT-2000 could hear, including beacons in Italy, Slovenia and Norway. I worked a couple of stations on SSB and got 57 reports.

I had a bit of a problem with mine. After storing it in the loft for two years the tuning control was a bit odd – in some positions it was fine, in others it would either not change channel or actually go backwards.

You can get new tuning control switches, but they are hard to get hold off. One US expert suggested carefully drilling a small hole in the side of the switch (between the green segments) and squirting in switch cleaner.

I managed to get switch cleaner in the LCD display while doing this and had to strip it out and put in a new strip of white backing paper, courtesy of some glossy ink-jet paper. It now looks like new again!

It took a couple of applications of cleaner while rotating the switch to different quadrants, but it now works perfectly.

In all, the Lincoln is a great monoband rig for 10m, but is ideally suited to SSB and FM simplex. You used to be able to order a new “Superchip” from the USA that would give you repeater shift, but at £50 plus it costs half as much as an average rig. The Lincoln is a bit bulky, especially compared with the Albrecht 485S and you can’t easily work through 10FM repeaters either, but it works well on SSB.

I spent an interesting Saturday afternoon in early May with a 10m whip and my Yaesu 817 in the car as static mobile, but didn’t actually manage to work anyone with 5W and SSB/CW, which surprised me. Perhaps 5W and a compromise (loaded) antenna is not a good idea. Heard lots though so it was all good fun. I'll try the Lincoln/Albrecht next time.

Albrecht AE 485S for 10m

Note: You can now buy the Albrecht (or the Magnum 257 as it is also called) at Amazon.

As the summer sporadic E season has started I thought I would drag out a couple of my 10m monoband rigs and see what I could work.

I thought readers might be interested in a quick review of the rigs, starting with the Albrecht 485S. This is also sold as the Magnum 257 which has a blue display background and not orange. Typical prices are around £199, although they come up on eBay secondhand for about £100.

The power output on mine is about 12W.

This rig is quite small and out of the box covers 28 – 29.7MHz. Press two buttons though and it opens up to include 25.160 to 29.699MHz in “bands”.

It is here that the rig shows its true background. It is really a CB, with AM, FM and LSB/USB modes.

As such it has some quirks that can be quite irritating to hams. Leaving it in ham mode and turning the tuning knob lets you move up and down the band in 10kHz steps. So far so good, but only if you want to work on 28.500, 28.510MHz etc.

If you want to work outside of these steps you have to press the “step button” which lets you switch to 1kHz steps. But now you have a problem. If you are on, say, 28.510MHz and hit the step button you can now tune from 28.510 – 28.519, but then it goes back to 28.510.

If you want to go 28.495 you have to switch back to 10KHz steps, move to 28.490 and start again.

This is really awkward and means that you can’t realistically use the radio mobile on SSB. However, its one saving grace is that it is brilliant for 10FM where 10kHz spacing is the norm.

The rig also has repeater shift, which is programmable. It took a few seconds to dial up 100kHz which is the standard and it will then happily tune 29.500 – 29.700MHz where the repeaters are –although I haven’t heard any European ones yet this season.

The rig also has an RIT, a noise blanker, a scan function and memories. On air it performed quite well, once you get used to the tuning.

I bought mine off eBay and some of the writing has worn off on the buttons, so watch that. I might try and get some new buttons.

The ability to scan the CB bands is also useful for finding out if 10m is about to open!

So, overall if you are looking for a lightweight, small mobile rig for 10FM it is brilliant. It is also OK for static mobile SSB work, but trying to move up and down the band while driving is recipe for disaster! Next the President Lincoln.

Update: I was able to buy some new buttons from Sharmans Wholesale for about £15 delivered.

International Marconi Day, 25th April 2009

Saturday 25th April 2009 is International Marconi Day when stations around the world celebrate the birthday of Guglielmo Marconi. it is also a good opportunity for you to gain a very nice certificate. All you have to do is work the requisite number of award stations and send in a log extract - you don't need QSL cards. I gave a talk to my local club about the best way to win the award and you can download the presentation in PDF format (10Mb). It is aimed at UK operators. You can also view my propagation predictions online. You can find out more at: http://www.gb4imd.org.uk/ Pictured above are the operators at the Poldhu Amateur Radio Club who will be on this year as GB2GM.

DXing from a small (or no) garden

This a is a presentation I gave to my local club. It talks about finding DX, the modes to use, what you can do with QRP and CW and also looks at a number of antenna designs and what I found.

I have made it into a 3.8Mb PDF and you might find it interesting, even without the narrative that obviously went with it.

Download the presentation.

Rybakov 806 vertical revisited - a stealth tree antenna?

In an earlier post I talked about the Rybakov 806 vertical – basically, a 7.6m vertical end fed with a 4:1 un-un (unbalanced-unbalanced transformer), so giving a reasonable match across a number of bands.

In practice you MUST use an ATU to bring it down to 1:1.
Anyway, while playing with the design I tried wrapping the wire around an 8m fishing pole and had an idea.

If you push the pole up through the branches of a tree, taping each joint as you go, do you end up with a stealth antenna?
I think the photograph says sit all!

The pole is practically invisible and the leaves aren’t even out yet. Next to the matching box is a single earth stake and then two 20ft radials go left and right on the ground – you could bury them. I think it would work better with more radials.

My FT-2000’s built-in ATU was able to match it to 1:1 on 40-6m. The SWR on 80m is too high and the rig wouldn’t match it. Mind you signals were well down on 80m as the antenna is too short.

So how does it perform. On 40m it was either equal to or one S point down on an 80m 132ft OCF Windom on EU signals – you can just see the long leg of that in the photograph. Given the length is under a quarter wave this is quite good.

On 30m it equalled or outperformed the Windom slightly. This doesn’t surprise me as it is virtually a quarter wave on that band. The measured SWR was 3.6:1, which if you think about it is roughly 1:1 into 50 Ohms before it goes through the 4:1 un-un.

It was a similar story on 20m – equal to or just slightly down on the Windom.
The RR90 (Russian) beacon was down about 1 S point, the 4X6TU 9(Israel) and 4U1UN (New York) beacon was the same. VY2 (Prince Edwards Island) was down 2 S points. KQ2M (CT) was equal or slightly worse. K1RX (NH) slightly better.

It has to be said that compared with a dedicated half-wave horizontal dipole signals were generally 1-2 S points down, but that antenna is not multiband.

18MHz was barely open, but it was a similar story to 14MHz – roughly the same, some signals better, some worse.

21, 24 and 28MHz were not open, although as I have said before, it hears CB stations very well out to about 12-15 miles so I have high hopes for 10m.

So there you are - a stealth antenna that works from 40m – 6m for about £10 plus the pole. If you string the wire up into the branches you don’t even need the pole to be honest.

HF propagation prediction: February-April 2009

The equinox periods provide longer daytime periods than winter, but logically, shorter night-time periods too. These tend to be the best months for working North-South paths, such as UK to South Africa.

On 160m (1.8MHz or Top Band), look for short-skip and DX openings at night. Again, no daylight skip is possible due to absorption, but openings out to 1,300 miles and occasionally further afield can be expected at night with conditions peaking around midnight and again at sunrise (greyline).

80m (3.5MHz) will generally follow the characteristics of Top Band at night, but will also provide good openings out to around 250 miles during the day. These will lengthen to around 500-2,300 miles at night with fairly good DX opportunities at times. At this point in the cycle 80m should still provide good DX as absorption is still quite low. Local communciation should be good as long as the critical frequency stays above 3.8MHz - register for the digisonde data at http://www.ukssdc.ac.uk/ionosondes/view_latest.html

40m (7MHz) Forty metres should open to DX in an easterly direction at sunset. Openings to the west should be possible after midnight and should peak just before sunrise. Contacts should be possible during the day, although, again, lower critical frequencies may mean that it is difficult to work other UK stations while perfectly possible to talk to European stations. If the flux rises then 40m may open up to NVIS contacts around the UK.

20m (14MHz) is likely to be the best DX band between sunrise and sunset. The bands may occasionally open after dark, perhaps to the southern hemisphere. Good openings will be possible during daylight hours out to around 2,300 miles.

17m/15m (18MHz/21MHz) should provide fairly good DX openings during daylight hours, especially to Africa and South America, with 17m being open more often than 15m. Once again, 15m may struggle to open during times of low solar flux, but could provide good openings if it rises above about 90-100. Both bands are likely to close after sunset.

12m/10m (24MHz/28MHz) These could be disappointing bands if the solar flux remains low. If the solar flux heads towards the high 80s/90s then openings will occur on both bands, although 24MHz will open first. If it breaks the 100 mark then expect to see some good DX openings on 10m, especially in early spring/late autumn.

The Rybakov 806 vertical

I have no idea why this is called a Rybakov 806, but essentially it is a 7.6m vertical fed with a 4:1 Un-Un (unbalanced to unbalanced transformer) as described by IV3SBE.

It works very well with a fibreglass fishing pole and can be put up in a few minutes. The pattern (right) is what you get on 20m.

You need to put down an earth stake, and it really, really needs radials – the more the merrier.

The idea is that the antenna represents a non 1:1 SWR match at all frequencies – 7.6m is chosen as it isn’t actually a half wave (high impedance) or quarter wave (low impedance) on any band. The Un-Un (see below right) transforms the impedance to something closer to 1:1 and therefore reduces coax losses.

Does it work? I have tried a 7.6m Rybakov at a few locations and yes it does. Is it as good as a dedicated resonant antenna – no. You get losses in the Un-Un and there will always be a residual SWR on the feedline, which adds to the losses. You will also need to use an ATU to get the SWR down to 1:1, although most internal ATUs can usually cope with the mismatch.

As a matter of interest, here is the SWR I found with the 7.6m vertical (with the 4:1 Un-Un) with a single earth stake and two 20ft radials:

7.50MHz - SWR 3.2:1
10.1MHz – SWR 3.6:1
14.2MHz – SWR 5.6:1
18.1MHz – SWR 5.4:1
21.2MHz – SWR 2.6:1
24.9MHz – SWR 2:1
28.5MHz – SWR 2.1:1


The radiation pattern on 10MHz and 14MHz is typical of a vertical and good for DX. It is not so good on the higher bands as the antenna is longer than a quarter wave and gets complex.

It is also rotten on 80m (SWR 330:10) as it is waaaaay too short – if you extend the wire to 8.6m it will be better on 40m but you may as well make it a proper quarter wave (about 10.4m).

In tests it could hear local CB stations that were inaudible on my Windom, W3EDP or horizontal dipole. I know most CBers use vertical polarisation, but it shows that it might be good for low-angle DX radiation on 10m too.

It is a bit short for 40m, but does work. It was ok on 20m - some stations louder than on a Windom at 30ft, some worse. Same on 17m.

For 20m–10m use I think you are better sticking to 7.6m. The modelling shows that the radials are critical. You may get different SWR readings depending on how many you have. A single earth stake might give you a low SWR, but will be lossy.

If you have little space and like experimenting it might be worth a go, but I never found it matched a proper half-wave dipole at 30ft. More radials might help –if laying on/under the ground they don’t have to be resonant, just make sure they are roughly the same length as the radiating element and aim for as many as possible (32+ is good). If you try this antenna with just a ground stake I think you will be disappointed.

Let me know how you get on.