AmateurRadio.com

Yaesu FT7 – a true classic

Way back in about 1979 I owned a Yaesu FT7. This was a 10W HF rig using a modular construction.  It was a beautiful radio with a lovely, quiet receiver.  It is probably the best radio I have ever owned and used. It predates WARC bands and only covered one 500kHz part of the 10m band and the non-WARC bands from 80m-10m. Today, it looks large. It was an analogue radio – no memories, no synthesisers – just a very good HF radio transceiver.  I worked all over the world with mine using QRP SSB and simple, low, wire antennas and no beams, mainly on 10m. In those days, most (all?) USA SSB was above 28.5MHz. Canadians were mainly below 28.5MHz.

My little FT817 has more bands and modes and is about 1/10th of the size.

I can thoroughly recommend the FT7, but they are very hard to find.  A later version was 50W pep and had full 10m coverage in 4 x 500kHz sections. The FT7 was a “real” radio – no gimmicks, just a truly amazing rig. Many who owned them and sold them (like me) later regretted selling them. As they say, these rigs are “keepers”.  If you find one you are unlikely to be disappointed.  Also, the handbook was complete so you could service it and not an SMA component in sight!

See https://sites.google.com/site/g3xbmqrp3/hf/ft7 .

A 56 inch long whip can only behave like a 56 inch whip. This is a basic law of physics. What the Miracle Whip (MW) and its derivatives do is match this whip on the HF and VHF bands. With a decent ground or counterpoise wire the MW may be only a couple of S-points down on a “decent” antenna on the higher HF bands. They work reasonably well and, in the past, I used my MW quite a bit, even from indoors.  They are definitely NOT a miracle antenna, although they are not too bad.  Since the owner, a Canadian called Robert, died there have been a few newcomers in the market.

Would I buy one today? Probably not. I have had better results with small loops.  As a simply deployed mainly RX antenna they make an ideal companion for an FT817 or similar. Their beauty is their simplicity. If you want optimum performance in a small antenna there are better solutions.  Small loops seem to work better, but then bandwidth becomes very narrow although loops don’t need grounds or counterpoises to work well. Personally, at QRP levels I’d use a loop every time.

As Wheeler showed years ago, efficient small antennas are reactive and unless losses are minimised, efficiency suffers. This is a fundamental limitation. Although high permeability ferrites and high permittivity ceramics can help to alter the size of space near an antenna and “magnify” the effective size of small antennas, the effect is small unless there is a lot of ferrite with high permeability or a lot of ceramic with a high permittivity. In theory, a tiny antenna can be very efficient but you’d need superconductors and lossless capacitors!  At the moment, sadly, neither are practical to mortals!

See https://sites.google.com/site/g3xbmqrp3/antennas/mwhip .

Here is this week’s space weather and geophysical report, issued 2015 May 18 0402 UTC.

Highlights of Solar and Geomagnetic Activity
11 – 17 May 2015

Solar activity was low from 11-15 May. The largest event of the
period was a C9/1n at 13/1838 UTC associated with a filament
eruption near Region 2345 (N16, L=113, class/area Axx/020 on 13
May). Region 2339 (N13, L=129, class/area Fkc/900 on 08 May) was the
most active region on the disk and produced 19 C-class events during
the period. There were several filament eruptions observed during
the period however, none of them turned out to be geoeffective.
Solar activity decreased to very low levels for 16-17 May.

The greater than 10 MeV proton flux at geosynchronous orbit was
enhanced on 12 May reaching a peak flux of 6 pfu at 12/0720 UTC but
never crossed alert threshold.

The greater than 2 MeV electron flux at geosynchronous orbit was at
normal to moderate levels on 11-13 May before reaching high levels
daily for the remainder of the period in response to effects from a
negative polarity coronal hole high speed stream (CH HSS).

Geomagnetic field activity was at unsettled to active levels on 11
May and mostly unsettled levels on 12 May due to extended periods of
negative Bz. On 13 May, geomagnetic field conditions increased to
active to major storm levels due to the onset of a recurrent
negative polarity CH HSS. Quiet to unsettled levels persisted on
14-15 May as effects from the HSS subsided. Quiet conditions
prevailed for the remainder of the period.

Forecast of Solar and Geomagnetic Activity
18 May – 13 June 2015

Solar activity is expected to be at very low levels with a chance
for C-class flares and a slight chance of M-class flares on 18 May
before decreasing further to only a chance for C-class flares once
Region 2339 rotates fully around the west limb on 19 May. The chance
for M-class activity increases on 25 May with the return of old
Region 2335 (S15, L=192) and remain elevated through the remainder
of the forecast period.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at moderate to high levels from 18-28 May due to
residual effects from last weeks negative polarity CH HSS followed
by effects from an anticipated positive polarity HSS due to become
geoeffective on 18 May. Normal to moderate levels are expected to
prevail with the exception of 31 May-01 Jun, 04-06 Jun, and 10-12
Jun following various recurrent CH high speed streams.

Geomagnetic field activity is expected to be quiet to active on
18-19 May due to effects from a positive polarity CH HSS. Mostly
quiet conditions are expected from 20 May to 01 Jun. Quiet to
unsettled conditions with a chance for active periods are expected
on 02-03 Jun due to effects from a negative polarity HSS followed by
quiet conditions through 06 Jun. Unsettled conditions are expected
on 07 and 10 Jun as well as active to minor storm conditions on
08-09 Jun due to the anticipated return of the recurrent negative
polarity CH HSS that yielded major storm conditions this week.
Mostly quiet conditions are expected for the remainder of the
period.

Don’t forget to visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com/

Live Aurora mapping is at http://aurora.sunspotwatch.com/

If you are on Twitter, please follow these two users:
+ https://Twitter.com/NW7US
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Get the space weather and radio propagation self-study course, today. Visit http://nw7us.us/swc for the latest sale and for more information!

Check out the stunning view of our Sun in action, as seen during the last five years with the Solar Dynamics Observatory (SDO):
https://www.youtube.com/watch?v=zXN-MdoGM9g

We’re on Facebook: http://NW7US.us/swhfr

It looks like the Microvert antenna may have originated in Japan? The Microvert is a very compact antenna. Some believe the coax is a major part of the radiating system. Having never tried this sort of antenna I am unable to comment.  This was posted to the Microvert Yahoo group earlier:

Whether you believe it’s the coax radiating or not, this is still interesting:

The Super Rad Antenna (Induced Secondary Radiation Antenna)

	The Super Rad Antenna (Induced Secondary Radiation Antenna) The Super Rad Antenna (The Induced Secondary Radiation Antenna) was thought up in 2006. It has high performance although small size.
	View on t54979899.blogspot.co.uk	Preview by Yahoo

There are other websites about SRA (secondary radiation antenna), but unfortunately all in Japanese. Its definetly a Japanese thing!

I have all the parts required here to make one of these. Whether you believe its the coax radiating or not the results will be interesting.

Rob
M0RZF

PS. My old 10m/12m modified microvert gives a good SWR.

See http://t54979899.blogspot.co.uk/?view=classic.

In the past, when fitter, I had a lot of casual fun working real HF DX with simple rig mounted antennas and batteries. In fact I have worked some impressive DX with QRP SSB using just the whip on the rig, mainly on 15m and 10m SSB.  Best DX includes South America from my late mother’s back garden on 15m SSB with the FT817 at 2.5W setting

One advantage is you can move the rig and antenna of optimum signal on receive. A small counterpoise wire is pretty essential to get best results. When fit again I’d like to do more of this, but currently my poor health is getting in the way.

Others, far more dedicated than me, have worked far better DX. Some get up early to work Australia from beaches with QRP on 20m. I have also worked a long way into Europe on 2m FM with QRP. 6m SSB Es is certainly workable with small rig mounted antennas.

I think you have to believe than this is possible (HF DX) and it will happen. Think how strong some signals are. On the higher HF bands a base loaded, or better still a centre loaded, whip is not that far down on a full sized vertical.

See https://sites.google.com/site/g3xbmqrp3/hf/pedestrian .

A spot reported by K1JT must be the ultimate goal for the WSPR mode. K1JT, Joseph Taylor, is the Nobel laureate who first developed this mode and other related two-way modes like JT65 and JT9.

My 0.1 W 21 MHz WSPR transmitter regularly makes it over the Atlantic, but never before to K1JT. The SWR was something like 7:1, but apparently that works fine, both for the transmitter and for radiation.

The antenna is a 13 m doublet oriented with the broadside facing East-West (the EU spots in the figure are from my Ultimate 3 on 21 MHz with another antenna and at another location). I feed the doublet with 450 ohm ladder line to a 4:1 Elecraft balun which is connected to the Ultimate 2 transmitter.

A spot reported by K1JT must be the ultimate goal for the WSPR mode. K1JT, Joseph Taylor, is the Nobel laureate who first developed this mode and other related two-way modes like JT65 and JT9.

My 0.1 W 21 MHz WSPR transmitter regularly makes it over the Atlantic, but never before to K1JT. The SWR was something like 7:1, but apparently that works fine, both for the transmitter and for radiation.

The antenna is a 13 m doublet oriented with the broadside facing East-West. I feed it with 450 ohm ladder line to a 4:1 Elecraft balun which is connected to the Ultimate 2 transmitter.