A review I did of the 4AQRP Antenna Tuner. I had at first bought the QRP
Guys version and, while that was a perfectly serviceable unit, this kit is
one that was a lot of fun to build and operate. The two features that were
terrific was the PCB case and the red/green LED VSWR indicator. Other tuners
are content witj one red LED but bright sunlight makes them hard to read.
With a green LED brightening and an LED fading, you're a lot surer of where
you you stand.
After assembling the 4 States antenna tuner kit, my overall impression was
very favorable. Not 100 percent a fan of the kit aspect but about 98.7
percent. My only complaints are trivial: the pictures are somewhat ambiguous
on some points and they trail the written instructions so you either pin up
3 sheets of pictures on your work area or leaf back and forth from
instructions to the picture pages. Another complaint is that winding of the
coil from the instructions is a tad confusing -- even including the
pictures. And, thirdly, the polyvaricon caps received in the kit were
festooned with connection tabs and it was not clear which tabs should be
soldered where.
But these are truly petty gripes when offset by the final result. First, let
me share what was learned.
One suspects the coil/switch assembly will be a toughie going in so it is
well to prepare and study and prepare some more. Having a spare T106-2 on
hand as well as a similar switch, I chose to wind a "practice"
switch/inductor assembly for another tuner I am making. After a little
struggle, it turned out pretty decently. However, the windings were the same
for all twelve positions without the inductive "front loading" or "back
loading" single-turn loops on the 4S tuner version. When I have some time, I
shall ask why they do that.
Also, with respect to the polyvaricon leads/tabs, David, NM0S, points out
that all but the three main tabs are not soldered to the board and can be
cut off. In the hopes of clearing up a possible assembly ambiguity, here is
the best picture from my build process that shows this.
That said, when I set out to test this, at first I had some difficulty
getting it to tune my station antenna. It is a fan dipole for 40, 30, 20,
15, and 10 meters that somehow came together magically in the attic with
decent SWRs on all of those bands. It's properties are that it presents a
bitch of a time for the autotuners I possess on 17 and 12 meters. The
internal K-2 tuner as well as the two LDG Z-11s on 17 or 12 meters have
absolute fits! There have been a couple of manual MFJs and the QRPGuys tuner
that were unable to obtain a match as well.
So that's the acid test. However, the 4State tuner handled it without
breaking a sweat.
Once I got the hang of it, the unit was quite easy to obtain a decent match.
The internal SWR bar graph on my FT-817 indicated that the radio was joyous
over what it was seeing -- as did an inline Swan dual SWR meter. So, the
little tuner will most likely accompany me across the way to the adjacent
park and serve well with random long wires thrown up in the towering
eucalyptus that abound there.
Anyway, here's some more shots of the testing process:
I just would like to add that it works wonderfully with my NorCal 40A radio.
In the course of testing, I hooked up with a couple of folks using that rig
and the tuner and got decent reports -- only to discover that I had left the
VSWR bridge in line -- probably diminishing the output 990 mW a bit!
Closing the loop in the $5 AN/URM-25D, this beast cleaned up very nicely and
is a good stand-in if the "A" unit fades. Love them both, to be honest. I had
a teriffic WaveTek that was click-dial acurate but it started misbehaving
inside and went back to WB6JDH from whom I seemingly "rent" my test equipment
from. These opld fellas are easy to operate and my work is mostly HF with a
little straying into the VHF regions..
..so life is good!
A while back, I walked picked up a couple of deals at the Pomona swap meet -
- a Heathkit HG-18 sine and square wave generator that looked like it was
fire-bombed and this AN/URM-25D signal generator that also looked like it
was at death's door.
Actually, you don't "pick up" an AN/URN-25D at a swap. They're magnetic
and..well, as I explained to the folks on the Antique Radio Forum:
Anyway, these things are not nearly as bad as they look. Military gear is
virtually hermetically sealed and the innards are usually pristine. I used
to collect military radio gear and some of the World War II and Korean War
stuff -- particularly that which was to serve in tropical environments were
water and fungus-proofed to beat the band. So, you can imagine how clean the
insides of test equipment that dwelt in a service shop must have been babied
was like.
Bottom line on this was that there was a cold solder joint on the frequency
turret and, once repaired, the little beast was dead bang on. All that was
left to do was get out the can of elbow grease and get 'er done.
..rock solid stable as well. Not bad for some old gal you pick up for $5 at a swap meet, eh?
Another blast from the past, this is a pair of posts showing an AN/URM-25D
I scored from a local swap meet for $5! It ruened out to be a real treasure
as you aill see in the next post shoing the restoration.
At a swap meet some years ago, I scored an AN/URM-25D that looked like
warmed-over dog poop outside but turned out to be very promising inside. I
have another one of these that is now in the starting line-up when my Wave-Tek
3001 got a bad case of unlock-itis. So this one is warming up in the bull
pen.
When I got it home and stuck it on the bench and checked it out just after
the swap meet, it was dead on and rock stable. Aside from the cosmetics, the
dial lights were burnt out and one of the bands was intermittent.
Here's the "before" pictures:
As figured when I forked over the five-spot to the seller, the outside
looked tragic, but it did not look as though the inside had seen the light
of day much and was relatively pristine.
I replaced the lights and related circuit with some bright LEDs but am less
than happy with their brilliance - but they'll do. As for the intermittent
band, I disassembled the unit and started poking and prodding but could not
find anything amiss with the circuit. In the procees of doing that, however,
I lifted the legs on a couple of components so they could be checked. When
they were re-soldered, the band seemed to function correctly. So, I saw no
reason to go further.
Here are the "during" pictures, The next post will be the
results of sprucing it up..
