[VHFcontesting] IC-905

[Terry Price]

I posted this a couple of places but I thought folks here might be
interested.

Hi all,



Just back from Dayton (Xenia), nice to see everyone that stopped by. I
received my IC-905 on the 13th but no 10Ghz module. After checking with DX
Engineering, they got one in late on Tuesday so Wednesday on our way to
Dayton, we made a 2hr detour to pick it up.



I took a Yaesu G450 rotor and one of our .6cm dishes with dual band feed so
we were anxious to hook it up and test. I’ve also been working with the
GREAT folks from N1MM to get it added to their radio list ( it should be
released in the coming days. After getting it assembled on the mast, the
first contact was with W8BYA in EN70, just over 100 miles away !!



When I first got the unit, I was very disappointed that ICOM did not give a
GPS antenna and I had to dig out one of my many “hockey puck” antennas but
a kind gentleman from ICOM stopped by and pointed out the GPS antenna was
in the parts bag, it’s maybe ¾” to 1” long and about 3/8” in diameter!! I
haven’t tried it yet but my hockey puck worked fine. The rig was VERY
stable and K1RZ carried on a lengthy SSB QSO and never touched the dial.



I’m VERY impressed with the mechanical details. Both remote units are very
solid diecast aluminum and the covers have built in gaskets to keep water
out. The mounting brackets are about the best I’ve ever seen, looks like
1/8” thick stainless steel with many slots and holes for just about any
kind of mounting you can imagine. Best of all, you mount the brackets on
the mast, start the screws in the modules and they slip into slots on the
bracket so mounting them on a tower should present no issues.



I grabbed some SMA cables that were too long (extra loss) but I didn’t have
time to make others. I’m not wild about SMA’s for the RF connections, they
are NOT wx proof and SMA’s can snap off if you are not careful so make sure
you support whatever cables you use(more on this later) and be sure to seal
up the connections good. The rig comes with about a 16ish foot CAT5E cable
to go between the radio and the remote head and a multi pin cable that goes
between the remote head and the 10GHz module. The included cable has a
large ferrite on it and a rubber gasket and nut to make the RJ45 connection
waterproof, problem is, how many of us would only put the RF unit 16 feet
or so up?? They offer 64ft and 164ft cables which hopefully come with the
same gasket and locking nut. I plan to get Shielded CAT6E cable which has
23 gauge wire instead of the normal smaller wire to keep the voltage drop
to minimum and make my own cable. ICOM does provide an “accessory” plug
which is the same as the cable that goes between the remote unit and the
10GHz transverter, it has gnd, PTT and ALC on it according to the manual
but there has to be other voltage to run the 10GHz unit when it’s
connected, I will test this later.



I tested the power output on 2m, 70cm and 23cm, I couldn’t test the other
bands as my microwave power meter was not available but I’ll do that this
coming weekend. 2m and 70cm easily did 12.5W and 23cm was right at 10w.
Interestingly, the rig uses a NXP AFT05MS031NR1 for 2m and 70cm which is an
LDMOS device rated at 30W. On 23cm they use a Ampleon BLP15M9S30 which is
also capable of 30w. I assume they limit the power output due to cooling
and higher current requirements since it all runs off Ethernet POE+. I
couldn’t see what devices they are using on 13cm and 6cm, the shielding was
all soldered.



The other VERY interesting thing is it “appears” that the communication
from the base unit to the remote RF unit is Ethernet. The RJ45 cable that
connects the two goes right in to a VP6159M 1000 BASE-T LAN Magnetics
device. If this is true, then you are limited to 100m in length which is an
Ethernet standard but it also makes one wonder if you could directly remote
the unit over the internet with the proper port forwarding set up on your
routers – more to test later.



This weekend, once I get to my lab, I’m going to check sensitivity and
power output on the upper bands and test stability. Several folks asked if
it was the same as the IC-9700 with respect to the GPS. I do not know for
sure but it appears to be a GPSDO as it does work as soon as it’s powered
on even before the GPS sync’s but I’ll test that later. I’m also going to
test several cables to see what kind of real world loss each has in the
lengths needed to go from a dual band feed to the RF units.



While the price tag is steep at $4500 for the entire unit with the 10GHz
module, it may be right for you or it may not. If you buy the transverters,
IF rig, all the SMA relays for rx and tx and the multi-position SMA relay
for IF switching, add in a remote power supply and lots of interconnect
cables, time and cussing getting everything going you can probably save
$1000. I’ve easily built 20 or more remote boxes with 902MHz through 47GHz
in them and it’s the little things that always get you. For someone that
doesn’t have the time, patience, test equipment or the know-how, it’s a
good way to get on the microwave bands.



I have some pix of the inside but I don’t know how to post them here, I can
send them to the admin’s if they would like to post them.



73,


Terry Price - W8ZN
Directive Systems and Engineering
703-754-3876