Showing posts with label Mobile HF operation. Show all posts
Showing posts with label Mobile HF operation. Show all posts

29 August 2014

My Dream "GO-BOX" for emergency communications. Or just for fun!

Well, I sibscribed recently to a FB group dedicated to emergency communications. Its a very nice group.
I do not believe in the FB because it's like the sand. You write something or find something but soon it's hard to find it again.
I like very much to have the possibility to go somewhere and try to make some QSO's. I am not a contester and I appreciate a nice chat with a fellow ham from here or anywhere. Therefore, I realise i really need a "GO-BOX" or a "GO-KIT" able to work all mode, all frequencies from HF to UHF.
Also the kit will be good for RVSU which is a network of hams involved in emergency communications for various NGO's here.
I will tell you my secret: My GO-BOX is on wheels!
It's a Nissan X-Trail "doped" with a lot of ham-stuff.

The main radio is a ICOM IC-7000 mounted in the trunk and the front panel remote. I finally made the permanent setup; the radio is under the trunk hood, bolted with the optional DC filter (OPC-639) and on the HF side I put a choke Balun  to reduce the common mode currents from the Codan antenna (or any  othe HF antenna) because the IC-7000 remote head is very sensitive to that issue.

The remote head is under the radio; i put it in place with the help of some industrial 3M velcro. In the left side is a small loudspeaker connected to the remote head. I use that velcro also for phones, portable radios etc...


The main attractions is the Codan 9350 auto-tuning antenna. Bulky but with outstanding performance, it's definetly a magnet for everyone's eyes, in march or in parking lot!

I wrote in other post about the custom mount for this antenna and about the connection with ICOM IC-7000 radio.

What I did lately was to put all the important wires in a protection harness.

 The main 12V DC is in harness, the RG58 and the command cable for the ATU antenna is in the harness also. Was a little tricky but the final result is amazing!



For VHF and UHF I use quarter wave antennas. I found that if I put a quarter wave on VHF, the same antenna is resonant also in UHF! A MMANA-GAL simulation showed that the UHF angles are somehow elevated but still a +2db at 0-15 deg. over the horizont so the antenna can be used well.

I preffer NMO (New Motorola Mount) for my mobile antennas. This is a special designed mount to accomodate proffessional antennas ant to whitstand to all the special conditions on a  mobile setup in full run. Do not ignore that! And also, keep in mind that a fixed mount is BETTER than any magnetic mount.

Here it is a NMO mount, VHF quarter wave antenna.















Now, for really serious things like emergency comms., I have a little toolbox with a 35 Ah SLA battery.
I was looking for a good battery eliminator but the price was too high and had to buy it from overseas! Hey, I think a little here and I know how to use a solder iron. Or solder station. Or something like that, you figure out...

So I made a very very simple "battery eliminator" or "separator", whatever, from a Schottky power diode. It was a bulky one, I don't know at what current is rated but did'nt burned at 14-16 Amps so must be better than that. In the little Hammond box I put a little 5 LED voltmeter to quick view the main battery status.
The later addition was a little digital voltmeter on a "Y" cable to view the voltage. Both of them are usefull.
The battery have two fuses, one for plus and one for minus.
Some hams think that if they put a single fuse, on the plus side, is enough!
Well, what if you make a shortcircuit between minus cable and the "plus" pole?

That toolbox cand accomodate the ICOM IC-7000 or anything else. In this setup made for Ciucas Trail Running (a 100 km mountain marathon) I have two Motorola mobile radios.

The lower is a GM360 VHF radio to talk to Salvamont (Mountain Rescue) teams and the upper is a DM3600 to use it with the Radioamateurs in the RVSU network (Radioamateurs for Emergency
Communications).
In order to be able to use a single antenna, a diplexer is used. Is a Diamond 2000 with modified RF cables. The original ones was too bulky and used PL and N connectors.
A lot of hams use amateur equipments for frequencies above the 146 or 148 MHz. They tend to ignore that out of the regular amateur bands, the radios are very ineffective!
I measured a lot of radios and they seems to loose power after 150 MHz and become very insensitive over 155 MHz. That's how they are made...  So, in a emergency network I found a little stupid to use deaf and mute radios! Therefore, I will go with proffessional radios for that particular case and the choice is Motorola!

A completion to my HF setup is a AH4 ATU with a collection of wires. I use two lenghts, 8,5 m and 4 m as they are not half-wave, as reccomended by ICOM to use them with AH-4.
The trick here is that I made two lenght of control cable and RF cable (tied together) so I can use 5m or 10m from radio to AH4.
The AH4 can be used for tuning a horizontal antenna (dipole) or a vertical one (erected on a fishpole stick) using 2 equal wires or 4 counterpoises with a vertical radiator. That's why there are 5 cables at the same lenght...


Well, this is my GO-BOX!

4 wheels and radios!


For final, here it is with a strange VHF antenna on the rooftop!







23 April 2014

1:1 UnUn, Choke BalUn

A few days ago I noticed that, while trying to work on 40m from mobile, my Icom IC-7000 suddenly stops, powering off.
So, investigating the trouble I put a (very) Ugly Balun at the output of the radio.
The problems went off so I planed to make some sort of Choke balun.
This broadband transformer is a 1:1 and block the current mode current.
Here it is the making off:





LE:
The main reason for making it with two RF connectors is that the choke is used in mobile installation and after it there is a small lenght of coaxial cable.
 73 de YO3HJV

21 April 2014

Back...

Well, I'm back in Bucharest from a long and exciting trip in Cheile Latoritei at Petrimanu Lake. Very nice!
Heavy road, a lot of rain and, of course, some snow. The rain almost destroyed the road so we had to use two chainsaws to make the road available...
The CODAN 9350 didn't performed as I was expect. Impossible to use it under 10 MHz but over worked as a charm. I have to think to a longer whip. Maybe one from a CB antenna with some sort of adapter.
We (YO3HJV and YO8RNI) used a improvised long wire to work from YOFF-420. I have a lot of paper-log to put into the PC so, please, be patience, I will do it in the next weeks...
As for today... Guess what? It was a sunny day with over 20 Celsius!










 I painted two orange strips on the CODAN 9350 antenna just for the other on the road. It's more visible and the lights make it visible into the deepest dark also.

73 de YO3HJV


10 April 2014

CODAN 9350 console for Nissan X-Trail

So, yesterday was my "sunny day" when I finally receive the custom-made console for my CODAN 9350/9360 antenna.
The assembly is made from a fixed steel plate and a elevated arm on which the antenna is affixed.
It's made from 5mm thick steel and it fixes onto the original rear trail hook. A few solder points and it's capable to support around 100 kg's!

Fixed plate:
Welding:
 Inspection:
 Final look:
 Testing:



22 August 2011

17m band mobile QSO with local stations

Saturday, while I was waiting on the road near Sinaia, I was surprised to hear a YO station in QSO with another one.
The surprise was the fact that I was in a valley and the frequency was too high to have a "local" QSO (18.144 MHz).
Of course, the real life often "beats" the theory, so I give a try and made the call for YO2MHJ...
Surprise! He answer back and we made QSY to 18.150 MHz where we had a beautiful QSO from mobile to fixed radio!
The approximative distance between the two stations was a little over 200 km and the path was over a 2k m mountain chain!!! (Sinaia to Deva)
The signal on my mobile setup was 59+20 in the clear with a very little QSB!
My mobile setup is a ICOM IC-7000 radio, followed by a LDG Z11 PRO antenna tuner and a Sirio Titan 4000 mobile CB antenna.
The interesting fact is that this antenna is a base load one with no ground connection wich made this antenna suitable for broadband HF operation.
In fact, I was able to work from 80m to 6m while mobile!

Here is a small movie about my mobile QSO:



I believe that two factors was involved:
-A high F0F2 and
-A high angle of radiation at both stations!

To be further investigated...

73!

14 June 2011

Europe trip, mobile HF calling...

Tomorrow I will be on the road to Friedrichschaffen.
The plan is to reach the destination on Thursday, 23rd of June.
Till then, I intend to go through Austria (South Tirol), Italy (Como), Switzerland (Interlaken).
My little VW Golf has extended HF capability (HI) from a ICOM IC-7000, LDZ Z-11 Pro II and a Sirio Turbo 4000 2m heigh antenna.
This equipment give me the possibility to work on HF bands, from 80m to 6m, so, from time to time check the following frequencies:

-3705 kHz;
-7150 kHz;
-14300 kHz;
-18150 kHz;
-21380 kHz;
-24940 kHz;
-28428 and 28.480 kHz;
-50133 kHz.

In VHF and UHF, I will try QSO on various repeaters. In simplex, I will be QRV on 145,500 MHz.

The maximum output power I will use will be 50 W.

Also, a TH-D72 with external antenna will transmit APRS position (SSID=YO3HJV-7).

The callsigns:
-Hungary (just passing): HA/YO3HJV/m
-Slovenia (just passing): S5/YO3HJV/m
-Austria: OE/YO3HJV/m or/p
-Italy: IN3/YO3HJV/m in Bolzano area and I2/YO3HJV/m or/p in Como area.
-Switzerland: HB9/YO3HJV/m
-Deutschland: DL/YO3HJV/m

Hope to catch you on the band!

73 de YO3HJV/m.

21 August 2009

SRR Mobile Comm Center

The initial purpose of this ARO is to display the capabilities of radio communications to the youngest. Also, it can play a important role in a Emmergency Communication Netwok as a message router between various frequencies and modes (incl. Digital modes: PSK31, RTTY, Digital Voice, HF and VHF Packet etc).
The main advantage is the quick field deployment in various places, on difficult road conditions or even in absence of roads! The tested top speed is around 120 Km/h on city roads. The car is capable of 4x4 traction on heavy condition due to Eaton Gearbox (5+1 gears) and the Andoria 2500 cmc, TDI engine. It has an astonishing autonomy of about 1000 km (incl.heavy roads)! The radio equipment covers frequencies between 1,5 MHz-450 MHz, all modes and can be used as a mobile crossband repeater to establish radiocommunications between portable radios (VHF/UHF) on a range of minimum 20 km around the car on flat surface and 100+ Km when placing on hills or mountains! In HF, the M.C.C can use NVIS antennas or Low Angle antennas, beeing able to communicate with ham stations placed, virtually, all over the world. The M.C.C can be ready to go in less than one hour from the call!

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