Samhoo DMR

More and more Chinese manufacturers dive into the DMR market. This e-mail from Samhoo shows that there’s still room for more.

Greetings form Samhoo Sci & Tech Co.,LTD (Samhoo).

For the coming International Wireless Communications Expo (IWCE 2015), taking place March 18–19, 2015 in Las Vegas, USA, Samhoo wishes to invite you to visit our company booth NO. 2027. We look forward to welcoming you at the show. At the same time, we wish you will have a good trip in IWCE2015.

Attachments are the introductions and details of our DMR radio products. If you want to know more, please feel free to contact us and we will do our best to further our understanding. You can also find more information via our website: www.samhoo-pmr.com.

DMR—-  Samhoo is delighted to formally launch our DMR Portable SPH6000 serial, SPH2000 serial and DMR Mobile SPM6000 serial, which all fully compliant with ETSI DMR Tier 3 & Tier 2, and be available in UHF (350-400MHz, 400-470MHz) and VHF (136-174MHz) bands will release soon. 

TETRA—  Samhoo could provide fully integrated all feature industry TETRA module(smart size :86 X 43x 8) for Portable and Mobile devices, and be available in 806-870MHz,350-400MHz,380-430MHz,410-470MHz bands.

Samhoo is willing and open to work with all kinds’ partners, who could be distributor, dealer, ODM, OEM and technical cooperation etc, to explore Digital PMR radio business opportunity.

Best Regards

Alex YE
Oversea Sales Assistant
Samhoo Sci&Tech Co.,Ltd

Address: Room 601,Building 2th,Huaqiangyun Industrial Park,No.1-1,Meixiu Road,Meilin,Futian District,Shenzhen,China

Tel:+86-755-8316 0260 Fax:+86-755 8226 3733

What I find interesting about these Samhoo SPH6000 series is that ordinary TF cards are used for storage. This makes it possible to copy the configuration of one radio to another, just by transferring files. It would also be the few brands I know of who’s developing a VHF model.

Samhoo DMR ModelsFull specs can be found in this PDF document: Samhoo DMR SPH6000 Series DS-en

Also interesting (but probably very expensive and not really for hams) is their LK838 portable base station. When power goes down, this would still work — at least for a while.

Portable Ad hoc BS_samhoo-P1

Antenna testing is hard (II)

This article follows up on this one. The title could also be: doing measurements on hand held radios is hard. Actually, some measurements I did in the past might not be so accurate after all.

Measuring in dBm
If you measure in dBm, what I always did, you assume that the device at the other end is 50 Ohms, just like the manufacturer promises you in the specs. Slowly but surely we are finding out that this is not always the case. As a result I might have to switch to microvolt (µV), a method which doesn’t require a perfect 50 Ohms at the other end.

Can’t we just convert it? 0.5 µV @ 50 ohms = -113 dBm, a piece of cake, right? No. You must know the actual impedance of the receiver if you want to convert from dBm to µV. Erik PE1RQF did some measurements on a few hand held radios. The outcome was, well, a bit scary.

Impedance

If a device is 50 Ohms, the SWR should be 1:1. Only a perfect dummy load and the Marconi RF generator are.

What this means for us
What this outcome basically means is that generating cold numbers on sensitivity and antenna performance are nice, but don’t tell the whole story, or could be misleading.

  • Antennas which prove to be the best performers (RX/TX, VSWR), tested under optimal conditions, are not necessarily the best performers on a specific brand/model of hand held radio.
  • There are antennas which aren’t 50 Ohms at all, but could very well outperform everything else on the market because your radio isn’t 50 Ohms either.

Do the test yourself
The best example I can give you is this one: take a Baofeng BF-666S, 777S or 888S, use the stock antenna, and make notes of the performance in the field. Try to hit repeaters which are barely in range. If you have a field strength meter, measure field strength when transmitting.

Remove the stock antenna and replace it by a Nagoya NA-701, NA-771, the $3.79 antenna, or the Baofeng UV-B5 antenna. I tried all of these; just pick whatever 3rd party antenna you have. Repeat the tests.

What happened here is that the short stock antenna was the best of the bunch, all 3rd party antennas had a negative influence on the performance of this specific Baofeng model. The same 3rd party antennas mentioned above did improve the performance of the Baofeng UV-5R, often by a wide margin.

Exception to the rules
The funny thing is that reception suffered greatly too. This is quite uncommon and a sign that hand held radios don’t follow the rules. For example, if you just want to receive on 20 meters and your dipole is 2×6 meters instead of 2×5 meters, you would never notice the difference. With your hand held radio however you will.

VR-6600PRO and FTM-350 Inside

The most frequently asked question is: how identical are these two radios? Vero Telecom made it clear from the start that the PCB design was their own.

On the outside it’s a close call. On the inside there are some similarities, but enough differences too. The VR-6600PRO isn’t a 100% copy of the Yaesu, a fact that was impossible to miss during tests. Some properties are in favor of the Yaesu, some things are in favor of the VGC. I’ll get back on that subject in the final review.

The Vero Telecom VR-6600PRO inside:

VR-6600Pro-inside-small

Click image for high-res version

The Yaesu FTM-350 inside:

FTM-350-Inside

Trading freedom for safety

Zendmast Lopik deels in gebruik

Courtesy hamnieuws.nl

Privacy and freedom are constantly traded in for a (often false) sense of security. This has nothing to do with ham radio, you’d probably think, but even our hobby isn’t immune.

Repeaters
Repeaters are only useful if the antennas can be placed high above ground. In the Netherlands we use a number of existing locations, most of which were once used for analog TV and radio. The owners of the towers decided that safety and security will prevail over (safe, terrorist-free) ham radio.

The following systems will be affected:

  • ATV repeater PI6ATV, both analog and digital,
  • 2 meter repeater PI3UTR,
  • D-star repeater PI1UTR,
  • DMR repeater PI1UTR,
  • RX co-location for the 70cm repeater PI2NOS,
  • RX co-location for the 10 meter repeater PI6TEN,
  • Four Hamnet access points and links.

There is a chance that the equipment can be relocated to a lower section of the tower while keeping the antennas on the original altitude. Even in the best case scenario the costs of relocating will exceed the minimal financial reserves – good coax cable is expensive, and we would need a lot of it.

I’ll end with this quote: Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety. (Benjamin Franklin)

Anytone Tech’s new models: User Manuals

As Brick also mentioned in in his last post about Anytone Tech: the reactions on the new models vary wildly. I think Brick said all there is to say, but I’ll add this thought:

– If a radio is cheap but crap, we complain, but buy it anyway.
– If a radio is good but costs more, we complain, but suddenly the price is all that matters.

Let’s see how these radios perform and at what price point before judging them. I know John of Miklor.com gets (or already has) review samples, and I’m on the list too. To give you some more insight in what these radios can and cannot do, here are some preliminary user manuals (PDF).

Display

ANILE-8R User Manual (Preliminary)

NSTIG-8R User Manual (Preliminary)

OBLTR-8R + TERMN-8R User Manual (Preliminary)