I got a HP EliteDesk 800 G1 USDT Ultra Slim Desktop computer for my ham schack. This is a small computer running on an external power supply just lika a laptop. It turned out to be the major source of RFI in my ham schack.
I suspected the power supply was the culrpit as those are switched ones and thought it might be possible to run the computer directly on my 13.8 VDC power supply that I use for my radios. The only voltages used in a computer is 12 and 5 volts, so there is probably a voltage regulator on the power input that regulates the voltage down from the 19 volts DC that the power supply outputs. Will it also run on 13.8 VDC?
The power cable to the HP EliteDesk 800 G1 USDT has a 3 pole connector, just the same as on laptops. One is negative, one is positive and the pin in the middle is a “power good” signal from the power supply. I read about people running 3rd party power supplies by connecting the power good over a resistor to the positive side, see this page.
Will it run if I just connect the power good to positive without a resistor? When I measured the voltages from the original power supply positive was +19 VDC and power good read about +12 VDC so it might be sufficient. Discussing it with a tech savvy friend, he suggested it might work and be worth a try.
I didn’t want to cut the cable on the original power supply but luckily I have a friend who hoardes old technical stuff and he happened to have an old broken HP laptop power supply, with the correct cable (who saves broken power supplies?, well it turned out to be useful in this case)
It turned out it works fine, no resistor needed. This might vary from model to model, but the HP EliteDesk 800 G1 USDT it works by directly connecting power good to the positive. This (image below) is the cable I now use to run my computer directly on 13.8 VDC. Black lead is negative, white is positive and blue is power good.
On 20 meters (14 MHz) my noise floor dropped from S5 to S0-A1!
https://media01.nerdia.net/uploads/IMG_20221103_173344-scaled.jpg25601920Stefan Helanderhttps://media01.nerdia.net/uploads/nerdia-logo-340x156.pngStefan Helander2022-11-05 10:31:112022-11-06 11:05:37Running HP EliteDesk 800 G1 USDT on 13.8 volts DC
After doing some updates of my Anytone D878UV and D578UV DMR radios I had an annoying problem where the talkgroup field was empty in the last call list as well as in the last call “ticker” scrolling by on top of the screen, just showing an empty “TG:”.
It turned out the problem was caused by the digital contact list that I had generated on radioid.net. I had generated the list with the “TG” checked which generates a contact list including all Brandmeister talk groups. Seems very practical but the problem is that the name field for the talk groups are empty and it seems that Anytone has priority to display the talkgroup info from digital contact list, if it exists, above the info from the talk groups list.
Solution was to generate the digital contact list from radioid.net without checking the TG.
https://media01.nerdia.net/uploads/IMG_20220708_143917.jpg23041728Stefan Helanderhttps://media01.nerdia.net/uploads/nerdia-logo-340x156.pngStefan Helander2022-07-09 09:15:472022-07-09 09:15:49Anytone D878UV/D578UV last call talkgroup empty
In an earlier post I described my experiences with the HyEndFed 5 band antenna but for several reasons I decided to quickly replace it with the 8 band version for 10/12/15/17/20/30/40/80 meters.
The reasons for this was, for one thing, that I soon discovered that I was missing the WARC bands for different reasons. One of them is contests. Contests are fun – when you are participating. When not, it makes the bands very hard to use. You will have a hard time finding non contest stations and sometimes I just switched the radio off, waiting for the contest to be over. The WARC bands are contest free and became my go to bands during contests.
Another reason for replacing the 5 band antenna was that it is rated for 200 watts SSB PEP. Nothing more than that is mentioned on their website when it comes to power. It was when unpacking the antenna, reading the instructions, I realized this means 30 watts limit for CW and DIGI-modes. It would have been very nice to mention this on the website as well. I am doing about 98% of my QSO:s in CW and I like to be able to use my rig’s full 100 watts of power.
The third reason I initially choose the 5 band antenna was it’s length – 23 meters. This is just about the size I can fit in on my property. But at the time considering a new antenna, I realized that endfed half waves (EFHW) actually doesn’t have to be installed in a straight line. Bend it like Beckham 🙂 It can be installed in an angle for example. The radiation pattern will of course suffer but they still work. The 8 band antenna is 40 meters long, so to fit it in, I must install it in an angle.
So I decided to replace it with the 1 kW model of HyEndFed 8 band antenna. I used the same fur tree as a fixing point, but insted of having the end at the tree, I now has a bend. I selected the 1 kW model to be able to cope with my 100 watts CW. The model chosen was the one with aluminium plate and strand relief on the plate.
I can use the antenna on most bands without a tuner but I do actually use my ICOM AT-180 on most bands to get the SWR down to as close as 1:1. With the AT-180 it actually also tunes on 160 meters but my QRM levels on that band are so high so I haven’t tried it in a QSO yet.
It have worked all other bands with the antenna I am quite happy with it, and considering it is a multiband antenna I think it is a very good compromise.
https://media01.nerdia.net/uploads/IMG_20220706_133047-scaled.jpg19202560Stefan Helanderhttps://media01.nerdia.net/uploads/nerdia-logo-340x156.pngStefan Helander2022-07-06 12:33:462022-07-06 12:33:47My experience with HyEndFed 8 band antenna – bend it like Beckham…
I purchased a new, unused Nagoya RB-400 lidmount antenna mount from a seller on eBay. After a couple of days of use, I was going to adjust the angle using the hexagon socket screw. When unscrewing it, a part of the mount just fell off (see photo).
I did not overload the mount (largest antenna used while driving was a 65 cm whip). Did I overtight the hexagon scew? Obviously 🙂 I’m quite used to dealing with mechanical stuff and I applied a resonable force while tighting it, to keep the antenna upright while driving but not really enormous force.
I guess it was a manufacturing fault but getting it replaced from the eBay seller would cost me a great part of the price as a new one as the seller policy for returns was that the buyer pays the return cost. Worst case is that it was a construction issue and in that case I will probably soon end up with the same result. I didn’t want this to be bothering me anymore.
Instead I went to a local ham shop and bought another (more expensive) brand and the RB-400 went into the trash.
Anyone else who have experiences like this with the RB-400? My experience with Nagoya products so far is not impressing (see my article on RB-66 rusting scews), so I will probably avoid them in the future.
https://media01.nerdia.net/uploads/Nagoya_RB-400_in_pieces-scaled.jpg19202560Stefan Helanderhttps://media01.nerdia.net/uploads/nerdia-logo-340x156.pngStefan Helander2022-05-16 10:11:202022-05-16 10:12:43Nagoya RB-400 – it just fell to pieces
I purchased a Nagoya RB-66 lidmount antenna mount from a seller on eBay. The product was new (not second hand used). After two weeks use, I noticed the screws had started rusting.
Dear Nagoya. The antenna mount is supposed to be used on cars. Cars are outside all year around, in all kinds of weather conditions. Why don’t you use stainless steel screws? Yes, I know they are more expensive.
I replaced the two screws and the four small hexagon socket screws (they also started to rust) with stainless steel ones so hopefully my problem is solved. But quite annoying. I think a product supposed to be used on a car should be able to handle all year weather conditions and it is quite annoying having to replace parts before being able to use the product properly.
Operating ham radio QRP, that is using low power, is probably not a good choise for the new beginner. To successfully operate ham radio QRP you need to use all your skills when it comes to selecting the correct bands, modes, propagation and evauluating current conditions. As a beginner to amateur radio it might be a better idea to start off with for example a 100 watt rig to get a lot of successful QSO:s and acquire knowledge about propagation and conditions first.
However, when you start to know how propagation and band conditions work, operating QRP from a portable location with a small temporary antenna can be an exciting and rewarding challenge. When operating QRP any contact is a success, not just far away DX stations. A contact just 500 or 1000 km:s away using a few watts is really exciting. But operating QRP requires patience. Don’t expect to come home with a log book with hundreds and hundreds of QSO:s.
Use CW. It comes through better with small amounts of power than SSB.
Listen around on the bands to estimate which bands are open and select the one with most or strongest stations. I usually start off on 10 meters and walk downwards on 12, 15, 17, 20, 30, 40 and 80 meters. If 10 meters is open, it can give you nice contacts with small amounts of power. That is during day time, if it is evening or night you might start off at 30 meters and walk your way down to 40 or 80. But as you know how propagation works, this is not news for you 😉
If you have Internet connection, send out a few CQ:s on each band and search for your call on Reverse Beacon Network (enter your callsign in the DX box) to see on what bands you show up and where your signals are strongest.
I prefer the WARC bands (12, 17 and 30 meters). They are contest free and generally less crowded.
Responding to CQ:s are way more efficient than sending CQ:s yourself. Even though your CQ might be heard, people have a tendency to respond to stronger signals and your will be weak when operating QRP.
If you decide to CQ yourself, use the QRP calling frequencies; 28.060, 24.906, 21.060, 18.086, 14.060, 10.116, 7.030 and 3.560 MHz. I usually add “QRP” one time before “PSE K” to indicate that I am operating QRP.
My QRP “go to” band usually is 30 meters. It is often open, it has propagation characteristics between 20 and 40 meters. And I usually get best results on RBN when I work 30 meters.
In the pictures below, I am operating QRP as SM0RGM/6 from a location nr Strömstad, Sweden.
Good luck and hope to see you on the bands! 73 de SM0RGM / OZ0RGM
https://media01.nerdia.net/uploads/IMG_20220416_171430-scaled.jpg19202560Stefan Helanderhttps://media01.nerdia.net/uploads/nerdia-logo-340x156.pngStefan Helander2022-04-18 09:47:152022-04-18 17:02:47How to operate QRP successfully
The antenna seems always to be a compromise between practical matters and performance. While not being the most high performance antenna, I find the end fed half wave (EFHW) a very practical antenna, especially during portable operations.
The EFHW doesn’t need to be straight. It can be bent in angles and be “abused” a lot.
In this video I have a temporary installation in a vacation home (time share) where I am not able to erect any masts, not being able to use trees or other houses as fixation points for my antenna. I used some zip ties only that can be removed without leaving any marks.
The antenna height is far from optimal and the antenna is bent several times. It is also close to the rain gutters made of metal. Still I have fine SWR levels on all bands (10/15/20/40 m) and can work all of Europe on my QRP rig (6 watts) (see the screenshot from Reverse Beacon Network).
https://media01.nerdia.net/uploads/reverse-beacon-network-efhw.png3941428Stefan Helanderhttps://media01.nerdia.net/uploads/nerdia-logo-340x156.pngStefan Helander2021-11-16 11:40:422021-11-16 12:10:21Why I love end fed half wave (EFHW) antennas
I wanted to make a “stealth installation” of my Anytone AT-D578UV radio in my Toyota Prius (2008) so I don’t have to worry so much for burglars when parking the car. Below the FM-radio is a compartment, when removed, leaves a space big enough for the radio.
There is plenty of space behind the compartment. I was a bit worried about that issue becase the radio is longer than the depth of the compartment, but it turned out there is enough empty space behind it.
I installed the radio with the programming cable connected as it will be very hard to connect it after the radio is mounted in the car. The microphone is extended and connected using a flat straight ethernet cable and both cables are dropped downwards and pulled out from behind the panel. That way I can easily hide the microphone when parking the car.
When the compartment under the radio is removed (and saved to be reinstalled when selling the car), the space between the metal plates is to wide, so I took a 5 mm nylon cutting bord that I cut into pieces and glued them together to form a suitable spacer and drilled a hole for the mounting screw. I did not use the mounting screws that came with the radio, instead I used one M4x20 mm and one M4x40 mm. On the right side of the radio I used 2 nylon pieces and on the left side 5 or 6. The screws went into the rear holes on the radio and to get some support for the front I used zip tie straps around the radio through the holes in the metal plates.
The GPS was just tucked up behind the navitor screen, just to the right of the speaker. A note about the GPS antenna connector. After about 6 months after installation, I had no GPS signal on the Anytone AT-D587UV. It turned out that the SMA-connector, that I tightened by hand, hade shaken loose by the vibrations. So do tight it a bit with a small wrench, not overtightening it but enough to keep it from getting loose.
For power, I routed two 6 mm2 wires directly from the battery (with a 30A fuse close to the battery) and routed them through the left trunk panel and inside the side panels below the doors to the front. The antenna cable went the same way and I didn’t want to drill a hole in the car so I used a trunk lid mount even though the performance for those are often not as good.
These are some useful tutorial videos as you need to uninstall and reinstall the stereo in order to install the Anytone AT-D578UV below it.
https://media01.nerdia.net/uploads/IMG_20211007_172828-scaled.jpg19202560Stefan Helanderhttps://media01.nerdia.net/uploads/nerdia-logo-340x156.pngStefan Helander2021-10-09 11:59:282022-05-27 07:49:24Anytone AT-D578UV stealth installation in Toyota Prius (2008)