Today started off like most others with some time at work in the morning and then I had a few hours around lunch to do an activation. In addition to the usual activities, I have been using a variety of radios lately to see what I like about each one. Since I had activated most recently with the IC705 (by far my most favorite POTA machine) and so I wanted to use a different radio. I have been using the TR-35 lately in the shack, but wanted more field time with it to see how easy it would be to work with.
33’ wire radiator and two 10’ counterpoises bundles for storage. I love these velcro tie back straps.
So on this outing, I used a 33’ wire “vertical” antenna that I pulled into the tree with my throwline. Once the vertical was up, I laid out both of my counter poise wires (I think they are 10’ each) and for good measure I spaced them into a v pattern for kicks… On my next trip out I plan to see if putting them at 90 degrees to the radiator and 180 degrees from each other helps, it probably does and I have been paying the price all along with my silly V setup I have been using… lol…anyway…
This is a great antenna tuner and still happens to be in production! The new version is a little more streamlined but it is the same internally as this older one.
Back of the antenna tuner is just as busy as the front!
Once the antenna was up, I connected it to my MFJ travel tuner to the random wire lugs on the back of the unit. Then I use a special coaxial cable I bought from Amazon that has a BNC on one end and a PL259 on the other. The antenna tuner uses SO 239 mounts on it so the PL259 couples that end and the other end is natively a BNC on the TR-35, but I have also adapted my nanoVNA to BNC as well for simple tuning. Since my Ten Tec Argonaut 5 is SO 239, I have bought an adapter to convert it to this same system so I can tune the antenna easily on it as well.
This is not my idea, my late friend K4GC Brian was the person that taught me and Roger how to do this. It makes perfect sense when you think about it though so I started doing it once I got the VNA. Otherwise it is this trick of tuning till you hear the noise level peak and that is the best you get. This way works but it is possibly not centered where you need to be. Since the TR-35 doesn’t have an SWR meter, it has lots of protection circuits built in to prevent you from damaging the transmitter from tuning or operating at full power with poorly matched antennas. It has a current protection circuit as well as a thermal protection circuit, if either one activates, you really should check the antenna and see what is wrong, then reset the radio and try again. Alternatively, you could bring an SWR meter with you to get the tuner set as well if you don’t have a nanoVNA…
Amazon is a great place to find these sorts of oddball parts, several of the items in this blog today came from them.
Since everything is now BNC connected, I can quickly pull the cable from the radio, then connect it to the nanoVNA and see the tune on the tuner visually! I run a trace with the smith chart and a trace with a SWR line graph as well, with both of these running at once, it is pretty simple to get the SWR and the impedance really close to what the transmitter likes. Once I get the tuner adjusted to the band I want to use, I simply move the coax back over to the radio and off I go…
BNC is where it’s at with this system…
Here I am tuning for the 17m band, note that the VNA is showing the SWR of 1.541:1 and the impedance is 54.8 ohms and slightly inductive at 18.096mhz. I could dial some more of this out with the tuner, but it becomes a law of diminishing returns at some point with the tuning and this worked just fine. Note also that the SWR is fairly flat in the range I planned to work in also. (the yellow line represents SWR vs. Frequency)
Some things to note about the TR-35 that I noticed. The first one is that the headphone jack is wired from the factory for a mono plug, not the stereo plug that every set of headphone made in the last 30 years uses…why? So you go to Amazon once again and buy this little adapter to convert your normal headphones to a mono plug… You can go into the radio and change this on the circuit board, and the instructions even detail this mod, but you have to risk damage to the radio and it is a lengthy tear down and assembly process to get the board out of the case. Lot’s of chances to break something important if you asked me…so the adapter it is… Another thing I cant seem to master is the keyer programming. It is a simple operation to input the message into the keyer, but upon playback, it has odd spacing and sounds disjointed for some reason, I have tried slowing down the keyer speed to no avail, I will figure it out at some point, but for now, I don’t have that one working right. To put it plainly, it just sounds wrong on playback, like I was saying, it could be my sending is causing it, but I have not figured it out as of this writing. I have seen videos of it working as advertised so I am confident I can get it to work…eventually.
Amazon…they have literally everything at this point.
I powered it with my battery I use for my 705 activations, actually lots of the accessories I used came out of the 705 kit today for this activation. But I found this battery is way overkill for the TR-35, so I plan to get a smaller one for the travel battery to build the kit with. Probably something in the 4 or 5Ah range instead will be fine. I am also going to eliminate the voltmeter inline for the travel rig too, just a cable with power-poles on one end, the 2.1mm plug on the other and a fuse in line with the power. It pulls 5 watts wide open, does it really need 14 gauge wire??? Lol. I actually used the power cord for my IC-705 to power this radio today, the connector worked just fine. But I will make a cord just for this rig to go in the kit.
I am also still using the N6ARA tiny 3D printed paddle that I bought a while back(also from the 705 kit today) this is a device that although I like it, it has some problems that I have found. For one, it is really small and I didn’t take that into account when I bought it. It is available in a couple bigger sizes and I should have gotten one of those. This one is in my mind, one that should be a backup or a SOTA paddle or something like that as it’s main advantages are that it is light and small. What I have found from using it regularly is that is gets dirty contacts and you have to mess with it some and clean the contacts before it will send right once it gets some age on it. This is because it is plain copper/brass contacts (pc board with a brass arm on the “levers”) and they tarnish in a matter of days to the point it wont send properly till I clean them. I am looking into three solutions here, a nice travel key like the Begali travel paddle, make my own travel key, or buy a used small foot print paddle off the boards. I am actually leaning towards the Begali for now to give me time to design a key I can share with the world as well as for my personal use. Anyway, who doesn’t like a nice Begali key?
My N6ARA tiny paddle… I love this little key.
I have an alternative reason for working with this radio so much as well. I am going to be doing some traveling in the coming weeks and months and I want to take a radio that is not too large so it is easy to pack and carry around and such. This means smaller is better and the TR-35 is my physically smallest radio. This means it gets the nod based on size and now it also gets points for performance. Even if I cant figure out how to program the memory right. 😂
The kit will fit into one of several of my camera bags that I currently have so I don’t have to purchase a new bag to carry it in. I have found that camera bags work really well for QRP radios too, they just fit really well into old camera bags for some reason. By the way, I didn’t think of this idea either. I got this idea from my cohort KV9L who did this for his FT8 rig and I straight stole the idea from him. LOL.
Parts everywhere today! I took the IC-705 bag to “rob” all the support gear from so it would be a simple deployment and I have not built out the TR-35 go bag kit as of yet either…
I really like the aesthetic of the TR-35 as it has everything you need and nothing you dont. It really is an incredible little radio. I didnt build mine from a kit, I bought mine factory built and aligned so I could get on the air sooner.
1 hour on the air netted two pages of QSOs! That is awesome for me!
Logbook looks good with a good spread of contacts today with several from Canada in the log for a change. I usually only get one or maybe two Canadians and today I think there are at least four! This was with only about an hour on the air too. That is really good for me since I run QRP power. The map below shows how far 5 watts into a wire vertical will reach with a little understanding of how to use it. All in all I really like the TR-35 from Penntek, it a great little QRP radio that fits into what I enjoy doing in amateur radio, low power CW operating…
So if you have not done it yet, please like this blog post and if you have a RSS feed, you can sign up there too. I really appreciate your reading along today and if you have not done it yet, get your gear out!!!
Thanks and 73
David - WK4DS