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Looking into APRS


#1

Looking into getting an APRS HT
Any recommendations???
I have been looking at the Kenwood TH-D72A vs TH-D74A
73
Tom~W1PTS


#2

Assuming you mean TH-D72 and not 71, both are pretty good for APRS, the choice really comes down to what other features you need and how much you are willing to spend. The TH-D72 also supports full duplex (useful for satellites) while the TH-D74 doesn’t.

I’m using Yaesu FT2D at the moment - it’s lighter than the Kenwoods and does the job but the user interface is typical Yaesu, awful.

Getting much use out of it: it really depends if there is enough activity in your area. APRS in the UK is pretty dead, but when I travel it’s quite useful. To get an idea of activity you can just run APRSdroid on your phone with an audio cable to any VHF radio.

Icom ID-51 is a very good radio and supports APRS too, but I haven’t used it.


#3

Thanks for your reply
it helps me
also thanks about the type-o I did not catch it


#4

Razvan mentioned using APRSDroid on your phone with an audio cable to listen for APRS activity.
I have been using APRSDroid with a Mobilinkd modem (http://www.mobilinkd.com/tnc2/) for a Bluetooth connection to the phone. This gives both receive and transmit capability in a portable package.
I chose this method as the display on the phone or tablet is easily upgraded, and it was cheaper than a new radio, as I already owned two 2m HTs. I have used the modem with an FT-65 and with an HTX-202 with no problems.
I use APRS mainly for posting spots on summits where there is no phone service.

Ian VE6IXD


#5

I had the Kenwood TH-D72 and it worked very well for me. I just got a Yaesu VX8GR for aprs and the menu seems less intuitive, though this is my first Yaesu ht. One potential advantage of APRSdroid is creating messages, I imagine that it’s much easier to tap out a message on a smartphone screen than the keys and/or knobs on an ht. I edited existing messages on the TH-D72 to reduce the time and effort required to create a new one.
Peter KD0YOB


#6

The idea of getting a mobilinkd and an HT with a stronger front end make a lot of sense to me. However, if you can live with 1 watt output, you could get the Pico Aprs:

http://www.picoaprs.de/index_en.html

I’ve used one quite a lot now here in Austria and it has worked well for me. An external antenna will boost the signal, a yagi would be even better. Most people working FM carry a yagi anyway, or a small linear. Also, it works as a KISS TNC, so you can run it with APRS Droid for a more user friendly interface. It also functions as an iGate, so if you go somewhere there is poor APRS coverage, you can create your own iGate in your car or hotel room. Of course, you will need another APRS device to send to your iGate.
73 de OE6FEG
Matt


#7

I use a Yaesu FT-1DX, which of course is no longer made. It has been a lifesaver on occasion, when a cell signal wasn’t there and the only way to send a spot was by APRS. Liz only does SSB (that may change in the future) so she is not picked up by the reverse beacon network.

As someone else said, Yaesu doesn’t make it especially easy to enter the spot information using knobs and buttons, but I found that if you enter a test message from home, you can go back and edit that message when on summit. That is much easier than creating a whole new message on the mountain. Hopefully that tip can be useful for other radios as well.

Hope that helps a little.

Ron, KI4TN


#8

Thank you all for your input, as I go through the decision making process.
Being new to the idea of APRS I am not real sure of my needs now vs in the future.
Right now what I think would be of great to me is a unit that will work 2m, and APRS GPS/tracing.
As well as being able to spot on SOTA. (TH-D72A)
BUT the TH-D74A has a lot of features, that might be nice to have in the future.
NOTE: what ever unit I go with will be used in the wilderness area of the Appellation Mountains ~ USA
73 Tom ~ W!PTS


#9

Tom,

I had purchased the Kenwood TH–D72 five years ago because I wanted get into APRS and I figured that since Kenwood had the first APRS radios, I would go with them. I did not really know about SOTA back then but a ham friend asked me to talk to his friend Mike N6MKW who wanted to use APRS while operating from mountaintops. This intrigued me so I talked with Mike to explain what I knew about APRS and Mike told me about SOTA. Since then I have used this same D72 for APRS2 SOTA on almost all my activations around the country. Besides for spotting, I carry the D72 in a side pocket on my backpack to send out beacons as WA9STI-7 while I hike to summits so chasers can track my progress if they wish. Occasionally when I can receive another activator’s beacons while on the summit, I send them a text message which would be RF to RF on 144.390 MHz.

I am an old fashioned guy who uses an old fashioned cellular flip phone. As I tell people, smart guys do not need smart phones. So I do not know anything about APRS via droids or computers to send beacons. I like the idea of using a radio to send and receive APRS beacons via RF although I know eventually one gets into the Internet through digipeaters when spots post to SOTAwatch and on aprs.fi. However I have taken a notepad occasionally on short hike SOTAs to post if digipeaters not accessible. Because I like Kenwoods for APRS, I have the TM-D710G in my Jeep which I also use as WA9STI-9 to send beacons en route to a SOTA so chasers can track my progress while I am driving. In summary, I like the D72 which has worked well these past five years. From what I have heard, the D72 is better for APRS and with its dual-receive than the newer D74.

Scott WA9STI
Los Angeles


#10

The Anytone AT-D878UV does analog (analogue?) and digital APRS, and also does DMR. Its US$217 which is a pretty good price for a handy with these features.

I have used a Yaesu VX-8 on most of my activations, which comes in handy for those summits without cell coverage.

Kent K9EZ


#11

I own all three: Anytone AT878 (well a flash-upgraded AT868), the TH-D72 and TH-D74.

The big disadvantages of the AT878:

  • Does not send APRS Messages - so useless for spotting.
  • Does not receive APRS, only transmit.
  • GPS receiver is worse than the Kenwoods: Takes longer for 1st position, larger position error.

Advantages of the AT878:

  • (less) than half the price of the Kenwoods
  • DMR if you want to use this mode

The AT878 is nice if you just want to transmit APRS positions and you are willing to accept some firmware bugs. In no way comparable with the Kenwoods.

Disadvantages of TH-D72:

  • Battery indicator nearly useless: 3 segments - 90% of operation time on 1 of 3 segments.
  • GPS receiver desensitized when running B-VFO on frequencies around 438.7 - 439 MHz.
  • Only three settings for TX power 5 W, 500 mW, 100 mW.

Advantages of TH-D72:

  • Nice protective bag with quick release belt clip.
  • cheaper than the TH-D74

Advantages of the TH-D74:

  • Slightly improved battery indicator. Now displays a large bar but still seems quite coarse and inexact.
  • Nice SDR-type receiver which supports SSB even on HF.
  • 4 TX-Power settings
  • Thinner, therefore appears to be smaller than the TH-D72.
  • DSTAR in case you are interested in this. I never use DSTAR.
  • Bluetooth. I never tried this out but may be a useful feature.

The APRS message functions of TH-D72 & TH-D74 are usable for spotting because you can simply edit an old message. So even with the limited input capabilities that’s managable.
Battery life is poor on both of them when the APRS-qrg is busy all the time. But that’s understandable when the receiver is on all the time.

I have purchased the TH-D72 long time before the TH-D74 was introduced and still use it for SOTA.

73 de Michael, DB7MM


#12

Thank you Michael, an excellent summary. I’ve been thinkng about a AT878 for APRS SOTA, but will think again now.


#13

Hi Tom,

I have a Yaesu VX-8GR which has served me well on SOTA activations. It doesn’t get used too often for spotting, but is great when you don’t have cell phone service or what I find even more annoying is the service that comes and goes unexpectedly. That usually seems to happen when I press send on a spot! :rofl:

I have found that here in the southeast US that APRS tracking pretty hit and miss. Until you get on a prominent ridgeline, we are usually terrain blocked unless the planets align and you just happen to get a beacon out. Beacons often get out just as I am approaching a summit. That’s not all bad as it does give chasers some idea of how close to being QRV you are. You can always go to https://aprs.fi/ki4svm-7 and look at my track history for an idea of how well it will work in our area.

And like others, I recycle my old spots instead of typing from scratch. I just pick the spot from the last activation that I used APRS on and edit as needed. One little trick that I can pass on is the APRS-SOTA gateway allows spaces as delimiters between fields and it doesn’t matter how many spaces between fields. I use extra spaces as padding and so it is easy to change ’ 7.285’ to ‘14.285’ or ‘ssb’ to ’ cw’.

73, pat - KI4SVM


#14

Michael,
A few questions if I may

  1. do you notice any difference in the APRS performance of the TH-D72A vs TH-D74A
  2. do like one better than the other (if so why)
  3. is there a reason you use the TH-D72A for SOTA (which is my primary need at this time)
    Thanks
    Tom ~ W!!PTS

#15

Dear Tom,

I’m happy to help:

  1. I never did a thorough side by side test but just used the two HTs alternatively. Regarding APRS performance (packed decoding, sending beacons) I did not notice a difference. The user interface is very similar. Of course the D74 takes some advantage of the higher resolution color display compared to the LCD of the D72. To my mind the the ability to send APRS objects is unique to the D74.
    The GPS receiver of the D74 seems to be a tiny bit faster in the intial fix. Especially, the D72 has problems with the initial fix when the B-VFO is tuned to frequencies around 439 MHz.
    You can use the B-VFO for APRS (imho 144.390 in the US, 144.800 in DL) to overcome this problem. But the A-VFO has a smaller tuning range out of the ham bands.
  2. From an objective point I should like the D74 better than the D72. Regarding versatility (wider RX frequency range, all mode RX, bluetooth, DSTAR, higher resolution color display) the D74 is the better radio. Of course it is a newer design.
    Subjectively the D72 has become a proven companion during many activations including rain and snow. So for emotional reasons I do not have a favourite.
  3. There are two silly, subjective reasons:
    The quick release belt clip on the D72 protective bag. I put it on the strap of the backpack near my shoulder. So I can easily remove it within the protective bag and put it on the ground. Both the D72 and D74 offer a belt clip screwed to the radio itself. But for the protective bag only the the D72 has a belt clip.
    The D72 does all I need for the typical SOTA activation. Sending position beacons during the hike, occassionally sending a message for SOTA spotting, monitoring the 2m call frequency. When I am playing with my KX3 on HF for SOTA the D72 only gets little attention. So no need to take the expensive, new toy out.

If price is not an issue I would recommend the D74.

73 de Michael, DB7MM


#16

I know it was not asked, but also look on a Yaesu FT2. I own one since 2 years and it is perfect for SOTA. Had it with me about the last 50 activations or so. I also like the user interface with the big touch screen. Here in DL the price dropped around 100 Euro which is around $112 US. There you would get the biggest bang for the buck. The TH-D74 costs exactly twice the price of a FT2 and just for SOTA I see no advantage on the Kenwood. I would not buy a chinese radio for 250 if you can get a serious Yaesu for 350. Exception only if you really need DMR, which I don’t need, especially not on a summit.


#17

that’s exactly what I experienced. after my th-d7 died some years ago i purchased a vx-8 but was not happy with the user interface. so i got rid of it again and bought the th-d72 … and did not regret the purchase. if you’re not interested in digital modes you should go for the th-d72.


#18

I have both Kenwood HTs, the TH-D72A and the TH-D74A and use them both. I have not tested the battery life scientifically, but it appears to me that the battery on the D72 lasts longer than the battery on the D74. I always carry a spare battery and for me it is easier to change the battery on the D74. I now use the Th-D74A on the trail and my TM-D710A in my car. My XYL follows my travels on the APRS map at home and she knows when I reach a summit, and when I am headed home. (happy wife/happy life) The TH-D72A has full duplex capability which is great for satellite ops; and the TH-D74A has three bands - 144, 220, 440. I have used the APRS spotting capability when the telephone does not connect.


#19

When I got interested in using APRS during activations, I almost fell over at the price for HTs with this feature built-in ;-). If I owned no HTs, I likely would have bought one of the Kenwoods. But I already own 2 working HTs, so the idea of paying a rather high price for another HT just to get APRS going wasn’t very appealing.

I bought the Mobilinkd solution, which works fine with my Yaesu HT. I also have used APRS apps that can use the cell network.

Unfortunately, due to the spotty coverage I’ve experienced with APRS, whether radio or cell based, I’ve not used it much in the last year. It’s also another thing to carry when I’m trying to keep my pack load light. However, I’d deal with the added weight in exchange for the added safety factor of my location being available if I could more reliably get into the APRS network.

73 Paula k9ir