Wouxun KG-UV8D for SO-50? Sure, but not full-duplex by itself...

Discussion in 'Satellite and Space Communications' started by WD9EWK, May 27, 2014.

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  1. WD9EWK

    WD9EWK Ham Member QRZ Page

    Hi!

    After I returned from Dayton last week, I ordered a Wouxun KG-UV8D 2m/70cm FM HT. Even after working Andy W5ACM while I was at Dayton, and reading his e-mail where he mentioned he used a KG-UV8D for that QSO, I still wanted to see for myself. I ordered the radio last Tuesday (20 May) from MTC, and it was delivered at my office by USPS Priority Mail two days later. Along with the radio, I ordered a programming cable.

    20140522-KGUV8D_stuff.jpg

    The programming cable was not necessary, as this radio is compatible with the programming cable used for Baofeng (and other Wouxun) radios, but I have it anyway.

    Out of the box, the radio was open from 135 to 174.995 MHz and 400 to 479.995 MHz. There is software from the Miklor UV8D pages that is supposed to open the radio up to 134-174 MHz and 400-519 MHz. I have not used this software, since I don't have a need to transmit above 480 MHz. This HT is not compatible with the open-source CHIRP radio-programming software at this time, so I had to use the Wouxun software to load the memory channels (I received a small CD with it, or the Miklor site also has it).

    This radio carries the same FCC ID number as Wouxun's KG-UV6D. On the back of the radio, below the FCC ID/warning label, the aluminum case was engraved with "MTC - USA version".

    20140522-KGUV8D_rear_plate_with_label_and_engraving.jpg

    It is interesting that this radio carries the same FCC ID number as the Wouxun KG-UV6D, although this radio appears to have more functionality than the UV6D - except in one regard. The UV8D does not tune in 2.5 kHz steps. For some reason, this was left out of the radio, but is present in the previous UV6D. I can enter frequencies that would normally be reached with 2.5 kHz steps in the VFOs, but those frequencies are rounded down when stored in memory channels (i.e., 436.8025 becomes 436.800). The UV8D has the capability to receive from both VFOs, regardless of the frequency in each VFO, and one VFO can be turned off, if you don't want to hear from both VFOs.

    Before continuing, I will answer the question that most FM satellite operators have about this radio. I won't make you wait to get the answer, since it really doesn't take many months to figure this out. Does the KG-UV8D do cross-band full-duplex operation for SO-50 (transmitting on 2m while simultaneously receiving the satellite downlink on 70cm)?

    No.

    As I transmitted on 145.850 MHz to SO-50, the other VFO with the 70cm downlink frequency was desensed. The behavior is similar to what I heard with the Alinco DJ-G7T 2m/70cm/23cm FM HT a few years ago, and what was (finally, after 6 months) reported for the Puxing PX-UV973 2m/70cm FM HT. Andy W5ACM told me about what he saw when he used his KG-UV8D on SO-50, and my findings mirror what he told me. This radio might work better if the uplink and downlink bands are reversed, as will be the case with AMSAT's Fox-1 satellite due to be launched next year, but it doesn't do full-duplex for SO-50. I used my Elk Antennas 2m/70cm log periodic antenna and (briefly) my Arrow Antenna 146/437-10WBP 2m/70cm Yagi for these tests, although all QSOs were completed with the Elk log periodic.

    The KG-UV8D's receiver is certainly better than the Alinco DJ-G7T, more sensitive and selective than that radio. Compared to the Baofeng UV-5R and UV-82 HTs I have been using for the past few weeks, I can say that the UV8D's receiver is at least as sensitive as the Baofeng HTs, and more selective. My Icom IC-2820H 2m/70cm FM mobile transceiver still has a more sensitivie and more selective receiver than any of these Chinese-made HTs, including the UV8D. The UV8D's transmitter is supposed to put out 5W on VHF and 4W on UHF, and tests have confirmed that the radio puts out at least that much.

    One peculiar "feature" - for lack of a better word - I see with the KG-UV8D is that when I would normally adjust my 70cm receive frequency to copy SO-50, there are moments when I wish this radio had the 2.5 kHz tuning steps. When I am having difficulties clearly hearing the voices on a frequency like 436.800 MHz, I'm not clearly hearing them on 436.795 MHz either. This doesn't appear to be an issue with most non-Chinese HTs or FM mobile transceivers I have used over the years. I just have to wait a moment for the satellite to move, and the downlink frequency get closer to the next (lower) tuning step to clearly hear the voices again. This repeats each time I need to tune down to the next tuning step during an SO-50 pass.

    After working SO-50 with the KG-UV8D and Elk log periodic antenna on 24 May, I went to a two-radio setup similar to what I have been doing with my Baofeng HTs. Taking advantage of the better receiver in the UV8D compared to the Baofengs, I used the UV8D as the 70cm downlink receiver. I used a Baofeng UV-82 with a dual-PTT speaker/mic as my transmit radio, since I could put 145.850 MHz in each of the UV-82's VFOs, with a different PL tone for each VFO (74.4 Hz for the upper VFO using the upper PTT on the speaker/mic, and 67.0 Hz for the lower VFO using the PTT on the left side of the speaker/mic).

    20140524-UV82_KGUV8D_for_SO50.jpg
    Plugged into the KG-UV8D's speaker jack is my splitter cable, to feed the receiver audio to an earpiece and my Sony audio recorder. The dual-PTT speaker-mic is plugged into the UV-82. The UV8D, like the Baofeng and many other Chinese-made HTs, are compatible with Kenwood speaker/mics if you already have one of those. Both radios are connected to a 2m/70cm diplexer, since the Elk has only one coax feedpoint.

    Other than the pecularities when it was about time to change my receive frequency, I saw no desense on the KG-UV8D's receiver when I transmitted with the UV-82. This leads me to believe the issues with the KG-UV8D and cross-band full-duplex operation are internal to the radio. When working with stronger signals - local repeaters, or when I transmit with one of my many Baofeng or other radios - the KG-UV8D had no problems serving as a cross-band repeater, no matter which direction it was retransmitting (receive 2m and transmit on 70cm, or receive on 70cm and transmit on 2m). As with other radios, or combinations of radios, that are capable of serving as a cross-band repeater, please comply with your local regulations on the operation of cross-band repeaters (in the USA, these are usually classified as "auxiliary stations" in the FCC Part 97 rules).

    The KG-UV8D has a female SMA antenna connector on the top of the radio, the same type of SMA connector used by Icom/Kenwood/Yaesu/Alinco HTs (and different from the male SMA connector on my Baofeng UV-5Rs and UV-82s). I put a Diamond BNCJ-SMAP adapter on this SMA connector, and now use antennas and coax with BNC connectors with this radio - my normal setup for all of my radios I use with satellites. I have an assortment of antennas and coax with BNC connectors, so I won't need to remove the adapter from the UV8D.

    Another practical observation... the LCD display. In bright sunlight, the KG-UV8D's display is difficult to see - similar to the LCD displays used on many mobile phones, tablets, and laptops. Without the backlighting activated, I could not read the LCD display at all, so I leave the backlighting on all the time. This doesn't appear to be a huge drain on battery life. Most other radios I have, or have used in the past, don't use LCD displays that are this difficult to read in bright sunlight.

    The supplied 7.4V/1700mAh lithium-ion battery pack is a good choice for this radio. Wouxun has a larger 7.4V/2600mAh pack, the BLO-009, but at present it doesn't appear to be available from stateside distributors. If I use eBay or other offshore radio shops, I can order them from the Far East. I have not seen any AA or AAA battery cases for this radio yet, but those may be coming later. This is still a relatively new radio.

    There you go. Is the KG-UV8D worth the purchase price? That is up to you. It is a neat radio, a little larger and heavier than other Wouxun and Baofeng radios I have used over the years. I'll keep the UV8D around, and use it as part of my SO-50 satellite demonstrations, along with another HT (probably a Baofeng UV-5R or UV-82) to demonstrate full-duplex FM satellite operation. It's one thing to talk about full-duplex operation, but another to actually demonstrate it for a crowd - something I did with a UV-82/UV-5R combination on SO-50 at a hamfest earlier this month in southern Arizona. With Fox-1 in the pipeline, and SO-50 having a weak downlink, working full-duplex becomes more important than in the past with satellites like AO-27 and AO-51.

    73!
     
    Last edited: May 27, 2014
  2. ND5Y

    ND5Y Ham Member QRZ Page

    There is at least one dealer that is selling a newer KG-UV8D version that has 2.5 kHz synthesizer steps.
    http://www.buytwowayradios.com/products/wouxun/kg-uv8d.aspx
     
  3. N8HM

    N8HM Premium Subscriber QRZ Page

    Great review, Patrick.

    Shame it doesn't do full duplex for SO-50, but hopefully it will work for Fox-1. Also remember that QB50p2 will be launching on a DNEPR from Yasny on June 19th. That satellite has an AMSAT-Francophone U/V FM transponder on board that should be activated about six months after launch. It may work for that satellite as well.
     
  4. W5PFG

    W5PFG Premium Subscriber QRZ Page

    Thanks for buying the rig and trying it, Patrick. You buy the chicom radios so we don't have tooooooooooooooooooo.........

    I do wish we had some modern, workable solutions besides the Kenwood TH-D72 for full-duplex HT/light portable satellite ops. When I first got back into satellites, I was mostly using a Kenwood TM-D700. It was great for AO-51, AO-27, SO-67, and SO-50. Full-duplex, very little desense issues. I had it mounted to a board with my preamp, diplexer, and output to my recorder. Works great, to this day. Great for working the only FM sat SO-50. The D72 is a fine rig. I owned the D7 for many years, selling it only when I was convinced I was going to buy a 72 before changing plans.
     
  5. WD9EWK

    WD9EWK Ham Member QRZ Page

    The Baofengs are really inexpensive, and ordering from Amazon.com means the easiest returns policy of any online seller. I get those radios from Amazon, not from someone else using that site as their storefront, and shipped from an Amazon warehouse. All of mine have come from Phoenix-area warehouses. I could have purchased my KG-UV8D on Amazon, but those storefronts would have shipped the radio from the Far East. MTC is in Texas.

    I bought one of the early Wouxun HTs when they finally started coming to the US with FCC certification at Dayton a few years ago. I didn't keep that one for long, but now I can mix and match between the two Baofeng models and the Wouxun for my demonstrations. I won't buy a second KG-UV8D, as one of those is more than enough.

    I think we are only going to see that from mobiles out of the traditional ham manufacturers, unless Kenwood decides to replace the TH-D72A with something similar in the future. Alinco tried and failed with the DJ-G7T a few years ago, and I don't see anything from Icom or Yaesu in an HT for full-duplex FM satellite operation (both are interested in digital voice, or APRS in the case of Yaesu). Maybe the Chinese manufacturers will figure things out, and make their dual-band HTs and mobiles work full-duplex for our FM satellites. The KG-UV8D is not that far away, since it can work full-duplex with a stronger 70cm signal when transmitting at 2m, but comes up a little short. The KG-UV8D's receiver, coupled with the missing 2.5 kHz tuning step available in other Chinese HTs, adds a little bit of complexity not present with other HTs.

    73!
     
  6. WD9EWK

    WD9EWK Ham Member QRZ Page

    OK, great! Maybe someone can purchase that KG-UV8D and try it on SO-50, or at least confirm that the memory channels and tuning steps can handle 2.5 kHz, or if that only works when entering frequencies in the VFOs. I'm not looking to have a collection of KG-UV8Ds from different vendors.

    73!
     
  7. WD9EWK

    WD9EWK Ham Member QRZ Page

    Hi!

    Like with many of the Chinese-made HTs, holding down the 3 button while powering the radio on shows information like the firmware version. This is what I saw when I tried that on my KG-UV8D this evening:

    KGUV8D-Hold_down_3_when_powering_on.jpg

    I don't know what the Chinese script is, but I might be able to ask a coworker about that if he is in the office. Everything else points to a relatively early - and recent - firmware revision.

    On another item... it is interesting that the Wouxun web site and the owner's manual for the KG-UV8D make no mention of the 2.5 kHz tuning step. It really should be easy to implement that, if this radio uses a chipset similar to the previous KG-UV6D (remember the FCC ID number on the UV8D is the same as for the UV6D) or what most of the Chinese-made HTs are using now. I wonder if there is a way to change that, as there apparently is for the upper and lower edges of the 2m and 70cm bands these radios can operate in. The VFO mode accepts frequencies that would be consistent with a 2.5 kHz tuning step, but won't store them in memories.

    That's all for tonight... time for bed. This has been a good weekend for satellite work, and especially today with what I've done on a few different satellites including SO-50 with my UV-82/KG-UV8D combination this afternoon. Back to work in the morning...

    73!
     
  8. K6LCS

    K6LCS Premium Subscriber QRZ Page

    I had already reported that the '8D - like the Puxing UV973 - although are true dual-receive units, that they are not suitable for
    U/V nor V/U sat ops ... Considering Alinco couldn't accomplish that with a $250 HT, I wasn't really surprised that these $100 units
    couldn't do it.

    Which just shows us how much engineering is involved and how Kenwood has led the pack. Starting with their TH-F6a and its
    tri-bands all at full TX power (not duplex) and now their TH-D72A (TRUE full duplex and V/U / U/V sat ops) - they offer us radios
    that no one else has been able to equal.
     
  9. N8HM

    N8HM Premium Subscriber QRZ Page

    How do you know that they aren't capable for U/V satellite operations? What U/V FM satellite have you tried it with?
     
  10. WD9EWK

    WD9EWK Ham Member QRZ Page

    Yes, you gave a quick report that the KG-UV8D was not capable of full-duplex operation on SO-50. You may have been the first to say this. But I don't recall seeing you say anything more than that about the KG-UV8D.

    I also heard the same from Andy W5ACM via e-mail after working him on the 18th from the AMSAT station at Dayton, when he was using a KG-UV8D. I don't think Andy has posted his thoughts about the KG-UV8D online yet. I wrote a bit more about the radio, besides whether or not it is suitable for full-duplex operation on SO-50. Judging from responses I have received, my review of the KG-UV8D seemed to be appreciated by other hams with an eye on this radio as a candidate for use with FM satellites (for now, just SO-50).

    I have not ruled out the KG-UV8D for U/V satellites, since I don't have anything to properly test that with at this time. Maybe Fox-1, or some other U/V FM satellite, will be available in the near future for me to try the KG-UV8D with. I did use it on many SO-50 passes between Saturday (24th) and Monday (26th), by itself and with a different radio as the uplink transmitter, taking advantage of the 3-day holiday weekend, before posting here.

    You have used a line like "Considering Alinco couldn't accomplish that with a $250 HT...." in other posts in other forums when it comes to these radios not being able to work full-duplex, where the TH-D72A can. If that statement is true, why did you take 5-6 months to say that about the Puxing PX-UV973 and its inability to work full-duplex on SO-50?

    You posted on the UV973 Yahoo! group in early September 2013 that you bought a PX-UV973:

    https://groups.yahoo.com/neo/groups/uv973/conversations/messages/97

    In December 2013, around the anniversary of SO-50's launch (and a couple of weeks before you announced you were selling the PX-UV973), you mentioned:

    (excerpted from an AMSAT-BB post, http://amsat.org/pipermail/amsat-bb/2013-December/047706.html )

    You were still working with Puxing in February on this radio and its (in)ability to work full-duplex on SO-50, while you were selling them. In March, you started with this line about the Alinco radio and the $100 radios compared to the TH-D72A. What was so different about the Puxing radio, where you needed almost 6 months of testing, when you took far less time with the KG-UV8D? Is there something radically different in the PX-UV973 compared to the KG-UV8D and the Alinco DJ-G7T? Or were you just trying to hold out hope for the PX-UV973 working full-duplex with SO-50, as a vendor selling those radios?

    I don't know if I would make the same statement.

    The TH-F6A has been on the market for over a decade. It is a good radio, and the only HT from the big 3 manufacturers with 5W output on the 222 MHz band and the all-mode receiver from HF up to 470 MHz. The TH-D72A, which has been on the market since late 2010, was a nice improvement over the previous TH-D7A that had been in production for many years, especially with its internal GPS module. Kenwood has done well with these two radios. I have both of them, and use them in satellite demonstrations at hamfests and other events I attend. It would be nice if Kenwood acknowledged in the manuals or its other literature (or web sites) how useful these radios are among satellite operators.

    What about Yaesu and the FT-817/FT-817ND, something that hasn't been approached by the other ham manufacturers in almost 14 years? Icom was trying, sort of, with the IC-703 that did not include 2m or 70cm (the initial IC-703 also omitted 6m) - but it is larger than the FT-817, with an internal antenna tuner in place of an internal battery pack, and an optional audio DSP module. I have used my IC-703 to try copying the mode A (10m) downlink from AO-7. Otherwise, it doesn't factor into my satellite operating. Two FT-817NDs are my normal all-mode satellite station, whether for demonstrations or whenever I want to work SSB/CW via satellite (and, occasionally, FM) anywhere I happen to be. A third FT-817ND is at home as a spare. What does the 817 say about Yaesu's engineering?

    It is probably more that the other manufacturers are trying to distinguish themselves in the marketplace, and not just copy what someone else already sells. For example, only Icom sells radios with D-Star, only Yaesu sells radios with a different digital-voice protocol incompatible with D-Star, and Yaesu makes radios with APRS TNCs but not full-function TNCs like with the Kenwood radios. Not a bad thing, generally - but a nuisance for those interested in some of those features like digital voice, or hoping to use the Yaesu radios' TNCs for more than APRS, etc.

    73!
     
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