Radtel RT-860/880/UV98 antenna caution

[EAFrizzle]

Pulled the trigger on an RT-880, but it'll take a couple of weeks, so I grabbed an RT-860 to have an extra googaw. Of course, the first thing I want to do is slap my best antenna on it and see how it performs. SMA female on the antenna? Got it covered with a great Retevis dual-bander. But... it's deaf. Nothing at all. It worked with the stock antenna, what's the deal?

L-R: stock Baofeng antenna, Good Retevis!, stock RT-860 antenna. One of these things is not like the others.



Yep, only the stock RT-860 antenna will make contact and function. A good piece of info before you start buying a better antenna that ultimately won't work. You could use a barrel connector and your favorite SDS100/436HP antenna, but that's only a solution if you're standing still. A barrel and antenna has the chance to put too much leverage on the radio's SMA jack, and this is a nicer rig than a $20 Baofeng.

Nice look and feel to the radio. I was attracted to it primarily because I've always loved vertical, shirt-pocket style of SW radio than a typical portable. I loved walking my dog late at night while listening to the BBC on my Trident HH (yes, it's big; I'm a big guy with a big shirt pocket). This is a much better size factor, but the donut antennas probably aren't meant to be body-worn!

Other than that, it seems OK. I'll know more after dark when I can get some decent HF reception. Haven't messed with the V/U side yet, so no impression of that yet.

What I can compliment before some real testing is the way the memories/zones are set up, and the RT systems software. 256 zones/personalities/agencies, etc., × 31 frequencies per bank/object/scapegoat = probably more than I can actually use. For me, this kind of system will work especially well for HF programming.

More to come regarding performance, but I'm excited to give it a workout in preparation for it's big brother's arrival.

 

[EAFrizzle]

Walked outside for a bit with the HF donut. Just ran a quick check on the 3 WWCR frequencies, and got all three legible, if not with a huge signal reading. I'm going to check it with the Stryker SAR-10 on the car later. I'm pretty sure it'll be better, but you never know from day to day.

I'll check out the AM BCB/LW loop later tonight. I'll let y'all know about VHF/UHF performance when I'm done playing with it on HF!

 

[EAFrizzle]

Walked around the neighborhood and had nice reception with the loops. The SW loop made a significant improvement after tuning adjustments. It's sloppy and fiddly to adjust, but easy enough to hit a spot that boosts the signal while killing the noise. The MW loop pulled in a lot of signals all over the band, while seeming not to have much effect when tuning. All in all, they're not bad. Good enough reception for the price, and I'm happy with it based only on SW and MW results.

 

[AB5ID]

I’ve been looking into what they call 'donut' loop antennas, is that the type you tested? I’m curious how well they perform and whether the tuning capacitor has a sharp Q factor. I’ve also seen some setups where the loop is connected to a high-impedance amplifier before the input of single-chip Si-based receivers.

 

[EAFrizzle]

Yes, it came with the blue SW and the red MW loops. Didn't have much luck during the day with either, but last night they performed well. Neither seem to have a very sharp curve when tuning, but the SW model was definitely better at reducing the noise floor and bringing up the signal. The MW model received well, but tuning seemed to do very little.

Tonight I'm going to try out a couple of verticals, one is a telescopic one that extends to 4', the other, a Stryker SAR-10 cb antenna. Hopefully conditions will be good again tonight.

There's some good YouTube videos about programming the LW - FMBCB operations and memories; it's not intuitive to get to the HF receiver, programming some of the keys makes it easier to navigate.

VHF recieve on the stock duck seems pretty good. I'm going to hook it to a dual-band antenna tomorrow and scan a few things during the day.

 

[EAFrizzle]

@AB5ID, i have a quick question before I toast this radio with a brilliant idea.

Knowing these donuts are a high-impedance antenna, if I run an active loop (MLA30+) to the RT-860, I should probably put some attenuation in line, right? I'm thinking maybe 10 dB or so?

 

[AB5ID]

@EAFrizzle That sounds like a good idea to start until you see how hard the input is bring driven.

 

[EAFrizzle]

Going to put up the MLA-30+ today; i also have a balun arriving to hook it to a 100' ground loop. I think that may work well with the 860, it's great with my Eton Executive. Probably won't be anything listenable with the expected geomagnetic storm.

New programming cable coming with the balun. The big pain is getting the LW-FMBCB radio programmed. The RT Systems program doesn't give full control of the HF section, I'm having to use the vendor CPS for it. That one won't import from RR, so this is a bit more involved than i would like.

The transceiver side is pretty good. VHF reception is better than my BC125AT or BCD325P2, but a bit below the DB-50 and RT-95. I'm going to put it on some airband frequencies this afternoon.

Battery life is impressive. From 6p yesterday to now, it's only gone down one bar out of three.

I'll post programming results once I figure out a solution, but I'll probably leave the HF section alone once I get it sorted.

 

[DocentLuzuge]

Going to put up the MLA-30+ today; i also have a balun arriving to hook it to a 100' ground loop. I think that may work well with the 860, it's great with my Eton Executive. Probably won't be anything listenable with the expected geomagnetic storm.

New programming cable coming with the balun. The big pain is getting the LW-FMBCB radio programmed. The RT Systems program doesn't give full control of the HF section, I'm having to use the vendor CPS for it. That one won't import from RR, so this is a bit more involved than i would like.

The transceiver side is pretty good. VHF reception is better than my BC125AT or BCD325P2, but a bit below the DB-50 and RT-95. I'm going to put it on some airband frequencies this afternoon.

Battery life is impressive. From 6p yesterday to now, it's only gone down one bar out of three.

I'll post programming results once I figure out a solution, but I'll probably leave the HF section alone once I get it sorted.

Any updates. I just bought one with the doughnut antennas.

 

[EAFrizzle]

The RT-860 and RT-880 work great with the MLA-30+. I use 6-10 dB of attenuation on them with that antenna, depending on conditions. They're already fairly hot on HF receive, and that little bit of attenuation keeps them from getting overloaded.

They also work well with a Loop on Ground antenna with no attenuation. Sometimes, when a vertical antenna is getting too much noise, the LoG gives me a better S/N ratio.

The doughnuts are ok for strong signals; the tuning knobs are fiddly to get adjusted, but it eventually gets dialed in.

Did you get the RT-860 or the RT-880? They're both good radios for the price. I use both mostly for monitoring military airbands, and they do well from HF through UHF.

Enjoy your new radio!

 

[rescuecomm]

Seems to be a common problem on the Chinese radios. I've got three 15 inch dual band antennas that only work on one radio. Center pin not making contact. I test any antennas by putting the radio on a weak NWS station and test versus the OEM one.
You would think the SMA manufacturing tolerances are close enough to work on any connection.

 

[PA3AZA]

Maybe good to share the following here: I bought my UV-98 Plus including the blue and red donut antennas. I noticed that tuning the blue one (for Hi/Lo SW) worked fine, but the tuning of the red one (for Hi/Lo MW) did nothing, and reception was poor, regardles of the Hi/Lo-switch position.

It turned out that the Hi/Lo-switch of the MW antenna was not connected to the two appropriate spots underneath the dial, respectively to antenna-GND. So I added two short wires from the switch to these spots, and connected the third switch contact to the (grounded) switch case.

After that also the reception and the tuning of the red antenna on MW was quite OK - both for Hi and Lo. Works fine.

The red donut antenna consists of two loops. In Lo only one is used, in Hi the two are in series. It appears that in fabricating the red antenna, they sometimes place the Hi/Lo-switch alright, but forget to connect it...

If you see no wires coming from the switch on your red donut antenna, check the loops, draw a schematic and find out how to connect the 3 switch contacts. Maybe the attached pic will help you.

 

[EAFrizzle]

Seems to be a common problem on the Chinese radios. I've got three 15 inch dual band antennas that only work on one radio. Center pin not making contact. I test any antennas by putting the radio on a weak NWS station and test versus the OEM one.
You would think the SMA manufacturing tolerances are close enough to work on any connection.

I solved the problem by trimming the base with a dremel. Now it goes in enough to make contact.

 

[rescuecomm]

I did one of mine with a razor knife, but the other 3 are still in the bags.