eBay Unication G4 G5 antenna to avoid

[cubn]

I had a $20 eBay gift card so decided to pull the trigger on an aftermarket 800 mhz antenna for the G4/G5.

https://www.ebay.com/itm/257270324557

The antenna shipped remarkably fast and looks beautiful on the scanner.

However signal reception is most important and I found it gets either the same or more often a bar or two less on distant sites than either the blue or purple band OEM Unication antennas.

Overall, I'm not gonna use this antenna in the future and continue to use the OEM or Kenwood K32 antennas.

 

[jtwalker]

I guess you haven’t read what has been posted about aftermarket antennas on Uni G pagers, and the possible damage that can be done?

 

[cubn]

These ones specifically have the correct anntenna connector, same as the OEM ones.

 

[hill]

Me I am just using the original antenna on both the G4 and G5, as I see no issues to make me want to switch.

They work great and no issue on possible damage to radios.

These small antennas pull in the signal great from my local county a few countries away.

 

[exkalibur]

It's a shame the external antenna is for the 800MHz band and not the VHF/UHF one where an external antenna would actually be beneficial.

 

[w2lie]

Unication will not honor their warranty if an aftermarket antenna is used and the center pin is pushed into the pager as a result.

 

[blackbelter]

I have never felt the needs to experiment with an after market on my G5 . The supplied antenna meets and exceeds my monitoring needs. My Unication amp charger is equipped with a legacy RS 800 antenna for seldom needed extra range . I truly enjoy the G5 and the stubby antenna form factor are more practical for everyday transport and monitoring. Apprehension of damaging the antenna port is another motivation.

 

[pokey]

I have no complaints with the stock antenna on the G5 either. Out of curiosity, I tried the Kenwood KRA 32K antenna, and trimmed the skirt to fit, as a few members on here raved about the improved performance. I personally barely saw a difference; sometimes one extra bar at most. Not worth it in my opinion.

 

[K9KLC]

I have never felt the needs to experiment with an after market on my G5 . The supplied antenna meets and exceeds my monitoring needs. My Unication amp charger is equipped with a legacy RS 800 antenna for seldom needed extra range . I truly enjoy the G5 and the stubby antenna form factor are more practical for everyday transport and monitoring. Apprehension of damaging the antenna port is another motivation.

I can "ditto" this exact post, right down to the legacy RS 800 antenna on the amplified charger.

 

[RCBi-Dave]

I had a $20 eBay gift card so decided to pull the trigger on an aftermarket 800 mhz antenna for the G4/G5.

https://www.ebay.com/itm/257270324557

The antenna shipped remarkably fast and looks beautiful on the scanner.

However signal reception is most important and I found it gets either the same or more often a bar or two less on distant sites than either the blue or purple band OEM Unication antennas.

Overall, I'm not gonna use this antenna in the future and continue to use the OEM or Kenwood K32 antennas.

Hello cubn, It seems that the tuned UPA78W with +4dB gain is causing internal RF overloading of your Unication pager receiver caused by the strong signals in your area from the many high-power UHF Digital Over-The-Air TV broadcast stations in Indianapolis. This overloading symptom is confirmed by have less signal bars with the UPA78W antenna than with the proven under performing OEM antenna on your P25 police signals. The tuned UPA78 or UPA78P antennas would be a much better choice for your strong signal area since they are made to ignore, reject, and filter out signals occurring outside of the 700/800 public safety band.

 

[CollinsURG]

The reception reports that @cubn posted does not indicate RF saturation. It indicates an antenna that provides less signal than the OEM antenna. The OEM antenna has an impressive performance, especially for it's size. I have a 3dBd antenna for 700/800 that is 10 inches long. It provides about 2-3 dBm increase in received signal and I have not observed RF saturation issues using it with the G5. Although that antenna increases received signal a little bit, I don't use it with the G5 because it has not improved performance in any meaningful way, and is 10 inches long. I had bought that antenna for my BCD325P2. But it does not stay on it either. I now use it on the HP2.


In the US, digital TV is not broadcast in the 763 to 870 Mhz range. The upper limit of TV is 608 MHz. Therefore, it would not be likely that it is interference from TV broadcast. Cellular telephone is within the 600 to 900 MHz range along with Public Safety between 763 and 870 MHz. I have had my G5 connected to a 6 dBi (3.85 dBd) mobile antenna and never had RF saturation, even within 100 feet of a cellular site 100 feet above ground, that I have purposely tested the G5 near because that site wipes out my SDS100 just using the Uniden OEM antenna.

The G5 OEM antenna works so well, that it is the only antenna that I use with it now. Reception in the car with the G5 sitting in the cup holder is very impressive. I don't connect it to the mobile antenna. I have only done that a few times testing.

 

[CollinsURG]

I looked at that SWR graph for that antenna that @cubn bought. SWR is not a measure of antenna gain or efficiency. It is only an indication of impedence mismatch that results in standing waves when transmitting. Also, saying anything above 1.5:1 VSWR is poor performance is incorrect even when transmitting. Even at 2.8:1 VSWR shown in the graph for the Unication antenna if it were used to transmit, would cause a return loss in power of about 24%. A 50 ohm dummy load will give a near perfect match and near 1:1 VSWR reading. But you cannot receive with it. When transmitting with an omnidirectional antenna, you would have to increase power by about 10x or 1000% to increase range by 2x. So, if you are transmitting say 7.6 watts instead of 10 watts due to 24% return loss, it will not cause any really significant loss of performance. I have always been amused by CB and GMRS operators chasing down very low VSWR measurements. Anything 2:1 or below is great. You mainly have to be concerned about 3:1 or more to keep transmitter finals from overheating, and any good non CCR radio folds back power to prevent damage. In practice, handheld low power transceivers hardly ever have optimal VSWR due to the antenna being near the human body or other objects.

 

[CollinsURG]

I decided to put my G5 antenna on the Vector Analyzer. At 760 MHz SWR 1.58, 880 MHz 1.05.

Pretty darn good!

 

[CollinsURG]

I am wondering what causes some antennas to push in the center pin of the SMA connector on the pager. At first I wondered if the socket of some antennas was shallow.

Comparing the center pin on the pager vs the center pin on some of my adapters and the antenna connector on my Alinco DJ-MD5, the center pin on the pager seemed a bit shorter, so you would not think it is due to the center socket of the female connector being too shallow.

Using a digital depth guage, I was able to measure the length of the pager pin by measuring the depth of the socket and measuring the distance from the top of the socket to the top if the pin and subtracting those measurements. The pin is 2 mm long. Looking up the specifications for a male SMA, the pin should measure 1.91 mm to 2.54 mm. Measuring the pins of some of my adapters and the Alinco radio, I measured pin lengths from 2.17 mm to 2.55 mm.

You would think the pin of the pager would be less likely to be pushed in. Is it that some connectors are poorly made and their female sockets are too shallow, or that the depth of the female connector is too shallow. The minimum spec for the depth of the female socket is 2.92 mm. Are some of the connector sockets off center or damaged in some way?

Checking a female SMA to female BNC adapter that I have, the center socket is 3 mm deep, and the depth of the connector is 1.46 mm and the depth of the OEM antenna connector is 1.29 mm. The socket is not off center or damaged, so it should be safe to use this adapter.

The male SMA connector on the pager seems to be within the specs for a common SMA connector. It seems likely that some antennas or adapters have damaged, off center, or too shallow sockets. Although the pin on the pager is 2 mm long and on the shorter end of the 1.91 to 2.54 mm spec to accommodate some shallow female connectors.

 

[RCBi-Dave]

I have no complaints with the stock antenna on the G5 either. Out of curiosity, I tried the Kenwood KRA 32K antenna, and trimmed the skirt to fit, as a few members on here raved about the improved performance. I personally barely saw a difference; sometimes one extra bar at most. Not worth it in my opinion.

Bogus Kenwood KRA-32K antenna to avoid from China. A friend that uses a Unication G5 pager with an OEM blue band antenna, purchased a few of the cheap Kenwood KRA-32K antennas off eBay to try to improve coverage. The antennas with the Kenwood name molded on the side are supposed to be a 763-870 MHz 6.5 inch tall half wave whip antenna with gain. Many users have reported good results with the KRA-32K on their pagers. After trimming the bottom of the KRA-32K antennas to correctly fit the Unication pager jack, the reception results from the Chinese antennas were all found to be worse than the Unication OEM antenna. Another G5 pager on the same very weak signal talk group with the OEM antenna would receive fairly good while the pager using the KRA-32K antenna 3 feet away sounded robotic with many parts of the dispatch message missing. Antennas were switched between the G5 pagers and the poor signals now followed the Chinese KRA-32K antennas. VSWR check of the KRA-32K antennas averaged 2.8:1 at 763 MHz and tapered down across the band to 1.3:1 at 870 MHz. Inspection with X-Ray found no half wave antenna element inside of the 6.5 inch tall antenna as shown in the images. A small helical antenna was confirmed to be inside the bottom of all the antennas after cutting them apart. Cheap antennas from eBay sellers in China are unpredictable like a box of chocolates, you never know what you're gonna get!