HP2 vs. BCD325P2 reception

[CollinsURG]

If anyone owns the HP2 and the BCD325P2, I am interested to know if you have observed that for the same 700/800 Mhz P25 non simulcast system, and using the same type antenna on each radio, if the HP2 has noticeably less sensitivity than the BCD325P2?

My BCD325P2 is able to receive sites noticeably farther away using the same antenna type. Meaning I have used the same antenna of the BCD325P2 on the HP2 with an adapter and vice versa. As well as testing with other antennas. It is not an issue with the adapters. On VHF, the BCD325P2 also has better sensitivty, but not as different as on 700/800. It is not a location problem that is affected by nearby signals. This issue is true regardless of location.

Unfortunately I no longer have access to test equipment for measuring reception parameters.

 

[Ubbe]

An antenna needs a groundplane, and that would be the metal in the scanner. If you have the HP2 in its holder the groundplane will then be at the side of the antenna and not below it.

Try holding the HP2 in your hand vertically with its antenna connector pointing up so that it looks more like a standard handheld scanner and do the comparison again. Any adapters you insert between antenna and groundplane will affect the distance between them and then also the performance of the antenna.

/Ubbe

 

[CollinsURG]

An antenna needs a groundplane, and that would be the metal in the scanner. If you have the HP2 in its holder the groundplane will then be at the side of the antenna and not below it.

Try holding the HP2 in your hand vertically with its antenna connector pointing up so that it looks more like a standard handheld scanner and do the comparison again. Any adapters you insert between antenna and groundplane will affect the distance between them and then also the performance of the antenna.

/Ubbe

I actually have tried using it vertical using the HP2 antenna. No difference. Used the HP2 antenna on the BCD325P2 with an adapter and it actually worked better than the OEM BCD325P2 antenna on VHF and the same on 700/800.

 

[Ubbe]

The distance between groundplane and antenna will have an effect on the antennas performance, making it better or worse depending of what the antenna where originally tuned to.

I believe the HP1/2 use an identical receiver design as the BCD436 but the BCD325 probably have a more modern and newer design that should handle strong signals better and not de-sense. But your tests show that location does not matter.

When I measure sensitivity of Unidens scanners using a signal generator they pretty much are identical to the tenth of a microvolt and it is first when connecting a roof antenna and injected the signal into the coax that they show different sensitivity due to de-sense issues.

/Ubbe

 

[CollinsURG]

The distance between groundplane and antenna will have an effect on the antennas performance, making it better or worse depending of what the antenna where originally tuned to.

I believe the HP1/2 use an identical receiver design as the BCD436 but the BCD325 probably have a more modern and newer design that should handle strong signals better and not de-sense. But your tests show that location does not matter.

When I measure sensitivity of Unidens scanners using a signal generator they pretty much are identical to the tenth of a microvolt and it is first when connecting a roof antenna and injected the signal into the coax that they show different sensitivity due to de-sense issues.

/Ubbe

I am very familiar with desense issues. I had a BCD436HP. Interestingly I remember it as being far less sensitive than the BCD325P2. But I never had it and the BCD325P2 at the same time to do real-time comparisons. Other than LSM and battery life, the BCD325P2 is one of the best performing scanners I have ever owned.

The SDS100 suffers severely from desense issues. It is one of the reasons I bought a Unication G5. I wish Unication had proceeded with making a scanner radio. However, the G5 serves me very well for LSM. It is even very sensitive on VHF with the internal antenna. The G5 can reliably receive LSM on 700/800 that the SDS100 never receives.