Air Band Scanner

[randybcd396t]

I have both the 15 and the 52. The 52 is much better for the money. Imho. Will be selling the 15 and keeping the 52.

Thanks prima19rider.

 

[G7RUX]

<snip>

We had a company making police scanners that had issues with overload and intermod and then came out with a markII version. The only thing they did where to replace the first transistor after the filter, that also worked as the mixer, to a much more powerful transistor that had its current going thru it increased by 25 times. It then became immune to overload. I worked together with a company that did RF interference investigations and they used a spectrum analyser with a 10dB preamplifier to make it sensitive enough. And that external preamplifier module got extremely hot that you couldn't touch it, and needed to have that high current going thru it to not get overload issues.

/Ubbe

I built and used a wideband receive antenna in the early 1990s which used a power FET for the first amplifier device, jsut to get the intermod performance to the point where it was good enough to use in the context it was designed for. That FET dissipated around 8 W...

 

[G7RUX]

Having used both the R15 and the ID52 for airband I would sugest the 52 if you have the need for V/UHF transmit although the R15 is a fine radio.

Regarding using filters, this will vary dramatically based on your local conditions. I have a Yaesu VR5000 wich is a sensitive VHF receiver but suffers terribly from intermods from local FM transmissions; for this set in my location a bandstop filter for FM is very much necessary.
Generally the effect of intermod is that the noise floor rises, sometimes quite dramatically but when it gets bad enough you'll start hearing the FM service audio all over everything you receive. I experimented with the the FM filter and the same antenna system and the R30, R6, ID52, AR3000 and an AOR 8000 and they all benefitted to some degree with reduced noise floor and noticeably cleaner received signals, although I would say that I have a number of very high output Band 2 FM services from a location very close to my QTH.

Taking the handhelds to the local airfield and trying out the filter I found that there wasn't a huge advantage to be had although the AR8000 benefitted somewhat.

I have several relevant filters I have accumulated over the years for projects; some I have made, a couple of Nooelec units (the Distil:FM barebones FM and the Flamingo+) and their performance is generally pretty good. I have a 400MHz low pass (ex-military aircraft) filter to knock TV and mobile stuff off the top end and this helps a fair bit. I also have a couple of MiniCircuits connectorised filters (bandpasses for civil and for mil airband) and a handful of 2, 3 and 4 pole helical bandpass filters from TEMwell for various projects that also work well.

In short, ideally you shouldn't need a filter to knock out FM or TV stuff but they can be very useful in certain circumstances. If you really are interested in a very specific range of frequencies then there are some definite advantages to tailoring the resonse of your antenna system to exclude things that you don't want to hear.

 

[G7RUX]

One more question re: the IC-R15. The ICOM ID-52A also has air band coverage. Specifically for air band coverage are there advantages with the IC-R15 over the ID-52A?

The ID-52 won't receive two airband frequencies at the same time, IIRC. It will allow you to select them but it will show the sub display with a crossed speaker icon; no audio available. AM receive is IIRC only available on the receiver A.

The R15 and R30 will receive two airband frequencies at the same time.

 

[bearcatrp]

The ID-52 won't receive two airband frequencies at the same time, IIRC. It will allow you to select them but it will show the sub display with a crossed speaker icon; no audio available. AM receive is IIRC only available on the receiver A.

The R15 and R30 will receive two airband frequencies at the same time.

Thats interesting. Good info to know though. Thanks.

 

[randybcd396t]

The ID-52 won't receive two airband frequencies at the same time, IIRC. It will allow you to select them but it will show the sub display with a crossed speaker icon; no audio available. AM receive is IIRC only available on the receiver A.

The R15 and R30 will receive two airband frequencies at the same time.

Thanks G7RUX. Good info.

 

[bearcatrp]

The ID-52 won't receive two airband frequencies at the same time, IIRC. It will allow you to select them but it will show the sub display with a crossed speaker icon; no audio available. AM receive is IIRC only available on the receiver A.

The R15 and R30 will receive two airband frequencies at the same time.

Is this for airband only that one is crossed out or is it anything when running split screen?

 

[G7RUX]

Is this for airband only that one is crossed out or is it anything when running split screen?

I think it is just when using AM as AM receiver is only possible on Rx A. Certainly running FM/FM or FM/DV (either way around) seems to work fine. Just no AM on Rx B.

 

[bearcatrp]

If you go to one screen only instead of split screen, select B screen, is it deaf on AM or only when using split screen?

 

[G7RUX]

If you go to one screen only instead of split screen, select B screen, is it deaf on AM or only when using split screen?

Indeed, there is no AM demodulator for the B VFO.

 

[bearcatrp]

Good to know. That sucks though. Thanks.

 

[LH2428]

and set the step range to the correct 25Khz frequency step when searching so that searching is not slowed down due to an 8.33khz step form 118-137Mhz or due to a 12.5khz step from 225-400 Mhz.

How did you do this? Thanks

 

[LH2428]

Also Would you use the 12.5 to 25khz frequency step if you also scan railroad on the same scanner as AIR?