kma371 said:
On 72.980 PL 179.9....
I heard the following this morning. Unit ID'd as "3952" and mentioned "County Road 9 and 33"
Now I don't know which office is 39 but 52 leads me to believe Hwy 152 near Los Banos. The County Road 9 and 33 reference leads me to believe Hwy 33 which I think runs through Modesto between 5 and 99.
Don't know why I can hear that freq better near Sacramento if it's more a Central Valley use.
Vertically polarized beam antennas are used to establish a path between the electronic sites being linked. Sometimes the path of a distant site lines up better with your location than a nearby site. The distant site can be aimed very closely to your location when the site it is aimed to wards is close to you. Nearby sites might have a path that runs parallel to your location and it is more difficult to pick up a signal that you are on the side of, rather than at the end of. This is a little difficult to explain without drawing a diagram, so I hope I've communicated my thoughts.
70 MHz is not as line of sight in nature as microwave so getting some signal off the sides of the path and even directly to the rear of the path is sometimes possible. I used to listen to a link in northern Mono County from southern Mono County and I was lined up nearly directly behind the direction the beam antenna was pointed in. This was from 40 miles away so I was quite pleased. The link was put in using 70 MHz because the site needing the link did not have microwave due to the lack of commercial power there. A few years back the CHP facilities people increased the solar generation capacity of the site along with adding more battery capacity. They then replaced the 70 MHz link and tied the site into the state microwave system. Too bad for me as I was picking up the mobile transmissions of CHP units in almost all of the northern half of my county and now I cannot hear anything past 5-10 miles of my house.
I would imagine, depending on the characteristics of the sites involved and availability of funding, that more and more 70 MHz linked sites will be replaced with microwave. If the site I mentioned can be linked by microwave I would imagine most can. The site does not have commercial power within 5 miles (and a rough 5 miles it is) and is accessed by a rough four wheel drive road that is covered by snow about 6 months of the year. Microwave requires a larger tower, where a mast may have sufficed for 70 MHz and if there is no room at the site for a tower this can be a limiting factor.
