broken coax cable
Persons who have spent most of their time at audio frequency world tend to discount the importance of high quality cabling and connections at radio frequencies. This was a "cheap" fix for you.......if you don't account for frustration and heartache and compromised performances.
I've never regretted purchasing my TTI 1301 handheld spectrum analyzer. It isn't Rhode & Schwartz quality, but I can confirm what is in the air
before I turn on any of my RF, and confirm the addition of each transmitter as added. I paid @ $1300 over 10 years ago, so it's cost per year has been minimal v. the ongoing education it provides.